Association between Air Pollution and the Development of Rheumatic Disease: A Systematic Review.

Objective. Environmental risk factors, such as air pollution, have been studied in relation to the risk of development of rheumatic diseases. We performed a systematic literature review to summarize the existing knowledge. Methods. MEDLINE (1946 to September 2016) and EMBASE (1980 to 2016, week 37) databases were searched using MeSH terms and keywords to identify cohort, case-control, and case cross-over studies reporting risk estimates for the development of select rheumatic diseases in relation to exposure of measured air pollutants (n = 8). We extracted information on the population sample and study period, method of case and exposure determination, and the estimate of association. Results. There was no consistent evidence of an increased risk for the development of rheumatoid arthritis (RA) with exposure to NO₂, SO₂, PM_2.5, or PM₁₀. Case-control studies in systemic autoimmune rheumatic diseases (SARDs) indicated higher odds of diagnosis with increasing PM_2.5 exposure, as well as an increased relative risk for juvenile idiopathic arthritis (JIA) in American children <5.5 years of age. There was no association with SARDs and NO₂ exposure. Conclusion. There is evidence for a possible association between air pollutant exposures and the development of SARDs and JIA, but relationships with other rheumatic diseases are less clear.