Boys ‘face bigger risk on passive smoking’

In later life this could lead to high blood pressure, or hypertension, and an increased risk of heart disease.

But in girls passive smoking appeared to be associated with a lowering of blood pressure.

The research, involving more than 6,400 young people, is the first to assess the effects of passive smoking on blood pressure in children.

Scientists found that boys aged eight to 17 who were exposed to second hand tobacco smoke had significantly higher blood pressure than those who did not inhale smoke.

Smoke exposure was linked to systolic blood pressure, which relates to surges of blood each time the heart contracts.

But the study also showed that girls who were exposed to second-hand smoke had lower blood pressure than those who were not.

“These findings support several previous studies suggesting that something about female gender may provide protection from harmful vascular changes due to second-hand smoke exposure,” said US researcher Dr Jill Baumgartner, from the University of Minnesota.

“An important next step is to understand why.”

The findings were presented today at the Pediatric Academic Societies’ annual meeting in Denver, Colorado, US.

Researchers analysed data from four health surveys conducted between 1999 and 2006 by the US Centers for Disease Control and Prevention.

Tobacco smoke exposure was assessed from children’s own reports, and levels of the nicotine break down chemical cotinine in their bodies.

Dr Baumgartner said: “The relationship between second-hand smoke exposure and blood pressure observed in our study provides further incentives for governments to support smoking bans and other legislation that protect children from second-hand smoke.”