Table 5.

Joint effects of the MTHFR C677T polymorphism and HRT use at baseline on breast cancer risk

Duration (y)CC
CT
TT
n*OR (95% CI)nOR (95% CI)nOR (95% CI)
HRT use
    Never240/6191.00170/4180.95 (0.74-1.21)63/1371.01 (0.71-1.43)
    1-3146/3251.07 (0.83-1.38)143/2621.14 (0.87-1.48)32/650.96 (0.60-1.53)
    >3129/1801.35 (1.01-1.79)121/1471.48 (1.10-1.99)31/530.94 (0.58-1.54)
    P0.35
  • * No. cases/no. controls (in comparison with Table 4, an additional 14 cases and 40 controls were excluded due to missing information on HRT duration).

  • ORs (95% CIs) adjusted for ethnicity and age at blood draw.

  • P value derived from a likelihood ratio test comparing a model with main effects for the MTHFR C677T genotype and the HRT use (Never, 1-3 years of use, >3 years of use), and a model with main effects and interaction terms (df, 4).