Table 4.
Adjusted HRs and 95% CIs of liver cancer for menstrual and reproductive factors among postmenopausal women (SWHS, 1996–2016)
| Cases | PYs | HR (95% CI)1 | HR (95% CI)2 | |
|---|---|---|---|---|
| Age at menarche | ||||
| <14 | 29 | 119559.6 | 1.00 [reference] | 1.00 [reference] |
| 14 | 31 | 112413.1 | 0.99 (0.95,1.02) | 0.97 (0.94,1.00) |
| 15 | 45 | 124579.7 | 1.01 (0.98,1.05) | 0.98 (0.95,1.01) |
| 16 | 36 | 112635.5 | 0.99 (0.95,1.02) | 0.94 (0.91,0.98) |
| 17 | 33 | 71478.9 | 1.04 (1.00,1.08) | 0.98 (0.94,1.02) |
| ≥18 | 23 | 58910.7 | 1.05 (1.01,1.09) | 0.99 (0.95,1.03) |
| P for trend | 0.015 | 0.322 | ||
| Age at menopause | ||||
| <45 | 29 | 99088.5 | 1.00 [reference] | 1.00 [reference] |
| 45–49 | 109 | 263274.8 | 0.93 (0.90,0.96) | 0.95 (0.92,0.98) |
| 50–54 | 50 | 213687.3 | 0.91 (0.88,0.94) | 0.95 (0.92,0.98) |
| ≥55 | 9 | 23526.8 | 0.93 (0.87,0.98) | 0.95 (0.90,1.01) |
| P for trend | <0.001 | 0.009 | ||
| Reproductive period | ||||
| <30 | 41 | 112639.7 | 1.00 [reference] | 1.00 [reference] |
| 30–34 | 104 | 251856.2 | 0.94 (0.91,0.96) | 0.96 (0.93,0.99) |
| 35–39 | 47 | 201826.1 | 0.92 (0.89,0.95) | 0.96 (0.93,0.99) |
| ≥40 | 5 | 33255.4 | 0.89 (0.84,0.93) | 0.95 (0.90,1.00) |
| P for trend | <0.001 | 0.031 | ||
| Hysterectomy | ||||
| No | 177 | 536211.7 | 1.00 [reference] | 1.00 [reference] |
| Yes | 20 | 63365.8 | 1.10 (1.06,1.14) | 1.07 (1.04,1.11) |
| Oophorectomy | ||||
| No | 181 | 561579.8 | 1.00 [reference] | 1.00 [reference] |
| Yes | 16 | 37997.6 | 1.05 (1.01,1.10) | 1.05 (1.01,1.10) |
| HRT | ||||
| No | 192 | 572786.6 | 1.00 [reference] | 1.00 [reference] |
| Yes | 5 | 26790.8 | 1.15 (1.09,1.21) | 1.23 (1.17,1.30) |
| Oral contraceptives | ||||
| No | 149 | 446320.2 | 1.00 [reference] | 1.00 [reference] |
| Yes | 48 | 153257.3 | 1.05 (1.02,1.07) | 1.06 (1.03,1.08) |
| Injective contraceptives | ||||
| No | 148 | 403233.6 | 1.00 [reference] | 1.00 [reference] |
| Yes | 49 | 196343.8 | 1.06 (1.04,1.09) | 1.08 (1.05,1.11) |
| Number of live births | ||||
| ≤1 | 39 | 156222.7 | 1.00 [reference] | 1.00 [reference] |
| 2 | 48 | 203819.4 | 0.82 (0.80,0.84) | 0.82 (0.79,0.84) |
| 3–4 | 91 | 192218.6 | 0.87 (0.84,0.89) | 0.78 (0.76,0.81) |
| 5+ | 19 | 47316.7 | 0.97 (0.92,1.01) | 0.83 (0.79,0.87) |
| P for trend | <0.001 | <0.001 |
Model 1 was adjusted by age at entry；
Model 2 was adjusted by age at entry, BMI, physical activity, calorie intake, education, family income, occupation, marital status, smoking, alcohol drinking, tea drinking, family history of liver cancer, medical history of hepatitis, cholelithiasis, diabetes, and high blood pressure.