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Dusty trades and associated rheumatoid arthritis in a population-based study in the coal mining counties of Appalachia
  1. Gabriela Schmajuk1,2,
  2. Laura Trupin2,
  3. Edward H Yelin2,
  4. Paul D Blanc1,2
  1. 1Medicine, Veterans Health Administration, San Francisco, California, USA
  2. 2Medicine, University of California San Francisco, San Francisco, California, USA
  1. Correspondence to Professor Paul D Blanc, Medicine, Veterans Health Administration, San Francisco, California, USA; paul.blanc{at}


Objectives We previously showed increased coal mining-associated risk of rheumatoid arthritis (RA). Using additional survey data, we sought to delineate this risk further.

Methods We used data from two cross-sectional, random-digit-dial, population-based surveys (males;≥50 years) in selected counties in the Appalachian region of the inland, mid-Atlantic USA with elevated pneumoconiosis mortality. Surveys ascertained age, smoking, coal mining and non-coal silica exposure jobs. In a subset, we surveyed ergonomic exposures, scored by intensity. We queried diagnosis of RA, corticosteroid use, and, in a subset, use of disease modifying antirheumatic drugs (DMARDs). Multivariable logistic regression modelled RA risk (defined by glucocorticoid or DMARDs use) associated with coal mining employment, other silica exposure, smoking status, and age and ergonomic exposures.

Results We analysed data for 2981 survey respondents (mean age 66.6 years; 15% current, 44% ex-smokers). The prevalence of glucocorticoid-treated and DMARD-treated RA was 11% and 4%, respectively. Glucocorticoid-treated RA was associated with coal mining (OR 3.5; 95% CI 2.5 to 4.9) and non-coal mining silica exposure (OR 3.2; 95% CI 2.4 to 4.4). For DMARD-treated RA, the odds associated with coal mining and other silica remained elevated: OR 2.3 (95% CI 1.18, 4.5) and OR 2.7 (95% CI 1.51, 5.0), respectively. In the same model, the highest intensity ergonomic exposure also was associated with increased odds of RA (OR 4.3; 95% CI 1.96 to 9.6).

Conclusions We observed a strong association between coal mining and other silica-exposing dusty trades and RA. Clinicians and insurers should consider occupational histories in the aetiology of RA.

  • coal mining
  • musculoskeletal system
  • autoimmune diseases

Data availability statement

All data relevant to the study are included in the article or uploaded as online supplemental information.

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Data availability statement

All data relevant to the study are included in the article or uploaded as online supplemental information.

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  • Contributors GS, LT, EHY and PB contributed to the planning, conduct, data analysis and reporting of the work described in the article; PB is responsible for the overall content as guarantor.

  • Funding This work was supported by a grant from the Alpha Foundation (AFC618SP-88).

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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