Table 2 Cross‐tabulation of categories of age at menarche derived from ages of menarche ascertained during adolescence and in middle age in the Medical Research Council National Survey of Health and Development cohort (n = 1050).
| Age at menarche (years), recorded at age 48 years | Age at menarche (years), recorded at age 14–15 years | Total | ||
|---|---|---|---|---|
| ⩽11 | 12–13 | ⩾14 | ||
| ⩽11 | 122 (71.3)* | 144 (22.0) | 2 (0.9) | 268 |
| 12–13 | 45 (26.3) | 386 (58.8)* | 44 (19.7) | 475 |
| ⩾14 | 4 (2.3) | 126 (19.2) | 177 (79.4)* | 307 |
| Total | 171 (100) | 656 (100) | 223 (100) | 1050 |
*The two measures are in agreement.
Values are n (%).