Early Life Exposure to Outdoor Air Pollution and Cardiometabolic Risk at Preschool Age

Abstract

Introduction Children with elevated cardiometabolic (CM) risk could be at greater risk of suffering cardiovascular disease later in life. Outdoor air pollution has been associated with some components of CM risk in children (eg obesity), but there is few literature on outdoor air pollution exposure and overall CM risk in children. Available findings suggest first trimester of pregnancy and first year of life as critical periods for air pollution exposure and CM risk in children. Our aim is to investigate the association between exposure to outdoor nitrogen dioxide (NO2) in different critical periods and CM risk in preschoolers. Methods We used data from a Spanish population-based birth cohort established between 2003 and 2008 in four regions. First trimester of pregnancy NO2 exposure levels were estimated by land-use regression models, extrapolated in time to exact periods of interest. CM risk components (i.e. body mass index [BMI], systolic blood pressure [SBP], low density lipoprotein [LDL]) were measured at 4 years. We tested the association between NO2 and selected CM risk components using linear regression models adjusted for age, sex and cohort. Results We found no association between an IQR increase in NO2 exposure levels in the first trimester of pregnancy (20.6 μg/m^3) and BMI z-score (N=1721; β=-0.02 [CI95% -0.10,0.07]), SBP (N=1296; β=0.00 [CI95% -0.08,0.08]), and LDL (N=849; β=-1.65 [CI95% -4.41,1.10]). Conclusions Results suggest that there is no association between NO2 exposure in the first trimester of pregnancy and selected individual CM risk components. Further analyses will address the association between exposure to NO2 and particulate matter in two critical periods (first pregnancy trimester and first year) and overall CM risk at 4 years, defined as a latent variable in structural equation models fed with CM components. Other exposure windows will also be explored.