Ambient air pollutants increase the risk of immunoglobulin E–mediated allergic diseases: a systematic review and meta-analysis

Immunoglobulin E (IgE)–mediated allergic diseases, including eczema, atopic dermatitis (AD), and allergic rhinitis (AR), have increased prevalence in recent decades. Recent studies have proved that environmental pollution might have correlations with IgE-mediated allergic diseases, but existing research findings were controversial. Thus, we performed a comprehensive meta-analysis from published observational studies to evaluate the risk of long-term and short-term exposure to air pollutants on eczema, AD, and AR in the population (per 10-μg/m(3) increase in PM(2.5) and PM(10); per 1-ppb increase in SO(2), NO(2), CO, and O(3)). PubMed, Embase, and Web of Science were searched to identify qualified literatures. The Cochran Q test was used to assess heterogeneity and quantified with the I(2) statistic. Pooled effects and the 95% confidence intervals (CIs) were used to evaluate outcome effects. A total of 55 articles were included in the study. The results showed that long-term and short-term exposure to PM(10) increased the risk of eczema (PM(10), RR(long) = 1.583, 95% CI: 1.328, 1.888; RR(short) = 1.006, 95% CI: 1.003–1.008) and short-term exposure to NO(2) (RR(short) = 1.009, 95% CI: 1.008–1.011) was associated with eczema. Short-term exposure to SO(2) (RR(short): 1.008, 95% CI: 1.001–1.015) was associated with the risk of AD. For AR, PM(2.5) (RR(long) = 1.058, 95% CI: 1.014–1.222) was harmful in the long term, and short-term exposure to PM(10) (RR(short): 1.028, 95% CI: 1.008–1.049) and NO(2) (RR(short): 1.018, 95% CI: 1.007–1.029) were risk factors. The findings indicated that exposure to air pollutants might increase the risk of IgE-mediated allergic diseases. Further studies are warranted to illustrate the potential mechanism for air pollutants and allergic diseases. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11356-022-20447-z.