Table 4

Polymorphisms of ER-α PvuII and XbaI and breast cancer risk by selected estrogen exposure-related factors and lifestyle factors, Shanghai Breast Cancer Study, 1996–1998

PvuII polymorphismXbaI polymorphism
PPPp or ppXXXx or xx
Case/controlORa (95% CI)Case/controlORa (95% CI)Case/controlORa (95% CI)Case/controlORa (95% CI)
Age at menarche (yr)
 ≤1398/1401.0 (ref)619/7071.3 (1.0–1.7)29/371.0 (ref)b698/8131.1 (0.6–1.8)
 >1338/471.0 (ref)298/2501.5 (1.0–2.4)7/111.0 (ref)327/2891.5 (0.6–4.1)
Age at menopause (yr)c
 <5026/451.0 (ref)176/2091.4 (0.8–2.4)7/131.0 (ref)196/2461.5 (0.6–3.9)
 ≥5018/241.0 (ref)122/1281.3 (0.7–2.4)3/41.0 (ref)139/1481.3 (0.3–5.7)
Years of menstruationd
 <Median (30 yr)54/851.0 (ref)396/4701.4 (0.9–2.0)19/261.0 (ref)431/5381.0 (0.6–1.9)
 ≥Median (30 yr)82/1021.0 (ref)523/4891.3 (1.0–1.8)17/221.0 (ref)596/5661.4 (0.7–2.6)
Ever diagnosed with breast fibroadenoma
 No119/1791.0 (ref)830/9061.4 (1.1–1.8)32/461.0 (ref)924/10461.2 (0.8–2.0)
 Yes16/81.0 (ref)89/530.9 (0.4–2.2)4/21.0 (ref)102/580.9 (0.2–5.0)
BMI
 <2593/1361.0 (ref)635/7061.4 (1.0–1.8)29/341.0 (ref)704/8071.0 (0.6–1.6)
 ≥2543/511.0 (ref)284/2531.3 (0.9–2.1)7/141.0 (ref)323/2972.1 (0.9–5.4)
BMIc
 <2522/431.0 (ref)168/2111.6 (0.9–2.7)6/101.0 (ref)185/2451.4 (0.5–3.8)
 ≥2522/261.0 (ref)130/1261.3 (0.7–2.4)4/71.0 (ref)150/1491.8 (0.5–6.4)
WHR
 ≤0.84102/1541.0 (ref)674/7571.4 (1.0–1.8)27/381.0 (ref)756/8781.2 (0.7–2.0)
 >0.8434/331.0 (ref)245/2021.2 (0.7–2.0)9/101.0 (ref)271/2261.3 (0.5–3.2)
Regular exercise during past 10 years
 Yes26/561.0 (ref)176/2401.5 (0.9–2.6)4/81.0 (ref)199/2861.3 (0.4–4.3)
 No110/1311.0 (ref)742/7191.3 (1.0–1.7)32/401.0 (ref)827/8181.2 (0.8–2.0)
Caloric intake
 <Medium64/941.0 (ref)452/4841.4 (1.0–1.9)17/241.0 (ref)505/5561.3 (0.7–2.5)
 ≥Medium72/931.0 (ref)467/4751.3 (1.0–1.9)19/241.0 (ref)522/5481.1 (0.6–2.0)
Fat intake
 <Medium62/831.0 (ref)436/4901.2 (0.8–1.7)16/261.0 (ref)489/5501.5 (0.8–2.8)
 ≥Medium74/1041.0 (ref)483/4691.5 (1.1–2.1)20/221.0 (ref)538/5541.0 (0.6–1.9)
Protein intake
 <Medium60/951.0 (ref)440/4821.4 (1.0–2.0)17/261.0 (ref)489/5531.4 (0.7–2.5)
 ≥Medium76/921.0 (ref)479/4771.3 (0.9–1.8)19/221.0 (ref)538/5511.1 (0.6–2.0)
Carbohydrate intake
 <Medium62/981.0 (ref)458/4801.5 (1.0–2.1)20/191.0 (ref)505/5560.9 (0.5–1.6)
 ≥Medium74/891.0 (ref)461/4791.2 (0.9–1.7)16/291.0 (ref)522/5481.6 (0.9–3.0)
  • a Adjusted for age.

  • b ref, reference.

  • c Among postmenopausal women only.

  • d Years of menstruation = menopausal age or age at interview for premenopausal women − menarche age.