Short-term exposure to gaseous ambient pollution and hospital admissions for mental health among children and adolescents: A time-stratified case-crossover study

Little evidence has demonstrated the linkage of gaseous air pollution and hospitalization rates for mental diseases among children and adolescents in China. Based on a time-stratified case-crossover design among children and adolescents in nine cities, Sichuan, a conditional logistic regression and a concentration-response (C–R) curve model were applied to investigate mental disorders in relation to gaseous air pollutants exposure at lag 0-lag 7, and lag 01-lag 07. Hospitalization costs were calculated through the attributable risk method. With daily data from official environmental monitoring centers, individual daily mean ambient pollutants estimates were evaluated via Inverse Distance Weighted method. Daily hospitalized records for mental illness were collected from medical organization or/and institutions from January 2016 to December 2019. There were 11479 inpatients suffering depression, anxiety, and/or other mental disorders. In single- and cumulative-day-lag analyses, with each 10 μg/m³ increment of NO₂, SO₂, and O₃, the greatest odds ratio (OR) for all-cause mental disorders were 1.114 (95% confidence interval [CI]: 1.067–1.164) (lag 0), 1.219 (95% CI: 1.040–1.430) (lag 4), and 1.039 (95% CI: 1.009–1.069) (lag 7), separately. Stronger associations were found in inpatients hospitalized in warm days in SO₂ analysis. C–R curve showed that all-cause mental disorders hospitalizations were positively related to SO₂ and O₃ exposure at relative high levels. During study period, the total economic cost of hospitalization for all-cause mental disorders caused by NO₂ pollution was 94.71 million CNY. These findings indicated that gaseous air pollutants exposure may increase the risk and economic burdens of mental disorders among children and adolescents.