Positive association between chlorinated paraffins and the risk of allergic diseases in children and adolescents.

Contaminants may induce immune response polarization, leading to immune diseases, such as allergic diseases. Evidence concerning the effects of chlorinated paraffins (CPs), an emerging persistent organic pollutant, on immune system is scarce, particularly for epidemiological evidence. This study explores the association between CPs exposure and allergic diseases (allergic rhinitis, atopic eczema, and allergic conjunctivitis) in children and adolescents in the Pearl River Delta (PRD) in China. Herein, 131,304 children and adolescents from primary and secondary schools in the PRD were included and completed the questionnaire survey. The particulate matter (PM) samples were collected in the PRD and the PM2.5-bound CP concentrations were analyzed. In the multivarious adjustment mixed effect model (MEM), an IQR increase in ∑CPs was significantly associated with allergic diseases (rhinitis, eczema, and conjunctivitis) with the estimated odds ratios (ORs) for 1.11 (95% CI: 1.10, 1.13), 1.17 (95% CI: 1.15, 1.19), and 1.82 (95% CI: 1.76, 1.88), respectively. Interaction analysis indicated that overweight and obese individuals might have greater risk. Similar effect estimates were observed in several sensitivity analyses. This study provided epidemiological evidence on the immunotoxicity of CPs. More studies to confirm our findings and investigate mechanisms are needed.