Ambient PM2.5, household environment and preterm birth: A birth cohort study in Shandong, China

Abstract

BackgroundThe associations between fine particulate matter with an aerodynamic diameter of 2.5 μm or less (PM2.5) and risk of preterm birth (PTB) are inconsistent, and the effect of household environment on PTB is largely unclear. AimTo investigate the association of ambient PM2.5 throughout pregnancy, household environmental factors and PTB, with further exploration of their potential interaction and joint effect on PTB. MethodsThe study included 5888 pregnant women between 2018 and 2021 in Weifang Maternal and Child Health hospital of Shandong, China. Maternal exposure to PM2.5 was extracted from ChinaHighAirPollutants datasets according to individual home address. Household environmental information including residential floor level, double-glazed window, heating fuel, cooking, smoking and window ventilation was collected by questionnaires at enrollment. PTB was defined as a birth before 37 completed weeks of gestation. General additive models were applied to examine the associations of PM2.5 exposure, household environment and PTB. ResultsOne-unit increase of PM2.5 throughout pregnancy was associated with significantly increased risk of PTB (OR = 1.069, 95% CI: 1.037, 1.103). In contrast, installation of double-glazed windows (OR = 0.763, 95% CI: 0.589, 0.990) and residential floor level of the 5th floor or above (OR = 0.746, 95% CI: 0.583, 0.955) were found to be associated with significantly reduced risk of PTB. The stratified analyses demonstrated that the protective associations remained among those with high PM2.5 exposure, urban residence, middle SES level and cesarean delivery. A negative interaction between residential floor level and PM2.5 exposure on PTB, and joint effect of installation of double-glazed windows plus residential floor level of the 5th floor or above on PTB were observed. ConclusionsThis study found the adverse effect of PM2.5 during the pregnancy on PTB, and identified protective associations between installing double-glazed windows, living on the 5th floor or above and PTB in relatively polluted regions.