Table 4

Joint association of folate and MTHFR C677T genotype with breast cancer risk stratified by cofactor intake among Chinese women, Shanghai Breast Cancer Study, 1996–1998

Folate cofactor intakeFolate intake, odds ratio (95% confidence interval)aP for trendP for interaction
T3 (high)T2T1
Vitamin B12b
 Low
  CC1.00 (reference)1.71 (0.74–3.94)1.77 (0.73–4.34)0.25
  CT1.62 (0.70–3.73)1.36 (0.61–3.05)1.74 (0.75–4.06)0.79
  TT0.83 (0.28–2.45)0.86 (0.31–2.40)2.36 (0.90–6.16)0.110.56
 Medium
  CC1.00 (reference)1.88 (0.97–3.67)2.11 (0.97–4.59)0.11
  CT1.01 (0.56–1.81)1.69 (0.92–3.11)1.81 (0.89–3.68)0.20
  TT0.84 (0.38–1.87)1.77 (0.83–3.83)3.00 (1.18–7.61)0.030.45
 High
  CC1.00 (reference)0.96 (0.51–1.81)1.10 (0.58–1.73)0.39
  CT1.00 (0.58–1.73)1.22 (0.67–2.22)1.26 (0.65–2.48)0.88
  TT0.61 (0.30–1.23)2.33 (1.03–5.26)1.25 (0.46–3.37)0.120.02
Vitamin B6c
 Low
  CC1.00 (reference)0.77 (0.16–3.86)1.24 (0.26–5.91)0.30
  CT0.70 (0.09–5.37)1.11 (0.23–5.41)1.43 (0.31–6.76)0.26
  TT2.19 (0.09–52.31)0.74 (0.13–4.27)1.89 (0.38–9.39)0.060.70
 Medium
  CC1.00 (reference)1.45 (0.68–3.07)1.67 (0.71–3.94)0.24
  CT0.84 (0.37–1.91)1.31 (0.63–2.74)1.18 (0.54–2.59)0.57
  TT0.66 (0.22–1.97)1.37 (0.60–3.17)1.74 (0.65–4.71)0.020.70
 High
  CC1.00 (reference)1.61 (0.88–2.96)1.28 (0.29–5.59)0.04
  CT1.27 (0.84–1.92)1.26 (0.75–2.11)1.01 (0.33–3.04)0.44
  TT0.71 (0.41–1.22)2.50 (1.11–5.63)0.68 (0.12–3.73)0.230.13
Methionined
 Low
  CC1.00 (reference)2.17 (0.50–9.38)1.87 (0.43–8.18)0.88
  CT2.82 (0.60–13.29)2.00 (0.47–8.51)2.06 (0.48–8.88)0.98
  TT3.24 (0.48–22.00)1.56 (0.33–7.45)2.89 (0.64–13.04)0.410.98
 Medium
  CC1.00 (reference)1.21 (0.61–2.40)1.99 (0.91–4.37)0.09
  CT0.99 (0.48–2.05)1.47 (0.76–2.84)1.75 (0.85–3.64)0.30
  TT0.96 (0.37–2.48)1.70 (0.77–3.73)2.05 (0.74–5.67)0.090.91
 High
  CC1.00 (reference)1.71 (0.90–3.23)1.57 (0.51–4.83)0.16
  CT1.08 (0.69–1.66)1.31 (0.76–2.24)1.16 (0.52–2.59)0.82
  TT0.59 (0.33–1.05)1.84 (0.83–4.08)1.53 (0.50–4.66)0.030.19
  • a All odds ratios are adjusted for age, waist-to-hip ratio, age at first live birth, physical activity, menopausal status, and total energy, meat, and intake of the other two cofactors.

  • b P for three-way interaction, 0.47.

  • c P for three-way interaction, 0.24.

  • d P for three-way interaction.