Researchers have found that passive smoking raises blood pressure in boys and decreases it in girls, reports the Guardian.
Researchers at the University of Minnesota’s Institute on the Environment collected data on passive smoking from questionnaires conducted by the U.S. Centers for Disease Control and Prevention between 1996 and 2006.
The surveys collected information on children aged 8 to 17, and noted who lived with smokers and the levels of cotinine in a child’s blood. Cotinine is a byproduct of the body’s metabolism of nicotine and is seen as a reliable marker for exposure to tobacco smoke.
The study found an average rise of 1.6 mmHg – or a 1 percent increase on average healthy levels – in the systolic blood pressure of boys who had been exposed to secondhand smoke compared to boys who had not. Girls who had been exposed to cigarette smoke had the opposite response, about a 1 percent decrease in blood pressure.
“While the increases in blood pressure observed among boys in our study may not be clinically meaningful for an individual child, they have large implications for populations,” lead researcher Jill Baumgartner said in statement. “Over one-third of children in the U.S. and globally are exposed to secondhand smoke levels similar to those associated with adverse cardiovascular effects in our study."
“These findings support several previous studies suggesting that something about female gender may provide protection from harmful vascular changes due to secondhand smoke exposure," she said. "An important next step is to understand why."