Elevated blood lead levels and reading readiness at the start of kindergarten

To evaluate the relationship between blood lead levels (BLLs) and reading readiness at kindergarten entry, an early marker of school performance, in a diverse urban school population.

Kindergarten reading readiness test scores for children attending public kindergarten in Providence, Rhode Island, were linked to state health department records of blood lead testing by using individual identifiers. The study population (N = 3406) was 59% Hispanic. For each child, the geometric mean BLL was estimated by using all previously reported BLLs. Analyses were adjusted for gender, age, year enrolled, race, child language, and free/reduced lunch status as a measure of socioeconomic status.

The median geometric mean BLL was 4.2 µg/dL; 20% of children had at least 1 venous BLL ≥10 µg/dL. Compared with children with BLLs <5 µg/dL, the adjusted prevalence ratios (95% confidence interval [CI]) for failing to achieve the national benchmark for reading readiness were 1.21 (1.19 to 1.23) and 1.56 (1.51 to 1.60) for children with BLLs of 5 to 9 and ≥10 µg/dL, respectively. On average, reading readiness scores decreased by 4.5 (95% CI: -2.9 to -6.2) and 10.0 (95% CI: -7.0 to -13.3) points for children with BLLs of 5 to 9 and ≥10 µg/dL, respectively, compared with BLLs <5 µg/dL.

BLLs well below 10 µg/dL were associated with lower reading readiness at kindergarten entry. The high prevalence of elevated BLLs warrants additional investigation in other high-risk US populations. Results suggest benefits from additional collaboration between public health, public education, and community data providers.