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Maternal exposure to outdoor air pollution and congenital limb deficiencies in the National Birth Defects Prevention Study
Citation:
Choi, G., J. Stingone, T. Desrosiers, A. Olshan, W. Nembhard, G. Shaw, S. Pruitt, P. Romitti, M. Yazdy, M. Browne, P. Langlois, L. Botto, AND Tom Luben. Maternal exposure to outdoor air pollution and congenital limb deficiencies in the National Birth Defects Prevention Study. ENVIRONMENTAL RESEARCH. Elsevier B.V., Amsterdam, Netherlands, 179(Part A):1-8, (2019). https://doi.org/10.1016/j.envres.2019.108716
Impact/Purpose:
To investigate the relationship between ambient air pollution during early pregnancy and risk of congenital limb deficiencies
Description:
Background: Congenital limb deficiencies (CLDs) are a relatively common group of birth defects whose etiology is mostly unknown. Recent studies suggest maternal air pollution exposure as a potential risk factor. Aim: To investigate the relationship between ambient air pollution during early pregnancy and risk of CLDs. Methods: The study population was identified from the National Birth Defects Prevention Study, a population-based multi-center case-control study, and consisted of 615 CLD cases and 5,701 controls with due dates during 1997 through 2006. Daily averages and/or maxima of six criteria air pollutants (particulate matter <2.5micrometers [PM2.5], particulate matter <10 micrometers [PM10], nitrogen dioxide [NO2], sulfur dioxide [SO2], carbon monoxide [CO], and ozone [O3]) were averaged over gestational weeks 2-8, as well as for individual weeks during this period, using data from EPA air monitors nearest to the maternal address. Logistic regression was used to estimate odds ratios (aORs) and 95% confidence intervals (CIs) adjusted for maternal age, race/ethnicity, education, and study center. We estimated aORs for any CLD and CLD subtypes (i.e., transverse, longitudinal, and preaxial). Potential confounding by co-pollutant was assessed by adjusting for one additional air pollutant. Using the single pollutant model, we further investigated effect measure modification by body mass index, cigarette smoking, and folic acid use. Sensitivity analyses were conducted restricting to those with a residence closer to an air monitor. Results: We observed near-null aORs for CLDs per interquartile range (IQR) increase in PM10, PM2.5, and O3. However, weekly averages of the daily average NO2 and SO2, and daily max NO2, SO2, and CO concentrations were associated with increased odds of CLDs. The ORs ranged from 1.03 to 1.13 per IQR increase in air pollution concentrations, and consistently elevated aORs were observed for CO. Stronger associations were observed for SO2 and O3 in subtype analysis (preaxial). In co-pollutant adjusted models, associations with CO remained elevated (aORs: 1.02-1.30) but aORs for SO2 and NO2 were attenuated. The aORs for CO remained elevated among mothers who did not use folic acid or lived within 20km of an air monitor. Conclusion: We observed an association between CLDs and CO exposures during pregnancy, though replication through further epidemiologic research is warranted.
URLs/Downloads:
DOI: Maternal exposure to outdoor air pollution and congenital limb deficiencies in the National Birth Defects Prevention Study