Table 1. Background Characteristics of Girls by Puberty Onset in Rural Western China (N = 294)a.
| Characteristic | All (N = 294) | Onset of puberty | |
|---|---|---|---|
| Yes (n = 241) | No (n = 53) | ||
| Parental during pregnancy | |||
| Maternal age, mean (SD), y | 23.43 (4.09) | 23.51 (4.12) | 23.08 (3.97) |
| Maternal educational attainment | |||
| <3 y | 12 (4.1) | 7 (58.3) | 5 (41.7) |
| Primary | 59 (20.1) | 50 (84.7) | 9 (15.3) |
| Secondary | 168 (57.3) | 139 (82.7) | 29 (17.3) |
| High school or higher | 54 (18.4) | 45 (83.3) | 9 (16.7) |
| Maternal occupation | |||
| Farmer | 237 (80.9) | 194 (81.9) | 43 (18.1) |
| Other | 56 (19.1) | 46 (82.1) | 10 (17.9) |
| Parity | |||
| 0 | 231 (78.6) | 186 (80.5) | 45 (19.5) |
| 1 | 49 (16.7) | 43 (87.8) | 6 (12.2) |
| ≥2 | 14 (4.8) | 12 (85.7) | 2 (14.3) |
| Maternal age at menarche, mean (SD), y | 15.23 (1.37) | 15.17 (1.39) | 15.46 (1.26) |
| Maternal BMI, mean (SD) | 20.56 (2.04) | 20.57 (2.04) | 20.50 (2.03) |
| Supplement regimen | |||
| Folic acid | 99 (33.7) | 76 (76.8) | 23 (23.2) |
| Iron and folic acid | 94 (32.0) | 78 (83.0) | 16 (17.0) |
| Multiple micronutrients | 101 (34.4) | 87 (86.1) | 14 (13.9) |
| Paternal age, mean (SD), y | 26.71 (3.96) | 26.73 (4.07) | 26.58 (3.42) |
| Paternal educational attainment | |||
| <3 y | 3 (1.0) | 3 (100) | 0 |
| Primary | 21 (7.1) | 19 (90.5) | 2 (9.5) |
| Secondary | 190 (64.6) | 150 (78.9) | 40 (21.1) |
| High school or higher | 80 (27.2) | 69 (86.3) | 11 (13.8) |
| Paternal occupation | |||
| Farmer | 207 (70.5) | 172 (83.1) | 35 (16.9) |
| Other | 87 (29.6) | 69 (79.3) | 18 (20.7) |
| Household wealth index | |||
| Low | 71 (24.1) | 59 (83.1) | 12 (16.9) |
| Middle | 110 (37.4) | 82 (74.5) | 28 (25.5) |
| High | 113 (38.4) | 100 (88.5) | 13 (11.5) |
| Infant at birth | |||
| Birth weight, mean (SD), g | 3094 (380) | 3112 (368) | 3013 (426) |
| Birth length, mean (SD), cm | 48.9 (2.3) | 48.9 (2.3) | 48.7 (2.3) |
| Gestational age at delivery, mean (SD), wk | 40 (1) | 40 (1) | 40 (2) |
| SGA (<10th population percentile) | |||
| No | 236 (82.5) | 198 (83.9) | 38 (16.1) |
| Yes | 50 (17.5) | 37 (74.0) | 13 (26.0) |
| LBW (<2500 g) | |||
| No | 279 (95.2) | 230 (82.4) | 49 (17.6) |
| Yes | 14 (4.8) | 10 (71.4) | 4 (28.6) |
| Preterm birth (<37 wk) | |||
| No | 287 (97.6) | 235 (81.9) | 52 (18.1) |
| Yes | 7 (2.4) | 6 (85.7) | 1 (14.3) |
| Infant at 12 mo | |||
| WAZ, mean (SD) | 0.33 (0.87) | 0.44 (0.81) | −0.19 (0.95) |
| Underweight (WAZ < −1.00 SD) | |||
| No | 245 (93.2) | 207 (84.5) | 38 (15.5) |
| Yes | 18 (6.8) | 9 (50.0) | 9 (50.0) |
| LAZ, mean (SD) | −0.58 (0.96) | −0.48 (0.92) | −1.03 (1.03) |
| Stunting (LAZ < −2.00 SD) | |||
| No | 247 (93.9) | 208 (84.2) | 39 (15.8) |
| Yes | 16 (6.1) | 8 (50.0) | 8 (50.0) |
| BAZ, mean (SD) | 0.92 (1.06) | 1.00 (1.04) | 0.57 (1.12) |
| Overweight (BAZ >2.00 SD) | |||
| No | 222 (84.7) | 182 (82.0) | 40 (18.0) |
| Yes | 40 (15.3) | 34 (85.0) | 6 (15.0) |
| Child at 24 mo | |||
| WAZ, mean (SD) | 0.18 (0.80) | 0.25 (0.78) | −0.19 (0.85) |
| Underweight (WAZ < −1.00 SD) | |||
| No | 236 (92.2) | 200 (84.7) | 36 (15.3) |
| Yes | 20 (7.8) | 12 (60.0) | 8 (40.0) |
| LAZ, mean (SD) | −0.89 (0.93) | −0.80 (0.91) | −1.33 (0.90) |
| Stunting (LAZ < −2.00 SD) | |||
| No | 228 (88.7) | 195 (85.5) | 33 (14.5) |
| Yes | 29 (11.3) | 19 (65.5) | 10 (34.5) |
| BAZ, mean (SD) | 1.00 (1.00) | 1.02 (0.97) | 0.86 (1.13) |
| Overweight (BAZ >2.00 SD) | |||
| No | 218 (85.5) | 181 (83.0) | 37 (17.0) |
| Yes | 37 (14.5) | 31 (83.8) | 6 (16.2) |
| Early adolescence | |||
| Age, mean (SD), y | 11.25 (0.57) | 11.30 (0.58) | 11.04 (0.48) |
| HAZ, mean (SD) | 0.11 (1.03) | 0.30 (0.97) | −0.74 (0.83) |
| Stunting (HAZ < −2.00 SD) | |||
| No | 285 (97.3) | 237 (83.2) | 48 (16.8) |
| Yes | 8 (2.7) | 3 (37.5) | 5 (62.5) |
| BAZ, mean (SD) | −0.39 (1.09) | −0.19 (1.00) | −1.29 (1.03) |
| Thinness (BAZ < −2.00 SD) | |||
| No | 268 (92.7) | 227 (84.7) | 41 (15.3) |
| Yes | 21 (7.3) | 9 (42.9) | 12 (57.1) |
Abbreviations: BAZ, BMI-for-age z score; BMI, body mass index (calculated as weight in kilograms divided by square of height in meters); HAZ, height-for-age z score; LAZ, length-for-age z score; LBW, low birth weight; SGA, small for gestational age; WAZ, weight-for-age z score.
Unless otherwise indicated, data are expressed as No. (%) of patients. Data are missing for maternal educational attainment (n = 1), occupation (n = 1), age at menarche (n = 6), and BMI (n = 8); at birth, infant birth weight (n = 1), birth length (n = 17), SGA (n = 8), and LBW (n = 1); at 12 months of age, WAZ (n = 31), underweight (n = 31), LAZ (n = 31), stunting (n = 31), BAZ (n = 32), and overweight (n = 32); at 24 months of age, WAZ (n = 38), underweight (n = 38), LAZ (n = 37), stunting (n = 37), BAZ (n = 39), and overweight (n = 39); and in early adolescence, HAZ (n = 1), stunting (n = 1), BAZ (n = 5), and thinness (n = 5).