Ambient air pollution exposure during pregnancy and cardio-metabolic markers in cord blood: The Healthy Start study

Abstract

BACKGROUND AND AIM: Prenatal air pollution exposure has been associated with adverse cardiometabolic outcomes in childhood. It is unknown whether evidence of metabolic disruption associated with air pollution may be identified at birth. We estimated associations between maternal residential exposure to air pollution during pregnancy and metabolic and lipid biomarkers in cord blood collected at delivery. METHODS: This study included 812 mother-infant pairs enrolled in the prospective, Colorado-based Healthy Start study (2009-2014). Using inverse-distance-weighted interpolation of data obtained from stationary monitors, we estimated daily particulate matter ≤2.5 micrometers (PM2.5) and ozone (O3) concentrations at participant residences. Daily estimates were averaged by trimester, full pregnancy, and the 7- and 30- days prior to delivery. Outcomes were cord blood concentrations of glucose, insulin, leptin, total and high-density lipoprotein cholesterol, free fatty acids, and triglycerides. Glucose-insulin ratio was calculated as an indirect measure of insulin sensitivity. We used multiple linear regression to estimate associations between PM2.5 and O3 and cord blood metabolic and lipid biomarkers. Covariates included maternal, infant, and meteorological characteristics. RESULTS:Higher O3 exposure, during both recent and longer-term exposure periods during pregnancy, was consistently associated with higher insulin and lower glucose-insulin ratio in cord blood. For example, an interquartile range increase in full pregnancy O3 (6.3 ppb) was associated with a 0.12 log-µIU/ml (95% confidence interval: 0.03, 0.21) increase in cord blood insulin, after adjusting for covariates. There was limited evidence supporting positive associations between PM2.5 and leptin and O3 and total cholesterol. There were inverse associations between PM2.5 and triglycerides, during certain periods of pregnancy. CONCLUSIONS:Prenatal air pollution exposure was associated with cardiometabolic biomarkers in cord blood, most notably for O3 and insulin. Future studies should examine whether these changes persist into childhood and their implications on offspring health. KEYWORDS: prenatal exposure, air pollution, lipids, metabolism, neonate