Chronic, high-level lead exposure is a known risk factor for kidney disease. The effect of current low-level environmental lead exposure is less well known, particularly among children, a population generally free from kidney disease risk factors such as hypertension and diabetes mellitus. Therefore, in this study, we investigated the association between lead exposure and kidney function in a representative sample of US adolescents.
Participants included 769 adolescents aged 12 to 20 years for whom whole blood lead and serum cystatin C were measured in the Third National Health and Nutrition Examination Survey, conducted from 1988-1994. The association between blood lead level and level of kidney function (glomerular filtration rate [GFR]), determined by cystatin C–based and creatinine-based estimating equations, was examined.
Median whole blood lead level was 1.5 μg/dL (to convert to micromoles per liter, multiply by 0.0483), and median cystatin C–estimated GFR was 112.9 mL/min/1.73 m2. Participants with lead levels in the highest quartile (≥3.0 μg/dL) had 6.6 mL/min/1.73 m2–lower estimated GFR (95% confidence interval, –0.7 to –12.6 mL/min/1.73 m2) compared with those in the first quartile (<1 μg/dL). A doubling of blood lead level was associated with a 2.9 mL/min/1.73 m2–lower estimated GFR (95% confidence interval, –0.7 to –5.0 mL/min/1.73 m2). Lead levels were also associated with lower creatinine-based estimated GFR levels, but the association was weaker than with cystatin C–based GFR and not statistically significant.
Higher blood lead levels in a range below the current Centers for Disease Control and Prevention–designated level of concern (10 μg/dL) were associated with lower estimated GFRs in a representative sample of US adolescents. This finding contributes to the increasing epidemiologic evidence indicating an adverse effect of low-level environmental lead exposure.