Table 1.
Characteristics of premenopausal women stratified by age at menarche
| Characteristic | Age at menarche (y) |
P-value | ||
|---|---|---|---|---|
| <12 (n=288) | 12–15 (n=2,321) | ≥16 (n=414) | ||
| Age at the time of survey (y) | 30.98±0.60 | 37.09±0.23 | 43.96±0.60 | <0.001 |
| Age at menarche (y) | 10.74±0.04 | 13.44±0.03 | 16.76±0.06 | <0.001 |
| Height (cm) | 160.03±0.38 | 160.04±0.14 | 158.50±0.35 | <0.001 |
| Weight (kg) | 59.00±0.70 | 57.64±0.21 | 57.36±0.50 | 0.122 |
| Married | 51.3 (3.4) | 70.8 (1.2) | 78.2 (2.2) | <0.001 |
| Household income | 0.683 | |||
| Low | 8.3 (1.8) | 7.5 (0.7) | 9.9 (2.1) | |
| Mid-low | 25.4 (3.0) | 25.4 (1.2) | 25.8 (2.6) | |
| Mid-high | 30.4 (2.8) | 32.9 (1.2) | 34.0 (2.6) | |
| High | 35.9 (3.1) | 34.2 (1.5) | 30.3 (2.9) | |
| College graduate or more | 61.8 (3.3) | 48.3 (1.3) | 29.3 (2.3) | <0.001 |
| Smoking status | 0.737 | |||
| Never | 86.4 (2.3) | 88.7 (0.8) | 87.0 (1.7) | |
| Past | 6.1 (1.5) | 4.9 (0.5) | 5.8 (1.3) | |
| Current | 7.5 (1.7) | 6.4 (0.6) | 7.1 (1.3) | |
| High-risk drinking | 10.1 (1.9) | 6.6 (0.6) | 8.2 (1.6) | 0.097 |
| Physically active | 43.0 (3.2) | 37.7 (1.1) | 31.2 (2.4) | 0.009 |
| No. of pregnancies ≥3 | 34.9 (4.2) | 54.1 (1.2) | 63.4 (2.4) | <0.001 |
| History of oral contraceptive use | 11.8 (2.2) | 10.3 (0.7) | 12.6 (1.9) | 0.437 |
| Duration of lactation | <0.001 | |||
| Never | 57.9 (3.2) | 43.4 (1.2) | 34.4 (2.8) | |
| <6 mo | 10.5 (1.8) | 11.7 (0.7) | 8.8 (1.5) | |
| 6–12 mo | 8.5 (1.8) | 10.4 (0.6) | 11.0 (1.6) | |
| ≥12 mo | 23.1 (2.9) | 34.5 (1.1) | 45.8 (2.8) | |
Values are presented as mean±standard error or % (standard error). Differences between early menarche (or late menarche) and reference group were compared using analysis of variance for continuous variables and the chi-square test for percentage.