Exposure to air pollution in the womb is associated with an increased risk for high blood pressure in childhood, researchers report.
The study, in the journal Hypertension, measured air pollution exposure in 1,293 pregnant women by matching each mother’s address with readings from the nearest air quality monitor. Researchers recorded levels of PM 2.5, particles so small that they can enter the lungs and bloodstream.
The investigators found that compared to the one-third of children exposed to the lowest PM 2.5 levels, the one-third exposed to the highest were 61 percent more likely to have high blood pressure between ages 3 and 9. Each 5-microgram per cubic meter increase in PM 2.5 led to a 46 percent increased risk for pediatric hypertension.
The study controlled for the mothers’ age, smoking, blood pressure and other factors as well as for preterm birth, gestational age and other variables in the babies.
The study does not prove cause and effect, but the researchers suggest that air pollution is linked to inflammation in the uterus and placenta, which may help explain the association.
“High blood pressure in children portends high blood pressure in adults, which leads to higher cardiovascular disease risk,” said a co-author, Noel T. Mueller, an assistant professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health. “Air pollution is a major contributor to premature death.”