Table 2.
Reproductive History of the Participants
| Variable | Premature menopause | ||
|---|---|---|---|
| No | Yes | P value | |
| No. | 1 139 406 | 19 999 | |
| Age at menopause, y | 50.22±3.55 | 36.75±2.59 | <0.01 |
| Lifetime duration of menstruation, y | 33.79±3.96 | 19.91±3.31 | <0.01 |
| Lifetime duration of menstruation, y | <0.01 | ||
| <30 | 139 331 (12.23) | 19 987 (99.94) | |
| 30–34 | 484 365 (42.51) | 12 (0.06) | |
| 35–39 | 444 468 (39.01) | 0 (0) | |
| ≥40 | 71 242 (6.25) | 0 (0) | |
| HRT, yes | 183 459 (16.1) | 3697 (18.49) | <0.01 |
| HRT duration | <0.01 | ||
| No | 955 947 (83.9) | 16 302 (81.51) | |
| <2 y | 107 473 (9.43) | 1623 (8.12) | |
| 2–5 y | 43 781 (3.84) | 843 (4.22) | |
| ≥5 y | 32 205 (2.83) | 1231 (6.16) | |
Data are given as mean±SD or number (percentage). P value was obtained by t test for continuous variables and χ2 test for categorical variables. HRT indicates hormone replacement therapy.