Air pollution is not just a problem for lungs. Increasingly, research suggests air pollution can influence childhood behavioral problems and even IQ. A new study led by the 91爆料 has added evidence showing that both prenatal and postnatal exposure to air pollution can harm kids.
The study, , found that children whose mothers experienced higher nitrogen dioxide聽(NO2) exposure during pregnancy, particularly in the first and second trimester, were more likely to have behavioral problems.
Researchers also reported that higher exposures to small-particle air pollution (PM2.5) when children were 2 to 4 years old was associated with poorer child behavioral functioning and cognitive performance.
鈥淓ven in cities like Seattle or San Francisco, which have a lot of traffic but where the pollution levels are still relatively low, we found that children with higher prenatal NO2 exposure had more behavioral problems, especially with NO2听exposure in the first and second trimester,鈥� said , lead author and a postdoctoral scholar in the Department of Environmental & Occupational Health Sciences.
Investigating the effects of air pollution on health
The 91爆料 Department of Environmental & Occupational Health Sciences is at the forefront of research into the health risks associated with air pollution, which causes 1 in 9 deaths worldwide.
Our research explores how air pollution is associated with a range of health risks鈥攆rom heart and lung diseases to dementia and Alzheimer鈥檚 disease鈥攚ith a special focus on the impacts on vulnerable populations such as children, the elderly and low-income communities.
The study involved data gathered from 1,967 mothers recruited during pregnancy from six cities: Memphis, Tennessee; Minneapolis; Rochester, N.Y.; San Francisco; and two in Washington, Seattle and Yakima. Originally, these participants were enrolled as part of three separate studies: , and . The three studies have been combined under a major NIH initiative called ECHO, which brings together multiple pregnancy cohorts to address key child health concerns. These three combined cohorts are known as the consortium.
The study employed a state-of-the-art model of air pollution levels in the United States over time and space that was developed at the 91爆料. Using participant address information, the researchers were able to estimate each mother and child鈥檚 exposures during the pregnancy period and early childhood.
Exposure to NO2 and PM2.5 pollution in early life is important to understand, Ni said, because 鈥渢here are known biological mechanisms that can link a mother鈥檚 inhalation of these pollutants to effects on placenta and fetal brain development.鈥�
Furthermore, once the child is born, the first few years are a critical time of ongoing brain development as the number of neural connections explodes and the brain reaches 90% of its future adult size, the researchers write. For young children, inhaled pollutants that invade deep in the lung and enter the central nervous system can cause damage in areas relevant for behavioral and cognitive function.
鈥淭his study reinforces the unique vulnerability of children to air pollution 鈥� both in fetal life where major organ development and function occurs as well as into childhood when those processes continue. These early life perturbations can have lasting impacts on lifelong brain function. This study underscores the importance of air pollution as a preventable risk factor for healthy child neurodevelopment,鈥� said senior author聽Dr.聽, a professor in the 91爆料 School of Public Health and School of Medicine.
More specifically, the researchers found that exposure to PM2.5 pollution was generally associated with more behavioral problems in girls than in boys, and that the adverse effect of PM2.5 exposure in the second trimester on IQ was stronger in boys.
鈥淲e hope the evidence from this study will contribute to informed policymaking in the future,鈥� Ni said. 鈥淚n terms of reducing air pollution, the U.S. has gone a long way under the Clean Air Act, but there are threats to continued improvement in the nation鈥檚 air quality. The evidence suggests there is reason to bring the level of air pollution down even further as we better understand the vulnerability of pregnant women and children.鈥�
Co-authors include Christine Loftus, Michael Young and Marnie Hazlehurst, 91爆料 Department of Environmental and Occupational Health Sciences; Sheela Sathyanarayana, 91爆料 School of Public Health and School of Medicine; Adam Szpiro, 91爆料 Department of Biostatistics; Laura Murphy, Frances Tylavsky and W. Alex Mason, University of Tennessee; Kaja LeWinn and Nicole Bush, University of California San Francisco; and Emily Barrett, Rutgers University. This research was funded by the National Institutes of Health through the ECHO-PATHWAYS consortium.
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For more information, contact Yu Ni at niyu@uw.edu.