Short-term air pollution exposure and anxiety symptoms in children from Mexico City

Abstract

BACKGROUND AND AIM: Short-term air pollution exposure has been linked to mental health conditions in adults; however, there is limited research in the younger populations in which symptoms often first arise. In this study, we examined the association between recent fine particulate matter (PM2.5) exposure and symptoms of anxiety in a cohort of 8–9-year-olds in Mexico City. METHODS: Participants included 455 mother-child pairs from a longitudinal birth cohort study in Mexico City. Anxiety symptoms were assessed at the 8–9-year study visit by trained psychologists using the Spanish version of the Revised Children’s Manifest Anxiety Scale. Daily PM2.5 predictions were estimated using a 1km satellite-based exposure model and averaged over several recent exposure windows including 1-12 months and 1-4 weeks prior to anxiety assessment. We additionally used recent weekly exposure averages in distributed lag models. Linear regression models were used to estimate the change in continuous anxiety symptoms with each 5-µg/m3 increase in PM2.5. Models were adjusted for maternal education, maternal age, child’s age at study visit, child sex, and season of study visit. We additionally assessed sex-specific effects by including an interaction term between PM2.5 and sex. RESULTS: A 5-unit increase in PM2.5 exposure averaged over the 1 month prior to study visit was associated with higher anxiety symptoms in the child (β= 0.65, 95% CI: 0.01, 1.30). These associations were primarily seen in females (β= 1.05, 95% CI: 0.10, 1.95, p-int: 0.10). Using DLM approaches, we identified a critical window for exposures 0-2 weeks prior to anxiety assessment. CONCLUSIONS: Fine particulate matter exposure was associated with elevated levels of child anxiety symptoms, particularly for more recent exposures. KEYWORDS: air pollution, mental health, LMIC, child health