Occupational Exposures in Rheumatoid Arthritis-related Airway Disease: A Missing Link?

To the Editor:

We read with great interest the recently published, “A Focused Review: Airway Disease in Rheumatoid Arthritis” (1). In this review, Matson and colleagues deftly summarize the pathophysiology and myriad clinical manifestations of airway disorders that cooccur with rheumatoid arthritis (RA). The authors note that asthma, chronic obstructive pulmonary disease (COPD), bronchiolitis, and bronchiectasis are all well-known manifestations or comorbidities in patients with RA. As part of their discussion of the complicated and incompletely understood pathogenesis of rheumatoid arthritis, the authors reference environmental insults and, specifically, tobacco smoke as triggers for autoantibody-mediated immune responses that lead to the development of autoimmune disease and potentially airway disease. Although the review was by definition focused, a discussion of occupational exposures that cooccur with RA and airway disease is warranted both to assess risk of airway disease and potentially prevent pulmonary disease progression.

Work exposures have been well described as a risk factor for RA. One telephone survey in an area with high mortality from coal workers’ pneumoconiosis found that residents with a history of coal mining exposure had more than threefold odds of reporting a diagnosis of RA, leading to a population attributable fraction of 33% of those studied (2). Military inorganic dust exposure has also been associated with the development of RA compared with other occupations within the armed forces (3). Prolonged exposure to the World Trade Center disaster site has also been associated with an increased rate of autoimmune disease, the most prevalent of which was RA (4). Other occupations have demonstrated gender-specific associations with RA: bricklayers and concrete workers have an increased risk of RA among men, whereas nurses and medical attendants have increased risk among women (5).

Occupational-associated lung disease in patients with connective tissue disease is increasingly recognized (6), and the well-known association between occupational exposures and asthma, COPD, and bronchiolitis suggest a shared causative environmental antigen may exist among patients with RA and airway disease. Ascertaining the association between RA and occupational exposures has enormous implications for assessment of those at high risk of disease development, such as individuals with a family history of autoimmune disease. Furthermore, more novel occupational exposure–pulmonary disease dyads in women may reveal more exposure–autoimmune disease connections in the future, given the female-predominant nature of connective tissue disease. Systematic assessment of lifetime occupational exposures, starting in clinic and continuing in research registries, is the key to further codifying exposure–disease relationships and early identification and ultimately prevention of airway disease in patients with RA.