Effects of air pollution exposure predicting sleep efficiency in children modified by exposure to violence, 4-7 years, in the PROGRESS birth cohort

BACKGROUND: Studies suggest that expose to both air pollution and violence may alter development trajectory, as it may disrupt the HPA-axis which plays an important role in how the human body reacts to environmental stressors affecting sleep. We propose that prenatal air pollution exposure may interact with violence to affect the efficiency of sleep, therefore, modified by exposure to violence. METHODS: We studied 412 children enrolled in Programming Research in Obesity, GRowth, Environment and Social Stressors (PROGRESS), a birth cohort study in Mexico City. We used a spatio-temporal model to estimate individual daily prenatal PM2.5 exposure at each participant’s residential address. We assessed the sleep efficiency (defined with time awake divided by time in bed) of all kids at age 4-7 years with assigned accelerometer worn during sleep, and recorded sleep patterns for a week to examine the association between PM2.5 exposure and sleep efficiency. RESULTS: Participants are mostly low SES families (54.6%) with slightly lower proportion of low maternal education (42.1%) and are racial/ethnicity uniformed. Sleep efficiencies are normally distributed and ranging from 63.5 to 91.8. At age 4, children who were exposed to low-to-mid violence are more likely to have their sleep efficiency disrupted by prenatal PM2.5 exposure (ETV at 10%tile, β=-0.26, CI:-1.19,0.68; However, at age 6, we found that PM2.5 reduced sleep efficiency at even lower levels, (ETV at 10%tile, β=-0.26, CI:-1.05,0.54; peak PM effect at ETV at 36%tile, β=-0.71, CI:-1.5,0.09; ETV at 90%tile, β=0.28, CI:-1,1.55; ). CONCLUSION: As the literature expands on sleep and sleep disparities, the sparseness of studies on children’s sleep highlights a research void that if addressed could mitigate the adverse impact of child sleep disparities on long term health. KEYWORDS: environmental stressors, violence, sleep health, disparities, exposure