Abstract and Introduction
Objectives: To estimate associations between fine particulate matter (PM2.5) and ozone and the onset of systemic autoimmune rheumatic diseases (SARDs).
Methods: An open cohort of over 6 million adults was constructed from provincial physician billing and hospitalization records between 2000 and 2013. We defined incident SARD cases (SLE, Sjogren's syndrome, scleroderma, polymyositis, dermatomyositis, polyarteritis nodosa and related conditions, polymyalgia rheumatic, other necrotizing vasculopathies, and undifferentiated connective tissue disease) based on at least two relevant billing diagnostic codes (within 2 years, with at least 1 billing from a rheumatologist), or at least one relevant hospitalization diagnostic code. Estimated PM2.5 and ozone concentrations (derived from remote sensing and/or chemical transport models) were assigned to subjects based on residential postal codes, updated throughout follow-up. Cox proportional hazards models with annual exposure levels were used to calculate hazard ratios (HRs) for SARDs incidence, adjusting for sex, age, urban-versus-rural residence, and socioeconomic status.
Results: The adjusted HR for SARDS related to one interquartile range increase in PM2.5 (3.97 μg/m3) was 1.12 (95% confidence interval 1.08–1.15), but there was no clear association with ozone. Indirectly controlling for smoking did not alter the findings.
Conclusions: We found associations between SARDs incidence and PM2.5, but no relationships with ozone. Additional studies are needed to better understand interplays between the many constituents of air pollution and rheumatic diseases.
Ambient air pollution is the fifth leading cause of deaths worldwide. Exposure to particulate matter, especially fine particles of diameter 2.5 μm or less (PM2.5), increases risk of developing or dying from cardiac, cerebrovascular, and chronic airway diseases. Only a few studies have investigated the effects of air pollution on rheumatic diseases, and the evidence of an association from these studies is not persuasive.
Systemic autoimmune rheumatic diseases (SARDs), including systemic lupus erythematosus (SLE) and related conditions, are complex chronic rheumatic disorders that cause high personal and societal burdens. The etiology of SARDs is poorly understood. Inhaled air pollutants (e.g., PM2.5 and ozone) can increase oxidative stress and inflammatory responses in the lung and potentially trigger systemic immune system changes. However, to date, no studies of air pollution and the incidence of SARDs have been published. Our purpose was to determine whether the incidence of SARDs is associated with exposures to ambient PM2.5 and ozone.
Arthritis Res Ther. 2022;24(151) © 2022 BioMed Central, Ltd.
Copyright to this article is held by the author(s), licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original citation.