Kidney function and tobacco smoke exposure in US adolescents.

Active smoking and secondhand smoke (SHS) are known risk factors for kidney disease in adults. We evaluated the association between exposure to active smoking or SHS and kidney function in US adolescents. This is a cross-sectional study in 7516 adolescents aged 12-17 who participated in NHANES 1999-2010 and had serum creatinine and cotinine measures. Active smoking was defined as self-reported smoking or serum cotinine concentrations >10 ng/mL. SHS was defined as nonactive smokers who self-reported living with ≥1 smokers or serum cotinine concentrations ≥ 0.05 ng/mL. Kidney function was determined by using the chronic kidney disease in children estimated glomerular filtration rate (eGFR) equation. Median (interquartile range) eGFR and serum cotinine concentrations were 96.8 (85.4-109.0) mL/minute per 1.73 m(2) and 0.07 (0.03-0.59) ng/mL, respectively. After multivariable adjustment, eGFR decreased 1.1 mL/minute per 1.73 m(2) (95% confidence interval [CI]: -1.8 to -0.3) per interquartile range increase in serum cotinine concentrations. The mean (95%CI) difference in eGFR for serum cotinine tertiles 1, 2, and 3 among children exposed to SHS compared to unexposed were -0.4 (-1.9 to 1.2), -0.9 (-2.7 to 0.9), and -2.2 (-4.0 to -0.4) mL/minute per 1.73 m(2), respectively (P = .03). The corresponding values among tertiles of active smokers compared to unexposed were 0.2 (-2.2 to 2.6), -1.9 (-3.8 to 0.0), and -2.6 (-4.6 to -0.6) mL/minute per 1.73 m(2) (P = .01). Tobacco smoke exposure was associated with decreased eGFR in US adolescents, supporting the possibility that tobacco smoke effects on kidney function begin in childhood.