Microplastic exposure in the lungs of young children and its associations with allergic rhinitis: A cross-sectional study in China

Exposure to microplastics (MPs) has emerged as a potential threat to chronic respiratory health. However, the association between MPs exposure and allergic rhinitis (AR) in children remains unclear. We evaluated the association between MP exposure and the prevalence of AR in children. We measured 11 types of MPs in bronchoalveolar lavage fluid (BALF) collected from 207 children aged 1-16 years using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) in 2023. Logistic regression models were employed to evaluate the association between MP concentration and prevalence of AR. Polyamide 66 (PA66), polyethylene (PE), polyvinyl chloride (PVC), and polystyrene (PS) were the predominant types detected, with median concentrations of 2.33, 0.45, 0.38, and 0.08 ​μg/mL in BALF, respectively. Higher concentrations of PA66 were associated with an increased prevalence of AR in all children, with odds ratios (ORs) of 3.00 (95% CI: 1.23, 7.34) after adjusting for potential confounders, indicating a statistically significant association (α ​< ​0.05). Higher concentrations of total MP exposure (<i>P</i> _overall ​= ​0.012, <i>P</i> _nonlinear ​= ​0.310) and PA66 exposure (<i>P</i> _overall ​= ​0.012, <i>P</i> _nonlinear ​= ​0.951) were significantly associated with the prevalence of AR in children aged ≤6 years but not in those aged >6 years. Our findings suggest that exposure to MPs, particularly PA66, may be associated with a higher risk of AR in younger children. Further large-scale, community-based pediatric cohort studies are needed to elucidate the underlying mechanisms.