Table 4.
Regression results
| Bone Outcome | Model Adj. r2 | Activity (h/wk) | Age (yrs) | Height (cm) | Fiber | Vit B12 No sup | Zn No sup | Carb | Vit C | Mg No sup |
|---|---|---|---|---|---|---|---|---|---|---|
| PA | 0.43c | 0.004a | --- | c | −0.005a | 0.01b | −0.007a | 0.000a | --- | --- |
| BMD (g/cm2) | (0.001, 0.007) | --- | (−0.009,−0.001) | (0.003,0.02) | (−0.02, 0.000) | (0.000, 0.001) | --- | --- | ||
| +0.28 | --- | +0.41 | −0.25 | +0.30 | −0.22 | +0.25 | --- | --- | ||
| PA | 0.64c | 0.08b | (0.06) | c | −0.06b | 0.12b | --- | --- | --- | --- |
| BMC (g) | (0.03, 0.13) | (−0.11, −0.02) | (0.03, 0.21) | --- | --- | --- | --- | |||
| +0.26 | −0.17 | +0.60 | −0.25 | +0.24 | --- | --- | --- | --- | ||
| LAT | 0.63c | 0.03a | --- | c | −0.03a | 0.07b | --- | --- | --- | --- |
| BMC (g) | (0.000, 0.05) | --- | (−0.06, −0.005) | (0.02, 0.12) | --- | --- | --- | --- | ||
| +0.18 | --- | +0.71 | −0.20 | +0.24 | --- | --- | --- | --- | ||
| LAT | 0.19c | --- | --- | c | --- | --- | --- | --- | --- | --- |
| DEPTH(cm) | --- | --- | --- | --- | --- | --- | --- | --- | ||
| --- | --- | +0.46 | --- | --- | --- | --- | --- | --- | ||
| LAT | 0.35c | −0.01b | c | XXXX | (0.09) | --- | --- | --- | --- | --- |
| HEIGHT(cm) | (−0.02, −0.005) | XXXX | --- | --- | --- | --- | --- | |||
| −0.34 | +0.54 | XXXX | −0.20 | --- | --- | --- | --- | --- | ||
| PA | 0.26b | 0.03a | a | c | --- | --- | --- | 0.003a | (0.06) | (0.06) |
| WIDTH (cm) | (0.006, 0.06) | --- | --- | --- | (0.000, 0.007) | |||||
| +0.30 | −0.26 | +0.44 | --- | --- | --- | +0.27 | −0.23 | −0.24 | ||
| PALAT | 0.21b | 0.17a | a | c | --- | --- | --- | --- | --- | --- |
| CSA (cm2) | (0.02, 0.31) | --- | --- | --- | --- | --- | --- | |||
| +0.29 | −0.27 | +0.48 | --- | --- | --- | --- | --- | --- | ||
| PALAT | 0.36c | 0.004b | --- | c | (0.09) | 0.008b | --- | --- | --- | --- |
| IBS(g2/cm4) | (0.001, 0.007) | --- | (0.002, 0.01) | --- | --- | --- | --- | |||
| +0.33 | --- | +0.43 | −0.20 | +0.31 | --- | --- | --- | --- | ||
| PALAT | 0.25c | −0.02c | c | XXXX | --- | --- | --- | --- | 0.001a | --- |
| lnFRI | (−0.03, −0.009) | XXXX | --- | --- | --- | --- | (0.000, 0.002) | --- | ||
| −0.44 | +0.42 | XXXX | --- | --- | --- | --- | +0.27 | --- | ||
For all models, focal nutritional variables, age, height and organized physical activity dose were initially entered for backward stepwise analysis.
Exceptions were: LATHEIGHT and lnFRI, for which height was not entered, as those variables are a function of total body height.
Due to high collinearity with other variables, calories and protein were run in separate regressions from other dietary variables; they were excluded from all models.
Model adjusted r2 is reported for the final model, as determined by backward stepwise regression.
Significance (beta t) and semi-partial correlation coefficients are reported for all included variables.
Significance is denoted as follows:
p<0.05
p<0.01
p<0.001
For strong non-significant trends, p is listed in superscript parentheses.
Other than for age and height, β (95% Confidence Interval) is reported for each significant independent variable.
Dependent variables are as follows: PABMD= postero-anterior areal bone mineral density; PABMC= PA bone mineral content; LATBMC= lateral BMC; LATDEPTH= lateral vertebral depth (out of PA scan plane); LATHEIGHT= lateral vertebral body height; PAWIDTH= PA width; PALATCSA= “3D” bone cross-sectional area (coronal plane); PALATIBS= “3D” index of structural strength in axial compression; lnFRI= natural logarithm of fracture risk index.
Due to low explanatory value (model adj. r2= 0.07) and high collinearity (variance inflation factors=6.9 to 26.6), the PALAT bone mineral apparent density model was discarded.