Association between short-term air pollution exposure and attention-deficit/hyperactivity disorder-related hospital admissions among adolescents: A nationwide time-series study

Long-term air pollution exposure has been suggested to increase the risk of attention-deficit/hyperactivity disorder (ADHD). However, the association between short-term air pollution exposure and ADHD-related outcomes is still unknown. We investigated the associations between short-term exposure to particulate matter with an aerodynamic diameter <10 mm (PM10), nitrogen oxide (NO2), and sulfur dioxide (SO2) and hospital admissions with a principal diagnosis of ADHD among adolescents (age 10-19 years) in 16 regions of the Republic of Korea from 2013 to 2015. We estimated the region-specific relative risks (RRs) and 95% confidence intervals (CIs) from quasi-Poisson regressions adjusted for potential confounders, considering single-day and moving average lag. Consequently, we performed meta-analyses to pool the region-specific estimates. The risks of ADHD-related hospital admissions were increased in the single-day and moving average lag models for PM10 (largest association for lag 1 in the single-day lag model, RR = 1.12, 95% CI: 1.05, 1.20; lag 0-2 in the moving average lag model, RR = 1.17, 95% CI: 1.07, 1.27), NO2 (lag 3, RR = 1.47, 95% CI: 1.25, 1.73; lag 1-3, RR = 1.68, 95% CI: 1.38, 2.04), and SO2 (lag 1, RR = 1.27, 95% CI: 1.14, 1.41; lag 1-3, RR = 1.29, 95% CI: 1.12, 1.49). The associations were similar between boys and girls, but they were stronger among adolescents aged 15-19 years than those aged 10-14 years for NO2 and SO2. In conclusion, the results indicate that short-term exposure to PM10, NO2, and SO2 may be a risk factor for the exacerbation of ADHD symptoms, leading to hospitalization. (C) 2020 Elsevier Ltd. All rights reserved.