Locally derived traffic-related air pollution and fetal growth restriction: a retrospective cohort study
- 1Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Subiaco, Western Australia, Australia
- 2School of Population Health, The University of Western Australia, Crawley, Western Australia, Australia
- 3The Department of Surgery, The Ottawa Hospital Research Institute, The University of Ottawa, Ottawa, Canada
- 4Perinatal Research, Kolling Institute of Medical Research, University of Sydney, Royal North Shore Hospital, Sydney, New South Wales, Australia
- Correspondence toDr Gavin Pereira Telethon Institute for Child Health Research PO Box 855 West Perth, Western Australia 6872 AustraliaPhone: +61 8 9489 7777Fax: +61 8 9489 7700
Contributors All authors (GP, FH, AGC, CB, NN) were involved in writing the article, interpretation of results and revisions. GP, AGC and NN were additionally involved in the conception and design. GP was also involved in data collection and statistical analysis.
- Accepted 3 July 2012
- Published Online First 31 July 2012
Background Fetal growth restriction has been inconsistently associated with maternal exposure to elevated levels of traffic-related air pollution.
Objective We investigated the relationship between an individualised measure of fetal growth and maternal exposure to a specific marker for traffic-related air pollution.
Methods We estimated maternal residential exposure to a marker for traffic-related air pollution (nitrogen dioxide, NO2) during pregnancy for 23 452 births using temporally adjusted land-use regression. Logistic regression was used to investigate associations with small for gestational age and sex (SGA) and fetal growth restriction, defined as proportion of optimal birth weight (POBW) below the 10th percentile. Sub-populations investigated were: women who spent most time at home, women who did not move house, women with respiratory or circulatory morbidity, women living in low/middle/high socio-economic areas, women who delivered before 37 weeks gestation, and women who delivered from 37 weeks gestation.
Results An IQR increase in traffic-related air pollution in the second trimester across all women was associated with an OR of 1.31 (95% CI 1.07 to 1.60) for fetal growth restriction. Effects on fetal growth restriction (low POBW) were highest among women who subsequently delivered before 37 weeks of gestation. Effects on SGA were highest among women who did not move house: OR 1.35 (95% CI 1.08 to 1.69).
Conclusions Larger effect sizes were observed for low POBW than for SGA. Exposure to traffic-related air pollution in mid to late pregnancy was associated with risk of SGA and low POBW in this study.
- Materials, exposures and occupational groups
- Air pollution
- fetal growth restriction
- traffic emissiosn
- small for gestational age
Funding CB and NN were supported by the National Health and Medical Research Council.
Competing interest None.
Ethics approval The ethics committees of the University of Western Australia and the Department of Health, Western Australia approved this study.
Provenance and peer review Not commissioned; externally peer reviewed.