Ambient Air Pollution, Housing Context, and Birth Outcomes Among Wisconsin Mothers

Abstract

Objectives

To assess the association between air pollution exposure and housing context during pregnancy and adverse birth outcomes.

Methods

We linked air pollution data from the Environmental Protection Agency and housing data from the American Community Survey with birth records from Wisconsin counties over a 9-year period. We calculated average daily pregnancy exposure to fine particulate matter and ozone and modeled its relationship to preterm birth, low birthweight and NICU admission, adjusting for individual characteristics and housing context.

Results

Ozone exposure and housing cost-burden had substantive and statistically significant negative associations with birthweight and gestational age, and positive associations with NICU admission, while a poor-quality housing environment had a significant negative effect on weeks of gestation. Fine particulate matter exposure had a negligible correlation with these outcomes.

Conclusions for practice

An additional tenth of one part-per-million daily average exposure to ozone is associated with a 33 g decrease in birthweight. This decrease in birthweight is about the same size as the association of gestational diabetes (32 g), larger than the association of chronic hypertension (22 g), and about 40% the size of the effect of smoking during pregnancy on birthweight (84 g). Given the magnitudes of the associations with atmospheric ozone and adverse birth outcomes, reducing atmospheric ozone should be a public health priority. Inclusion of controls for housing cost-burden and poor-quality housing reduces the magnitude of the association with mothers who identify as Black, suggesting the importance of these structural factors in understanding adverse birth outcomes by race.

Significance

What is already known on this subject

It is well documented that poor birth outcomes are linked to experiences of social and economic disadvantage, however, environmental correlates of poor birth outcomes are under-researched. Existing research does not account for the ways in which environmental, sociodemographic, and structural factors could confound each other given the concentration of environmental pollutants in communities of color and low-income communities.

What this study adds

In this paper, we account for individual sociodemographic characteristics, access to emergency infant healthcare, and neighborhood housing factors to clarify the independent association of air pollution on birth outcomes in Wisconsin across a nine-year period.