Early-Life Exposure to PM2.5 and Sleep Disturbances in Preschoolers from 551 Cities of China.

Rationale: Air pollution has been linked with sleep disturbance in adults, but the association in children remains unclear. Objectives: To examine the associations of prenatal and postnatal exposure to fine particulate matter (particulate matter ⩽2.5 µm in aerodynamic diameter; PM2.5) with sleep quality and sleep disturbances among children in 551 Chinese cities. Methods: 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). PM2.5 exposure was estimated using a satellite-based model. Generalized additive mixed models with Gaussian and binomial distributions were used to examine the associations of PM2.5 exposure with CSHQ scores and risk of sleep disturbance, respectively, adjusting for demographic characteristics and temporal trends. Measurements and Main Results: Early-life PM2.5 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 PM2.5 = 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 PM2.5 exposure was associated with increased risk of sleep disturbance (adjusted odds ratio for per-interquartile range increase of PM2.5 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 PM2.5 exposure. Conclusions: PM2.5 exposure can impair sleep quality in preschool children.

Evaluating the Impact of Maternal Exposure to Ozone on Twin Fetal Growth in China.

Unlike singletons, twins require attention not only to the birth weight of the fetuses but also to discordance (i.e., the differences between weights) because twin growth discordance is a significant factor contributing to perinatal mortality and morbidity in twin pregnancies. However, the impact of maternal air pollution exposure on twin growth discordance has rarely been investigated. We examined the association of long-term ozone exposure during preconception and pregnancy with the birth weight of twins and twin growth discordance among 35,795 twins from the National Free Preconception Health Examination Project between January 2010 and December 2019. Linear mixed-effect models and random-effect logistic regression models were used to examine the associations of ozone exposure with the birth weight-related outcomes (i.e., birth weight of twins and within-pair birth weight difference) and risk of twin growth discordance, respectively, after adjustment for demographic characteristics and lifestyle. We found that an interquartile range (IQR) increase (15 µg/m3) in ozone exposure during the entire pregnancy was associated with a reduction (-28.96g, 95% confidence interval [CI]: -46.37, -11.56) in the total birth weight of twins, and ozone had a more pronounced impact on the birth weight of the smaller fetuses (-18.28 g, 95% CI: -27.22, -9.34) compared to the larger fetuses (-9.88 g, 95% CI: -18.84, -0.92) in twin pregnancies. An IQR increase in ozone exposure during the entire pregnancy was associated with a significant increase (8.41 g, 95% CI: 4.13, 12.69) in the within-pair birth weight difference; the odds ratio (OR) of twin growth discordance related to ozone exposure increased by 9% (OR = 1.09, 95% CI: 1.01, 1.18). However, no consistently significant associations were observed for ozone exposure during prepregnancy. Male-male twin pairs and those who were born prematurely appeared to be more susceptible to ozone exposure than their counterparts. Long-term ozone exposure during pregnancy was associated with twin growth discordance, and our findings provide reference data for future studies.

Association of developmental coordination disorder with early-life exposure to fine particulate matter in Chinese preschoolers.

Although fine particulate matter (PM2.5) is a neurotoxicant, little is known about whether early-life PM2.5 exposure is associated with an increased risk of developmental coordination disorder (DCD). We conducted a cohort study of 109 731 children aged 3-5 years from 551 county-level cities in China between April 2018 and December 2019. Residential PM2.5 exposure was estimated using a hybrid satellite-based exposure model. Children's motor performance was assessed using the Little DCD Questionnaire (LDCDQ). Linear mixed-effect models and generalized linear mixed models with a binomial distribution were used to examine the associations of PM2.5 exposure with LDCDQ scores and risk of DCD, respectively. Both prenatal and postnatal exposure to a higher level of PM2.5 was significantly associated with reduced total LDCDQ score, and the impacts were evident on subscales of control during movement and general coordination function but not fine motor function. For example, an interquartile range increase in PM2.5 exposure in ages 0-3 was associated with a 0.19 (95% confidence interval [CI]: 0.05, 0.33) decrement in the total score. Additionally, higher PM2.5 exposure was associated with increased risk of DCD, and the adjusted odds ratios were 1.06 (95% CI: 1.01, 1.10) and 1.06 (95% CI: 1.01, 1.13) for each interquartile range increase in PM2.5 exposure during the first trimester and the first 3 years, respectively. Children who were from rural areas, had neonatal intensive care unit admission, or were exclusively breastfed for less than 6 months appeared to be more susceptible to PM2.5 exposure than their counterparts. Our findings provide robust evidence that early-life PM2.5 exposure contributes to an elevated risk of DCD.