Table 4.

Joint effects of CYP1A2*1F and age at menarche, body mass index, hormone replacement therapy use, and pack-years on breast cancer risk

AA
AC
CC
n*OR (95% CI)nOR (95% CI)nOR (95% CI)
Age at menarche (y)
    <12347/3201.0336/3180.9 (0.7-1.1)46/650.6 (0.4-1.0)
    13-14217/2140.7 (0.3-1.5)208/2400.6 (0.2-1.2)34/430.6 (0.2-1.5)
    >1466/710.5 (0.1-2.7)59/620.5 (0.1-2.5)9/140.4 (0.1-2.3)
    Pinteraction0.20
Body mass index (kg/m2)
    <23.8244/2031.0247/2070.9 (0.7-1.2)30/310.8 (0.5-1.4)
    23.9-28.2213/1941.1 (0.8-1.4)185/2150.8 (0.6-1.0)32/430.7 (0.4-1.2)
    >28.2173/2081.0 (0.7-1.3)171/1981.0 (0.7-1.3)27/480.7 (0.4-1.2)
    Pinteraction0.51
Hormone replacement therapy use (y)
    Never270/3251.0255/3140.9 (0.7-1.2)41/590.9 (0.6-1.4)
    <5186/1541.3 (1.0-1.7)171/1830.9 (0.7-1.2)26/360.8 (0.4-1.3)
    >5167/1091.3 (1.0-1.8)162/1081.2 (0.9-1.7)19/240.7 (0.4-1.4)
    Pinteraction0.51
Pack-years
    0346/3291.0339/3600.8 (0.7-1.0)48/740.6 (0.4-1.0)
    0.1-12.0150/1551.0 (0.8-1.3)136/1461.0 (0.7-1.3)20/280.8 (0.4-1.5)
    >12.0134/1211.1 (0.8-1.4)128/1141.0 (0.8-1.4)21/201.1 (0.6-2.1)
    Pinteraction0.76
  • Abbreviations: OR, odds ratio; 95% CI, 95% confidence interval.

  • * No. of cases/no. of controls. Numbers of subjects vary due to missing information.

  • ORs (95% CIs) adjusted for age at blood draw, age at menarche, parity, and age at first birth.

  • P value derived from a likelihood ratio test comparing a model with main effects for the CYP1A2*1F genotype and the risk factor, and a model with main effects and interaction terms.