Passive smoking can raise blood pressure levels in boys, scientists have found. This will put them at higher risk in later life of hypertension or high blood pressure, which is associated with a greater chance of heart and kidney disease.
Jill Baumgartner of the University of Minnesota’s Institute on the Environment looked at more than 6 400 children aged eight to 17 who had been exposed to secondhand tobacco smoke. She found a 1% 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.
“For that individual child, it won’t have a huge impact,” said Mike Knapton, associate medical director at the British Heart Foundation. “But if you’ve got two million kids with a 1% increase, you start to see changes in the prevalence of respiratory disease, heart disease and cancer.”
Baumgartner said more than a third of children were exposed to smoke levels associated with adverse effects in her study. Previous research has linked secondhand smoke and increased blood pressure in adults, but the effect had not been measured in children.
Baumgartner showed that girls exposed to secondhand smoke had lower systolic blood pressures than girls who were not. “These findings support several previous studies suggesting that something about female gender may provide protection from harmful vascular changes.”
The researchers collected information on passive smoking from questionnaires conducted by the United States Centres for Disease Control and Prevention between 1996 and 2006. The surveys collected information on levels of cotinine in a child’s blood, which is a byproduct of the metabolism of nicotine by the body.
Baumgartner said the study provided “further incentive for governments to support smoking bans and other legislation that protects children”.
Knapton said passive smoking was only part of the story. “There has been an association between cot death and smoking in the home — 86% of cot deaths occur in families where the mother smokes. We know that children from families that smoke are more likely to smoke themselves.” —