Table 2.
Results of the mixed linear model for the dependent variable total IGF-I
| Effect | Parameter estimate | se | P value |
|---|---|---|---|
| Intercept | −0.899 | 1.223 | <0.0001 |
| Tanner I | −1.402 | 0.622 | 0.0254 |
| Tanner II | −2.001 | 0.729 | 0.0066 |
| Tanner III | −1.830 | 0.912 | 0.0466 |
| Age (Tanner I) | 0.156 | 0.128 | 0.0224 |
| Age (Tanner II) | 0.464 | 0.220 | 0.0349 |
| Age (Tanner III) | 0.425 | 0.319 | 0.0183 |
| Age (Tanner IV and V) | −0.330 | 0.231 | 0.9540 |
| Fat mass | 0.019 | 0.029 | 0.5026 |
| Lean mass | 0.664 | 0.120 | <0.0001 |
| Sex | 0.278 | 0.049 | <0.0001 |
| E2 | 0.094 | 0.019 | <0.0001 |
| Testosterone | 0.073 | 0.017 | <0.0001 |
| Ethnicity | 0.083 | 0.019 | <0.0001 |
Significant effects are in bold type. All continuously distributed variables were log transformed to correct for skewed distributions. Ethnicity and sex were coded in the models as follows: EA = 0; AA = 1; male = 0; female = 1. Age (Tanner), The age nested in the TS variable was used to account for changes in age within each TS.