Prenatal and early life particulate air pollution exposure and respiratory symptoms in childhood

Abstract

OPS 52: Air pollution and respiratory health, Room 110, Floor 1, August 28, 2019, 10:30 AM - 12:00 PM Background: Particulate matter <2.5 microns in diameter (PM2.5) can produce respiratory morbidity starting in utero. Children remain vulnerable in early life as the lung and related systems continue to mature. Here we examine the associations between exposure to prenatal and early life PM2.5 and respiratory outcomes in children and explore sex differences. Methods: We studied 514 mother-child dyads in the Programming Research in Obesity, GRowth, Environment and Social Stressors (PROGRESS) study in Mexico City. Exposure to PM2.5 was estimated using residence in pregnancy and child’s first year of life and a satellite-based spatio-temporal model. The International Study of Asthma and Allergies in Childhood questionnaire was administered at the 4 and 6 year visits. Outcomes included repeated wheeze - defined as report of wheeze in the past year at both visits, and report of wheeze in the past year at the 4 year visit, or at the 6 year visit in separate models. Associations were modeled using distributed lag models with weekly PM2.5 averages, adjusting for child’s sex, mother’s age at enrollment, birth season and maternal asthma. Results: No associations were found between prenatal PM2.5 exposure and respiratory outcomes. We found significant associations between higher PM2.5 exposure during the first year of life and higher cumulative odds of repeated wheeze (OR: 4.25, 95%CI [1.12, 16.07] per 5 µg/m3) and wheezing in the past year at age 6 (OR:3.84, 95%CI [1.49, 9.92] per 5 µg/m3). In sex-stratified models, associations were stronger in boys when compared to girls. Conclusions: Increased PM2.5 during the first year of life was most strongly associated with greater odds of respiratory symptoms later in childhood. Understanding temporal relationships that affect the biological response to air pollution may provide unique insights into mechanisms affecting lung growth and assist in the development of behavioral or policy measures that will reduce exposure.