Urinary 1-hydroxypyrene in pregnant women in a Northeastern U.S. city: socioeconomic disparity and contributions from air pollution sources.

ABSTRACT

BACKGROUND: Maternal exposure to polycyclic aromatic hydrocarbons (PAHs), ubiquitous constituents of air pollution, has been associated with adverse birth outcomes. Yet it remains unclear whether and how socioeconomic status (SES) affects gestational PAH exposure. OBJECTIVE: To examine whether there are socioeconomic disparities in PAHs exposure among pregnant women from Rochester, NY, and if so, to what extent disproportionate proximity to air pollution sources, measured by residential distance to transportation-related sources, contributed to the exposure disparity. METHODS: We measured 1-hydroxypyrene concentrations in 726 urine samples collected from 305 pregnant women up to three samples throughout pregnancy. Residential distances to transportation-related sources were calculated based on participants' home addresses. We used linear mixed-effects models with random intercepts of participants to examine associations between 1-hydroxypyrene, SES indicators, and distance to transportation-related sources. We used structural equation modelling to assess to what extent distance to transportation-related sources contributes to the socioeconomic disparity in 1-hydroxypyrene concentrations. RESULTS: Reduced household income and maternal education level were both significant SES predictors of 1-hydroxypyrene concentrations, after the adjustment for other maternal demographic characteristics. Each interquartile range (IQR) increases in residential proximity to the airport (from 14.3 to 6.0 km), the railroad yard (from 22.3 to 6.0 km), and annual average daily traffic within 300 m (from 3796 to 99,933 vehicles/year) were associated with 15.0% (95%CI 7.0-22.2%), 15.4% (95%CI 6.5-23.5%), and 13.6% (95%CI 4.7-23.3%) increases in 1-hydroxypyrene concentrations, respectively. Proximity to these sources jointly explained 10% (95%CI 1.6-18.4%) of the 1-hydroxypyrene concentration change associated with decreases in SES as a latent variable defined by both household income and education level. IMPACT STATEMENT Our findings suggest that efforts to address disproportionate residential proximity to transportation-related sources may reduce the socioeconomic disparity in PAH exposure.