Table 1.
Correlation coefficients between standardized properties in bone from (a)–(d) young and (e)–(h) adult groups
| Predictors | a. Young LFD (n = 15) | b. Young HFD (n = 15) | ||||
| Size-independent measures | Size-dependent measures | Size-independent measures | Size-dependent measures | |||
| (σ y, σ u, E) | K c | P u | (σ y, σ u, E) | K c | P u | |
| aBMD | −0.3357 | 0.2225 | 0.3055 | 0.0317 | 0.5767* | 0.5089 |
| BMC | −0.2654 | 0.3362 | 0.4731 | 0.1793 | 0.4383 | 0.2907 |
| (D, t, M.A.) | −0.7497** | 0.4931 | 0.1384 | −0.4951 | 0.0037 | 0.214 |
| LBM | −0.4108 | 0.319 | 0.3969 | −0.2584 | 0.0167 | 0.1194 |
| FBM | 0.1384 | −0.2299 | −0.1014 | 0.1582 | −0.4439 | −0.2404 |
| c. Bone size in LFD—(D, t, M.A.) | d. Bone size in HFD—(D, t, M.A.) | |||||
| LBM | 0.8133*** | 0.4982 | ||||
| FBM | −0.1433 | −0.4298 | ||||
| Predictors | e. Adult LFD (n = 13a) | f. Adult HFD (n = 14) | ||||
| Size-independent measures | Size-dependent measures | Size-independent measures | Size-dependent measures | |||
| (σ y, σ u, E) | K c | P u | (σ y, σ u, E) | K c | P u | |
| aBMD | 0.0808 | 0.2741 | 0.0574 | −0.4976 | 0.2376 | −0.2333 |
| BMC | −0.1709 | 0.1131 | 0.3577 | −0.4312 | −0.0746 | −0.0991 |
| (D, t, M.A.) | −0.5559* | 0.3858 | 0.7536* | −0.5046 | −0.3889 | 0.4426 |
| LBM | 0.1485 | 0.3775 | 0.5138 | −0.2061 | −0.1537 | 0.6519* |
| FBM | −0.1075 | 0.0715 | −0.4535 | −0.1394 | −0.3774 | −0.0796 |
| g. Bone size in LFD—(D, t, M.A.) | h. Bone size in HFD—(D, t, M.A.) | |||||
| LBM | 0.4587 | 0.6377* | ||||
| FBM | −0.1284 | −0.0023 | ||||
Coefficients from correlation analysis applied between standardized mechanical properties and standardized bone and physiological properties of (a), (c) young LFD group; (b), (d) young HFD group; (e), (g) adult LFD group; (f), (h) adult HFD group. In cases where measurements were related and highly positively correlated, a composite score was used in the analysis. Bone size is the largest predictor of mechanical properties, more so than bone mineral measures or body composition. Interestingly, size-independent measures of bone quality are most affected by the size of the bone, which implies a reduced quality with increasing quantity. Correlation coefficients between body mass measures and bone size measures show that LBM is positively correlated with bone size in both groups (c), (d), (g), (h) and that FBM is very weakly negatively correlated with bone size. Correlation coefficients are conducted separately for young and adult groups
vBMD volumetric bone mineral density, M.A. second moment of area, A Ct. cross-sectional area, R o outer Ct. Rd, LBM lean body mass, FBM fat body mass, σ y yield strength, σ u maximum strength, E bending modulus, K c fracture toughness, P y yield load, P u maximum load, (D, t, M.A.) composite bone size score, (σ y , σ u , E) composite strength and modulus score
* p < 0.05, ** p < 0.01, *** p < 0.001
aOne mouse died in week 4 of the study from fighting