Table 5.
Cluster analysis of bone microarchitectural parameters in women
| Cluster 1 (n=26) | Cluster 2 (n=20) | Cluster 3 (n=39) | Cluster 4 (n=39) | Cluster 5 (n=35) | |
|---|---|---|---|---|---|
| HRpQCT | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) |
| Total area (mm2) | 307.0 (37.7) | 280.4 (34.8) | 255.1 (28.6) | 326.8 (36.6) | 262.2 (23.3) |
| Trabecular area (mm2) | 267.7 (36.3) | 232.7 (33.3) | 205.7 (26.6) | 277.9 (34.6) | 205.6 (23.5) |
| Cortical area (mm2) | 38.3 (4.6)↓ | 46.5 (8.1) | 47.3 (6.2) | 47.6 (7.3) | 54.8 (7.1) |
| Cortical thickness (µm) | 481.7 (60.3)↓ | 680.8 (129.6) | 732.3 (105.4) | 627.3 (99.2) | 855.7 (133.9)↑ |
| Cortical density (mg/cm3) | 834.9 (46.7)↓ | 919.1 (42.9) | 947.7 (29.8) | 882.3 (40.4) | 929.5 (40.1) |
| Cortical porosity (%) | 3.4 (1.1) | 2.7 (1.4) | 2.8 (1.0) | 3.9 (1.2) | 4.6 (1.2) |
| Trabecular density (mg/cm3) | 110.0 (19.9) | 76.9 (17.9)↓ | 145.3 (23.9) | 151.9 (20.2) | 192.5 (24.7)↑ |
| Trabecular number (cm−1) | 19.3 (3.2) | 13.4 (2.5)↓ | 20.5 (2.4) | 22.7 (2.1) | 24.4 (1.7) |
| Trabecular thickness (µm) | 47.9 (6.5) | 48.0 (10.4) | 59.3 (8.6) | 56.1 (7.1) | 65.9 (6.9) |
| Trabecular separation (µm) | 485.9 (97.8) | 722.2 (146.0)↑ | 434.8 (61.1) | 388.8 (41.2) | 346.6 (30.6) |
| DXA | |||||
| Femoral neck aBMD (g/cm2)a | 0.75*** | 0.73*** | 0.85* | 0.85* | 0.94 |
| Normalb | 2 (7.7) | 5 (25.0) | 16 (41.0) | 17 (43.6) | 24 (68.6) |
| Osteopenic | 21 (80.8) | 8 (40.0) | 21 (55.9) | 20 (51.3) | 10 (28.6) |
| Osteoporotic | 3 (11.5) | 7 (35.0) | 2 (5.1) | 2 (5.1) | 1 (2.8) |
| Fracture | |||||
| Proportion with prevalent fracture | 50.0% | 50.0% | 30.8% | 20.5% | 14.3% |
| OR (95% CI) of fracturea | 6.0* (1.77,20.31) | 6.0* (1.65,21.80) | 2.67 (0.83,8.55) | 1.55 (0.45,5.27) | 1.0 Reference |
Key: p value for difference between clusters 0.006.
a
p value for difference when compared to lowest risk cluster (cluster 5);
b
Count (percentage).
*
p<0.05,
**
p<0.01,
***
p<0.001.
Bold if mean is >1SD from sex-specific mean;
↑
indicates mean is >1SD above the sex-specific mean;
↓
indicates mean is >1SD below the sex-specific mean.