ECHO PATHWAYS investigators conducted a study of outdoor air pollution and child IQ in the CANDLE cohort, published in the Sept 2019 issue of Environmental Research. Prior research has suggested that exposure to air pollution prenatally or during early childhood can interfere with healthy neurodevelopment, increasing risk of variety of adverse outcomes throughout childhood, such as behavior problems, diagnosis of ADHD and lower cognitive ability. The findings are largely based in animal studies, however, and evidence in humans is mixed. Also, little is known about factors that may increase susceptibility or protect against neurotoxic effects of air pollution, such as child sex, poverty, or maternal nutrition during pregnancy.
In our study, we leveraged the rich data collection of the CANDLE study, a large sample size, and national air pollution models developed at the University of Washington to investigate these questions. We observed a reduction in child IQ at age 4 associated with higher particulate matter exposure in pregnancy. We also found that these adverse effects appeared to be stronger with lower concentrations of folate, a B-vitamin necessary for many essential cellular functions. This suggests a possible protective effect of prenatal folate on the neurotoxic effects of air pollution; if confirmed with additional research, these findings could hold importance for public health practice.
Dr. Kaja LeWinn, ECHO PATHWAYS PI, was senior author and Dr. Christine Loftus, ECHO PATHWAYS epidemiologist, was first author on this paper. Media coverage included a front page article in The Times of London, a story on KQED, a local radio station in San Francisco, and a story on WKNO, an NPR affiliate in Memphis.