Pulmonary

The Southwest Journal of Pulmonary and Critical Care publishes articles broadly related to pulmonary medicine including thoracic surgery, transplantation, airways disease, pediatric pulmonology, anesthesiolgy, pharmacology, nursing and more. Manuscripts may be either basic or clinical original investigations or review articles. Potential authors of review articles are encouraged to contact the editors before submission, however, unsolicited review articles will be considered.

Rick Robbins, M.D. 2/13/21 Rick Robbins, M.D. 2/13/21

Association between Spirometric Parameters and Depressive Symptoms in New Mexico Uranium Workers

Shiva Sharma MD, MPH¹

Xin W. Shore MS²

Satyajit Mohite MD, MPH³

Orrin Myers PhD²

Denece Kesler MD, MPH¹

Kevin Vlahovich MD, MS¹

Akshay Sood MD, MPH⁴

¹Preventive Medicine Section, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM USA

²Department of Family and Community Medicine, University of New Mexico School of Medicine, Albuquerque, NM USA

³Department of Behavioral Health, Psychiatry & Psychology, Mayo Clinic Health System, Mankato, MN USA

⁴Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM USA

Abstract

Background: Uranium workers are at risk of developing lung disease, characterized by low forced expiratory volume in one second (FEV1) and/or forced vital capacity (FVC). Previous studies have found an association between decreased lung function and depressive symptoms in patients with pulmonary pathologies, but this association has not been well examined in occupational cohorts, especially uranium workers.

Methods: This cross-sectional study evaluated the association between spirometric measures and depressive symptoms in a sample of elderly former uranium workers screened by the New Mexico Radiation Exposure Screening & Education Program (NM-RESEP). Race- and ethnicity-specific reference equations were used to determine predicted spirometric indices (predictor variable). At least one depressive symptom [depressed mood and/or anhedonia, as determined by a modified Patient Health Questionnaire-2 (PHQ-2)], was the outcome variables. Chi-square tests and multivariable logistic regression models were used for statistical analyses.

Results: At least one depressive symptom was self-reported by 7.6% of uranium workers. Depressed mood was reported over twice as much as anhedonia (7.2% versus 3.3%). Abnormal FVC was associated with at least one depressive symptom after adjustment for covariates. There was no significant interaction between race/ethnicity and spirometric indices on depressive symptoms.

Conclusions: Although depressive symptoms are uncommonly reported in uranium workers, they are an important comorbidity due to their overall clinical impact. Abnormal FVC was associated with depressive symptoms. Race/ethnicity was not found to be an effect modifier for the association between abnormal FVC and depressive symptoms. To better understand the mechanism underlying this association and determine if a causal relationship exists between spirometric indices and depressive symptoms in occupational populations at risk for developing lung disease, larger longitudinal studies are required. We recommend screening for depressive symptoms for current and former uranium workers as part of routine health surveillance of this occupational cohort. Such screening may help overcome workers’ reluctance to self-report and seek treatment for depression and may avoid negative consequences to health and safety from missed diagnoses.

Introduction

Uranium workers are at risk of pulmonary injury via two primary mechanisms: inhalation of radon daughters causing radiation-induced lung damage (1,2) and dust inhalation (3). Exposed workers are additionally at risk for developing cardiovascular pathology (4). Lung diseases can result in a clinically significant decline in pulmonary function and have been associated with various neuropsychiatric sequelae (5,6). Screening for and treatment of depression in interstitial lung disease (ILD) has been proposed to improve quality of life (6-8). Significant levels of depressive symptoms are described in patients with silicosis (8) and may adversely affect quality of life (9). In a study of patients with ILD, depressive symptoms correlate with dyspnea, forced vital capacity (FVC), sleep quality, and pain (7).

Presence of depressed mood or anhedonia, which is a significant decrease in deriving pleasure from the majority of one’s daily activities, on most days, is requisite for diagnosis of major depressive disorder (10). Individual inquiry of depressed mood has demonstrated 85-90% sensitivity for detection of depression; and addition of another question, specific for anhedonia, raises overall sensitivity to 95% for the two-question inquiry (11).

Our objective was to evaluate the prevalence of depressive symptoms in uranium workers, to examine their association with spirometric values, and examine race/ethnicity interaction with spirometry on depressive symptoms. We studied uranium workers enrolled in the New Mexico Radiation Exposure Screening and Education Program (NM-RESEP). New Mexico workers have been significantly impacted by uranium extraction activities and many are compensated through the Radiation Exposure Compensation Act (RECA) (12). The findings from this study may help elucidate the biopsychosocial impact of uranium-related lung abnormalities in New Mexico workers.

Methods

Study Design:

This is a cross-sectional analysis of baseline evaluation data from former New Mexico uranium workers (i.e., miners, millers, and ore transporters) voluntarily enrolled between 2004 and 2017 in NM-RESEP, a federally-funded health-screening and education program, located at the University of New Mexico (UNM) Health Sciences Center, serving Albuquerque and surrounding communities.

Data Collection:

Data were obtained from a self-reported questionnaire administered by a trained interviewer and confirmed by a physician/nurse practitioner. The questionnaire included demographics, severity of dyspnea via the modified Medical Research Council (mMRC) Dyspnea Scale (13), information on smoking history, cardiovascular status, and screening for depressive symptoms (using the modified Patient Health Questionnaire or PHQ-2) which includes two items on depressed mood and anhedonia (14). Body mass index (BMI) was calculated using measured height and weight. A prebronchodilator spirometry was obtained by trained technicians, utilizing standard guidelines from the American Thoracic Society and the European Respiratory Society (15). Test results were independently reviewed for quality by a pulmonologist. Gender- and race/ethnicity- specific reference equations were used to determine predicted normative values for spirometry (16). Abnormal values were defined by the lower limit of normal obtained from reference standards. Data was entered into a secure web-based Research Electronic Data Capture (REDCap) database.

Predictor and Outcome Variables:

The outcome included a positive response for PHQ-2 item on either depressive symptom, i.e., depressed mood or anhedonia. Predictor variables included spirometric parameters and race/ethnicity, including the absolute and percent-predicted values for FVC), forced expiratory volume in one second (FEV1), and the absolute value of the FEV1/FVC ratio. Lower limits of normal obtained from the reference standards from the Third National Health and Nutrition Examination Survey (NHANES III) were used to define abnormal spirometric values (16).

Statistical Methods:

Frequencies, percentages, means, and standard deviations in a univariate analysis were reported. For the purpose of analyses, the outcome variable was endorsement of either depressive symptom. Chi-Square tests were used to analyze categorical outcome variables and generate p-values to determine significance of the findings. In the multivariable logistic regression analysis, variables that were evaluated for potential confounding included smoking status and pack-years.

Ethical Approval and Funding:

This study was approved by the UNM Institutional Review Board or Human Resources Protections Office (14-058). The study was supported by NM-RESEP, which is funded by the Health Resources Services Administration (HRSA), and UNM Health Science Center CTSC Grant Number: UL1TR001449.

Results

Subject characteristics are shown in Table 1. Of the 570 uranium workers, 97.1% were men, 66.7% were of racial/ethnic minority with the largest group being American Indian (36.6%). Most workers were older (mean age of 68.5 ± 8.1 years) with BMI values in the overweight or obese categories (82.1%). 7.6% of workers reported at least one depressive symptom, with 7.2% and 3.3% reporting depressed mood and anhedonia, respectively. The prevalence of at least one depressive symptom in Hispanic, American Indian, and non-Hispanic White workers were 11.4%, 7.2%, and 4.1%, respectively (p=0.14 for all race/ethnicity group comparison) and post-hoc comparison between Hispanic and non-Hispanic White workers was significant (p=0.001) (not shown in Table 1). 66.9% of workers were either former or current smokers. With regards to previous pulmonary history, 15.3% and 10.0% of workers reported positive history of COPD and asthma, respectively.

Table 1. NM-RESEP Uranium Workers (2004-2017).

Both unadjusted univariate and adjusted multivariable analyses revealed that workers with abnormal FVC were at least 2.9 times more likely to endorse at least one depressive symptom. No associations were found between abnormal FEV1 or abnormal FEV1/FVC ratios and depressive symptoms (Table 2).

Table 2. Unadjusted and Adjusted Associations of the Presence of Depressive Symptoms on Spirometric Indices.

*Covariates in the above multivariable model using logistic regression analysis included: smoking status and smoking pack-years. **Further adjustment for the following covariates: age, gender, and race/ethnicity did not change results in the multivariable model (FVC OR: 2.86, 95% CI: 1.18-6.96, p=0.02).

Although the associations between spirometric indices and depressive symptoms appeared stronger among Hispanic workers than other race/ethnicity subgroups, this was not borne by a formal test of interaction between race/ethnicity and spirometric indices on either depressive symptom. However, interaction testing identified a trend towards significance for Hispanic workers between abnormal FEV1 and self-reporting of depressive symptoms (p=0.07) (Table 3).

Table 3: Interaction between Spirometric Indices and Race/Ethnicity on Depressive Symptoms.

*Logistic regression analysis was used.

Discussion

A minority of uranium workers sampled in this secondary analysis self-reported at least one depressive symptom (7.6%). Depressed mood was reported over twice as much as anhedonia was reported (7.2% vs 3.3%). Abnormal FVC on spirometry was found to be associated with depressive symptoms after adjustment for covariates. There was no significant interaction between race/ethnicity and spirometric indices on depressive symptoms.

Uranium ore extraction in New Mexico occurs in open pit or underground mines. Subsequently, uranium is isolated from ore via milling or heap leaching (17). Most of the workers in this study were subjected to hazardous working conditions marked by lack of provision of personal protective equipment (including respirators) to handle uranium and inhalational dust exposure. Inadequate ventilation in underground mines also led to increased radon and dust exposure and workers were not adequately informed of these occupational exposures by mining companies or federal agencies (i.e. US Atomic Energy Commission, Nuclear Regulatory Commission, US Department of Energy) (12).

Uranium enters the human body primarily via inhalation and ingestion (18). It deposits primarily in the lungs and skeleton (insoluble uranium) and kidneys (soluble uranium) (19) where it causes chemical and radiological damage to these organs (20). In a murine study, uranium was found to enter the central nervous system, crossing the blood-brain barrier and accumulating in the hippocampus, resulting in detrimental neurophysiological effects and changes in REM sleep patterns (21). A case study involving 81 American Indian uranium workers found anxiety and depression to be the most common mental health problems, and respiratory complaints and skin rashes were the most common physical health issues (22). Radon gas, a byproduct of the uranium decay process, attaches to dust particles and when inhaled into the lungs the alpha radiation released by radon daughters damages lung tissue. Like non-uranium industry workers engaged in other types of mining-related activities, uranium workers are at risk for occupational pneumoconiosis, presenting with features similar to silicosis (23), and chronic fibrotic ILD (3). Pneumoconiosis has been associated with increased risk of other pulmonary conditions, including pulmonary emboli (24), lung carcinoma (23), chronic obstructive pulmonary disease (COPD) (26), tuberculosis (27), and clinically significant decline in lung function (28).

Many chronic pulmonary conditions such as asthma, COPD (29), bronchiectasis (30), and lung cancer (31) are associated with depressive symptoms. In a prospective study of patients with bronchiectasis, low FEV1 values were observed among patients with depressive symptoms (30). In a study of French dairy farmers, Guillien (32) found depression was associated with lower FEV1. A 2013 systematic review and meta-analysis revealed that the relationship between COPD and depression is bidirectional (33). Our study did not contain information regarding history of a prior or current diagnosis of depression for enrolled patients, thus our secondary analysis is not a like-for-like comparison to existing literature on this topic. Our study involved individuals with mostly normal lung function, indicating that the association between abnormal FVC and depressive symptoms may be seen relatively early in the disease course.

Psychosocial factors may play a role in the development of workplace-associated disability in workers with respiratory impairment, but evidence-based guidance to address these psychosocial factors is limited (34). The low prevalence of depressive symptoms in our study may reflect the high proportion of men enrolled (97.1%), as overall prevalence of depression in men is approximately half that of women (35). Alternatively, men may under-report due to a lack of awareness and understanding of depression and fear of stigmatization for self-reporting amongst coworkers or wider society. Additionally, use of the standard PHQ-2 and DSM diagnostic criteria in American Indians may not produce reliable results due to potential cultural and linguistic differences (36). The rate of depression in American indigenous populations has found to be 8.9% (which is higher than all other racial/ethnic groups except biracial individuals) and can range from 10-30% (37), however, the prevalence of depressive symptoms in American Indian workers in our study was 7.2%. To the best of our knowledge, no validation studies have been performed for use of any version of the PHQ-2 in New Mexican American Indian populations. The PHQ-2 has been validated in English- and Spanish-speaking Hispanic Americans (38). Perini found ethnic minorities diagnosed with “chronic nonspecific lung disease” exhibited higher absolute prevalence of depressive symptoms than the ethnic majority (29). Our study findings partially agree with Perini’s findings in that Hispanic uranium workers were more likely to endorse depressed mood than non-Hispanic White workers.

Our study was a cross-sectional, secondary analysis of an occupational cohort of mostly elderly, former uranium workers enrolled in NM-RESEP. Longitudinal analysis of this association may further elucidate the direction of the association. Our study could benefit from culture-specific depression diagnostic criteria paired with spirometric measures to specific pulmonary diagnoses. While anhedonia has customarily been associated with loss of pleasure (10), the construct has recently expanded to include interest in activity, effort, and discrimination between anticipation and consummatory forms of pleasure. New approaches for anhedonia assessment are in development (39). Our assessment of anhedonia may have been limited and a more robust screening tool that screens for additional depressive symptoms beyond depressed mood and anhedonia, such as the PHQ-9 or Hospital Anxiety and Depression Scale (HADS) rather than the PHQ-2, could improve result validity. As depression has a complex nature, a more rigorous biopsychosocial assessment would help in determining the role pulmonary pathology plays in depression in this study sample. To the best of our knowledge, this is the first study to examine the association of spirometric indices with depressive symptoms in former uranium workers. The strengths of our study include the robust participation of minority workers due to use of a mobile screening unit, its clinical relevance in light of ongoing uranium-associated activity, and potential future impact on health. Further study on this topic is merited as untreated depression in workers poses potential risks to workplace safety. As industrial use of nuclear material continues in the United States and other countries such as Kazakhstan, Canada, and Australia, this area of study is relevant to occupational health on a global scale. We recommend screening for depressive symptoms in current and former uranium workers as part of routine health surveillance to better address reluctance to self-report and seek treatment for depression, as well as to avoid potential negative consequences to health and safety from a missed diagnosis.

Acknowledgments

Guarantor: Akshay Sood MD, MPH takes responsibility for the content of the manuscript, including the data and analysis.

Author contributions: All authors had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. All authors contributed substantially to the data analysis and interpretation and the writing of the manuscript.

Financial/non-financial disclosures: All authors report no conflict of interest.

Abbreviation List

BMI: body mass index
COPD: chronic obstructive pulmonary disease
CTSC: Clinical and Translational Science Center
DSM: Diagnostic and Statistical Manual of Mental Disorders
FEV1: forced expiratory volume in one second
FVC: forced vital capacity
HADS: Hospital Anxiety and Depression Scale
ILD: interstitial lung disease
mMRC: modified Medical Research Council
NHANES III: The Third National Health and Nutrition Examination Survey
NM-RESEP: New Mexico Radiation Exposure Screening and Education Program
PHQ-2/PHQ-9: Patient Health Questionnaire-2/Patient Health Questionnaire-9
RECA: Radiation Exposure Compensation Act
REDCap: Research Electronic Data Capture
UNM: University of New Mexico

References

Bersimbaev RI, Bulgakova O. The health effects of radon and uranium on the population of Kazakhstan. Genes Environ. 2015 Oct 1;37:18. [CrossRef] [PubMed]
Faa A, Gerosa C, Fanni D, Floris G, Eyken PV, Lachowicz JI, Nurchi VM. Depleted Uranium and Human Health. Curr Med Chem. 2018;25(1):49-64. [CrossRef] [PubMed]
Yen CM, Lin CL, Lin MC, Chen HY, Lu NH, Kao CH. Pneumoconiosis increases the risk of congestive heart failure: A nationwide population-based cohort study. Medicine (Baltimore). 2016 Jun;95(25):e3972. [CrossRef] [PubMed]
Al Rashida VJM, Wang X, Myers OB, Boyce TW, Kocher E, Moreno M, Karr R, Ass'ad N, Cook LS, Sood A. Greater Odds for Angina in Uranium Miners Than Nonuranium Miners in New Mexico. J Occup Environ Med. 2019 Jan;61(1):1-7. [CrossRef] [PubMed]
Dodd JW. Lung disease as a determinant of cognitive decline and dementia. Alzheimers Res Ther. 2015 Mar 21;7(1):32. [CrossRef] [PubMed]
Ryerson CJ, Arean PA, Berkeley J, Carrieri-Kohlman VL, Pantilat SZ, Landefeld CS, Collard HR. Depression is a common and chronic comorbidity in patients with interstitial lung disease. Respirology. 2012 Apr;17(3):525-32. [CrossRef] [PubMed]
Ryerson CJ, Berkeley J, Carrieri-Kohlman VL, Pantilat SZ, Landefeld CS, Collard HR. Depression and functional status are strongly associated with dyspnea in interstitial lung disease. Chest. 2011 Mar;139(3):609-616. [CrossRef] [PubMed]
Wang C, Yang LS, Shi XH, Yang YF, Liu K, Liu RY. Depressive symptoms in aged Chinese patients with silicosis. Aging Ment Health. 2008 May;12(3):343-8. [CrossRef] [PubMed]
Yildiz T, Eşsizoğlu A, Onal S, Ateş G, Akyildiz L, Yaşan A, Özmen CA, Cimrin AH. Quality of life, depression and anxiety in young male patients with silicosis due to denim sandblasting. Tuberk Toraks. 2011;59(2):120-5. [CrossRef] [PubMed]
Diagnostic and Statistical Manual of Mental Disorders: DSM-5. American Psychiatric Association, 2013.
Whooley MA, Avins AL, Miranda J, Browner WS. Case-finding instruments for depression. Two questions are as good as many. J Gen Intern Med. 1997 Jul;12(7):439-45. https://doi.org/10.1046/j.1525-1497.1997.00076.x [PubMed]
Dawson SE, Madsen GE. Psychosocial and health impacts of uranium mining and milling on Navajo lands. Health Phys. 2011 Nov;101(5):618-25. [CrossRef] [PubMed]
Mahler DA, Wells CK. Evaluation of clinical methods for rating dyspnea. Chest. 1988 Mar;93(3):580-6. [CrossRef] [PubMed]
Arroll B, Goodyear-Smith F, Crengle S, Gunn J, Kerse N, Fishman T, Falloon K, Hatcher S. Validation of PHQ-2 and PHQ-9 to screen for major depression in the primary care population. Ann Fam Med. 2010 Jul-Aug;8(4):348-53. [CrossRef] [PubMed]
Graham BL, Steenbruggen I, Miller MR, Barjaktarevic IZ, Cooper BG, Hall GL, Hallstrand TS, Kaminsky DA, McCarthy K, McCormack MC, Oropez CE, Rosenfeld M, Stanojevic S, Swanney MP, Thompson BR. Standardization of Spirometry 2019 Update. An Official American Thoracic Society and European Respiratory Society Technical Statement. Am J Respir Crit Care Med. 2019 Oct 15;200(8):e70-e88. [CrossRef] [PubMed]
Hankinson JL, Odencrantz JR, Fedan KB. Spirometric reference values from a sample of the general U.S. population. Am J Respir Crit Care Med. 1999 Jan;159(1):179-87. [CrossRef] [PubMed]
Radioactive Waste From Uranium Mining and Milling. 2 Mar. 2020, www.epa.gov/radtown/radioactive-waste-uranium-mining-and-milling.
Bjørklund G, Christophersen OA, Chirumbolo S, Selinus O, Aaseth J. Recent aspects of uranium toxicology in medical geology. Environ Res. 2017 Jul;156:526-533. [CrossRef][PubMed]
Yiin JH, Anderson JL, Daniels RD, Bertke SJ, Fleming DA, Tollerud DJ, Tseng CY, Chen PH, Waters KM. Mortality in a combined cohort of uranium enrichment workers. Am J Ind Med. 2017 Jan;60(1):96-108. [CrossRef] [PubMed]
“Uranium Health Effects.” Uranium Health Effects, The Depleted UF6 Management Program Information Network, web.evs.anl.gov/uranium/guide/ucompound/health/index.cfm.
Lestaevel P, Bussy C, Paquet F, Dhieux B, Clarençon D, Houpert P, Gourmelon P. Changes in sleep-wake cycle after chronic exposure to uranium in rats. Neurotoxicol Teratol. 2005 Nov-Dec;27(6):835-40. [CrossRef] [PubMed]
Dawson SE, Madsen GE. American Indian uranium millworkers: a study of the perceived effects of occupational exposure. J Health Soc Policy. 1995;7(2):19-31. [CrossRef] [PubMed]
Kreuzer M, Sogl M, Brüske I, Möhner M, Nowak D, Schnelzer M, Walsh L. Silica dust, radon and death from non-malignant respiratory diseases in German uranium miners. Occup Environ Med. 2013 Dec;70(12):869-75. [CrossRef] [PubMed]
Shen CH, Chen HJ, Lin TY, Huang WY, Li TC, Kao CH. Association between pneumoconiosis and pulmonary emboli. A Nationwide Population-Based Study in Taiwan. Thromb Haemost. 2015 May;113(5):952-7. [CrossRef] [PubMed]
Yu H, Zhang H, Wang Y, Cui X, Han J. Detection of lung cancer in patients with pneumoconiosis by fluorodeoxyglucose-positron emission tomography/computed tomography: four cases. Clin Imaging. 2013 Jul-Aug;37(4):769-71. [CrossRef] [PubMed]
Graber JM, Stayner LT, Cohen RA, Conroy LM, Attfield MD. Respiratory disease mortality among US coal miners; results after 37 years of follow-up. Occup Environ Med. 2014 Jan;71(1):30-9. [CrossRef] [PubMed]
Lu J, Jiang S, Ye S, Deng Y, Ma S, Li CP. Sequence analysis of the drug‑resistant rpoB gene in the Mycobacterium tuberculosis L‑form among patients with pneumoconiosis complicated by tuberculosis. Mol Med Rep. 2014 Apr;9(4):1325-30. [CrossRef] [PubMed]
Go LH, Krefft SD, Cohen RA, Rose CS. Lung disease and coal mining: what pulmonologists need to know. Curr Opin Pulm Med. 2016 Mar;22(2):170-8. [CrossRef] [PubMed]
Perini W, Snijder MB, Schene AH, Kunst AE. Prevalence of depressive symptoms among patients with a chronic nonspecific lung disease in five ethnic minority groups. Gen Hosp Psychiatry. 2015 Nov-Dec;37(6):513-7. [CrossRef] [PubMed]
Boussoffara L, Boudawara N, Gharsallaoui Z, Sakka M, Knani J. Troubles anxiodépressifs et dilatation des bronches [Anxiety-depressive disorders and bronchiectasis]. Rev Mal Respir. 2014 Mar;31(3):230-6. French. [CrossRef] [PubMed]
Kim Y, van Ryn M, Jensen RE, Griffin JM, Potosky A, Rowland J. Effects of gender and depressive symptoms on quality of life among colorectal and lung cancer patients and their family caregivers. Psychooncology. 2015 Jan;24(1):95-105. https://doi.org/10.1002/pon.3580 [PubMed]
Guillien A, Laurent L, Soumagne T, Puyraveau M, Laplante JJ, Andujar P, Annesi-Maesano I, Roche N, Degano B, Dalphin JC. Anxiety and depression among dairy farmers: the impact of COPD. Int J Chron Obstruct Pulmon Dis. 2017 Dec 19;13:1-9. [CrossRef] [PubMed]
Atlantis E, Fahey P, Cochrane B, Smith S. Bidirectional associations between clinically relevant depression or anxiety and COPD: a systematic review and meta-analysis. Chest. 2013 Sep;144(3):766-777. [CrossRef] [PubMed]
Slatore CG, Harber P, Haggerty MC; American Thoracic Society Respiratory Impairment and Disability Evaluation Group. An official American Thoracic Society systematic review: Influence of psychosocial characteristics on workplace disability among workers with respiratory impairment. Am J Respir Crit Care Med. 2013 Nov 1;188(9):1147-60. [CrossRef] [PubMed]
Salk RH, Hyde JS, Abramson LY. Gender differences in depression in representative national samples: Meta-analyses of diagnoses and symptoms. Psychol Bull. 2017 Aug;143(8):783-822. [CrossRef] [PubMed]
Csordas TJ, Storck MJ, Strauss M. Diagnosis and distress in Navajo healing. J Nerv Ment Dis. 2008 Aug;196(8):585-96. [CrossRef] [PubMed]
Ka'apu K, Burnette CE. A Culturally Informed Systematic Review of Mental Health Disparities Among Adult Indigenous Men and Women of the USA: What is known? Br J Soc Work. 2019 Jun;49(4):880-898. [CrossRef] [PubMed]
Mills SD, Fox RS, Pan TM, Malcarne VL, Roesch SC, Sadler GR. Psychometric Evaluation of the Patient Health Questionnaire-4 in Hispanic Americans. Hisp J Behav Sci. 2015 Nov;37(4):560-571. [CrossRef] [PubMed]
Rizvi SJ, Pizzagalli DA, Sproule BA, Kennedy SH. Assessing anhedonia in depression: Potentials and pitfalls. Neurosci Biobehav Rev. 2016 Jun;65:21-35. [CrossRef] [PubMed]

Cite as: Sharma S, Shore XW, Mohite S, Myers O, Kesler D, Vlahovich K, Sood A. Association between Spirometric Parameters and Depressive Symptoms in New Mexico Uranium Workers. Southwest J Pulm Crit Care. 2021;21(2):58-68. doi: https://doi.org/10.13175/swjpcc015-20 PDF

Rick Robbins, M.D. 1/13/21 Rick Robbins, M.D. 1/13/21

A Population-Based Feasibility Study of Occupation and Thoracic Malignancies in New Mexico

Claire R. Pestak, MPH ^1,2

Tawny W. Boyce, MS, MPH ¹

Orrin B. Myers, PhD ⁴

L. Olivia Hopkins^,MD ³

Charles L. Wiggins, PhD^1,2,3

Bruce R. Wissore, JD, PhD, MA, MS, MS^3,6

Akshay Sood, MPH, MD ^3,5

Linda S. Cook, PhD ^1,3

¹UNM Comprehensive Cancer Center, University of New Mexico, MSC 07-4025,
1 UNM, Albuquerque, NM, 87131, USA

²New Mexico Tumor Registry, University of New Mexico, MSC 11 6020, 1 UNM, Albuquerque, NM, 87131, USA

³Department of Internal Medicine, University of New Mexico School of Medicine, MSC 10 5550, 1 UNM, Albuquerque, NM, 87131, USA

⁴Department of Family and Community Medicine, University of New Mexico School of Medicine, MSC 09-5040, 1 UNM, Albuquerque, NM, 87131, USA

⁵Miners Colfax Medical Center, Raton, NM, 87740, USA

⁶Southwestern Illinois College, Belleville, IL, 62221, USA

Abstract

Background

Occupational exposures in mining and oil/gas extraction are known risk factors for thoracic malignancies (TMs). Given the relatively high proportion of these industries in New Mexico (NM), we conducted a feasibility study of adult lifetime occupational history among TM cases. We hypothesized a higher proportion of occupational TM in NM relative to the estimated national average of 10-14%.

Methods

We identified incident TM cases through the population-based New Mexico Tumor Registry (NMTR), from 2017- 2018. Cases completed a telephone interview. An adjudication panel reviewed case histories and classified cancers as probable, possible, or non-occupational related, taking into account the presence, duration, and latency of exposures. We characterized recruitment and describe job titles and exposures among those with occupational TMs. We also compared the distributions of industry between those with and without occupational TM.

Results

The NMTR identified 400 eligible TM cases, 290 of which were available to be recruited (n=285 lung/bronchial cancer; n=5 mesotheliomas). Of the latter, 60% refused and 18% were deceased, 9% had invalid addresses, 11% were unable to be reached by telephone, and 3% were too ill to participate. The 43 cases who completed an interview held 236 jobs. A total of 33% of cases were classified as probable occupational TM and 5% as possible occupational TM.

Conclusions

High rates of early mortality and refusals were significant barriers to study participation. Nonetheless, the proportion of probable occupational TMs greatly exceeded the estimated national average, highlighting the need for further study of occupational TM in the state.

Editor's Note: See The Best Laid Plans of Mice and Men for accompanying editorial.

Introduction

Lung cancer and mesothelioma are the most common thoracic malignancies (TMs). Lung cancer is the second most common cancer in the United States (US) and in New Mexico (NM) and the leading cause of cancer death (1). Mesothelioma is relatively rare but has a specific association with occupational exposure to asbestos. For this paper, lung cancer and pleural mesotheliomas are combined as TMs. Despite some treatment advances (2,3), five-year relative survival is less than 20% for all TM (4).

The strongest risk factor for lung cancer is cigarette smoking (5). Other established risk factors for TMs include exposure to asbestos, uranium, radon gas, and other cancer-causing agents in the workplace, radiation therapy to the lungs, and a family history of lung cancer (6-8). The importance of occupation in TMs is emphasized by the Global Burden of Disease (GBD) report indicating that the two main cancers caused by occupational exposures worldwide were lung cancer (274,000 deaths annually) and mesothelioma (27,000 deaths annually) (9). Various estimates attributing occupation to lung cancer include: a 1981 US estimate of 15% for men and 5% for women, or 10% overall (10), a 1987 NM estimate of 14% in men (11); and, a 2003 US estimate for deaths of 8.0%–19.2% for men and 2% for females, or 6.3%-13.0% overall (12,13). Thus we estimated that overall in the US, 10%-14% of TMs could be attributable to occupation.

Historic and current occupational exposures are of particular interest in NM. Mining, in particular uranium mining, was a major operation in NM from 1950-1970. Mining is still an important industry in this region: between 2011 and 2015, the NM mining industry saw a 20% increase in employment for all types of mining (14). NM also has significant employment in the Mining, Quarrying, and Oil and Gas Extraction industry relative to other parts of the Southwest (15). These industries have a greater share of local employment in NM than in the US overall (16). Additionally, NM was the ninth highest natural gas producer in the US in 2018, producing 1.49 million cubic feet of natural gas (17).

Given the historic and current extraction activities in NM, we hypothesized that NM would have a higher proportion of occupational TMs than the estimated national average of 10%-14%. As an initial step in estimating this occupational TM cancer burden in NM, we conducted a feasibility study to obtain adult lifetime occupational histories for TM cases.

Methods

Recruitment and Data Collection

This feasibility study was approved (#16-306) by the Human Research Review Committee at the University of New Mexico and cases provided signed, informed consent. We identified incident TM cases from February 1, 2017 to February 2, 2018 via the population-based New Mexico Tumor Registry (NMTR), a founding member of the National Cancer Institute’s (NCI) Surveillance Epidemiology and End Results (SEER) Program. Cases were identified by two methods: (1) rapid case ascertainment (RCA) via electronic pathology reports and (2) usual case ascertainment (UCA) via tumor registrars manually collecting data from around the state. Contact with eligible cases involved a three-step process. In step 1, the NMTR contacted treating physicians explaining the study and advising them of their patient’s eligibility allowing the physician to state any objection to patient contact. In step 2, the NMTR contacted the patient (letter and study brochure in English and Spanish) informing them about the study and allowing them to opt-out from further contact. In the special case of no physician of record, patients were contacted after a three month wait period. Patients who refused participation or were deceased were ineligible for study contact. In step 3, for the remainder, contact information was released to study personnel.

All potential cases in step 3 were mailed documents in both English and Spanish including: an introductory letter, a flyer about benefits counseling, a Frequently Asked Questions sheet, two copies of a Residence and Work History worksheet, a Life Events Calendar, showcards, and two copies of the consent form. One consent form was for the case to sign and keep and the other was signed and returned to the study, along with one copy of the Residence and Work History worksheet. Showcards functioned as a visual aid by listing possible answers to interview questions. The Life Events Calendar functioned as a memory aid to anchor major life events like marriages, births, deaths, relocations, job changes, and other historical events. The Residence and Work History Worksheet gave the cases a time frame to date their paid jobs and occupations, held for at least 6 months, during their adult life and was used for reference during the interview. Work did not have to occur in the state of NM. Study interviewers contacted cases by telephone to answer questions. Those who expressed a willingness to participate were asked to complete and return the worksheets/consent form and to schedule an interview.

Consenting cases completed the same structured telephone interview with an embedded script that obtained information on demographics, lifestyle factors, medical history, reproductive history (women only) and adult lifetime occupational history. For each and every job held for six months or longer from age 18 years onwards, the cases provided job title, city and country of job location, job status (full-time/part-time), job duties, exposure information on relevant agents (18) (a list of more than 30 relevant exposures was provided to cases) including the duration of each exposure, and age at start and end of the job. All cases were asked all job-related questions providing a detailed and specific work history for each individual. Data were recorded in Research Electronic Data Capture (REDCap) database (19). Cases received a small merchandise card in appreciation. All potential cases and surviving family members were given an optional referral to a benefits counselor regardless of their self-reported exposures or determination by the Data Adjudication Committee (DAC).

Determination of Occupational TM

De-identified occupational history summaries were reviewed by the DAC to determine if each case was attributable to occupational exposures, as summarized below. The DAC was composed of three voting members: a pulmonologist with expertise in occupational pulmonary diseases associated with the coal and uranium mining industries; a preventive medicine specialist with expertise in occupational health who works in the Center for Occupational Environmental Health Promotion; and, an attorney with expertise in the medicolegal definitions for causation in the occupational setting. A non-voting member (CRP) served as the committee Chair to tally votes and mediate further discussion if necessary.

This expert panel independently reviewed the de-identified individual job histories for each case, and considered exposures that had a latency of at least 10 years, exposure durations of at least one year, and exposure intensity through self-reported frequency of exposure on the job. To aid in assessment, each panel member was provided a summary table of the known strength of the association between relevant exposures and TM occurrence (available upon request) (20-27). After independent review, the panel would meet to discuss and vote on classification. If all three DAC members found sufficient evidence for relevant occupational exposure, the case was classified as a probable occupational TM. If at least one DAC member found insufficient evidence for relevant occupational exposure, the case was classified as a possible occupational TM. If all DAC members found insufficient evidence for relevant occupational exposure, the case was classified as non-occupational TM. Smoking history for each case was provided to the DAC, but occupational cancer was decided independent of smoking, except in the case of asbestos exposure where a synergistic relationship is well supported by the published literature (28). Because of the participant burden and the high likelihood of misclassification, we did not collect information on environmental tobacco smoke or biomass/coal smoke for each job reported in this study. A letter was sent to each case with the DAC’s determination.

Analysis

After the determination of occupational TM status by the DAC, each job title for each case was coded to an industry using the NIOSH Industry and Occupation Computerized Coding System (NIOCCS) (29). Each job title was submitted, and using the "Census 2010/NAICS 2007/SOC 2010" coding scheme, the most appropriate 2010 Industry Census Code provided by the industry and occupation output was selected. If the industry was unclear based on the job title alone, the work history was reviewed for the company name, job duties, or other relevant notes. In these situations, once an industry was selected, the industry was independently verified by another study team member. The possible 269 industry categories in the 2010 census system were further summarized into 20 North American Industry Classification System (NAICS) sectors (30).

Results

Of the 400 eligible cases initially identified via the NMTR, 110 (28%) were not released to study personnel for the following reasons: 33 (30%) refused to have their information released to investigators; 47 (43%) were deceased; 23 (21%) had no physician of record and were in the 3-month wait period; four (4%) had an invalid address; two (2%) were subsequently determined to be ineligible, and one case (1%) was determined to have a duplicate record in the NMTR. The remaining 290 eligible cases were invited to join the study, of which 285 had lung cancer and 5 had mesothelioma. Over-all, refusals (60%) and deaths (18%) were the two major reasons for non-participation in the interview, but cases also had invalid addresses (9%), were unable to be reached by telephone (11%), or were too ill to participate (3%). Of the 43 cases, 98% agreed to future tumor tissue testing and medical record reviews.

Demographic characteristics of cases are detailed in Table I.

Table I. Demographics of Thoracic Malignancies (TM) cases

Among the cases, 51% were women, 70% were Non-Hispanic White, 86% were >60 years of age, 19% reported a parent had lung cancer. In terms of insurance and benefits, 95% had some type of health insurance, but only 9% had sought compensation through Social Security Disability, Worker's Compensation, or the Veterans Administration before the study. Medical Histories of cases are detailed in Table II.

Table II. Medical History of Thoracic Malignancies (TM) cases.

Among the cases, 49% were overweight/obese. Both smoking (72% current/former cigarette smokers) and non-malignant respiratory diseases (40% reporting pulmonary fibrosis, COPD, or chronic bronchitis) were common.

Cases reported 236 jobs representing 20 NAICS sectors, and 14 (33%) were classified as probable and 2 (5%) as possible occupational TM. Among the probable occupational TM cases, 11 (79%) were men, and both the possible occupational TMs were men. The 14 cases with a probable occupational TM self-reported one or more of the following occupational exposures: aluminum production (n=1), arsenic (n=1), asbestos (n=7), cadmium (n=1), coal-tar (n=1), diesel (n=7), ether (n=5), nickel (n=2), paint (n=1), radiation (n=1), silica (n=9), and soot (n=2). The joint distribution of these cases by job title and exposure category is shown in Figure 1.

Figure 1. Relevant Self-Reported Exposures by Job Titles per Industry Sector for the Cases with Occupationally Related Thoracic Malignancies*

*Exposures deemed to be causal by the Data Adjudication Committee.

The study population only included those who were diagnosed and captured by the NMTR from February 1, 2017 to February 2, 2018 (n=400). Case identification at the NMTR, especially for cancers like TMs where there may not be a pathology report, may be ascertained more than a year after diagnosis. A NMTR query in March 2020 for diagnoses in the same time period noted above yielded more than double the number of TM cases (n=913). Thus we had the opportunity to compare those identified early (n=400) and up to two years later (n=513) as well as those released to the study for contact (n=290) with those whose names were not released for study contact (n=110) by selected demographic and histological characteristics (Table III).

Table III. Summary of the characteristics of the lung cancer and mesothelioma cases diagnosed between 2/1/17 – 2/2/18 for the OCTOPUS Study. Data source New Mexico Tumor Registry (NMTR).

There were differences in age between the 400 cases identified during the study period (50% for those 70 years and older) and the 513 cases identified later (57% for those 70 years and older) (p<0.05) and rurality between the 400 cases identified during the study period (23% rural) and the 513 cases identified later (44% rural) (p<0.001). Apart from the obvious difference in death as this was a criteria for not releasing contact to the study, a difference in histology was noted for those released to the study (77% non-small cell carcinoma) and those not released (66% non-small cell carcinoma) (p<0.05).

Discussion

This feasibility study was designed to obtain lifetime occupational histories from a population-based sample of TM cases and to determine the proportion of such cases that were likely attributable to occupational exposures. Despite our efforts to recruit these subjects in a timely manner, high rates of early mortality and refusals were significant barriers to study enrollment, indicating that a definitive study is not possible based on these methods. Among those who participated in the study, the proportion of cases with occupational TM (33%) was two to three times higher than prevailing national estimates (10-14%). While this result is intriguing and may warrant further study, we cannot say with certainty if this result is due to the low response percentage and the possible selection bias of having cases that were more likely to have relevant occupational exposures, or if this result truly reflects the occupational exposures in NM.

Recruiting TM cases via a population-based cancer registry is challenging. In total, 25% of eligible cases died before they could be recruited to the study via the NMTR or study personnel. An even higher proportion refused, 52% of eligible cases, in part due to poor health as cancer progressed and to the burden of treatment concurrent with study participation. Such a high refusal percentage could be a source of selection bias in which various occupations were under- or over-represented, but we had no data to address this bias directly. Additionally, the study only included those who were diagnosed and captured by the NMTR from February 1, 2017 to February 2, 2018 (n=400). We noted a substantial difference in rurality between the 400 cases identified for our study (23% rural) and the 513 cases identified later (44% rural). The majority of counties in NM are rural or frontier (26/33) (31). TM cases diagnosed among residents of these areas are less likely to receive health care in facilities that are served by pathology laboratories with electronic reporting; instead cancer registrars visit the facilities to manually abstract medical records leading to a longer reporting timeline. These results imply that rural TM cases were under-represented in our study, and since those with mining and other extraction occupations are more likely to reside and get health care in rural areas, our estimate of 33% occupational TM might be an underestimate.

From the list of more than 30 possible exposures that are known or suspected carcinogens for lung cancer (32), probable occupational TM cases reported exposures to aluminum production, arsenic, asbestos, cadmium, coal-tar, diesel fumes, ether, nickel, paint, radiation, silica, and soot. Limitations of these results include the difficulty of retrospective estimation of the intensity and duration of each of these exposures at each job, and the fact that the study did not have enough cases to conduct an analysis accounting for other exposures such as tobacco use, comorbidities, and socioeconomic factors (33). Further, we did not have information on exposures to indoor smoke in the home from, for example, wood burning stoves.

The U.S. does not have a comprehensive employment and exposure database or an occupational disease mortality surveillance system that could provide more objective and comprehensive occupational information than self-report. In some countries, researchers can link data from national cancer registries and occupational databases to help confirm associations between occupational exposures and cancers (34). Inclusion of an occupational history in medical records could also provide more objective data, but such practices are currently sporadic and non-uniform. While death certificates often record a decedent’s longest or lifetime occupation, no exposure details are included, and access to this minimal data is often restricted in an effort to maintain confidentiality (35). Thus, improvements to the evaluation of occupation and occupational exposures for cancers such as TMs on a population-basis remains a challenge.

Other strengths of our study not indicated above include: our success in ascertaining a detailed adult lifetime occupational history from lung cancer survivors using an English or Spanish interview; inclusion of racial/ethnic minorities; inclusion of both men and women (with 21% of women in our study having a probable occupational TM); no eligibility restriction to a specific industry or exposure; a rigorous procedure via the DAC to establish a probable-occupational, possible-occupational, or non-occupational classification for each case; and offering cases a referral for benefits counseling (65% accepted). The limitations of this study have been discussed above.

This feasibility study suggests that 33% of cases had a probable occupational TM, two to three times the national historical estimate, highlighting the importance of exposures and jobs in the NM population that can lead to occupational TMs. However, a more definitive study is not feasible based on the methods used in this study as the ability to overcome the above-described methodological and recruitment challenges remains a significant barrier to further population-based studies of occupation-related TM in NM and the US.

Acknowledgements: This research utilized the UNM Comprehensive Cancer Center (UNMCCC) Biostatistics Shared Resource, and the UNM Clinical & Translational Science Center, the Surveillance, Epidemiology and End Results Program (SEER) data for New Mexico, and REDCap (DHHS/NIH/NCRR #8UL1TR000041).

Funding: The grant sponsor was the UNM Foundation, a non-profit corporation, organized exclusively for charitable and educational purposes under Section 501(c)(3). CRP, TWB, and LSC and the Biostatistics Shared Resource received support from the UNM Comprehensive Cancer Center (NCI P30 CA118100). CRP and CLW received support by Contract HHSN261201800014I, Task Order HHSN26100001 from the National Cancer Institute.

Institution and Ethics approval and informed consent: The work was performed at the University of New Mexico and the Human Research Review Committee (Federal wide Assurance FWA00003255) approved this study. Study participants provided written informed consent.

References

Siegel RL, Miller KD, Jemal A. Cancer statistics, 2020. CA Cancer J Clin. 2020 Jan;70(1):7-30. [CrossRef] [PubMed]
American Cancer Society. What's new in malignant mesothelioma research? 2020 (Available from: https://www.cancer.org/cancer/malignant-mesothelioma/about/new-research.html)
Howlader N, Forjaz G, Mooradian MJ, Meza R, Kong CY, Cronin KA, Mariotto AB, Lowy DR, Feuer EJ. The Effect of Advances in Lung-Cancer Treatment on Population Mortality. N Engl J Med. 2020 Aug 13;383(7):640-649. [CrossRef] [PubMed]
American Cancer Society. Survival rates for mesothelioma 2020. Available at: https://www.cancer.org/cancer/malignant-mesothelioma/detection-diagnosis-staging/survival-statistics.html (accessed 1/12/21).
Islami F, Goding Sauer A, Miller KD, Siegel RL, Fedewa SA, Jacobs EJ, McCullough ML, Patel AV, Ma J, Soerjomataram I, Flanders WD, Brawley OW, Gapstur SM, Jemal A. Proportion and number of cancer cases and deaths attributable to potentially modifiable risk factors in the United States. CA Cancer J Clin. 2018 Jan;68(1):31-54. [CrossRef] [PubMed]
Thun MJ, Henley SJ, Travis WD. Lung cancer. In: Fraumeni Jr. JF, Schottenfeld D, editors. Cancer epidemiology and prevention. Fourth ed. New York, NY: Oxford University Press; 2018. p. 519-42.
Ge C, Peters S, Olsson A, Portengen L, Schüz J, Almansa J, et al. Respirable Crystalline Silica Exposure, Smoking, and Lung Cancer Subtype Risks. A Pooled Analysis of Case-Control Studies. Am J Respir Crit Care Med. 2020 Aug 1;202(3):412-421. [CrossRef] [PubMed]
Ge C, Peters S, Olsson A, Portengen L, Schuz J, Almansa J, et al. Diesel engine exhaust exposure, smoking, and lung cancer subtype risks. A pooled exposure-response analysis of 14 case-control studies. Am J Respir Crit Care Med. 2020;202(3):402-11. [CrossRef] [PubMed]
Institute for Health Metrics and Evaluation. Global burden of disease compare viz hub Available at: https://vizhub.healthdata.org/gbd-compare/ (accessed 1/12/21).
Doll R, Peto R. The causes of cancer: quantitative estimates of avoidable risks of cancer in the United States today. J Natl Cancer Inst. 1981 Jun;66(6):1191-308. [PubMed]
Lerchen ML, Wiggins CL, Samet JM. Lung cancer and occupation in New Mexico. J Natl Cancer Inst. 1987 Oct;79(4):639-45. [PubMed]
Canadian Centre for Occupational Health and Safety. Osh answers fact sheets 2017. Available at: https://www.ccohs.ca/oshanswers/diseases/occupational_cancer.html (accessed 1/12/21).
Steenland K, Burnett C, Lalich N, Ward E, Hurrell J. Dying for work: The magnitude of US mortality from selected causes of death associated with occupation. Am J Ind Med. 2003 May;43(5):461-82. [CrossRef] [PubMed]
New Mexico Department of Workforce Solutions. New Mexico 2017 state of the workforce report 2017. Available at: https://www.dws.state.nm.us/Portals/0/DM/LMI/NM_2017_SOTW_Report.pdf (accessed 1/12/21).
New Mexico Department of Workforce Solutions. Industry spotlight 2013. Available at: https://www.dws.state.nm.us/Portals/0/DM/LMI/IndSpotlight_Oct2013.pdf (accesed 1/12/21).
New Mexico Department of Workforce Solutions. New Mexico 2018 state of the workforce 2018. Avaialble at: https://www.dws.state.nm.us/Portals/0/DM/LMI/NM_2018_SOTW_Report.pdf (accessed 1/12/21).
U.S. Energy Information Administration. Rankings: Natural gas marketed production, 2018. Available at: https://www.eia.gov/state/rankings/?sid=US#/series/47 (accessed 1/12/21).
International Agency for Research on Cancer. IARC. Monographs on the evaluation of carcinogenic risks to humans, vol 100, a review of human carcinogens. Lyon, France: International Agency for Research on Cancer; 2011. Available from: https://publications.iarc.fr/124 (accessed 1/12/21).
Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. Research electronic data capture (REDCap)--a metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform. 2009 Apr;42(2):377-81. [CrossRef] [PubMed]
Algranti E, Buschinelli JT, De Capitani EM. Occupational lung cancer. J Bras Pneumol. 2010 Nov-Dec;36(6):784-94. English, Portuguese. [CrossRef] [PubMed]
Delva F, Andujar P, Lacourt A, Brochard P, Pairon JC. Facteurs de risque professionnels du cancer bronchopulmonaire [Occupational risk factors for lung cancer]. Rev Mal Respir. 2016 Jun;33(6):444-59. French. [CrossRef] [PubMed]
Field RW, Withers BL. Occupational and environmental causes of lung cancer. Clin Chest Med. 2012 Dec;33(4):681-703. [CrossRef] [PubMed]
Hashim D, Boffetta P. Occupational and environmental exposures and cancers in developing countries. Ann Glob Health. 2014;80(5):393-411.
Hubaux R, Becker-Santos DD, Enfield KS, Lam S, Lam WL, Martinez VD. Arsenic, asbestos and radon: emerging players in lung tumorigenesis. Environ Health. 2012 Nov 22;11:89. [CrossRef] [PubMed]
Peto J, Doll R, Hermon C, Binns W, Clayton R, Goffe T. Relationship of mortality to measures of environmental asbestos pollution in an asbestos textile factory. Ann Occup Hyg. 1985;29(3):305-55. [CrossRef] [PubMed]
Rajer M, Zwitter M, Rajer B. Pollution in the working place and social status: co-factors in lung cancer carcinogenesis. Lung Cancer. 2014 Sep;85(3):346-50. [CrossRef] [PubMed]
Steenland K, Loomis D, Shy C, Simonsen N. Review of occupational lung carcinogens. Am J Ind Med. 1996 May;29(5):474-90. [CrossRef] [PubMed]
Klebe S, Leigh J, Henderson DW, Nurminen M. Asbestos, Smoking and Lung Cancer: An Update. Int J Environ Res Public Health. 2019 Dec 30;17(1):258. [CrossRef] [PubMed]
U.S. Department of Health and Human Services PHS, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Division of Surveillance, Hazard Evaluation and Field Studies, Surveillance Branch. NIOSH industry and occupation computerized coding system (NIOCCS). 2018 (cited 2017). Available at: https://wwwn.cdc.gov/nioccs3/ (accessed 1/12/21).
North American Industry Classification System. The National Institute for Occupational Safety and Health (NIOSH). Available at: https://www.cdc.gov/niosh/topics/coding/pdfs/Census2010CodingInstruction.pdf (accessed 1/12/21).
Economic Research Service United States Department of Agriculture. Rural-urban continnuum codes Available at: https://www.ers.usda.gov/data-products/rural-urban-continuum-codes/ (accessed 1/12/21).
Cogliano VJ, Baan R, Straif K, Grosse Y, Lauby-Secretan B, El Ghissassi F, et al. Preventable exposures associated with human cancers. J Natl Cancer Inst. 2011;103(24):1827-39. [CrossRef] [PubMed]
Spyratos D, Zarogoulidis P, Porpodis K, Tsakiridis K, Machairiotis N, Katsikogiannis N, et al. Occupational exposure and lung cancer. J Thorac Dis. 2013 Sep;5 Suppl 4(Suppl 4):S440-5. [CrossRef] [PubMed]
Pukkala E, Martinsen JI, Lynge E, Gunnarsdottir HK, Sparén P, Tryggvadottir L, Weiderpass E, Kjaerheim K. Occupation and cancer - follow-up of 15 million people in five Nordic countries. Acta Oncol. 2009;48(5):646-790. [CrossRef] [PubMed]
National Center for Health Statistics. Restricted-use vital statistics data Available at: https://www.cdc.gov/nchs/nvss/nvss-restricted-data.htm (Accessed 1/12/21).

Cite as: Pestak CR, Boyce TW, Myers OB, Hopkins LO, Wiggins CL, Wissore BR, Sood A, Cook LS. A Population-Based Feasibility Study of Occupation and Thoracic Malignancies in New Mexico. Southwest J Pulm Crit Care. 2021;22(1):23-35. doi: https://doi.org/10.13175/swjpcc057-20 PDF

Rick Robbins, M.D. 1/8/19 Rick Robbins, M.D. 1/8/19

Progressive Massive Fibrosis in Workers Outside the Coal Industry: A Case Series from New Mexico

Landon Casaus, MD¹

Sapna Bhatia, MD¹

Akshay Sood, MD, MPH^{1, 2}

¹Department of Internal Medicine

University of New Mexico School of Medicine

Albuquerque, NM, USA

²Miners’ Colfax Medical Center

Raton, NM USA

Abstract

Introduction

The worldwide prevalence of silicosis peaked by the beginning of the 20^th century during the development of mechanized industry (1). Outbreaks of silicosis are still noted in the developed world, particularly where workers are consistently exposed to silica particles that are small enough to be inhaled (≤10 µm in diameter) and at levels above a “safe” concentration (action level of 25 µm/m³as a time-weighted average over an 8-hour work day, as recommended by the U.S. Occupational Safety and Health Administration or OSHA) (2,3). The four Appalachian coal mining states of Pennsylvania, West Virginia, Virginia, and Kentucky accounted for more than 75 percent of all silicosis-related deaths in the United States (U.S.) in 2007 (4). A recent study however indicates that the age-standardized mortality rate from silicosis in the U.S. in 2014 was amongst the highest in the mining intense regions of the Southwest, particularly in the Four Corners area where the borders of New Mexico, Arizona, Utah, and Colorado meet (5). The number of diagnosed silicosis cases has increased in New Mexico between 2000 and 2011, and residents of New Mexico are twice as likely to die from or with silicosis when compared to the rest of the country for reasons that are unexplained (6).

Four clinical patterns of diffuse lung disease may be seen with silicosis: acute silicosis or silicoproteinosis (the latter resembling pulmonary alveolar proteinosis), simple nodular sclerosis, accelerated silicosis, and progressive massive fibrosis (PMF). PMF represents the coalescence of multiple small pneumoconiotic opacities to form larger opacities or conglomerate masses measuring over 10 millimeters in size on a chest radiograph, with smaller rounded opacities usually seen in simple silicosis. Silicotic opacities are classified on their shape, size, and profusion using the International Labour Organization’s (ILO) International Classification of Radiographs for Pneumoconiosis system (commonly referred to as B reads) (7-9). The 1970-2017 radiographic data from the National Institute for Occupational Safety and Health (NIOSH) surveillance program concluded that the national prevalence of coal workers’ pneumoconiosis in coal miners with 25 years or more of tenure now exceeds 10% (10). This is an increase from the previous estimate of 7% in 2012 (11,12). A resurgence of progressive massive fibrosis in coal miners has also been described, particularly those working in smaller mines (13). The rate of PMF in silica exposed workers outside of the coal mine industry, similar to those illustrated in this paper, is unknown. We herein describe three New Mexico non-coal miners with PMF that were followed at the University of New Mexico Occupational Pulmonary Medicine Clinic. Each of the three cases had already received compensation under the United States Energy Employees Occupational Illness Compensation Program, based upon prior abnormal B reads of chest radiographs. The epidemiology, pathogenesis, and management of PMF is also reviewed.

Case reports

Case 1

An 83-year-old man presented in 2017 with worsening dyspnea over the prior 10 years. He worked at a federal national laboratory in northern New Mexico, from 1962-1992 as a construction worker. His work included digging ditches, removing insulation, demolishing buildings, breaking up concrete with jackhammers, and working around sandblasters in enclosed areas, without any respiratory protection. He had a 5-pack year smoking history, and quit 50 years prior.

A 2017 chest radiograph showed small, upper lobe predominant, nodular opacities. A high-resolution computed tomography (CT) scan in 2009 showed innumerable micronodules in the upper lobes of the lung with a centrilobular distribution. A repeat CT scan obtained in 2017 (Figure 1) showed new-onset coalescence of several upper lobe nodules, as large as 1.5 cm x 2 cm.

Figure 1. Computed tomography scan of the chest showing several silicotic opacities in both lung apices and coalescence to progressive massive fibrosis in right apex.

His pulmonary function tests (PFT) showed mild obstruction with evidence of air trapping. A diagnostic bronchoscopy showed no evidence of infection or neoplasm.

Case 2

A 78-year-old man presented in 2014 with several-years history of progressive New York Heart Association Class III dyspnea. The patient worked as an underground uranium miner from 1960 to 1989 where he was exposed to hauling, “mucking” (a term referring to the loading of fragmented ore), and blasting. He wore a respirator intermittently. He had a five-pack year smoking history, quitting in 1981.

Chest x-ray showed innumerable micronodules, predominately in the upper lobes. A CT scan of the chest with 3 mm cuts in 2012 showed innumerable upper lobe predominant micronodules in a perilymphatic and centrilobular distribution, with coalescence in the upper lobes. Repeat CT scans in 2014 and 2015 demonstrated no disease progression (Figure 2).

Figure 2. Computed tomography scan of the chest demonstrating progressive massive fibrosis in the right upper lung and several silicotic opacities in bilateral upper lungs.

PFTs showed a mild restrictive defect. An infectious etiology was ruled out by negative sputum acid fast bacilli (AFB), and bacterial smears and cultures.

Case 3

A 79-year-old man presented with dyspnea at rest and upon exertion, and chronic bronchitis symptoms, with occasional hemoptysis. The patient worked as an underground uranium miner from 1959-1980 performing drilling, blasting and “mucking”, with significant self-reported exposure to dust and without use of respiratory protection. The patient reported a 15-pack year smoking history, but quit in 1976.

A chest x-ray showed hilar and mediastinal nodal calcifications with small scattered lung nodules. A HRCT scan of the chest in 2016 (Figure 3) showed multiple calcified nodules as well as calcified hilar and mediastinal lymph nodes.

Figure 3. Computed tomography scan of the chest demonstrating progressive massive fibrosis with evidence of traction in both lobes.

Conglomerate masses in the upper lobes measuring up to 3.3 cm were noted and moderate background emphysematous changes were also noted. The PFTs on initial evaluation were within normal limits. He was noted to be hypoxic on room air, necessitating 2 L/min oxygen supplementation. Sputum AFB smears and cultures were negative.

Discussion

PMF is seen in workers employed in industries that cut, grind, or drill silica-containing materials such as concrete, masonry, tile and/or rock (3). Most cases of PMF in the literature have been reported among coal miners, likely a reflection of the fact that coal miners undergo active surveillance due to governmental regulations (12). Although more commonly believed to occur in underground coal miners, PMF can be seen in surface coal miners as well (14). PMF outside the coal industry has been described in limited studies of barium miners, sandblasters, blacksmiths, welders, metal polishers, and quartz surface fabricators (15-17). More recently, PMF has been reported in ‘distressed’ denim jean industry workers (18). In this case series, we report PMF in New Mexico construction and uranium workers.

The latency for PMF is usually 10-30 years. Latency is greatly impacted by the exposure concentration and duration, as well as type of silica exposure. Additionally, it is influenced by underlying diseases, genetics, and smoking. Although PMF typically occurs in a setting of high cumulative dust exposures (14), some studies indicate that the host patterns of deposition and clearance of dust may be more relevant (19).

The pathogenesis of PMF is not completely understood; however, it is known that alveolar macrophages initiate a complex cascade results in inflammation and fibrosis (20). Histopathological findings include nodules, usually located near the respiratory bronchioles, composed of silica particles surrounded by whorled collagen in concentric layers. Larger masses of collagen define the lesion of PMF, which may be associated with avascular necrosis in the center and endarteritis in the periphery (21). The extensive fibrotic reaction in PMF is associated with high serum levels of interleukin (IL)-8 and intercellular adhesion molecule (ICAM)-1, which are important as neutrophil attractants and adhesion molecules (22).

The clinical diagnosis of PMF has three requirements: the patient must have a history of inhalational silica exposure significant enough to cause disease; chest imaging must be consistent with PMF; and other illnesses that mimic PMF must be reasonably ruled out (1). The disease presentation of PMF is highly variable. Patients may have debilitating symptoms of dyspnea on exertion and exercise intolerance, obstructive and/or restrictive patterns on PFTs, as well as experience complications such as cor pulmonale, spontaneous pneumothorax, and hypoxic respiratory failure (23). On the other hand, a normal spirogram is described in up to 11% of subjects with PMF, as also noted in Case 3 above (23). The level of pulmonary impairment in patients with PMF generally increases with increasing radiologic size of large opacities (23). Spirometry is repeated upon follow-up visits to assess for functional deterioration (24). Invasive tests such as arterial blood gas or cardiopulmonary exercise test are usually not indicated. Surveillance chest radiographs are classified for small and large opacities using the International Labour Organization’s (ILO) International Classification of Radiographs for Pneumoconiosis system (7-9). CT scan of the chest is more sensitive in diagnosing PMF than chest radiographs, and may be considered if the radiograph fails to show large opacities but demonstrates small opacities of relatively larger diameter or a tendency for opacities to coalesce (25,26). Lung tissue for histology or mineral analysis is rarely needed. The presence of atypical features in a patient with simple silicosis such as fever, hemoptysis, worsening dyspnea, weight loss, disproportionate fatigue, and the presence of a new infiltrate or cavitation of a pre-existing lesion on chest imaging should prompt the clinician to look for PMF, tuberculosis, or lung cancer. Patients with PMF are at elevated risk for concomitant tuberculosis. This risk is directly proportional to the level of profusion of silicotic small opacities (27), and the risk in patients with the highest level of profusion is comparable to that in patients with HIV infection (3). Autopsy studies from Welsh coal workers during the period 1952–1954 demonstrated tubercle bacilli in as many as 35% of cases with PMF (21). A recently published study from Brazil reported coexisting microbiologically confirmed tuberculosis in about half of patients with PMF, raising concerns about tuberculosis infection as a risk factor for the development of PMF ¹⁵. Patients with silicosis are also at high risk for lung cancer (28), with a greater risk for lung cancer described in patients with PMF as compared to patients with simple coal workers pneumoconiosis in one study (29). Positron emission tomography with F-18 fluorodeoxyglucose is of limited utility in differentiating malignancy from PMF lesions (30).

The prevention of PMF remains a focus at the exposed workplace. This includes primary prevention such as worker education; control of airborne dust exposure via engineering and work practice interventions such as improving ventilation, providing a means of exhaust, adding water to the cutting surface, and using enclosed cabs or booths; and use of respiratory protective devices (3). In June 2018, OSHA mandated personal breathing zone air sampling to monitor exposure and medical surveillance of workers with exposure above the permissible exposure limits (31). Medical surveillance constitutes secondary prevention, facilitating early diagnosis and treatment. Surveillance should be done periodically and should include a medical examination and occupational questionnaire, chest radiograph with B read interpretation, tuberculosis screening, and spirometry, with referral of affected workers to a pulmonologist or occupational medicine physician for further evaluation (32).

Once PMF has been diagnosed, it is important to immunize the patient against influenza and pneumococcal infection, assess the need for oxygen supplementation, and encourage pulmonary rehabilitation. Exclusion of active tuberculosis is recommended and screening for latent tuberculosis infection by either skin testing or interferon gamma release assay should be considered (33). Systemic corticosteroids, inhaled aluminum citrate, poly(vinlypyridine-N-oxide) and whole lung lavage are unlikely to benefit patients with PMF and lung transplantation may be considered (4).

Patients with PMF are considered ‘totally disabled’ from coal mine employment under the Black Lung Benefits Act in the United States. Outside the coal industry, they may be eligible for benefits under the Social Security Impairment system or the state workers’ compensation systems.

Conclusion

PMF represents the coalescence of smaller radiographic pneumoconiotic opacities to those over 10 millimeters in size. The rate of PMF in American coal miners has recently increased. Although most cases of PMF are reported among coal miners, this is likely a reflection of the fact that coal miners undergo active surveillance due to governmental regulations ¹². In this case series, we report PMF in workers outside the coal industry. Physicians and policymakers need to be aware of this condition in workers exposed to silica within and outside the coal industry.

Acknowledgments

Guarantor: Landon Casaus, M.D., takes responsibility for the content of the manuscript, including the data and analysis.

Financial/non-financial disclosures: All authors report no conflict of interest.

Abbreviations List

AFB: Acid fast bacilli
CT: computed tomography
HIV: Human immunodeficiency virus
HRCT: High resolution computed tomography
IL: interleukin
ICAM: Intercellular adhesion molecule
NIOSH: National Institute for Occupational Safety and Health
OSHA: Occupational Safety and Health Administration
PMF: Progressive massive fibrosis
PFT: Pulmonary function test
US: United States

References

Banks D. Silicosis. In: Rosenstock L, Cullen M, Brodkin C, Redlich C, eds. Textbook of clinical occupational and environmental medicine. 2nd edition ed. China: Elsevier Saunders; 2005.
Occupational Safety and Health Administration. Occupational Exposure to Respirable Crystalline Silica; Final Rule. In. Federal Register. Vol 81. Washington DC: Government Publishing Office; 2016:16285-16890. [PubMed]
Adverse effects of crystalline silica exposure. American Thoracic Society Committee of the Scientific Assembly on Environmental and Occupational Health. Am J Respir Crit Care Med. 1997 Feb;155(2):761-8. [CrossRef] [PubMed]
National Institute for Occupational Safety and Health, Department of Health and Human Services Centers for Disease Control and Prevention. The Work-Related Lung Disease Surveillance Report 2007. Available at: https://www.cdc.gov/niosh/docs/2008-143/default.html.
Dwyer-Lindgren L, Bertozzi-Villa A, Stubbs RW, Morozoff C, Shirude S, Naghavi M, Mokdad AH, Murray CJL. Trends and Patterns of Differences in Chronic Respiratory Disease Mortality Among US Counties, 1980-2014. JAMA. 2017;318(12):1136-49. [CrossRef] [PubMed]
New Mexico Occupational Health Surveillance Program New Mexico Department of Health. Silicosis in New Mexico Infographic. Available at https://nmhealth.org/about/erd/eheb/ohsp/.
Welch LS, Hunting KL, Balmes J, Bresnitz EA, Guidotti TL, Lockey JE, Myo-Lwin T. Variability in the classification of radiographs using the 1980 International Labor Organization Classification for Pneumoconioses. Chest. 1998 Dec;114(6):1740-8. [CrossRef] [PubMed]
Halldin CN, Blackley DJ, Petsonk EL, Laney AS. Pneumoconioses Radiographs in a Large Population of U.S. Coal Workers: Variability in A Reader and B Reader Classifications by Using the International Labour Office Classification. Radiology. 2017 Sep;284(3):870-6. [CrossRef] [PubMed]
International Labor Organization. Guidelines for the use of the ILO International Classification of Radiographs of Pneumoconioses. In. Vol Occupational Safety and Health Series, No. 22. 2000 ed. Geneva: International Labor Office; 2002.
Blackley DJ, Halldin CN, Laney AS. Continued increase in prevalence of coal workers' pneumoconiosis in the United States, 1970-2017. Am J Public Health. 2018 Sep;108(9):1220-2. [CrossRef] [PubMed]
Laney AS, Weissman DN. Respiratory diseases caused by coal mine dust. J Occup Environ Med. 2014 Oct;56 Suppl 10:S18-22. [CrossRef] [PubMed]
Blackley DJ, Halldin CN, Laney AS. Resurgence of a debilitating and entirely preventable respiratory disease among working coal miners. Am J Respir Crit Care Med. 2014 Sep 15;190(6):708-9. [CrossRef] [PubMed]
Blackley DJ, Halldin CN, Wang ML, Laney AS. Small mine size is associated with lung function abnormality and pneumoconiosis among underground coal miners in Kentucky, Virginia and West Virginia. Occup Environ Med. 2014 Oct;71(10):690-4. [CrossRef] [PubMed]
Halldin CN, Reed WR, Joy GJ, et al. Debilitating lung disease among surface coal miners with no underground mining tenure. J Occup Environ Med. 2015 Jan;57(1):62-7. [CrossRef] [PubMed]
Ferreira AS, Moreira VB, Ricardo HM, Coutinho R, Gabetto JM, Marchiori E. Progressive massive fibrosis in silica-exposed workers. High-resolution computed tomography findings. J Bras Pneumol. 2006 Nov-Dec;32(6):523-8. [CrossRef] [PubMed]
Friedman GK, Harrison R, Bojes H, Worthington K, Filios M; Centers for Disease Control and Prevention (CDC). Notes from the field: silicosis in a countertop fabricator - Texas, 2014. MMWR Morb Mortal Wkly Rep. 2015 Feb 13;64(5):129-30. [PubMed]
Seaton A, Ruckley VA, Addison J, Brown WR. Silicosis in barium miners. Thorax. 1986;41(8):591-5. [CrossRef] [PubMed]
Bakan ND, Özkan G, Çamsari G, Gür A, Bayram M, Açikmeşe B, Çetinkaya E. Silicosis in denim sandblasters. Chest. 2011;140(5):1300-4. [CrossRef] [PubMed]
Douglas AN, Robertson A, Chapman JS, Ruckley VA. Dust exposure, dust recovered from the lung, and associated pathology in a group of British coalminers. Br J Ind Med. 1986 Dec;43(12):795-801. [CrossRef] [PubMed]
Sayan M, Mossman BT. The NLRP3 inflammasome in pathogenic particle and fibre-associated lung inflammation and diseases. Part Fibre Toxicol. 2016 Sep 20;13(1):51. [CrossRef] [PubMed]
Davies DG, James WR, Rivers D, Thomson S. The prevalence of tuberculosis at necropsy in progressive massive fibrosis of coalworkers. Br J Ind Med. 1957 Jan;14(1):39-42. [PubMed]
Lee JS, Shin JH, Choi BS. Serum levels of IL-8 and ICAM-1 as biomarkers for progressive massive fibrosis in coal workers' pneumoconiosis. J Korean Med Sci. 2015 Feb;30(2):140-4. [CrossRef] [PubMed]
Yeoh CI, Yang SC. Pulmonary function impairment in pneumoconiotic patients with progressive massive fibrosis. Chang Gung Med J. 2002 Feb;25(2):72-80. [PubMed]
Fernandez Alvarez R, Martinez Gonzalez C, Quero Martinez A, Blanco Perez JJ, Carazo Fernandez L, Prieto Fernandez A. Guidelines for the diagnosis and monitoring of silicosis. Arch Bronconeumol. 2015;51(2):86-93. [CrossRef] [PubMed]
Martinez Gonzalez C, Fernandez Rego G, Jimenez Fernandez-Blanco JR. [Value of computerized tomography in the diagnosis of complicated pneumoconiosis in coal miners]. Arch Bronconeumol. 1997;33(1):12-5. [CrossRef]
Ooi GC, Tsang KW, Cheung TF, Khong PL, Ho IW, Ip MS, Tam CM, Ngan H, Lam WK, Chan FL, Chan-Yeung M. Silicosis in 76 men: qualitative and quantitative CT evaluation-clinical-radiologic correlation study. Radiology. 2003;228(3):816-25. [CrossRef] [PubMed]
Rees D, Murray J. Silica, silicosis and tuberculosis. Int J Tuberc Lung Dis. 2007 May;11(5):474-84. [PubMed]
Poinen-Rughooputh S, Rughooputh MS, Guo Y, Rong Y, Chen W. Occupational exposure to silica dust and risk of lung cancer: an updated meta-analysis of epidemiological studies. BMC Public Health. 2016 Nov 4;16(1):1137. [CrossRef] [PubMed]
Tomaskova H, Jirak Z, Splichalova A, Urban P. Cancer incidence in Czech black coal miners in association with coalworkers' pneumoconiosis. Int J Occup Med Environ Health. 2012 Jun;25(2):137-44. [CrossRef] [PubMed]
Reichert M, Bensadoun ES. PET imaging in patients with coal workers pneumoconiosis and suspected malignancy. J Thorac Oncol. 2009 May;4(5):649-51. [CrossRef] [PubMed]
Occupational Safety and Health Administration. Respirable crystalline silica. In. Vol 1926. Washington DC: Occupational Safety and Health Administration; Federal Register; 2016:1153. Available from: https://www.osha.gov/silica/SilicaConstructionRegText.pdf (last accessed 2018 Jul 1125).
Deslauriers JR, Redlich CA. Silica Exposure, Silicosis, and the New Occupational Safety and Health Administration Silica Standard. What Pulmonologists Need to Know. Ann Am Thorac Soc. 2018 Dec;15(12):1391-1392. [CrossRef] [PubMed]
Lewinsohn DM, Leonard MK, LoBue PA, et al. Official American Thoracic Society/Infectious Diseases Society of America/Centers for Disease Control and Prevention Clinical Practice Guidelines: Diagnosis of Tuberculosis in Adults and Children. Clin Infect Dis. 2017 Jan 15;64(2):111-5. [CrossRef] [PubMed]

Cite as: Casaus L, Bhatia S, Sood A. Progressive massive fibrosis in workers outside the coal industry: A case series from New Mexico. Southwest J Pulm Crit Care. 2019;18(1):10-9. doi: https://doi.org/10.13175/swjpcc110-18 PDF

Rick Robbins, M.D. 4/6/18 Rick Robbins, M.D. 4/6/18

Social Media: A Novel Engagement Tool for Miners in Rural New Mexico

Shreya Wigh¹

William Cotton Jarrell, CMSP³

Elizabeth Kocher, MPH¹

Roger Karr²

Xin Wang, MS¹

Akshay Sood, MD, MPH^1,2

¹University of New Mexico Health Sciences Center School of Medicine

Albuquerque, NM, USA

²Miners Colfax Medical Center

Raton, NM, USA

³Peabody New Mexico Services

Grants, NM, USA

Abstract

Background: New Mexico miners usually live in rural areas. As compared to urban areas, rural areas in the United States demonstrate a lower use of the Internet and lower adoption of new technologies such as the smartphone and social media. Our study objective was to examine the use of these technologies among miners in rural New Mexico. Our long-term goal is to utilize these technologies to increase our program’s engagement with miners to provide medical screening and education services. Methods: We anonymously surveyed 212 miners at two town hall meetings in rural New Mexico communities, predominantly Hispanic and American Indian, in 2017. We then compiled that data in a Research Electronic Data Capture (REDCap) database and performed a statistical analysis using Statistical Analysis Software (SAS). IRB approval was obtained. Results: 60.8% of the 212 surveyed miners reported using social media. Among social media users, 88.4% reported using Facebook. Most miners expressed willingness to use social media to keep in contact with other miners (51.2% overall) or to receive information about our miners’ program services (53.9% overall); and social media users were more likely to do so than non-users (p<0.001 for both analyses). Additionally, 79.7% of miners who owned a smartphone utilized it for texting. Conclusions: A majority of miners in rural New Mexico report use of social media and express willingness to use social media to network with other miners and with our program. The adoption of these communication technologies by rural New Mexico miners in our study is comparable or superior to that reported by rural Americans overall. It is possible to utilize this newer technology to increase program engagement with miners.

Introduction

New Mexico miners usually live in rural and medically underserved areas and suffer from multiple chronic diseases, particularly dust related lung diseases or pneumoconiosis. Rural counties in northern New Mexico have among the highest mortality rates for silicosis and pneumoconiosis, including coal workers’ pneumoconiosis, in the United States (1). To address this challenge, Miners’ Colfax Medical Center and the University of New Mexico have partnered in a federally funded medical screening program for rural miners. As compared to urban areas, those who live in rural areas reportedly have a lower use of the Internet and are less willing to adopt new communication technologies such as the smartphone and social media (2). We have previously published that the primary source of information about miners’ health related activities for attendees at our miners’ health screening programs are traditional routes of communication such as a relative, friend, and community newspaper or flyer (3). Traditional media is, however, a one-way communication system that doesn’t create program engagement or work towards promoting word-of-mouth - the hallmark of social media (4). Our programs could utilize social media to promote awareness, encourage miner engagement, and increase the spread of accurate health messaging among New Mexico miners. Serving older, less educated, poorer, racial/ethnic minority, miners living in geographically remote and medically underserved rural areas of New Mexico may however affect the use and effectiveness of this communication tool.

The objective of our study was to examine the use of Internet-based smartphone and social media technology among miners in rural New Mexico. We hypothesized a low usage rate of these novel communication technologies among rural miners in New Mexico. Our long-term goal is to use these technologies to increase bidirectional engagement with miners with our federally funded Black Lung and Radiation Exposure Screening and Education Programs that currently provide medical screening, health care, and education services to coal and uranium miners in New Mexico.

Methods

Study design: This is a cross sectional survey of 212 miners, mostly coal miners, at two town hall meetings held in rural and medically underserved communities of Grants and Socorro, New Mexico, in 2017. These communities are predominantly American Indian and Hispanic respectively. The town hall meetings were held in conjunction with mobile health screening clinics for miners.

Survey creation: We created a survey on the use of the smartphone and social media, which asked construct-specific questions with either Yes/No responses or multiple choices. Examples of questions included whether miners would be willing to use social media to stay in touch with the mining community and if they had access to a computer with internet. The questions were formatted for an eighth-grade vocabulary, since our previous studies have shown that 57.2% of New Mexico miners do not complete high school education (3).

Survey administration: The paper copy of the survey was given to miners to fill out during the town hall meeting by the mine safety officer, on a voluntary and anonymous basis.

Analytic and database strategy: We compiled the survey data into a Research Electronic Data Capture (REDCap) database. We compared characteristics between social media users with social media non-users. Statistical analysis included an analysis of frequency distributions and Chi-square test, using Statistical Analysis Software (SAS 13.0, Cary, NC). A p-value less than 0.05 was considered statistically significant. We obtained human Institutional Review Board (IRB) approval for research exempt status (HRPO 14-058). The study was sponsored by Health Resource Services and Administration (HRSA) and Patient Centered Outcomes Research Institute (PCORI).

Results

60.8% of the 212 miners surveyed reported using social media. Among the social media users, 88.4% reported using Facebook, 27.9% reported using Instagram, and 26.4% reported using Snapchat. Social media users reported utilizing the technology for an average of 47.9 ± 134.3 (SD) minutes daily, for approximately 6.0 ± 4.4 (SD) years. Most miners expressed willingness to use social media to keep in contact with other miners (51.2% overall) or to receive information about our miners’ program services (53.9% overall); and social media users were more likely to do so than non-users (p<0.001 for both analyses, Table 1).

Table 1. Difference in characteristics between self-reported social media users and nonusers, among rural miners in New Mexico.

86.3% of the miners surveyed also reported possessing a smart phone (93.8% versus 74.7% of the social media users and non-users respectively; p<0.001). 79.7% of miners owning a smartphone utilized it for texting (91.5% versus 61.5% of social media users versus nonusers respectively; p<0.001).

94.3% of rural miners reported having access to the Internet. Social media users were more likely to report having Internet access via computer or via phone than non-users (p = 0.08 and <0.001 respectively, Table 1). 24.0% of all miners however reported poor Internet connection as a challenge, and as compared to nonusers, social media users were more likely to report this challenge (p=0.01). 13.2% of all miners complained of the high expense of the Internet and the social media user status did not predict this characteristic (p=0.67). There was also no difference between the two groups with respect to the reported difficulty in navigating social media sites (p=0.32).

Discussion

Based on our results, we conclude that the majority of miners in rural New Mexico use Internet-based smartphone and social media technologies and are willing to use social media to network with other miners or programs that deliver health services to miners. We found that Facebook was the most popular social media site. The adoption of these communication technologies by rural New Mexico miners in our study is comparable or superior to that reported by rural Americans overall. This suggests that it is possible to use smartphone texting and social media technology to increase bidirectional program engagement with miners in rural New Mexico.

In 2017, the proportion of US population with a social media profile was variably estimated at 69-81% (5-7). Rural Americans in the US were approximately 8% less likely to use social media than urban Americans (2). The market leader in social media was Facebook, used by 68% and 79% of all and online American adults respectively (7). In our study, 60.8% of the rural miners reported using social media and 53.8% reported using Facebook, which is comparable to that reported in other US rural communities. In 2017, the proportion of American adults who owned a smartphone was 83%, 78%, and 65% for urban, suburban, and rural locations respectively (8). In comparison, 86.3% of rural miners in our study reported possessing a smartphone, indicating a higher level of smartphone possession than that reported by rural Americans overall. In 2017-2018, 89% of all American adults used the Internet (9). In an earlier survey from November 2016, 81% of rural Americans used the Internet, as compared to 89% of urban Americans (10). 63% of rural Americans had a broadband Internet connection at home, 10 percentage points less likely than Americans overall (10). In comparison, 94.3% of rural New Mexico miners in our study reported having access to the Internet, indicating a higher level of Internet access than that reported by rural Americans overall. Contrary to our initial hypothesis, we found that rural New Mexico miners in our study reported adoption of newer communication technologies at a level that was comparable or superior to that reported by rural Americans overall.

Racial/ethnic and health status-related disparities exist with respect to Internet access in the U.S. (9). However, among those with Internet access, these characteristics do not affect their social media use (11). New Internet-based technologies including smartphone and social media, may be changing the communication pattern throughout the U.S. and the world but this change has not been well studied, particularly in rural areas (11). Potential overarching benefits of social media for health communication are (1) increased interactions with others, (2) more available, shared, and tailored information, (3) increased accessibility and widening access to health information, (4) peer/social/emotional support, (5) public health surveillance, and (6) potential to influence health policy (12). Our findings indicate that social media can similarly be used for health communication purposes among rural miners in New Mexico. Our HRSA-funded miners’ health and benefits programs in New Mexico have established a social media platform to provide rural miners with information on our clinical programs, research, education and other interventions as well as to provide opportunities for bidirectional engagement between the program and miners as well as among miners themselves. Our program has also launched a social media literacy campaign for miners, with the help of a rural mine safety officer.

Currently there is a limited amount of literature evaluating the use of social media for sustained engagement of diverse communities in health promotion (13,14). For instance, the Youth Voices Research Group has reported creating novel opportunities to engage young people to explore health topics ranging from tobacco use, food security, mental health, and navigation of health services, by combining social organizing with arts-informed methods for creative expression, using information technology (14). Creating opportunities for engagement alone is however insufficient. The information exchanged needs to be monitored for quality and reliability, users’ confidentiality and privacy need to be maintained (12), and its impact evaluated. Use of social media in health promotion in underserved populations, such as indigenous populations in Australia, is associated with limited evidence of benefit (15). Online social network health behavior interventions are reported to have small effect sizes, often statistically nonsignificant, with high participant attrition and low fidelity (16). It is therefore necessary for our program to critically evaluate the role and effectiveness of these new technologies in health promotion and health care for our population of rural miners.

The strength of our study includes inclusion of miners from rural and predominantly Hispanic and American Indian communities. Limitations of our study include small sample size and lack of information on individual demographic characteristics. Although our study was limited to New Mexico, our findings may be generalizable to other rural and medically underserved areas of the United States outside of New Mexico.

Conclusions

Most miners in rural New Mexico have Internet access, use smartphones and social media, and are willing to use social media to network with other miners or programs that deliver health services to miners. Rural New Mexico miners in our study report adoption of newer communication technologies at a level that is comparable or superior to that reported by rural Americans overall. This study provides preliminary information on a potential and novel way in which rural mining communities and miners’ health and benefits programs can engage with each other to promote miners’ health by assisting in clinical programs, research, education and other interventions. Miners’ program may consider interactive blogging, photograph elicitation, and video documentaries, alongside real-world social media projects, to promote this engagement. Potential barriers in rural miners include low social media literacy and poor Internet connection. Low social media literacy can however be addressed by targeted education of miners. Emerging areas of research include evaluating the effectiveness of the use of smartphones and social networking platforms such as Facebook, in building effective interventions for health promotion and providing healthcare for miners in rural communities.

Acknowledgments

SW, WCJ, EK, RK, KW, AS made substantial contributions to the conception or design of the work; SW, WCJ, EK, RK, KW, AS made substantial contributions to the acquisition, analysis, or interpretation of data for the work. SW, WCJ, EK, RK, KW, AS made substantial contribution towards drafting the work or revising it critically for important intellectual content. SW, WCJ, EK, RK, KW, AS provided the final approval of the version to be published. SW, WCJ, EK, RK, KW, AS agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

References

Dwyer-Lindgren L, Bertozzi-Villa A, Stubbs RW, et al. Trends and Patterns of Differences in Chronic Respiratory Disease Mortality Among US Counties, 1980-2014. JAMA. 2017;318(12):1136-49. [CrossRef] [PubMed]
Perrin A. Social Networking Usage: 2005-2015. Pew Research Center. 2015. Available at: http://www.pewinternet.org/2015/10/08/2015/Social-Networking-Usage-2005-2015/, last accessed on March 28, 2018.
Evans K, Lerch S, Boyce TW, et al. An innovative approach to enhancing access to medical screening for miners using a mobile clinic with telemedicine capability. J Health Care Poor Underserved. 2016;27(4A):62-72. [CrossRef] [PubMed]
Hausman A. Social media versus traditional media. 2014. Available at https://www.hausmanmarketingletter.com/social-media-versus-traditional-media/, accessed on January 9, 2018.
Statistica – The Statistics Portal. Percentage of U.S. population with a social media profile from 2008 to 2017. 2018. Available at https://www.statista.com/statistics/273476/percentage-of-us-population-with-a-social-network-profile/, accessed on March 28, 2018.
Perrin A. Social Media Fact Sheet. Pew Research Center. 2018. Available at: http://www.pewinternet.org/fact-sheet/social-media/, last accessed on March 28, 2018.
Perrin A. Social Media Update 2016. Pew Research Center. 2016. Available at: http://www.pewinternet.org/2016/11/11/social-media-update-2016/, last accessed on March 28, 2018. 2016.
Statistica – The Statistics Portal. Share of adults in the United States who owned a smartphone from 2011 to 2017, by location. 2018. Available at https://www.statista.com/statistics/195003/percentage-of-us-smartphone-owners-by-geographic-location/; accessed on March 28, 2018. 2018.
Perrin A. Internet/Broadband Fact Sheet. Pew Research Center. 2018. Available at: http://www.pewinternet.org/fact-sheet/internet-broadband/, last accessed on March 28, 2018.
Perrin A. Digital gap between rural and non-rural America persists. 2017. Pew Research Center. Available at: http://www.pewresearch.org/fact-tank/2017/05/19/digital-gap-between-rural-and-nonrural-america-persists/, last accessed on March 28, 2018.
Chou WY, Hunt YM, Beckjord EB, Moser RP, Hesse BW. Social media use in the United States: implications for health communication. J Med Internet Res. 2009;11(4):e48. [CrossRef] [PubMed]
Moorhead SA, Hazlett DE, Harrison L, Carroll JK, Irwin A, Hoving C. A new dimension of health care: systematic review of the uses, benefits, and limitations of social media for health communication. J Med Internet Res. 2013;15(4):e85. [CrossRef] [PubMed]
Yonker LM, Zan S, Scirica CV, Jethwani K, Kinane TB. "Friending" teens: systematic review of social media in adolescent and young adult health care. J Med Internet Res. 2015;17(1):e4. [CrossRef] [PubMed]
Norman CD, Yip AL. eHealth promotion and social innovation with youth: using social and visual media to engage diverse communities. Studies in health technology and informatics. 2012;172:54-70. [PubMed]
Brusse C, Gardner K, McAullay D, Dowden M. Social media and mobile apps for health promotion in Australian Indigenous populations: scoping review. J Med Internet Res. 2014;16(12):e280. [CrossRef] [PubMed]
Maher CA, Lewis LK, Ferrar K, Marshall S, De Bourdeaudhuij I, Vandelanotte C. Are health behavior change interventions that use online social networks effective? A systematic review. J Med Internet Res. 2014;16(2):e40. [CrossRef] [PubMed]

Cite as: Wigh S, Jarrell WC, Kocher E, Karr R, Wang X, Sood A. Social media: A novel engagement tool for miners in rural New Mexico. Southwest J Pulm Crit Care. 2018;16(4):206-11. doi: https://doi.org/10.13175/swjpcc017-18 PDF