Table 7.
Associations between IGF-I and body composition at term age
| Fat mass term age, r (95% CI)1 | Fat free mass term age, r (95% CI)1 | Fat mass percentage term age, B (95% CI)2 | Fat free mass percentage term age, B (95% CI)2 | |
|---|---|---|---|---|
| IGF-I 4 wks PNA | 0.14 (−0.18 to 0.43) | 0.53 (0.27 to 0.72) | −0.2 (−1.0 to 0.5)a | 0.2 (−0.6 to 1.0)b |
| IGF-I 36 wks PMA | 0.18 (−0.18 to 0.48) | 0.16 (−0.19 to 0.47) | 0.4 (−0.4 to 1.1)c | 0.4 (−1.1 to −0.4)d |
| IGF-I Term age | 0.24 (−0.16 to 0.57)3 | 0.43 (0.06 to 0.69) 3 | 0.0 (−0.5 to 0.5)e | 0.0 (−0.5 to 0.5)f |
| Change in IGF-I birth—4 wks PNA | 0.22 (−0.12 to 0.51) | 0.59 (0.33 to 0.77) | −2.5 (−35.7 to 30.7)g | 2.2 (−32.1 to 36.5)h |
| Change in IGF-I birth—36 weeks PMA | 0.23 (−0.04 to 0.47)4 | 0.33 (0.07 to 0.55) 4 | 4.4 (−4.2 to 13.1) i4 | −4.6 (−13.5 to 4.2)j4 |
| Change in IGF-I from 30 weeks PMA onward | 0.06 (−0.21 to 0.32)4 | 0.03 (−0.24 to 0.30)4 | 2.0 (−3.0 to 7.1)k4 | −2.2 (−7.4 to 3.0)l4 |
Associations in bold were statistically significant P < 0.05.
Abbreviations: PMA, postmenstrual age; PNA, postnatal age.
1 Correlations were controlled for gestational age at birth and postmenstrual age at time of body composition measurement
2 Gestational age at birth and postmenstrual age at the time of body composition measurement were entered in the regression model as covariates
3 Also corrected for postmenstrual age at blood sampling
4 Not controlled for gestational age at birth, because gestational age did not correlate with change in IGF-I across PMA nor did it correlate with body composition.
a R2 0.070, P 0.448; b R2 0.078, P 0.396; c R2 0.133, P 0.226; d R2 0.140, P 0.204; e R2 0.136, P 0.330; f R2 0.146, P 0.294; g R2 0.066, P 0.530; h R2 0.073, P 0.483; i R2 0.069, P 0.160; j R2 0.075, P 0.136; k R2 0.062, P 0.195; l R2 0.069, P 0.159.