Early-Life Exposure to PM_2.5 and Sleep Disturbances in Preschoolers from 551 Cities of China.

Abstract

<b>Rationale:</b> Air pollution has been linked with sleep disturbance in adults, but the association in children remains unclear. <b>Objectives:</b> To examine the associations of prenatal and postnatal exposure to fine particulate matter (particulate matter ⩽2.5 μm in aerodynamic diameter; PM_2.5) with sleep quality and sleep disturbances among children in 551 Chinese cities. <b>Methods:</b> A total of 1,15,023 children aged 3-7 years from the Chinese National Cohort of Motor Development were included. Sleep quality was measured using the Children's Sleep Habits Questionnaire (CSHQ). PM_2.5 exposure was estimated using a satellite-based model. Generalized additive mixed models with Gaussian and binomial distributions were used to examine the associations of PM_2.5 exposure with CSHQ scores and risk of sleep disturbance, respectively, adjusting for demographic characteristics and temporal trends. <b>Measurements and Main Results:</b> Early-life PM_2.5 exposure was associated with higher total CSHQ score, and the association was stronger for exposure at age 0-3 years (change of CSHQ score per interquartile range increase of PM_2.5 = 0.46; 95% confidence interval [CI], 0.29-0.63) than during pregnancy (0.22; 95% CI, 0.12-0.32). The associations were more evident in sleep-disordered breathing and daytime sleepiness. Postnatal PM_2.5 exposure was associated with increased risk of sleep disturbance (adjusted odds ratio for per-interquartile range increase of PM_2.5 exposure at age 0-3 years, 1.10; 95% CI, 1.04-1.15), but no associations were found for prenatal exposure. Children who were exclusively breastfed for <6 months and had neonatal ICU admission may be more vulnerable to sleep disturbance related to PM_2.5 exposure. <b>Conclusions:</b> PM_2.5 exposure can impair sleep quality in preschool children.