Table 2.
CC N = 82 % |
LC N = 49 % |
CC/LC | ||
---|---|---|---|---|
| ||||
Crude OR, 95% CI | OR, 95% CI | |||
Age at menarche (year) | ||||
Missing value | 9.8 | 6.1 | “–” | “–” |
≤12 (reference) | 28.0 | 18.4 | 1.00 | 1.00 |
>12 to <15 | 47.6 | 51.0 | 1.64 (0.65–4.11) | 1.68 (0.62–4.54) |
≥15 | 14.6 | 24.5 | 2.56 (0.84–7.76) | 3.42 (0.96–12.14) |
Parity | ||||
Missing value | 3.7 | 2.0 | “–” | “–” |
Nullipara (reference) | 4.9 | 16.3 | 1.00 | 1.00 |
Parous | 91.5 | 81.6 | 0.27 (0.08–0.94) | 0.20 (0.05–0.86) |
Age at first childbirth (year) | ||||
Missing value | 4.9 | 2.0 | “–” | “–” |
Nullipara (reference) | 4.9 | 16.3 | 1.00 | 1.00 |
≤25 | 62.2 | 61.2 | 0.29 (0.08–1.06) | 0.22 (0.05–0.98) |
>25 | 28.0 | 20.4 | 0.22 (0.05–0.89) | 0.16 (0.03–0.79) |
Age at menopause (year) | ||||
Missing value* | 25.6 | 16.3 | “–” | “–” |
≤45 (reference) | 22.0 | 18.4 | 1.00 | 1.00 |
>45 to <53 | 28.0 | 40.8 | 1.74 (0.64–4.73) | 1.92 (0.64–5.81) |
≥53 | 24.4 | 24.5 | 1.20 (0.41–3.51) | 1.09 (0.33–3.64) |
Exposure to OC | ||||
Missing value | 2.4 | 0 | “–” | “–” |
Never (reference) | 23.2 | 24.5 | 1.00 | 1.00 |
Ever | 74.4 | 75.5 | 0.96 (0.42–2.20) | 0.97 (0.40–2.37) |
Exposure to HRT | ||||
Missing value | 0 | 0 | “–” | “–” |
Non (reference) | 91.5 | 91.8 | 1.00 | 1.00 |
Current | 8.5 | 8.2 | 0.95 (0.26–3.44) | 0.91 (0.23–3.59) |
Bilateral oophorectomy | ||||
Missing value | 7.3 | 8.2 | “–” | “–” |
No (reference) | 79.3 | 71.4 | 1.00 | 1.00 |
Yes | 13.4 | 20.4 | 1.69 (0.65–4.36) | 1.68 (0.58–4.88) |
Notes:
Missing values includes missing values and premenopausal women. Calculations were adjusted for age, smoking habits, alcohol habits, civil status, and employment.
Abbreviations: HRT, hormonal replacement therapy; CI, Confidence interval; OC, oral contraceptives; OR, Odds ratio.