Long-term exposure to ambient fine particulate pollution, sleep disturbance and their interaction effects on suicide attempts among Chinese adolescents

Background: There is a lack of literature about the joint effects of PM2.5 exposure and sleep disturbance on suicide attempts. This study aimed to estimate the association of PM2.5 exposure or sleep disturbance with suicide attempts among Chinese adolescents and to test their interaction effects on both additive and multiplicative scales. Methods: Data was drawn from a subsample of the School-based Chinese Adolescents Health Survey (SCAHS) during 2014-2015 in Guangdong province, including 21,780 eligible participants. The 3-year (2011-2013) annual average concentration of PM2.5 was estimated using satellite data. Multi-level logistic regression models with weights were fitted, and both multiplicative and additive interactions for PM2.5 and sleep disturbance were tested. Results: A total of 608 students (2.8%) reported having suicide attempts. After adjusting for significant demographics and depressive symptoms, PM2.5 exposure (Adjusted odds ratio [AOR]=1.25, 95% CI=1.03-1.56) and sleep disturbance (AOR = 1.69, 95% CI=1.41-2.02) were positively associated with suicide attempts, respectively. The adjusted additive interaction effect of PM2.5 and sleep disturbance was 2.42 (95% CI=1.80-3.26) with a synergistic index of 1.31. The multivariable multi-level logistic regression models did not find any significant multiplicative interaction item (P>0.05). Limitation: The school-based cross-sectional study design Conclusion: Long-term exposure to PM2.5 may elevate the risks of suicide attempts among Chinese adolescents. Moreover, the significant interaction effects of PM2.5 exposure and sleep disturbance on suicide attempts were found in the additive model, suggesting decreasing long-term exposure to a higher level of PM2.5 may be helpful to reduce the risk of suicide attempts among adolescents with sleep disturbance.