Smoking may impair kidney function among teens

Exposure to tobacco smoke could negatively affect kidney function in teenagers, researchers warn.
Researchers examined the association between exposure to active smoking and kidney function among US adolescents and found the effects of tobacco smoke on kidney function begin in childhood.
"Tobacco use and exposure to secondhand tobacco smoke are major health problems for adolescents, resulting in short-term and long-term adverse health effects," said Ana Navas-Acien, senior researcher from Johns Hopkins Bloomberg School of Public Health.
"In this nationally representative sample of US adolescents, exposure to tobacco, including secondhand smoke and active smoking, was associated with lower estimated glomerular filtration rates-a common measure of how well the kidneys are working.

"In addition, we found a modest but positive association between serum cotinine concentrations, a bio-marker of tobacco exposure, among first-morning albumin to creatinine ratio. These findings further support the conclusion that tobacco smoke may damage the kidneys," Navas-Acien said in a statement.
Using a cross-sectional study of 7,516 adolescents aged 12 to 17, the researchers assessed participant tobacco use and exposure to secondhand smoke through self-reported data from a home questionnaire and serum cotinine.

Participants who reported having smoked "at least one day" in the last month or "at least one cigarette" in the last month, or those who had serum cotinine concentrations over 10 ng/ml were classified as active smokers.

Secondhand smoke exposure was defined as non-active smokers who reported living with at least one person who smoked, or who had cotinine levels greater than or equal to 0.05 ng/ml, but less than or equal to 10 ng/ml even if they reported not living with a smoker.
Participants with serum cotinine levels below 0.05 ng/ml, not living with a smoker and not smoking in the last month, were classified as unexposed to tobacco.
The study was published in the journal Pediatrics.