Table 4.

Analysis of birth order in a study of leukemia risk among California children diagnosed between 1988 and 2007

All casesnon-Hispanic whiteHispanic
Controls (n = 68,040)Cases (n = 3,402)ORa (95% CI)Controls (n = 24,695)Cases (n = 1,233)ORb (95% CI)Controls (n = 30,526)Cases (n = 1,680)ORb (95% CI)
Birth order
 First26,8031,28810,562534Ref10,904563Ref
 Second21,1311,0761.00 (0.92–1.09)8,3274200.95 (0.83–1.09)8,8384901.03 (0.90–1.17)
 Third11,5205930.95 (0.85–1.05)3,8141950.94 (0.79–1.12)5,8883260.99 (0.85–1.15)
 ≥Fourth8,5494430.91 (0.81–1.03)1,978840.76 (0.59–0.96)4,8873001.05 (0.89–1.24)
 missing37214091
  • aAdjusted for birth year, maternal race, and mother's age.

  • bAdjusted for birth year and maternal age.