To systematically evaluate the role of air pollutants in the development and exacerbation of autoimmune rheumatic diseases.

We followed PRISMA guidelines and searched EMBASE, Scopus, PubMed, and Cochrane Library databases using keywords and MeSH terms from inception to July 2019. Observational studies reporting the relationship between autoimmune rheumatic diseases and exposure to certain air pollutants were included. Screening of literature according to established inclusion and exclusion criteria. No meta-analysis but the qualitative analysis was conducted due to the high methodological heterogeneity.

A total of 24 studies were included. Rheumatoid arthritis (RA) (n=6), anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) (n=1), ankylosing spondylitis (AS) (n=1), systemic lupus erythematosus (SLE) (n=3), childhood-onset systemic lupus erythematosus (cSLE) (n=3), juvenile idiopathic arthritis (JIA) (n=2), Kawasaki disease (KD) (n=4), systemic autoimmune rheumatic diseases (SARD) (n=4). The results of the study suggested that short-term elevation in particulate matter (PM)2.5 concentration was possibly associated with an increased risk of SLE and cSLE flare-ups, disease activity of AS, JIA and SARDs exacerbation. Studies demonstrated an increased risk of RA with cumulative exposure to carbon monoxide (CO), nitrogen dioxide (NO₂), ozone (O₃), and sulfur dioxide (SO₂). Only one study demonstrated an increased risk of KD admission with elevated O₃ levels. No association was found between AAV and ambient air pollution.

Air pollution is likely to be involved in the development and exacerbation of certain autoimmune diseases. At the same time, the mechanism of autoimmune diseases of ambient air pollutants should be actively studied, so as to promote the early prevention of cardiovascular diseases.

Air pollution; Autoimmune diseases; Disease Activity; Epidemiology