Factors | Cases (N = 2261) | Controls (N = 2261) | Model 1 | Model 2 | Model 3 | Model 4 | ||||
---|---|---|---|---|---|---|---|---|---|---|
OR† | 95% CI | OR† | 95% CI | OR† | 95% CI | OR† | 95% CI | |||
Menstrual factors | ||||||||||
Age at menarche (years) | ||||||||||
≦ 12 | 104 | 99 | 0.51 | 0.23–1.12 | 0.72 | 0.18–2.92 | 0.77 | 0.19–3.17 | 0.67 | 0.15–3.10 |
13–14 | 974 | 995 | Ref | Ref | Ref | Ref | ||||
15–16 | 857 | 859 | 0.90 | 0.69–1.18 | 0.73 | 0.46–1.17 | 0.72 | 0.45–1.16 | 0.79 | 0.48–1.30 |
≥ 17 | 304 | 290 | 0.85 | 0.61–1.19 | 0.54 | 0.29–0.99 | 0.52 | 0.28–0.97 | 0.59 | 0.31–1.12 |
P for trend | 0.650 | |||||||||
Had regular menstrual cycles | ||||||||||
No | 187 | 182 | 1.27 | 0.82–1.96 | 0.66 | 0.32–1.40 | 0.63 | 0.30–1.34 | 0.61 | 0.28–1.35 |
Yes | 2054 | 2067 | Ref | Ref | Ref | Ref | ||||
Had dysmenorrhea | ||||||||||
No | 1757 | 1719 | Ref | Ref | Ref | Ref | ||||
Yes | 495 | 535 | 0.92 | 0.70–1.21 | 0.82 | 0.51–1.32 | 0.81 | 0.50–1.31 | 0.70 | 0.42–1.18 |
Age at menopause (years) | ||||||||||
≦ 44 | 68 | 64 | 0.97 | 0.60–1.58 | 1.08 | 0.49–2.39 | 1.03 | 0.46–2.30 | 0.98 | 0.42–2.29 |
45–49 | 249 | 224 | 1.03 | 0.77–1.39 | 0.98 | 0.57–1.67 | 0.96 | 0.56–1.65 | 0.92 | 0.52–1.61 |
50–51 | 307 | 315 | Ref | Ref | Ref | Ref | ||||
≥ 52 | 307 | 303 | 1.07 | 0.82–1.39 | 0.90 | 0.57–1.41 | 0.86 | 0.54–1.36 | 0.89 | 0.55–1.44 |
P for trend | 0.496 | |||||||||
Reproductive factors | ||||||||||
Number of pregnancy | ||||||||||
1 | 613 | 631 | Ref | Ref | Ref | Ref | ||||
2 | 771 | 796 | 0.96 | 0.77–1.18 | 0.63 | 0.36–1.12 | 0.62 | 0.35–1.11 | 0.67 | 0.37–1.23 |
≥ 3 | 774 | 728 | 1.04 | 0.81–1.34 | 0.64 | 0.34–1.20 | 0.62 | 0.33–1.18 | 0.66 | 0.34–1.28 |
P for trend | 0.222 | |||||||||
Age at first pregnancy (years) | ||||||||||
≦ 20 | 336 | 325 | Ref | Ref | Ref | Ref | ||||
20–25 | 1387 | 1354 | 0.99 | 0.78–1.25 | 1.03 | 0.63–1.69 | 1.03 | 0.63–1.70 | 0.96 | 0.57–1.61 |
> 25 | 426 | 465 | 0.87 | 0.64–1.19 | 0.47 | 0.24–0.93 | 0.47 | 0.23–0.94 | 0.47 | 0.23–0.96 |
P for trend | 0.200 | |||||||||
Outcome of the first pregnancy | ||||||||||
Live birth | 1920 | 1946 | Ref | Ref | Ref | Ref | ||||
Miscarriage | 81 | 80 | 1.13 | 0.78–1.64 | 0.93 | 0.37–2.33 | 0.94 | 0.37–2.35 | 0.85 | 0.33–2.20 |
Abortion | 125 | 95 | 1.39 | 0.99–1.96 | 0.81 | 0.31–2.07 | 0.78 | 0.30–2.03 | 0.80 | 0.30–2.09 |
Stillbirth or ectopic | 22 | 18 | 1.28 | 0.65–2.53 | 1.36 | 0.34–5.53 | 1.37 | 0.34–5.57 | 1.37 | 0.33–5.62 |
Age at last pregnancy (years) | ||||||||||
≦ 25 | 806 | 777 | Ref | Ref | Ref | Ref | ||||
25–30 | 883 | 924 | 0.97 | 0.81–1.17 | 1.17 | 0.76–1.81 | 1.17 | 0.75–1.81 | 1.21 | 0.77–1.90 |
> 30 | 418 | 409 | 1.04 | 0.81–1.33 | 1.54 | 0.86–2.76 | 1.50 | 0.83–2.73 | 1.63 | 0.88–3.00 |
P for trend | 0.667 | |||||||||
Duration of breast feeding (months) | ||||||||||
≦ 6 | 293 | 234 | Ref | Ref | Ref | Ref | ||||
6–12 | 1040 | 1087 | 0.69 | 0.55–0.88 | 0.52 | 0.26–1.03 | 0.53 | 0.27–1.05 | 0.49 | 0.24–0.98 |
> 12 | 674 | 685 | 0.68 | 0.52–0.90 | 0.67 | 0.31–1.44 | 0.68 | 0.31–1.46 | 0.60 | 0.27–1.31 |
P for trend | 0.090 | |||||||||
Hormonal factors | ||||||||||
Oral contraceptive use | ||||||||||
No | 1637 | 1667 | Ref | Ref | Ref | Ref | ||||
Yes | 62 | 56 | 0.96 | 0.63–1.46 | 1.24 | 0.51–3.03 | 1.17 | 0.48–2.87 | 1.18 | 0.47–2.96 |
Hormone therapy use | ||||||||||
No | 2204 | 2233 | Ref | Ref | Ref | Ref | ||||
Yes | 57 | 28 | 2.16 | 1.13–4.14 | 2.24 | 0.53–9.56 | 2.06 | 0.47–9.06 | 1.47 | 0.30–7.38 |
Hysterectomy and oophorectomy status | ||||||||||
None | 2107 | 2162 | Ref | Ref | Ref | Ref | ||||
Hysterectomy alone | 119 | 74 | 1.71 | 1.19–2.46 | 1.36 | 0.74–2.52 | 1.37 | 0.74–2.54 | 1.45 | 0.77–2.73 |
Oophorectomy alone | 28 | 15 | 2.01 | 0.93–4.34 | 1.84 | 0.42–7.96 | 1.74 | 0.41–7.41 | 1.93 | 0.43–8.72 |
Hysterectomy and oophorectomy | 7 | 10 | 1.19 | 0.36–3.97 | 4.60 | 0.51–41.45 | 4.67 | 0.52–41.98 | 3.85 | 0.43–34.59 |