Early-life ozone exposure and childhood otitis media: Unveiling critical windows of risk

Background: Despite increasing evidence of a strong correlation between air pollution and otitis media (OM), the impact of early-life ozone (O-3) exposure on the development of OM in children remains uncertain. Objectives: To explore the connection between early-life O-3 exposure and OM, and to identify the critical time period(s) during which O-3 exposure significantly influences the development of OM in children. Methods: We conducted a study involving 8689 children living in Changsha, China. Information regarding personal factors, health conditions, and the indoor environment was gathered using questionnaires. Personal exposure to outdoor O-3 and other major pollutants at the place of residence during the periods before conception, prenatal periods, and after birth was calculated by applying the inverse distance weighted (IDW) method with data gathered from ten air quality monitoring stations. Multiple logistic regression analyses were employed to investigate the associations between O-3 exposure and children's OM. Results: After controlling for covariates and ambient temperature, exposure to O-3 during the year preceding pregnancy was correlated with childhood lifetime OM, showing ORs (95 % CI) of 1.28 (1.01-1.64). O-3 exposures in the 10th-12th, 7th-9th, and 4th-6th months before pregnancy were all linked to children's lifetime OM. Within the multi-window model, we detected that O-3 exposure in the 10th to 12th month prior to pregnancy was significantly related to lifetime OM, showing ORs (95 % CI) of 1.28 (1.05-1.55). A significant link was discovered between childhood OM and O-3 exposure after controlling for six other pollutants (SO2, PM2.5, NO2, PM2.5-10, CO, and PM10) during the 10th to 12th month prior to conception. Exposure to O(3)during the 36th gestational week significantly raised the likelihood of childhood lifetime OM. There is a significant interaction between O-3 and temperature exposure during the first trimester of pregnancy and one year before pregnancy on childhood lifetime OM. Conclusions: Preconceptional O-3 exposure and its interaction with low temperature played critical roles in children's OM development, backing the hypothesis of "(pre) fetal origins of childhood OM".