[Effects of indoor environmental pollutants on allergic diseases in children: a Meta-analysis]

Objective: To evaluate the impact of indoor environmental pollution on childhood allergic diseases in recent years through Meta-analysis and explore the potential effects of pollution exposure on children's health. Methods: Literature published between January 2015 and March 2025 was retrieved from China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform, VIP Information Database, PubMed, and Web of Science. Additional studies were identified through reference tracing and manual supplementation. Studies meeting inclusion criteria were screened, and relevant data were extracted and analyzed. Results: A total of 36 studies from 9 countries were included, including 25 studies conducted in China. Most studies were cross-sectional ones (21), followed by cohort ones (8), case-control ones (4), and combined (cross-sectional and cohort) ones (3). Study participants were children aged 0-12 years. Indoor pollutants closely associated with allergic diseases included particulate matter, chemical pollutants, and biological pollutants. Meta-analysis results indicated that environmental tobacco exposure (OR=1.51, 95%CI:1.16-1.98, P=0.003) significantly increased the risk for childhood asthma; the exposure to new furniture (OR=1.44, 95%CI:1.13-1.83, P=0.003) was significantly associated with allergic rhinitis; the exposures to mold (OR=2.81, 95%CI:2.25-3.51, P<0.001), cockroach (OR=1.59, 95%CI:1.26-2.00, P<0.001), and damp or mouldy environmental surface (OR=1.42, 95%CI:1.26-1.62, P<0.001) significantly increased asthma risk. The exposure sensitivity varied across the development stages of children, with high sensitivity in infancy and early childhood. Conclusion: Children can expose to indoor environmental pollutants through multiple routes, including inhalation and skin contact, in daily life, which might increase the risk for allergic diseases by inducing abnormal immune responses and pose a significant threat to children's health.