Effects of In Utero and Early Life PM2.5 Exposure on Disease Risk Among Infants and Young Children

Particulate matter with a diameter of 2.5 microns or less (PM2.5), a surrogate estimate of traffic-related air pollution, is widespread and a risk to public health. In-utero exposures to PM2.5 may increase risk of birth defects, the leading cause of infant death during the first year of life in the United States, while early life exposures may increase risk of morbidities, such as bronchiolitis, the leading cause of infant hospitalizations, or otitis media (OM), the most common childhood infection. Infants may be more susceptible to negative PM2.5 effects because they are more likely to be active, breathe more air per pound of body mass, and are still developing. The effects of in utero and early life PM2.5 exposure on the risk of birth defects and infant bronchiolitis and OM are assessed among all births from 2001-2009 using the Pregnancy Early Life Longitudinal Data System (PELL), a Massachusetts birth cohort that has been linked to all subsequent records of clinical encounter. PM2.5 exposure models were based on data from satellite remote sensing, which provide extensive spatial coverage throughout Massachusetts. Findings suggest in utero PM2.5 exposure during specific critical windows of exposure may be associated with risk of specific cardiac defects. Acute early life PM2.5 exposure was associated with risk of infant bronchiolitis and OM clinical encounters, especially among preterm infants. Investigations of chronic PM2.5 exposure indicate null associations with infant bronchiolitis and OM clinical encounters, even after rigorous control for confounding