Warm weather, walkable neighborhoods tied to lower blood pressure in kids

Kids who grow up in warmer climates and in walkable neighborhoods may have lower blood pressure than those who live where it’s cooler and people drive everywhere, a new European study suggests.

Researchers examined data on 1,277 mother-child pairs from the U.K., France, Spain, Lithuania, Norway, and Greece to see how exposures to outdoor factors like air pollution and weather, chemicals like pesticides and metals, and lifestyle factors like diet and exercise impacted blood pressure in kids age 6 to 11 years old. The study team focused on a total of 89 exposures in the womb and 128 exposures during early childhood.

“Our results show that, starting in the fetal stage, where we live, the food we eat, the air we breathe and the chemical compounds that reach our bodies can affect blood pressure before adolescence,” said Charline Warembourg, lead author of the study and a researcher at the Barcelona Institute for Global Health (ISGlobal).

“This is important because evidence shows that children with high blood pressure are more likely to be hypertensive as adults,” Warembourg said by email.

Exposure to negative lifestyle factors in pregnancy, such as obesity, physical inactivity, poor diet, and alcohol and tobacco consumption has long been established as heart disease risk factors for mothers, researchers note in the Journal of the American College of Cardiology.

In the current study, researchers analyzed data from blood and urine tests of young children to see what environmental, chemical and lifestyle factors might be associated with higher or lower blood pressure.

Overall, about one in 10 kids had high blood pressure or slightly elevated test results that suggested they were at risk for developing it.

Kids whose mothers lived in a walkable environment with access to green spaces, shops, restaurants and public transportation during pregnancy were more likely to have normal blood pressure than those whose mothers who lived outside cities or in communities where walking wasn’t possible.

It’s possible that mothers in walkable areas got more exercise during pregnancy, contributing to lower blood pressure for their offspring, the study team concludes.

Exposure to higher temperatures during the time of blood pressure checks was also associated with lower blood pressure in kids.

When kids had prenatal exposure to higher bisphenol-A (BPA) concentrations – a chemical once found in baby bottles and many other plastic products – they had higher blood pressure than children without this exposure in the womb. Children’s own exposure to copper and perfluorooctanoate (PFOA) – a chemical found in cosmetics, cleaners and clothes – were also associated with higher childhood blood pressure.

Eating too little fish, or too much, were both associated with higher blood pressure in kids, the study also found. While the omega-3 fatty acids found in fish are beneficial for overall cardiovascular health, fish contaminated by chemicals or metals could reduce any positive effects of omega-3 fatty acids, the study team notes.

Beyond its small size, other limitations of the study include the potential for children’s blood pressure to have been influenced by factors beyond those examined.

“There is overwhelming and widely known evidence showing that alcohol and smoking during pregnancy adversely affect the fetus, and there is growing evidence that manmade chemicals during pregnancy also may have effects on children,” said Andrea Baccarelli, author of an accompanying editorial and an environmental health researcher at Columbia University Mailman School of Public Health in New York City.

“It is safe to say that being mindful of the high variety of manmade chemicals that can be found in food, plastic, personal care products, etc. is important during pregnancy,” Baccarelli said by email. “However, it is also important to say that this study doesn’t show that these chemicals lead to disease, though the difference in blood pressure found here may be predictive of disease later in life.”