January 14, 2011 (Heidelberg, Germany) — The preschool children of smokers have a 20% increased risk of having blood pressure in the highest normal value even after other risk factors are adjusted for, new research from Germany shows . This is the first study to show that breathing tobacco smoke increases the BP of children as young as four or five, say Dr Giacomo D Simonetti (University of Berne, Switzerland) and colleagues in their paper published online January 10, 2011 in Circulation.
Simonetti, who conducted the research while working at the University of Heidelberg in Germany, told heartwire : "Parental smoking is not only negative for children's lung function, it poses a risk to their future cardiovascular health.
We know childhood BP tracks to adult BP, so the most important conclusion here is that if you avoid risk factors--such as secondhand smoke--as a child, you will have lower BP and probably lower BP values as an adult."
The findings "complete the picture of tobacco exposure interfering with cardiovascular maturation and health from gestation to adulthood," say Simonetti and colleagues.
He adds that parents should be counseled to stop smoking, as the benefits would likely extend even to the youngest family members.
And at the very least, a strictly smoke-free environment should be implemented in the home.
Maternal Smoking Had More Impact Than Paternal Smoking
In an extension of a standard school health exam, Simonetti and colleagues measured the BP of 4236 kindergarten boys and girls (average age 5.7). Parents had to say whether they smoked or not: in 28.5% of the families the father smoked; in 20.7% it was the mother; and in 11.9% of cases, both parents were smokers. The mean number of cigarettes smoked per day was 11.6 for mothers and 13.9 for fathers.
Children with a smoking parent were 21% more likely to have systolic blood pressure in the highest normal value (ie, above the 85th percentile). Although this is a small BP-raising effect, it was consistent and remained significant event even after adjustment for all known risk factors that could influence BP--including body-mass index and height of the children and whether the mother suffered from pregnancy-related hypertension, for example.
Simonetti said they did not try to differentiate between people who did not smoke in the home and those who did, because this would have been too difficult to determine. Of interest, smoking by mothers had a larger impact than smoking by fathers, probably because more of their smoking was done in the home, while fathers smoked more at their workplaces, he suggests.
"Smoking adds to other risk factors," says Simonetti. "Passive smoking increased the risk of having blood pressure at the upper end of normal, and some of these children already had high blood pressure."
"The findings of this study add an important pediatric perspective to the issue of prevention and containment of active and passive smoking," he and his colleagues conclude.