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. 2021 Dec 1;175(12):1252-1260.
doi: 10.1001/jamapediatrics.2021.3518.

Individual- and Community-Level Factors Associated With Detectable and Elevated Blood Lead Levels in US Children: Results From a National Clinical Laboratory

Marissa Hauptman  1   2 , Justin K Niles  3 , Jeffrey Gudin  3   4 , Harvey W Kaufman  3
Affiliations

Individual- and Community-Level Factors Associated With Detectable and Elevated Blood Lead Levels in US Children: Results From a National Clinical Laboratory

Marissa Hauptman et al. JAMA Pediatr. .

Abstract

Importance: No safe level of exposure to lead has been identified.

Objective: To evaluate individual- and community-level factors associated with detectable and elevated blood lead levels (BLLs) in children.

Design, setting, and participants: This cross-sectional, retrospective study analyzed deidentified results from blood lead tests performed at a large clinical laboratory from October 1, 2018, to February 29, 2020. Participants were 1 141 441 children younger than 6 years living in all 50 US states and the District of Columbia who underwent blood lead testing during the study period. Children who underwent lead testing of unknown source and those with elevated BLLs who received capillary blood lead testing without confirmatory venous testing were excluded.

Exposures: Individual demographic categories included sex, age, and insurance type; community-level demographic categories included pre-1950s housing, poverty, predominant race and ethnicity, and geographical regions.

Main outcomes and measures: Proportions of children with detectable (≥1.0 μg/dL) and elevated (≥5.0 μg/dL) BLLs, by exposure category.

Results: Of the 1 141 441 children (586 703 boys [51.4%]; mean [SD] age, 2.3 [1.4] years) in the study, more than half of the children tested (576 092 [50.5%; 95% CI, 50.4%-50.6%]) had detectable BLLs, and 21 172 children (1.9% [95% CI, 1.8%-1.9%]) had BLLs of 5.0 μg/dL or more. In multivariable analyses, children with public insurance had greater odds of having detectable BLLs (adjusted odds ratio [AOR], 2.01 [95% CI, 1.99-2.04]) and elevated BLLs (AOR, 1.08 [95% CI, 1.04-1.12]). The proportion of children with detectable and elevated BLLs increased significantly for progressive pre-1950s housing and poverty quintiles (P < .001). The odds of detectable BLLs were significantly higher among children in the highest vs lowest quintile of pre-1950s housing (AOR, 1.65 [95% CI, 1.62-1.68]) and of poverty (AOR, 1.89 [95% CI, 1.86-1.93]). A similar association was found for those with elevated BLLs, with an AOR of 3.06 (95% CI, 2.86-3.27) for the highest vs lowest quintile of pre-1950 housing and 1.99 (95% CI, 1.88-2.11) for the highest quintile of poverty. Children residing in zip codes with predominantly Black non-Hispanic and non-Latinx populations had higher odds of detectable BLLs (AOR, 1.13 [95% CI, 1.11-1.15]) but lower odds for elevated BLL (AOR, 0.83 [95% CI, 0.80-0.88]).

Conclusions and relevance: This study suggests that, despite progress in reducing pediatric lead exposure, substantial individual- and community-level disparities persist.

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Conflict of interest statement

Conflict of Interest Disclosures: Dr Hauptman reported receiving grants from the National Institutes of Health/National Institute of Environmental Health Sciences during the conduct of the study; and grants from the Agency for Toxic Substances and Disease Registry and the US Environmental Protection Agency outside the submitted work. Mr Niles reported receiving salary from Quest Diagnostics during the conduct of the study. Dr Gudin reported serving as a consultant for Quest Diagnostics during the conduct of the study. Dr Kaufman reported receiving salary from and having stock ownership in Quest Diagnostics outside the submitted work.

Figures

Figure 1.
Figure 1.. Children With Detectable or Elevated Blood Lead Levels by State
A, Percentage of children with detectable blood lead levels. B, Percentage of children with elevated blood lead levels. Analysis limited to states and the Discrict of Columbia with results for more than 500 children. Detectable blood lead level, 1.0 μg/dL or more; elevated blood lead level, 5.0 μg/dL or more (to convert to micromoles per liter, multiply by 0.0483).
Figure 2.
Figure 2.. Distribution of Blood Lead Levels Based on Risk Factor Quintiles Assessed by Zip Code
A, Pre-1950s housing quintile; 6778 missing estimates. B, Poverty quintile; 6901 missing estimates. C, Predominant race and ethnicity. “Predominant” refers to zip codes with estimated proportions of the given race and ethnicity over 50%. To convert blood lead levels to micromoles per liter, multiply by 0.0483. Cochran-Armitage test for trend, P < .001 for progressive quintiles of pre-1950s housing construction (A) and poverty (B) within each blood lead measurement level.
Figure 3.
Figure 3.. Factors Associated With Detectable Blood Lead Levels in Children Younger Than 6 Years: Multivariable Model
Included in this model were 942 428 children, with no values missing for any variable (83% of those included). Area under receiver operator curve = 0.66. AOR indicates adjusted odds ratio. aReference, female. bReference, 5 to 5.9 years. cReference, private payers. dPredominantly White non-Hispanic and non-Latinx populations. eReference, all other zip codes. fReference, pre-1950 housing quintile (Q) 1. gReference, poverty Q1. hReference, southern latitudes.
Figure 4.
Figure 4.. Factors Associated With Elevated Blood Lead Levels in Children Younger Than 6 Years: Multivariable Model
Included in this model were 942 428 children, with no values missing for any variable (83% of those included). Area under receiver operator curve = 0.68. AOR indicates adjusted odds ratio. aReference, female. bReference, 3 to 5.9 years. cReference, private payers. dPredominantly White non-Hispanic and non-Latinx populations. eReference, all other zip codes. fReference, pre-1950 housing quintile (Q) 1. gReference, poverty Q1. hReference, southern latitudes.
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