Table 1 Baseline characteristics by maternal age of menarche from the SCHEDULE study in China
From: Maternal age at menarche and offspring body mass index in childhood
Maternal age of menarche (in complete years), %* | |||||||
|---|---|---|---|---|---|---|---|
Characteristics | n | ≤11 (1608) | 12 (2955) | 13 (3939) | 14 (2819) | ≥ 15 (3173) | p value |
Sex | |||||||
 Boys | 8180 | 48.4 | 48.5 | 52.4 | 54.5 | 61.6 | < 0.001 |
 Girls | 7057 | 51.6 | 51.5 | 47.6 | 45.5 | 38.4 |  |
Low birthweight | Â | Â | Â | Â | Â | Â | 0.17 |
 No | 15,241 | 96.2 | 97.0 | 96.8 | 95.9 | 96.3 |  |
 Yes | 558 | 3.8 | 3.0 | 3.2 | 4.1 | 3.7 |  |
Mode of delivery |  |  |  |  |  |  | < 0.001 |
 Vaginal | 7661 | 41.3 | 45.8 | 47.7 | 51.3 | 58.5 |  |
 Cesarean | 7655 | 58.7 | 54.2 | 52.3 | 48.7 | 41.5 |  |
Child age (Mean (SE)) | 16,677 | 9.3 | 9.2 | 9.2 | 9.3 | 9.1 | < 0.01 |
Maternal education |  |  |  |  |  |  | < 0.001 |
 Middle school or below | 5341 | 16.9 | 22.5 | 27.6 | 38.1 | 50.3 |  |
 High school | 4268 | 21.2 | 28.1 | 26.9 | 28.9 | 25.7 |  |
 College or above | 6219 | 60.9 | 49.4 | 45.5 | 33.0 | 24.0 |  |
Household income annually ($ in RMB) |  |  |  |  | < 0.001 | ||
  ≤ 30,000 | 1471 | 8.1 | 8.4 | 9.2 | 13.3 | 22.3 |  |
 30,000-100,000 | 5122 | 34.1 | 42.2 | 42.7 | 46.8 | 49.6 |  |
 100,000-300,000 | 4063 | 46.1 | 41.4 | 40.2 | 33.1 | 23.6 |  |
  ≥ 300,000 | 834 | 11.7 | 8.0 | 7.8 | 6.8 | 4.5 |  |
Maternal gestational diabetes |  |  |  |  |  |  | < 0.001 |
 No | 15,093 | 95.3 | 97.1 | 97.2 | 97.9 | 98.6 |  |
 Yes | 395 | 4.7 | 2.9 | 2.8 | 2.1 | 1.4 |  |
Maternal BMI (Mean (SE)) | 16,001 | 22.3 (3.4) | 21.9 (3.2) | 21.7 (3.2) | 21.7 (3.3) | 21.9 (3.7) | < 0.001 |