Ambient air pollution and low birthweight: a European cohort study (ESCAPE)

Dr Marie Pedersen PhD a b c

, Lise Giorgis-Allemand MSc c d, Claire Bernard MSc c d, Inmaculada Aguilera PhD a b, Prof Anne-Marie Nybo Andersen PhD e, Prof Ferran Ballester PhD b f g h, Rob M J Beelen PhD i, Leda Chatzi PhD j, Marta Cirach MSc a, Asta Danileviciute PhD l, Audrius Dedele PhD l, Manon van Eijsden PhD m, Marisa Estarlich PhD b h, Ana Fernández-Somoano PhD b n, Mariana F Fernández PhD b o, Prof Francesco Forastiere PhD p, Ulrike Gehring PhD i, Prof Regina Grazuleviciene PhD l, Olena Gruzieva PhD q, Barbara Heude PhD r s, Gerard Hoek PhD i, Kees de Hoogh PhD t, Edith H van den Hooven MSc u, Siri E Håberg PhD v, Vincent W V Jaddoe PhD u, Claudia Klümper PhD w, Michal Korek MSc q, Ursula Krämer PhD w, Aitana Lerchundi PhD x, Johanna Lepeule PhD c d y, Prof Per Nafstad PhD v z, Wenche Nystad PhD v, Evridiki Patelarou PhD j aa, Daniela Porta PhD p, Prof Dirkje Postma PhD ab, Ole Raaschou-Nielsen PhD ac, Peter Rudnai MD ad, Prof Jordi Sunyer PhD a b ae, Prof Euripides Stephanou PhD k, Mette Sørensen PhD ac, Elisabeth Thiering PhD af, Prof Derek Tuffnell FRCOG ag, Mihály J Varró MD ad, Tanja G M Vrijkotte PhD ah, Alet Wijga PhD ai, Michael Wilhelm PhD aj, John Wright FRCP ag, Prof Mark J Nieuwenhuijsen PhD a b, Prof Göran Pershagen PhD q ak, Prof Bert Brunekreef PhD i al, Prof Manolis Kogevinas PhD a b am an †, Rémy Slama PhD c d †

Summary

Background

Ambient air pollution has been associated with restricted fetal growth, which is linked with adverse respiratory health in childhood. We assessed the effect of maternal exposure to low concentrations of ambient air pollution on birthweight.

Methods

We pooled data from 14 population-based mother—child cohort studies in 12 European countries. Overall, the study population included 74 178 women who had singleton deliveries between Feb 11, 1994, and June 2, 2011, and for whom information about infant birthweight, gestational age, and sex was available. The primary outcome of interest was low birthweight at term (weight <2500 2="" 37="" aerodynamic="" after="" an="" at="" birth="" class="ja50-ce-inf" concentrations="" diameter="" g="" gestation="" less="" m="" matter="" mean="" of="" particulate="" span="" than="" weeks="" with="">2·5

), less than 10 μm (PM10), and between 2·5 μm and 10 μm during pregnancy were estimated at maternal home addresses with temporally adjusted land-use regression models, as was PM2·5 absorbance and concentrations of nitrogen dioxide (NO2) and nitrogen oxides. We also investigated traffic density on the nearest road and total traffic load. We calculated pooled effect estimates with random-effects models.

Findings

A 5 μg/m3 increase in concentration of PM2·5 during pregnancy was associated with an increased risk of low birthweight at term (adjusted odds ratio [OR] 1·18, 95% CI 1·06—1·33). An increased risk was also recorded for pregnancy concentrations lower than the present European Union annual PM2·5 limit of 25 μg/m3 (OR for 5 μg/m3 increase in participants exposed to concentrations of less than 20 μg/m3 1·41, 95% CI 1·20—1·65). PM10 (OR for 10 μg/m3 increase 1·16, 95% CI 1·00—1·35), NO2 (OR for 10 μg/m3 increase 1·09, 1·00—1·19), and traffic density on nearest street (OR for increase of 5000 vehicles per day 1·06, 1·01—1·11) were also associated with increased risk of low birthweight at term. The population attributable risk estimated for a reduction in PM2·5 concentration to 10 μg/m3 during pregnancy corresponded to a decrease of 22% (95% CI 8—33%) in cases of low birthweight at term.

Interpretation

Exposure to ambient air pollutants and traffic during pregnancy is associated with restricted fetal growth. A substantial proportion of cases of low birthweight at term could be prevented in Europe if urban air pollution was reduced.