Tobacco Smoke Linked to Lower eGFR in Teens

Active or passive exposure to tobacco smoke is associated with decreased kidney function in adolescents, according to a study in Pediatrics.

The study included data on 7516 participants, aged 12 to 17 years, in the National Health and Nutrition Examination Survey from 1999 to 2010. All had available data on serum creatinine and cotinine. Active and secondhand smoking were assessed on the basis of self-report or serum cotinine levels above 10 ng/mL or at least 0.05 ng/mL, respectively. The relationships between either type of smoking and estimated GFR (eGFR) were analyzed.

The adolescents had a median eGFR of 96.8 mL/min per 1.73 m2 and a median serum cotinine concentration of 0.07 ng/mL. With multivariable adjustment, each interquartile range increase in serum cotinine (0.03 to 0.59 ng/mL) was associated with a 1.1 mL/min per 1.73 m2 decrease in eGFR.

In comparison with unexposed adolescents, the mean differences in eGFR were −0.4 mL/min per 1.73 m2 in the first tertile of serum cotinine concentration, −0.9 mL/min per 1.73 m2 in the second tertile, and −2.2 mL/min per 1.73 m2 in the third tertile. Among active smokers, the differences by tertile were 0.2, −1.9, and −2.6 mL/min per 1.73 m2, respectively. The association between cotinine and eGFR appeared stronger in boys and in younger and lighter adolescents.

Active and passive smoking are demonstrated risk factors for kidney disease in adults. This cross-sectional study links tobacco smoke exposure to reduced eGFR in adolescents, suggesting that the adverse effects of smoking on kidney function may start in childhood. The authors note that although the associations are modest, they could have a major impact on kidney disease at the population level [Garcia-Esquinas E, et al. Kidney function and tobacco smoke exposure in US adolescents. Pediatrics 2013; 131:e1415–e1423].

July 2013 (Vol. 5, Number 7)