BOSTON, June 7 (UPI) -- Children and teens who live in counties banning smoking in public places have much lower levels of a secondhand smoke biomarker, U.S. researchers found.
Study leader Melanie Dove, who received her doctorate in environmental health at Harvard School of Public Health this year, said the team examined data from the 1999-2006 National Health and Nutrition Examination Survey, a cross-sectional survey designed to monitor the health of the U.S. population.
The researchers analyzed the cotinine levels in 11,486 non-smoking children and teens ages 3-19 from 117 counties, both with and without exposure to secondhand smoke in the home.
The study, published in the journal Pediatrics, found children living where smoking is banned at workplaces, colleges and stores had 39 percent lower prevalence of cotinine in their blood -- an indicator of tobacco smoke exposure -- compared to children exposed to secondhand smoke.
"The laws have been shown to reduce exposure to secondhand smoke among adults. Our results show a similar association in children and adolescents not living with a smoker in the home," senior author Gregory Connolly said in a statement.
Children who lived in homes with smokers exhibited little or no benefit from the public smoking bans, the study found.