Prenatal Fine Particulate Matter Exposure and Childhood Anxiety Symptoms

Abstract

Background: Air pollution has been linked to neurotoxic effects; however, there is limited research on mental health, particularly in younger populations in which symptoms often first arise. We studied the association between prenatal fine particulate matter (PM2.5) exposure and symptoms of anxiety in a cohort of 8-9 year olds in Mexico City.Methods: Participants included 173 mother-child pairs from the Programming Research in Obesity, Growth, Environment and Social Stressors longitudinal birth cohort in Mexico City. Daily PM2.5 predictions were estimated using a 1km satellite-based exposure model and averaged over trimesters and the entire pregnancy. Symptoms of anxiety were assessed using the Revised Children’s Manifest Anxiety Scale (RCMAS-2) (Spanish Version) administered by psychologists during the face-to-face interview at the 8-9 year study visit. Linear regression models were used to estimate the change in continuous anxiety symptoms with each 5-µg/m3 increase in PM2.5, for each trimester and the entire pregnancy. Models were adjusted for maternal education, maternal SES, maternal depression, maternal age, child’s age at study visit, and season of conception. We additionally assessed sex-specific effects by including an interaction term between PM2.5 and sex.Results: Higher levels of PM2.5 exposure averaged over the entire pregnancy was associated with increases in childhood anxiety symptoms at age 8-9, in males only (β for males = 2.06, 95% CI: 0.20, 3.91; β for females = -0.45, 95% CI: -2.38, 1.48; p-int: 0.02). This sex-specific effect was primarily seen for exposures during the 1st trimester (β for males= 1.13, 95% CI: -0.06, 2.32, p-int: 0.06).Conclusions: PM2.5 exposure in early pregnancy may be a critical window for elevated symptoms of anxiety in the mid/late childhood period. Future analyses will use distributed lag models to further define time and sex-specific effects, as well as adjust for other urban stress correlates such as environmental noise.