Being exposed to secondhand smoke places boys at an increased risk of having higher blood pressure levels and subsequently developing hypertension later on in life.
University of Minnesota researchers reviewed data from four US national studies focusing on the exposure of 6,421 children to secondhand smoke.
The findings showed that boys aged 8 to 17, who passively inhaled tobacco smoke, had 1.6 mmHg higher systolic blood pressure values than their counterparts who were not exposed to smoke, scientists reported at the annual meeting of the Pediatric Academic Societies specialists in Denver.
Systolic blood pressure is the first or higher number in a blood pressure reading that shows the pressure that blood exerts on the walls of the blood vessels as it passes through them.
According to the findings, children living with smokers have higher blood levels of cotinine, a metabolite of Nicotine produced in the body of the people exposed to tobacco smoke.
The study also showed that unlike boys, girls exposed to secondhand smoke have 1.8 mmHg on average lower systolic blood pressure values than their peers who were not.
"These findings support several previous studies suggesting that something about female gender may provide protection from harmful vascular changes due to secondhand smoke exposure," said lead author Jill Baumgartner.
Scientists believe the acute effect of secondhand exposure on blood may be secondary to the particles found in smoke that inappropriately stimulate the sympathetic nervous system. In addition, tobacco may cause systemic inflammation and oxidative stress in long-term.
However, Baumgartner noted "we know that elevated blood pressure in childhood is a predictor of adult hypertension, so from that standpoint, understanding what the risk factors are early in life is important so that preventative measures can be taken."
"Given that you have almost 50 percent of the world's children who are exposed to secondhand smoke, there could be considerable impact of even a small increase in blood pressure," she added.
