Table 1.
Background characteristics of infants included in group-based trajectory analysis in a Chinese birth cohort study (N = 1388)a.
| Factors | No. (%)/Mean (SD) | Factors | No. (%)/Mean (SD) |
|---|---|---|---|
| Maternal age | 24.4(4.4) | Child characteristics | |
| Maternal education | Male | 845(60.9) | |
| <3 years | 61(4.4) | Birth weight (g) | 3185(410) |
| Primary | 341(24.6) | Weeks of gestation at birth | 39.9(1.6) |
| Secondary | 798(57.6) | Preterm (<37 weeks gestation) | 50(3.6) |
| High school+ | 185(13.4) | Low birth weight (<2500 g) | 50(3.7) |
| Maternal occupation | Small for gestational age(<10th percentile) | 165(12.3) | |
| Farmer | 1172(84.8) | Age at middle childhood/years | |
| Others | 210(15.2) | Mean (SD) | 7.8(0.6) |
| Paternal age (years) | 27.7(4.2) | Range | 7–9 |
| Paternal education | Age at adolescence/years | ||
| <3 years | 12(0.9) | Mean (SD) | 11.3(0.6) |
| Primary | 139(10.1) | Range | 10–12 |
| Secondary | 914(66.1) | MDI at 30 months of age | 86.7(18.7) |
| High school+ | 317(22.9) | WISC-IV at school age(7–9 years) | |
| Paternal occupation | FSIQ | 89.5(12.6) | |
| Farmer | 1054(76.1) | VCI | 87.4(15.5) |
| Others | 332(24.0) | WMI | 91.2(12.0) |
| Household wealth at enrollment | PRI | 93.6(13.3) | |
| Low | 324(23.3) | PSI | 95.3(12.9) |
| Medium | 562(40.5) | WISC-IV at adolescence(10–12 years) | |
| High | 502(36.2) | FSIQ | 98.1(12.5) |
| Parity at enrollment | VCI | 102.9(15.6) | |
| 0 | 943(67.9) | WMI | 94.5(11.0) |
| ≥1 | 445(32.1) | PRI | 96.0(12.5) |
| Maternal MUAC (cm) | PSI | 100.0(13.7) | |
| <21.5 | 219(15.9) | ||
| ≥21.5 | 1159(84.1) | ||
| Trial treatment | |||
| Folic acid | 496(35.7) | ||
| Iron/folic acid | 467(33.7) | ||
| Multiple micronutrients | 425(30.6) |
aData are missing for maternal age (n = 2), maternal education (n = 3), maternal occupation(n = 6), paternal age(n = 2), paternal education(n = 6), paternal occupation(n = 2), maternal MUAC(n = 10), birth weight(n = 21), preterm(n = 21), and SGA(n = 51).
Abbreviation: VCI, verbal comprehension index; FSIQ, full-scale intelligence quotient derived from WISC-IV, Wechsler Intelligence Scale for Children-Fourth Edition; MDI, mental development index; MUAC, mid-upper arm circumference; PRI, perceptual reasoning index; PSI, processing speed index; SD, standard deviation; SGA, small for gestational age; WMI, working memory index.