Multilevel regression analysis of weight gain (kg) of infants, adjusted for sex and age
| Random variable | Constant | Age |
|---|---|---|
| Level 1 (within individuals) | ||
| Constant | 0.138 (0.0031) | |
| Level 2 (between individuals) | ||
| Constant | 0.414 (0.027) | |
| Age | 0.0014 (0.00014) | 0.000013 (0.000001) |
| Explanatory variables | Estimate | SEE |
| Constant | 4.26 | 0.22 |
| Age | 0.023 | 0.0013 |
| Age2 | −0.000021 | 0.0000007 |
| Sex | −0.28 | 0.059 |
| Initial weight | 0.86 | 0.051 |
| BF1–BF2 | −0.24 | 0.054 |
| BF0–BF2 | −0.31 | 0.099 |
| PA | −0.045 | 0.014 |
| CI | −0.092 | 0.032 |
| Interaction | ||
| Age*Sex | −0.0013 | 0.00037 |
| Age*NWT | −0.0010 | 0.00032 |
| Age*BF0 | 0.0013 | 0.00059 |
| Age*PA | −0.00024 | 0.000086 |
| Age*CI | −0.00034 | 0.00019 |
Values are means (standard error of the estimate (SEE)). Weight was expressed in kg. For statistical accuracy age is measured about an origin of 156 days. Sex: 0 for boys; 1 for girls.
BF2, breast feeding at 6 months; BF1, breast feeding at first visit; BF0, no breast feeding. BF2 is used as base measurement, and for statistical analysis other feeding groups are compared with it.
CI, crowding index; NWT, neonatal weight, PA, maternal parity.