Casey Morgan Luc, Gloria C Chi, Rudy Patrick, Vicki Y Chiu, Matt Feaster, Sara Y Tartof
Blood lead testing rates changed little over time, whereas BLLs ≥3.5 μg/dL declined. However, differences in BLL ≥3.5 μg/dL persisted across sociodemographic groups, and a clinically important number of children continued to have elevated levels. Ongoing strategic prevention efforts remain important to reduce childhood lead exposure in Southern California.
BACKGROUND: Lead exposure can cause long-term developmental deficits in children. We examined associations between sociodemographic characteristics and blood lead testing and levels in Southern California, where environmental lead hazards might exacerbate blood lead risk.
METHODS: We conducted a population-based analysis using repeated annual observations among Kaiser Permanente Southern California (KPSC) members aged 6-30 months from January 1, 2016-September 30, 2025 (with 2025 observations available through September only) to assess trends over time. Measured exposures included individual- and neighborhood-level sociodemographic characteristics. Outcomes included receipt of blood lead testing and blood lead levels (BLLs) ≥3.5 μg/dL. Modified Poisson regression with generalized estimating equations was used to estimate adjusted prevalence ratios (aPRs), accounting for age, sex, race and ethnicity, county, Medi-Cal status, neighborhood deprivation index (NDI), and year.
RESULTS: Among 923,144 KPSC annual records from 529,869 unique children, testing was relatively stable over time, with a modest ∼1% annual decline (aPR, 0.99; 95% CI: 0.98-0.99). Testing was more common among Medi-Cal recipients and children residing in higher NDI quartiles. Among 324,291 total tests (277,361 unique children), 0.7% of tests had BLLs ≥3.5 μg/dL (n=2,134), and prevalence declined over time (aPR, 0.91; 95% CI: 0.88-0.94). BLLs ≥3.5 μg/dL were lower among Hispanic children compared with non-Hispanic White children, with variation observed by Medi-Cal status and NDI.
CONCLUSIONS: Blood lead testing rates changed little over time, whereas BLLs ≥3.5 μg/dL declined. However, differences in BLL ≥3.5 μg/dL persisted across sociodemographic groups, and a clinically important number of children continued to have elevated levels. Ongoing strategic prevention efforts remain important to reduce childhood lead exposure in Southern California.