Table 2.
Infant growth by household socioeconomic status and covariates
| Birth weight | Three-month weight | Change in weight1 | Rapid growth | ||||||
|---|---|---|---|---|---|---|---|---|---|
| n | SDS (95% CI) | n | SDS (95% CI) | n | SDS (95% CI) | % | OR (95% CI) | ||
| Overall | 2313 | −0.56 (−0.59, −0.52) | 2099 | −0.27 (−0.32, −0.23) | 2081 | 0.28 (0.23, 0.32) | 34 | - | |
| SES2 | Higher | 1470 | −0.56 (−0.61, −0.51) | 1367 | −0.33 (−0.39, −0.27) | 1351 | 0.23 (0.18, 0.28) | 32 | Ref |
| Intermediate | 394 | −0.52 (−0.61, −0.42) | 348 | −0.16 (−0.27, −0.05) | 348 | 0.33 (0.22, 0.43) | 34 | 1.08 (0.85, 1.40) | |
| Lower | 449 | −0.57 (−0.65, −0.49) | 384 | −0.18 (−0.28, −0.07) | 3832 | 0.40 (0.30, 0.50) | 39 | 1.36 (1.07, 1.72) | |
| p for trend (weighted) |
0.93 | 0.003 | 0.001 | 0.0133 | |||||
| Potential Explaining variables | |||||||||
| Smoking | No | 2062 | −0.54 (−0.58, −0.50) | 1888 | −0.27 (−0.32, −0.22) | 1873 | 0.27 (0.22, 0.31) | 33 | Ref |
| Yes | 256 | −0.69 (−0.80, −0.57) | 217 | −0.30 (−0.44, −0.16) | 214 | 0.36 (0.23, 0.50) | 40 | 1.34 (1.00, 1.78) | |
| p for difference | 0.02 | 0.72 | 0.17 | 0.06 | |||||
| Mother BMI4 | Desirable | 1319 | −0.61 (−0.66, −0.56) | 1197 | −0.30 (−0.36, −0.24) | 1185 | 0.31 (0.25, 0.36) | 35 | Ref |
| Overweight | 692 | −0.49 (−0.57, −0.42) | 625 | −0.32 (−0.40, −0.23) | 622 | 0.18 (0.10, 0.26) | 32 | 0.90 (0.73, 1.11) | |
| Obese | 309 | −0.45 (−0.56, −0.35) | 284 | −0.08 (−0.20, 0.04) | 281 | 0.37 (0.26, 0.48) | 34 | 0.97 (0.74, 1.28) | |
| p for trend (weighted) |
0.001 | Deviation: 0.03 | Deviation: 0.002 | 0.553 | |||||
| Partner BMI4 | Desirable | 846 | −0.57 (−0.64, −0.50) | 770 | −0.33 (−0.41, −0.26) | 763 | 0.23 (0.16, 0.30) | 32 | Ref |
| Overweight | 1168 | −0.56 (−0.62, −0.51) | 1054 | −0.26 (−0.33, −0.20) | 1045 | 0.30 (0.25, 0.36) | 35 | 1.12 (0.92, 1.36) | |
| Obese | 306 | −0.49 (−0.58, −0.39) | 282 | −0.16 (−0.28, −0.03) | 280 | 0.30 (0.19, 0.41) | 34 | 1.08 (0.81, 1.44) | |
| p for trend (weighted) |
0.28 | 0.02 | 0.17 | 0.413 | |||||
| Breast feeding duration |
No breastfeeding | 529 | −0.53 (−0.61,−0.45) | 449 | −0.08 (−0.18, 0.02) | 445 | 0.44 (0.35, 0.52) | 40 | Ref |
| 0 – 1 month | 480 | −0.53 (−0.62, −0.45) | 453 | −0.08 (−0.18, 0.01) | 450 | 0.45 (0.37, 0.54) | 39 | 0.95 (0.72, 1.24) | |
| 1 – 2 months | 323 | −0.63 (−0.74, −0.53) | 292 | −0.28 (−0.41, −0.15) | 289 | 0.36 (0.26, 0.45) | 34 | 0.77 (0.57, 1.05) | |
| 2 – 3 months | 173 | −0.54 (−0.68, −0.39) | 158 | −0.28 (−0.45, −0.11) | 156 | 0.21 (0.06, 0.37) | 31 | 0.68 (0.46, 1.00) | |
| ≥ 3 months | 705 | −0.56 (−0.63, −0.49) | 661 | −0.53 (−0.61, −0.45) | 655 | 0.03 (−0.04, 0.11) | 26 | 0.53 (0.41, 0.68) | |
| p for trend (weighted) |
0.56 | <0.001 | <0.001 | <0.001 | |||||
Abbreviation: BMI, Body Mass Index; CI, confidence interval; SDS, standard deviation score; OR, odds ratio
1
Change in weight SDS: weight at three months SDS minus birth weight SDS
2
Higher SES: managerial and professional occupations; Intermediate SES: intermediate occupation; lower SES: routine and manual occupations
3
p-value for overall SES effect
4
Mother and partner BMI: desirable BMI ≤ 25; overweight: BMI 25 – 30; obese: BMI > 30