Blood Lead Levels in U.S. Children Ages 1-11 Years, 1976-2016

Abstract

Background: Lead can adversely affect child health across a wide range of exposure levels. We describe the distribution of blood lead levels (BLLs) in U.S. children ages 1-11 y by selected sociodemographic and housing characteristics over a 40-y period.

Methods: Data from the National Health and Nutrition Examination Survey (NHANES) II (1976-1980), NHANES III (Phase 1: 1988-1991 and Phase II: 1991-1994), and Continuous NHANES (1999-2016) were used to describe the distribution of BLLs (in micrograms per deciliter; $1\mu g/\text{dL}=0.0483\mu \text{mol}/L$) in U.S. children ages 1-11 y from 1976 to 2016. For all children with valid BLLs ($n=\mathrm{27,122}$), geometric mean (GM) BLLs [95% confidence intervals (CI)] and estimated prevalence $\ge 5\mu g/\text{dL}$ (95% CI) were calculated overall and by selected characteristics, stratified by age group (1-5 y and 6-11 y).

Results: The GM BLL in U.S. children ages 1-5 y declined from $15.2\mu g/\text{dL}$ (95% CI: 14.3, 16.1) in 1976-1980 to $0.83\mu g/\text{dL}$ (95% CI: 0.78, 0.88) in 2011-2016, representing a 94.5% decrease over time. For children ages 6-11 y, GM BLL declined from $12.7\mu g/\text{dL}$ (95% CI: 11.9, 13.4) in 1976-1980 to $0.60\mu g/\text{dL}$ (95% CI: 0.58, 0.63) in 2011-2016, representing a 95.3% decrease over time. Even so, for the most recent period (2011-2016), estimates indicate that approximately 385,775 children ages 1-11 y had BLLs greater than or equal to the CDC blood lead reference value of $5\mu g/\text{dL}$. Higher GM BLLs were associated with non-Hispanic Black race/ethnicity, lower family income-to-poverty-ratio, and older housing age.

Discussion: Overall, BLLs in U.S. children ages 1-11 y have decreased substantially over the past 40 y. Despite these notable declines in population exposures to lead over time, higher GM BLLs are consistently associated with risk factors such as race/ethnicity, poverty, and housing age that can be used to target blood lead screening efforts. https://doi.org/10.1289/EHP7932.