Table 3. Multivariate-adjusted relative risks (RRs) and 95% confidence intervals of overweight and underweight in Chinese children aged 3–6 years.
| Birth weight (kg) | Overweight | Underweight | ||||
| No. of cases | RR1a | RR2b | No. of cases | RR1a | RR2b | |
| <2.50 | 88 | 0.77 (0.61–0.97) | 0.80 (0.64–1.01) | 513 | 2.53 (2.27–2.83) | 2.31 (2.07–2.58) |
| 2.50– | 237 | 0.77 (0.67–0.89) | 0.80 (0.69–0.92) | 1005 | 1.69 (1.56–1.82) | 1.56 (1.45–1.69) |
| 2.75– | 448 | 0.86 (0.78–0.96) | 0.88 (0.79–0.98) | 1379 | 1.33 (1.25–1.43) | 1.28 (1.20–1.37) |
| 3.00– | 1713 | 1.00 (Ref) | 1.00 (Ref) | 3030 | 1.00 (Ref) | 1.00 (Ref) |
| 3.25– | 1259 | 1.05 (0.97–1.13) | 1.03 (0.96–1.11) | 1660 | 0.74 (0.70–0.79) | 0.77 (0.73–0.82) |
| 3.50– | 1624 | 1.21 (1.13–1.30) | 1.18 (1.10–1.26) | 1563 | 0.63 (0.59–0.67) | 0.68 (0.64–0.73) |
| 3.75– | 576 | 1.39 (1.26–1.53) | 1.32 (1.20–1.46) | 413 | 0.45 (0.41–0.50) | 0.51 (0.46–0.56) |
| 4.00– | 473 | 1.90 (1.70–2.12) | 1.78 (1.60–1.99) | 286 | 0.52 (0.46–0.60) | 0.60 (0.53–0.68) |
| ≥4.25 | 162 | 2.38 (2.01–2.83) | 2.17 (1.83–2.59) | 72 | 0.41 (0.33–0.53) | 0.50 (0.39–0.64) |
| P for linear trend | <0.001 | <0.001 | <0.001 | <0.001 | ||
| P for quadratic trend | <0.001 | <0.001 | <0.001 | <0.001 | ||
aRR1: Adjusted for residence area (northern/southern); child’s sex (male/female); child’s age at follow-up (40–41, 42–47, 48–53, 54–59, 60–65, 66–71, 72–77, 78–79 months); maternal age at delivery (<22, 22–24, 25–27, 28–30, 31–34, ≥35 years); occupation (farmer/non-farmer); education (high school or above, middle school, primary school or below); folic acid supplementation before or during pregnancy, primiparous (yes/no); child’s gestational age at birth (<37, 37–39, 40–41, ≥42 weeks); child’s body length at birth (<P5 (43.0), P5 to <P50 (50.0), P50 to <P95 (52.0), ≥P95 cm); pregnancy-induced hypertension (yes/no); and maternal weight gain during pregnancy (<P25 (8.0), P25 to <P50 (11.0), P50 to <P75 (14.0), ≥P75 kg).
bRR2: Further adjusted for maternal height (<P5 (1.51), P5 to <P25 (1.56), P25 to <P50 (1.59), P50 to <P75 (1.61), P75 to <P95 (1.66), ≥P95 cm) and weight at first prenatal visit during pregnancy (<P5 (43.0), P5 to <P25 (48.0), P25 to <P50 (52.0), P50 to <P75 (56.0), P75 to <P95 (63.0), ≥P95 kg).