Table 4.

Estimated risk of brain tumors with lead exposure after exclusion of proxy interviews, after 10-year exposure lag, and separate analysis for glioblastoma (NCI Brain Tumor Study, 1994-1998)

Cases/controls (n)Overall, OR (95% CI)Cases/controls (n)ALAD1 individuals, OR (95% CI)Cases/controls (n)ALAD2 individuals, OR (95% CI)*
Meningioma
Ever exposed to lead
    No1.0 (reference)1.0 (reference)1.0 (reference)
    Yes, excluding proxy interviews44/2770.8 (0.5-1.3)20/1590.5 (0.3-1.1)12/272.8 (0.7-10.3)
    Yes, with 10-year lag46/2640.9 (0.5-1.3)21/1510.6 (0.3-1.1)13/233.7 (0.9-14.8)
Cumulative exposure to lead, excluding proxy interviews
    β, P0.003, 0.040.002, 0.50.016, 0.01
    OR for a 50 μg/m3-y increase1.161.162.19
Cumulative exposure to lead, with 10-year lag
    β, P0.003, 0.050.00, 1.00.008, 0.05
    OR for a 50 μg/m3-y increase1.161.001.46
Glioma
Ever exposed to lead
    No1.0 (reference)1.0 (reference)1.0 (reference)
    Yes, excluding proxy interviews156/2770.8 (0.6-1.1)98/1590.7 (0.5-1.0)20/270.6 (0.2-1.8)
    Yes, with 10-year lag148/2540.9 (0.7-1.2)91/1440.8 (0.5-1.1)20/221.1 (0.4-3.1)
    Yes, glioblastoma only106/2870.9 (0.6-1.3)62/1660.9 (0.6-1.6)12/280.6 (0.2-2.6)
Cumulative exposure to lead, excluding proxy interviews
    β, P0.0, 1.0−0.001, 0.60.004, 0.3
    OR for a 50 μg/m3-y increase1.000.971.23
Cumulative exposure to lead, with 10-year lag
    β, P0.0, 0.9−0.002, 0.30.002, 0.5
    OR for a 50 μg/m3-y increase1.000.931.13
Cumulative exposure to lead, glioblastoma only
    β, P0.0, 0.20.001, 0.50.002, 0.4
    OR for a 50 μg/m3-y increase1.11.051.11
  • * Includes ALAD1-2 heterozygotes and ALAD2-2 homozygotes.

  • Models were adjusted for matching factors: age, sex, race, hospital, and distance of residence from hospital.

  • Numbers of cases and controls not provided for reference category because the numbers change depending on the analysis (exclusion of proxy/10-year lag/glioblastoma only).