Smoking can do more than damage your lungs and give you bad breath. It's also linked to kidney disease in adults – and possibly in children as well.
A recent study looked at the link between kidney health and secondhand smoke in teenagers.
The researchers found that a link did exist, though they cannot be sure that secondhand smoke exposure causes kidney problems. They found enough evidence to make it worth looking deeper.
The study, led by Esther Garcia-Esquinas, MD, of the Department of Environmental Health Sciences at John Hopkins University Bloomberg School of Public Health, aimed to find out whether chronic kidney disease was a risk for children exposed to secondhand smoke.
The researchers analyzed the data from 7,516 teens, aged 12 to 17, who were participants in the 1999-2010 National Health and Nutrition Examination Survey.
As part of the survey, the teens had their blood tested for creatinine and cotinine. Creatinine is a breakdown product in the body that can be used to determine a person's kidney health.
Cotinine is a chemical found in tobacco and a product created by metabolizing nicotine. Its levels can be used to determine how much tobacco smoke individuals have been exposed to.
Teens who reported that they smoked or those that had cotinine levels over 10 ng/mL were classified as active smokers. Those who lived with at least one smoker or had cotinine levels of at least 0.05 ng/mL were classified as being exposed to secondhand smoke.
The researchers looked at the estimated glomerular filtration rate, or eGFR, measure in the teens based on their creatinine levels. This measurement determines how much blood a person's kidneys are filtering to get a sense of their kidney health.
In this study, the researchers found that the teens' eGFR decreased at the same rate that the individual's cotinine concentration in the blood increased.
This relationship remained even when the researchers took into account the participants' weight and socioeconomic and demographic characteristics.
This finding offers evidence that secondhand smoke might contribute to kidney dysfunction in teens.
"Evidence from studies in adult populations suggest that smoking, particularly heavy smoking and cumulative smoking exposure, is an independent risk factor for chronic kidney disease in both genders, as shown in large, prospective observational studies," the researchers wrote.
However, the data on links between secondhand smoke and kidney disease are still not conclusive. Also, this study had several limitations, including the methods used, since participants may be exposed to other lifestyle factors that influence their kidney health.
The study was published April 8 in the journal Pediatrics. The research was funded by Dr Navas-Acien was supported by the Flight Attendant Medical Research Institute, the Bloomberg Initiative to Reduce Tobacco Use, the US National Cancer Institute and a Río Hortega Research Fellowship from the Instituto de Salud Carlos III, Spain. The authors declared no conflicts of interest.