Lead Service Lines Linked to Higher Lead Levels in Children

Children aged 6 years or younger living in Flint, Michigan, homes with verified lead service lines (LSLs) had higher odds of blood lead level (BLL) threshold exceedances than those in homes with copper service lines (CSLs), according to a retrospective cross-sectional study published in JAMA Network Open. The analysis covered 2010 through 2019, including the Flint water crisis.

Investigators linked capillary and venous BLL records from Michigan Department of Health and Human Services with replacement-verified utility records. Of 19,060 records, 14,349 matched confirmed LSL or CSL addresses; all but 2 were unique child-year observations. Annual exceedances were assessed at 3.5, 5.0, and 10.0 μg/dL, with housing-age adjustment used in a sensitivity analysis.

Among the matched children, mean age was 2.5 years, 50% were male, 33% lived in LSL homes, and 67% lived in CSL homes. In 2014, exceedance rates in LSL homes were 14.2%, 5.2%, and 1.5% at the respective thresholds. By 2019, 7.2% of children in LSL homes had BLLs of 3.5 μg/dL or higher.

During the 2014-2015 crisis, crude odds ratios for LSL compared with CSL homes at the 3.5 μg/dL threshold ranged from 3.08 (95% CI, 2.03-4.74) to 3.13 (95% CI, 2.07-4.82). Housing-age adjustment attenuated most annual associations, but pooled associations remained statistically significant at 3.5 μg/dL or higher (OR, 1.29; 95% CI, 1.06-1.56) and 5.0 μg/dL or higher (OR, 1.42; 95% CI, 1.08-1.89).

The authors noted that surveillance BLLs may underestimate drinking-water lead exposure because blood lead has a short half-life and testing ages may not capture formula-fed infants. Other limitations included the observational design, the single-city setting, and potential unmeasured confounding. They concluded that verified residential LSLs were associated with elevated childhood BLLs across the decade and said the findings reinforced the public health rationale for accelerated LSL replacement.

Source: Land D, Cwiertny DM, Latta DE, Scherer MM, Hanna M. Residential lead service lines and child blood lead levels in Flint, Michigan, 2010-2019. JAMA Netw Open. 2026;9(9):e2632884. doi:10.1001/jamanetworkopen.2026.32884