Longitudinal associations of in utero and early life near-roadway air pollution with trajectories of childhood body mass index

Jeniffer S Kim,Rima Habre,Tanya L Alderete,Fred Lurmann,Zhanghua Chen,Kiros Berhane,Ed Rappaport,Frank D Gilliland

doi:10.1186/s12940-018-0409-7

Abstract

BackgroundEvidence suggests that childhood near-roadway air pollution (NRAP) exposures contribute to increased body mass index (BMI); however, effects of NRAP exposure during the vulnerable periods including in utero and first year of life have yet to be established. In this study, we examined whether exposure to elevated concentrations of NRAP during in utero and/or first year of life increase childhood BMI growth.MethodsParticipants in the Children’s Health Study enrolled from 2002 to 2003 with annual visits over a four-year period and who changed residences before study entry were included (n = 2318). Annual height and weight were measured and lifetime residential NRAP exposures including in utero and first year of life periods were estimated by nitrogen oxides (NOx) using the California line-source dispersion model. Linear mixed effects models assessed in utero or first year near-road freeway and non-freeway NOx exposures and BMI growth after adjusting for age, sex, race/ethnicity, parental education, Spanish questionnaire, and later childhood near-road NOx exposure.ResultsA two-standard deviation difference in first year of life near-road freeway NOx exposure was associated with a 0.1 kg/m2 (95% confidence interval (CI): 0.03, 0.2) faster increase in BMI growth per year and a 0.5 kg/m2 (95% CI: 0.02, 0.9) higher attained BMI at age 10 years.ConclusionsHigher exposure to early life NRAP increased the rate of change of childhood BMI and resulted in a higher attained BMI at age 10 years that were independent of later childhood exposures. These findings suggest that elevated early life NRAP exposures contribute to increased obesity risk in children.

Highlights

Evidence suggests that childhood near-roadway air pollution (NRAP) exposures contribute to increased body mass index (BMI); effects of NRAP exposure during the vulnerable periods including in utero and first year of life have yet to be established
These studies suggest that elevated NRAP exposures during early life and childhood may increase future obesity risk, studies have not been entirely consistent as a European birth cohort recently reported no association of first 4 years of life NRAP exposure and childhood obesity at 4 years and 8 years of age [15]
Children were predominately Hispanic (56%) or Non-Hispanic White (33%), where 22% of the parents completed the baseline questionnaire in Spanish, which was used a marker of recent immigration status

Summary

Introduction

Evidence suggests that childhood near-roadway air pollution (NRAP) exposures contribute to increased body mass index (BMI); effects of NRAP exposure during the vulnerable periods including in utero and first year of life have yet to be established. Recent data from the Boston Birth Cohort showed that in utero and early life exposures to ambient, fine particulate matter ≤2.5 μm in diameter (PM2.5) were significantly associated with increased risk of childhood overweight or obesity in children 2–9 years of age [14]. These studies suggest that elevated NRAP exposures during early life and childhood may increase future obesity risk, studies have not been entirely consistent as a European birth cohort recently reported no association of first 4 years of life NRAP exposure and childhood obesity at 4 years and 8 years of age [15]

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