Association between PM2.5 and Systemic Autoimmune Rheumatic Diseases: A Cohort Study in Taiwan from 2001 to 2011

Abstract

Background: Systemic autoimmune rheumatic diseases (SARDs) are a group of diseases with abnormally inflammatory reactions, such as dermatomyositis (DM), polymyositis (PM), systemic sclerosis (SSc). The pathogenesis of systemic autoimmune diseases is still unclear. Only a few studies accessed the relation between exposure to air pollution and systemic inflammation and provide inconsistent results. We conducted a prospective cohort study to investigate the associations between fine particulate matter (PM2.5) and SARDs, namely DM, PM, SSc, in Taiwan.Methods: The study population were obtained from Taiwan National Health Insurance Research Database (NHIRD) and followed up from 2001 to 2011. All participants were followed end when diagnosis of SARDs (DM, PM, SSc), or death, or end of the study. We developed a model integrated 3-km AOD with meteorological parameters and land use data to predict daily PM2.5 concentrations across Taiwan. We performed a time dependent Cox models to assess the effects of yearly average PM2.5 on SARDs (DM, PM, SSc). The results were reported as hazard ratios (HRs) with 95% confidence interval (CI).Results: A total of 3119 DM cases, 3259 PM cases, and 2824 SSc cases were identified during the study period. The mean age of DM, PM, and SSc cases were 54.4±18.7, 53.8±16.8, and 49.9±15.9 years, respectively. After adjusting for sex, age, and socioeconomic status, the results showed that exposure to an Interquartile range (IQR) increase in PM2.5 level (14.29 μg/m3) were associated with an approximately 48% increased risk of DM (95% CI 1.39¬-1.59) and a 23% increased risk of PM (95% CI 1.16-1.32). We did not observe significant associations between PM2.5 and SSc.Conclusions: Our study suggests that exposure to PM2.5 may increase the risk of DM and PM. The future studies would be needed to confirm these associations, and explore potential toxicants on SARDs other than PM2.5.