title: Fetal growth and maternal exposure to particulate air pollution--More marked effects at lower exposure and modification by gestational duration.
abstract: While there is growing evidence that air pollution reduces fetal growth, results are inconclusive with respect to the gestational window of effect. We investigated maternal exposure to particulate matter (PM10) in association with birth weight and fetus growth with a focus on the shape of the association and gestational age at birth as a potential effect modifier. The study population consisted of 525,635 singleton live births in Flanders (Belgium) between 1999 and 2009. PM10 exposure at maternal residence was averaged over various time windows. We used robust linear and logistic regression to estimate the effect of PM10 on birth weight and small for gestational age (SGA). Segmented regression models were applied for non-linear associations. Among moderately preterm (32-36 weeks) and term (>36 weeks) births, we found significant lower birth weight for all studied time windows. The estimated reduction in birth weight for a 10 µg/m(3) increase in average PM10 during pregnancy was 39.0 g (95% confidence interval [CI]: 26.4, 51.5 g) for moderately preterm births and 24.0 g (95% CI: 20.9, 27.2g) for term births. The corresponding odds ratios for SGA were 1.19 (95% CI: 1.07, 1.32) and 1.09 (95% CI: 1.06, 1.12) respectively. Segmented regression models showed stronger effects of PM10 on fetal growth at lower concentrations. Maternal PM10 exposure was significantly associated with a reduction in fetal growth among term and moderately preterm births, with a tendency of stronger effects for the latter and a flattening out of the slope at higher PM10 concentrations.
authors.affiliation: Centre for Environmental Sciences, Hasselt University, Agoralaan gebouw D, 3590 Diepenbeek, Belgium.
authors.forename: Ellen
authors.initials: E
authors.lastname: Winckelmans
authors.affiliation: Centre for Environmental Sciences, Hasselt University, Agoralaan gebouw D, 3590 Diepenbeek, Belgium.
authors.forename: Bianca
authors.initials: B
authors.lastname: Cox
authors.affiliation: Study Centre for Perinatal Epidemiology, Hallepoortlaan 27, 1060 Brussel, Belgium.
authors.forename: Evelyne
authors.initials: E
authors.lastname: Martens
authors.affiliation: Belgian Interregional Environment Agency, Kunstlaan 10-11, 1210 Brussel, Belgium.
authors.forename: Frans
authors.initials: F
authors.lastname: Fierens
authors.affiliation: Department of Public Health and Primary Care, Environment and Health, University of Leuven (KU Leuven), Kapucijnenvoer 35 blok d, box 7001, 3000 Leuven, Belgium.
authors.forename: Benoit
authors.initials: B
authors.lastname: Nemery
authors.affiliation: Centre for Environmental Sciences, Hasselt University, Agoralaan gebouw D, 3590 Diepenbeek, Belgium; Department of Public Health and Primary Care, Environment and Health, University of Leuven (KU Leuven), Kapucijnenvoer 35 blok d, box 7001, 3000 Leuven, Belgium. Electronic address: tim.nawrot@uhasselt.be.
authors.forename: Tim S
authors.initials: TS
authors.lastname: Nawrot
mesh_terms: D000328:Adult; D001530:Belgium; D004305:Dose-Response Relationship, Drug; D005260:Female; D047109:Fetal Development; D006801:Humans; D018811:Maternal Exposure; D052638:Particulate Matter / Q000008:administration & dosage / Q000633:toxicity*
chemical_list: D052638:Particulate Matter
keywords: Air pollution; Birth weight; Fetal growth; Gestational age; PM(10)