Another study in a sea of papers documenting the harmful effects of air pollution on health has been released by University of Utah Health researchers.
This time, the study found prenatal exposure to ozone pollution may be causing harm to the cognitive development of unborn children.
The study, according to a press release, revealed a strong link between a pregnant mother's ozone exposure having an increased risk in the chances her baby may develop an intellectual disability.
"The body of evidence suggests that it is important that we never take our foot off the gas in terms of working to reduce the levels of air pollution that Utahns are breathing," said Sara Grineski, U of U professor of sociology and lead researcher."We don't want to neglect these issues related to ozone and cognitive health moving forward. Our findings here for Utah suggest a troubling association."
The study, which was published in the November issue of the Journal of Exposure Science & Environmental Epidemiology, is a collaboration between the U of U School of Medicine and the College of Social & Behavioral Science.
Findings are based on data gathered on the Wasatch Front, which is Utah's largest metropolitan area, known for its long struggle with high ozone in the summer and high particulates in the winter. Salt Lake and Davis counties and parts of Weber and Utah counties often are out of compliance with federal ozone standards, Grineski said.
The study concentrated on ozone exposure during pregnancy utilizing exposure data linked to children born between 2003 and 2014 with intellectual disabilities, as well as their sibling and population controls. Researchers studied the dates in each trimester to calculate ozone exposure metrics specific to each child, based on when they were born, where the mother lived during her pregnancy and the length of gestation.
In addition, researchers used the Utah Population Database, maintained by the Huntsman Cancer Center Institute to assist research on genetics, epidemiology, demography, public health and raw ozone data from the U.S. Environmental Protection Agency. With that information, researchers were allowed to look at daily ozone concentration estimates for the nation's counties.
The finding showed the second trimester was the most critical period for ozone exposure, with a 55.3% higher likelihood of intellectual disability compared to full siblings and a 228% increase compared to population controls. Even though the second trimester was the most critical risk, the study found exposure in all three trimesters increased the risk of intellectual disabilities. During the second trimester, the brain of the fetus grows rapidly, with neurons developing at a rate of 250,000 per minute.
"This research emphasizes that ozone exposure during pregnancy is a clear risk factor for intellectual disability," Grineski said. "We were particularly struck by the consistency of the findings across all trimesters and the strength of the sibling-based analysis."
Amanda Bakian, research associate professor of psychiatry at the U of U Huntsman Mental Health Institute, said the study is unique in its use of both population controls and the sibling design.
"Because this is an epidemiological study, it uses observational data," Bakian said. "Sibling designs allow us to control for some of these population factors that just would be really challenging to do. It just gives another layer of robustness of rigor to this study, and that would be very challenging on a population level to do without the Utah Population Database and their access to genealogical data."
Bakin said when it comes to intellectual disability, there's a prevalence estimate of about 1.3% or so, and that has been pretty consistent over time.
"That's 1.3% of the kids that are born in any one year, and we still don't have a great understanding of all the risk factors that are involved," Bakin said. "What are the underlying mechanisms that drive this risk? Having intellectual disability has lifelong implications."