Children exposed to higher levels of air pollution in late pregnancy are at elevated risk of high BP, according to a new research
Children exposed to the highest level of air pollution in the womb during the third trimester were 61 percent more likely to have elevated blood pressure in childhood compared to those exposed to the lowest level.
“Ours is one of the first studies to show breathing polluted air during pregnancy may have a direct negative influence on the cardiovascular health of the offspring during childhood,” said senior author Noel T. Mueller, Ph.D., M.P.H., an assistant professor of epidemiology at the Johns Hopkins University Bloomberg School of Public Health in Baltimore.
Findings were published in the American Heart Association’s journal Hypertension. Â
A total of 1,293 mothers and their children were included in the study. Blood pressure was measured at each childhood physical examination at 3 to 9 years old. A systolic (top number) blood pressure was considered elevated if it was in the highest 10 percent for children the same age on national data. Other risk factors for hypertension like birth weight and maternal smoking were adjusted for in the study.
Results showed that children exposed to the top third level of ambient fine-particulate pollution in the womb during the third trimester were 61 percent more likely to have elevated systolic blood pressure in childhood compared to those exposed to the the bottom third. The association with elevated blood pressure was regardless of whether a child was of low, normal or high birth weight. Mother’s exposure to fine-particulate matter before pregnancy was not associated with blood pressure in her offspring, thus providing evidence of the significant impact of in-utero exposure.
Not only does exposure increase the risk of illness and death in those directly exposed, but it may also cross the placental barrier in pregnancy and effect fetal growth and increase future risks for high blood pressure
The Global Burden of Disease report estimated that 1.1 million deaths in India were linked to PM 2.5 air pollution in 2015. Fine particulate matter of 2.5 microns or less (PM2.5) is a form of air pollution produced by motor vehicles and the burning of oil and coal and has been linked to conditions that can damage  lungs and brains in children. Of the 15 most polluted cities in the world, 14 are in India, according to a WHO report.
“These results reinforce the importance of reducing emissions of PM2.5 in the environment. Not only does exposure increase the risk of illness and death in those directly exposed, but it may also cross the placental barrier in pregnancy and effect fetal growth and increase future risks for high blood pressure,” Mueller said.
A recent UNICEF paper had reported that more than 12 million children under the age of one live in South Asia, where air pollution is at least six times higher than international limits.
