Table 5.

Analysis of interaction between common MDR1 haplotypes, indoor insecticide exposure, and risk of childhood ALL

HaplotypePesticideCasesControlsOR (95% CI)*P
Hap CGC × Indoor insecticide
    −No19 (6.5)39 (10.6)1.00 (Reference)
    −Yes92 (31.3)86 (23.3)3.03 (1.54-6.00)
    +No35 (11.9)53 (14.4)1.87 (0.90-3.91)
    +Yes148 (50.3)191 (51.8)2.09 (1.12-3.91)
Interaction0.37 (0.15-0.88)0.025
Hap TTT × Indoor insecticide
    −No18 (6.1)29 (7.9)1.00 (Reference)
    −Yes90 (30.6)109 (29.5)1.46 (0.73-2.90)
    +No36 (12.2)63 (17.1)0.95 (0.46-1.99)
    +Yes150 (51.0)168 (45.5)1.68 (0.86-3.27)
Interaction1.21 (0.53-2.74)0.649
  • * ORs and 95% CIs were calculated using conditional logistic regression (matching factors: date of birth, sex, Hispanic status, and maternal race) adjusting for household income.

  • Interaction OR (ORInteraction) based on the multiplicative model of interaction defined as the ratio of the joint effect of the MDR1 haplotype and indoor insecticide exposure and product of the individual effects [ORInteraction = ORGE / (ORGE′ × ORGE)].