Polycyclic Aromatic Hydrocarbons and Birth Outcomes in Mexico City

Principal Investigator

Marie O'Neill

Co-Investigators

Brisa Sánchez, Felipe Vadillo-Ortega, Leonora Rojas-Bracho, Alvaro Osornio-Vargas, Deliang Tang

Funding Sources

National Institutes of Health (NIH) National Institute for Environmental Health Sciences (NIEHS)

About this Project

The size and weight of a baby at birth are important determinants of its survival and future health across the life course. Although multiple factors influence birth weight and size, air pollution exposure during pregnancy has been recently explored as a contributor. Millions of women are exposed to ambient air pollution, and levels can be especially high in developing countries. Reducing infant mortality is one of the Millenium Development Goals, so the public health importance of understanding and minimizing environmental contributors to poor birth outcomes is great. Most published epidemiology studies are based on population birth registries and lack the individual, clinical data and repeated measures needed to elucidate possible biological mechanisms mediating epidemiological associations between pollution and adverse birth outcomes. This proposed work presents a unique opportunity to study those mechanisms in a new cohort of 800 pregnant women residing in diverse regions of Mexico City, a mega-city with high air pollution levels. We will investigate how air pollution and the polycyclic aromatic hydrocarbon (PAH) component of particles can influence the outcome of pregnancy, and whether certain periods of gestation represent critical time windows and opportunities for preventive intervention. We will obtain biomarkers relevant to PAH exposure in blood samples provided by participants monthly during their pregnancies, and umbilical cord blood obtained at birth. We will also collect information on health history, clinical characteristics, tobacco smoke exposure, diet and time-activity patterns. Simultaneously, we will estimate spatial and temporal variability in air pollution exposure with data from the Mexico City Metropolitan Area (MCMA) air quality monitoring network, matched to the exact locations of participants' homes. DNA samples from mother and infant will be used to type genetic polymorphisms relevant to the hypothesized mechanisms.