Association of particulate matter with autoimmune rheumatic diseases among adults in South Korea.

ABSTRACT

OBJECTIVE: The primary objective of this study was to investigate adverse effects of ambient particulate matter of various sizes on the incidence of the prevalent autoimmune rheumatic diseases (AIRDs) RA, AS and SLE. METHODS: We investigated 230 034 participants in three metropolitan cities of South Korea from the National Health Insurance Service-National Sample Cohort (NHIS-NSC). Starting from January 2010, subjects were followed up until the first event of prevalent AIRDs, death, or December 2013. The 2008-2009 respective averages of particulate matter2.5 (<2.5 µm) and particulate mattercoarse (2.5 µm to 10 µm) were linked with participants' administrative district codes. Adjusted hazard ratios (aHRs) and 95% CIs were estimated using Cox regression analysis in one- and two-pollutant models. RESULTS: Adjusted for age, sex, region, and household income, in the two-pollutant model, RA incidence was positively associated with the 10 µg/m³ increment of particulate matter2.5 (aHR = 1.74, 95% CI 1.06, 2.86), but not with particulate mattercoarse (aHR = 1.27, 95% CI 0.87, 1.85). In the one-pollutant model, the elevated incidence rate of RA was slightly attenuated (particulate matter2.5 aHR = 1.61, 95% CI 0.99, 2.61; particulate mattercoarse aHR = 1.13, 95% CI 0.80, 1.61), with marginal statistical significance for particulate matter2.5. The RA incidence was also higher in the 4th quartile group of particulate matter2.5 compared with the first quartile group (aHR = 1.83, 95% CI 1.07, 3.11). Adverse effects from particulate matter were not found for AS or SLE in either the one- or two-pollutant models. CONCLUSION: The important components of particulate matter10 associated with RA incidence were the fine fractions (particulate matter2.5); no positive association was found between particulate matter and AS or SLE.