TUESDAY, Oct. 20 (HealthDay News) -- Secondhand smoke brings increased risk of respiratory symptoms even in adolescents who smoke, and secondhand smoke exposure outside the home has dropped substantially for children since the early 1990s, according to two studies published online Oct. 19 in Pediatrics.

Hak-Kan Lai, Ph.D., of the University of Hong Kong, and colleagues analyzed data from 32,506 students, ages 11 through 20 years, who self-reported persistent respiratory symptoms in the past year, secondhand smoke exposure, and smoking status. Current smokers exposed to secondhand smoke at home for one to four and five to seven days weekly had a 50 and 77 percent greater chance of respiratory symptoms, respectively, than youths without exposure. Exposure outside the home was also associated with symptoms, while the link between secondhand smoke and symptoms was stronger in smokers than never-smokers.

Cinzia Marano, Ph.D., of the Centers for Disease Control and Prevention in Hyattsville, Md., and colleagues analyzed data from 5,518 children and adolescents in the 2003 to 2006 National Health and Nutrition Examination Survey. Cotinine levels were found to be much higher in those with home secondhand smoke exposure than those without (1.05 versus 0.05 ng/mL), suggesting that young peoples' exposure outside the home has substantially decreased since the early 1990s.

"The impact of secondhand smoke exposure on public health would be underestimated by not taking into account the effects of secondhand smoke on current smokers. Health promotion programs should aim at secondhand smoke reduction as well as smoking cessation among adolescent smokers," Lai and colleagues conclude.

Abstract - Lai
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Abstract - Marano
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