Table 4.
Mean (SD) parameters within each cluster analysis group among men
| Cluster 1 (n = 36) | Cluster 2 (n = 51) | Cluster 3 (n = 49) | Cluster 4 (n = 52) | |
|---|---|---|---|---|
| Bone microarchitectural (standardised) | ||||
| Total area | 0.94 (0.73) | −0.19 (0.84) | 0.37 (0.69) | −0.82 (0.83) |
| Cortical area | −0.82 (0.89) | −0.52 (0.74) | 0.26 (0.77) | 0.82 (0.73) |
| Cortical thickness | −1.13 (0.70) | −0.32 (0.55) | 0.03 (0.64) | 1.07 (0.70) |
| Cortical density | −1.08 (0.76) | 0.08 (0.74) | -0.15 (0.79) | 0.81 (0.79) |
| Cortical porosity | 0.09 (0.80) | −0.39 (0.94) | 0.52 (0.99) | −0.17 (1.00) |
| Trabecular area | 1.10 (0.78) | −0.11 (0.73) | 0.28 (0.72) | −0.92 (0.67) |
| Trabecular density | −0.68 (0.86) | −0.64 (0.68) | 0.85 (0.65) | 0.30 (0.88) |
| Trabecular number | −0.12 (0.94) | −0.65 (0.84) | 0.57 (0.88) | 0.18 (0.93) |
| Trabecular thickness | −0.84 (0.88) | −0.41 (0.77) | 0.75 (0.64) | 0.28 (0.94) |
| Trabecular separation | 0.29 (0.88) | 0.69 (0.79) | −0.70 (0.85) | −0.22 (0.89) |
| FEA (standardised) | ||||
| Bone stiffness | −0.91 (0.84) | −0.68 (0.54) | 0.90 (0.72) | 0.44 (0.61) |
| Bone failure load | −0.82 (0.87) | −0.70 (0.57) | 0.92 (0.73) | 0.39 (0.62) |
| % load trabecular (distal) | 1.07 (0.55) | 0.11 (0.67) | 0.32 (0.52) | −1.15 (0.70) |
| % load trabecular (proximal) | 0.84 (0.94) | −0.39 (0.76) | 0.59 (0.57) | −0.76 (0.78) |
| Young modulus | −1.31 (0.62) | −0.48 (0.39) | 0.49 (0.57) | 0.92 (0.65) |
| Von Mises stresses (trabecular) | −0.84 (0.71) | −0.43 (0.80) | 0.80 (0.65) | 0.25 (0.97) |
| Von Mises stresses (cortical) | −1.11 (1.01) | 0.06 (0.77) | 0.03 (0.76) | 0.69 (0.68) |
| Trabecular strain | −0.88 (0.74) | −0.40 (0.84) | 0.77 (0.61) | 0.27 (0.94) |
| Cortical strain | −1.17 (1.14) | 0.12 (0.68) | 0.07 (0.81) | 0.62 (0.58) |
| DXA | ||||
| Femoral neck aBMD (g/cm2) | 0.88 (0.12) | 0.87 (0.11) | 1.02 (0.14) | 0.98 (0.12) |
| Pvalue | < 0.001 | < 0.001 | 0.108 | Reference |
| Normal* | 13 (37.1%) | 12 (25.0%) | 33 (71.7%) | 26 (51.0%) |
| Osteopenic* | 16 (45.7%) | 30 (62.5%) | 13 (28.3%) | 24 (47.1%) |
| Osteoporosis* | 6 (17.1%) | 6 (12.5%) | 0 (0.0%) | 1 (2.0%) |
| Fracture | ||||
| Prevalent fracture* | 12 (36.4%) | 13 (27.1%) | 12 (26.1%) | 8 (17.8%) |
| Relative risk of fracture | 2.05 (0.94,4.44) | 1.52 (0.70,3.33) | 1.47 (0.66,3.26) | Reference |
| Pvalue | 0.071 | 0.292 | 0.346 | Reference |
| Vertebral fracture* | 3 (8.3%) | 4 (8.0%) | 1 (2.1%) | 2 (3.8%) |
Cluster analysis was performed on the combined set of bone microarchitectural and FEA parameters
Bold if mean > 1 standard deviation from sample mean
P values for relative risk of prevalent fracture were calculated using Poisson regression with robust variance estimation. P values for differences in femoral neck aBMD were calculated using linear regression. P values are for differences compared to Cluster 4 (lowest risk)
*N (%)