Dr. Alex Chang, MD, MS, Johns Hopkins University Nephrology Fellow
Quitting smoking still remains the most important lifestyle modification one can make to decrease risk of cardiovascular disease, cancer, lung disease, and live longer. Despite strong public health campaigns to reduce smoking over the last few decades, more than 3 million high school students are estimated to smoke cigarettes, and roughly 1 in every 7 adolescents is exposed to secondhand smoke. Less discussed is that smoking appears to increase the risk of chronic kidney disease in adults.
In an article recently published in Pediatrics, researchers from Johns Hopkins investigated the association of smoking exposure with kidney function in a cross-sectional nationally representative sample of U.S. adolescents. Secondhand smoking was defined as living with at least 1 person who smoked, or having an elevated level of cotinine (a breakdown product of nicotine) in their blood. The researchers found that active smoking was associated with slightly lower kidney function and higher amounts of protein in the urine. Interestingly, secondhand smoke exposure was also associated with slightly lower kidney function in this study even after taking account differences in age, sex, weight, demographics and parental education level.
Differences in kidney function observed in the study were relatively small, but these small differences could have important effects on risk of developing hypertension and chronic kidney disease. It should be noted that in this type of study, it is difficult to account for all factors that may also be related to smoking exposure such as diet quality, exposure to other environmental agents toxic to kidneys, and low birth weight.
Still, children exposed to secondhand smoke are at increased risk for asthma, reduced lung function. Perhaps most importantly, children living in smoking households are more likely to take on this harmful habit. Given all the health hazards including possible kidney harm, all efforts should be made to quit smoking. Health benefits are not only tremendous for an individual quitting smoking—but could also have lasting benefits to the health of children in the household.