TABLE 2

Distribution of BLLs According to Selected Demographic Characteristics, Children Aged 1 to 5 Years, NHANES III, Phase 1 (1988–1991)

nGeometric Mean (95% CI), μg/dL<1 μg/dL, % (95% CI)1 to <2.5 μg/dL, % (95% CI)2.5 to <5 μg/dL, % (95% CI)5 to <7.5 μg/dL, % (95% CI)7.5 to <10 μg/dL, % (95% CI)≥10 μg/dL, % (95% CI)
Overall22323.6 (3.2–3.9)a4.4 (2.6–6.6)b25.6 (20.9–30.5)38.7 (34.2–43.2)15.7 (13.5–18.0)7.1 (5.6–8.8)8.6 (5.0–13.0)b
Gender
    Girl11443.5 (3.2–3.9)a4.8 (2.5–7.6)b25.6 (19.0–32.9)38.3 (32.7–44.1)15.9 (13.2–18.9)6.9 (4.9–9.2)8.5 (5.2–12.5)b
    Boy10883.6 (3.2–4.0)4.1 (2.4–6.2)b25.5 (21.4–29.8)39.0 (33.6–44.4)15.5 (12.5–18.8)7.3 (5.4–9.5)8.7 (4.5–14.1)b
Age
    1–2 y9244.0 (3.6–4.5)a3.3 (2.0–4.9)b19.1 (14.6–24.1)38.6 (32.0–45.4)20.5 (16.6–24.6)7.4 (4.9–10.4)11.1 (7.2–15.6)b
    3–5 y13083.3 (2.9–3.7)a5.1 (2.8–8.0)b29.5 (23.9–35.4)38.7 (34.3–43.2)12.8 (10.5–15.3)6.9 (5.0–9.1)7.0 (3.3–12.0)b,c
Race/ethnicity
    Non-Hispanic black6795.2 (4.7–5.7)a2.9 (1.1–5.5)c11.8 (9.1–14.8)32.2 (25.4–39.4)20.4 (17.1–23.9)14.0 (10.7–17.7)18.6 (13.3–24.6)b
    Mexican American8033.9 (3.0–4.8)a3.3 (0.2–9.5)b,c19.6 (11.5–29.2)42.3 (37.6–46.9)19.3 (13.2–26.1)8.4 (3.9–14.5)7.2 (4.3–10.9)
    Non-Hispanic white6583.1 (2.9–3.4)a5.4 (3.1–8.3)b30.4 (25.2–35.9)39.6 (34.0–45.4)14.0 (11.1–17.1)5.1 (3.1–7.5)5.5 (2.9–8.9)b
PIR
    ≤1.310194.7 (4.0–5.4)a2.1 (0.8–3.9)b,c13.4 (8.3–19.5)39.0 (31.9–46.2)20.4 (17.0–24.0)10.2 (7.4–13.3)15.0 (9.0–22.2)b
    >1.310043.1 (2.8–3.3)a6.0 (3.5–9.2)b31.5 (26.9–36.2)39.0 (33.6–44.6)13.1 (10.8–15.6)5.4 (3.6–7.6)5.0 (2.5–8.3)b
Medicaid status
    Yes6265.3 (4.2–6.3)a1.9 (0.5–4.2)b,c9.7 (4.4–16.8)37.5 (28.7–46.8)18.8 (14.1–24.4)11.1 (7.3–15.6)21.0 (12.0–31.7)b
    No12663.1 (2.9–3.4)a5.6 (3.3–8.3)b30.9 (25.9–36.2)39.6 (34.1–45.2)13.9 (11.4–16.6)5.0 (3.6–6.6)5.0 (2.8–7.8)b
Year housing built (risk of lead exposure)d
    Low risk6022.9 (2.5–3.3)a5.3 (2.0–9.9)b,c34.9 (27.6–42.6)40.3 (33.8–46.9)10.0 (7.1–13.3)4.7 (2.6–7.3)4.8 (1.6–9.8)c
    Medium risk9313.6 (3.2–4.0)a5.0 (3.3–7.1)b23.2 (17.0–30.0)37.7 (32.0–43.6)19.2 (15.0–23.7)6.5 (4.8–8.5)8.3 (5.2–12.0)b
    High risk3785.2 (4.4–5.9)a1.2 (0.1–3.6)c12.2 (7.6–17.8)37.3 (28.9–46.2)17.5 (11.2–24.8)13.6 (8.7–19.4)18.2 (12.0–25.5)
    Not known1704.9 (3.8–5.9)0.6 (0.0–2.4)c14.6 (6.3–25.6)c38.6 (25.4–52.8)20.9 (13.1–30.1)11.3 (4.3–21.1)c14.0 (4.3–28.1)c
  • a Difference between 1988–1991 and 1999–2004 statistically significant at P < .05 after Bonferroni adjustment.

  • b Difference between 1988–1991 and 1999–2004 within lead categories BLL <1 μg/dL and/ BLL ≥10 μg/dL statistically significant at P < .05 after Bonferroni adjustment.

  • c Relative SE of point estimate ≥30%; does not meet standard of statistical reliability and precision.

  • d Risk of lead exposure by year housing built defined as follows:

    NHANES 1999–2004: low risk, built 1978 and later; medium risk, built between 1950 and 1977; high risk, built before 1950.

    NHANES III phases 1 and 2: low risk, built 1974 and later; medium risk, built between 1946 and 1973; high risk, built before 1946.