Trends and variability in blood lead concentrations among US children and adolescents.

Using data from the National Health and Nutrition Examination Survey for the period 2003-2012, the objective of this study was to evaluate trends in blood lead levels (BLL) among children aged 1-5 and 6-11 years and smoker and nonsmoker adolescents aged 12-19 years. Regression models with log10 transformed values of BLLs as dependent variable were fitted to evaluate how gender, race/ethnicity, smoking, and exposure to secondhand smoke at home affect BLLs. Irrespective of age, gender, and race/ethnicity, BLLs declined over the study period (p ≤ 0.01). Overall, adjusted BLLs declined by 0.00114 μg/dL for every 2 years. Children aged 1-5 years had about 50 % higher BLLs than smoker adolescents, about 75 % higher BLLs than nonsmoker adolescents, and about 45 % higher BLLs than children aged 6-11 years. While overall, children aged 1-5 years with BLL ≥ 5 μg/dL made up 3.24 %, 7.8 % non-Hispanic Black children aged 1-5 years had BLL ≥ 5 μg/dL. Males were found to have higher adjusted BLLs than females, and non-Hispanic Blacks were found to have higher adjusted BLLs than non-Hispanic Whites. Higher poverty income ratio was associated with lower adjusted BLLs (β = -0.02916, p < 0.01). Children living in owner-occupied homes had lower adjusted BLLs than children living in renter-occupied homes. BLLs increased with increase in number of smokers smoking inside the home (β = 0.02496, p = 0.02). In conclusion, while BLLs have declined for all age groups, genders, and races/ethnicities, certain races/ethnicities like non-Hispanic Blacks continue to have substantially higher BLLs than non-Hispanic Whites.