Variables associated with low BMD (Z≤-2) in univariate analysis (N=332)
| Low BMD | Low lumbar spine BMD | Low hip BMD | ||||
|---|---|---|---|---|---|---|
| OR (95% CI) | p Value | OR (95% CI) | p Value | OR (95% CI) | p Value | |
| Age | 0.98 (0.95 to 1.02) | 0.346 | 0.99 (0.95 to 1.03) | 0.485 | 1.00 (0.95 to 1.05) | 0.955 |
| Gender (male) | 6.84 (3.00 to 18.48) | <0.0001 | 9.35 (3.24 to 27.01) | <0.0001 | 11.29 (2.61 to 48.84) | 0.001 |
| BMI | 0.92 (0.84 to 1.00) | 0.061 | 0.91 (0.83 to 1.01) | 0.069 | 0.88 (0.77 to 1.00) | 0.046 |
| BASDAI >40 | 1.00 (0.53 to 1.93) | 0.994 | 1.10 (0.56 to 2.19) | 0.778 | 0.93 (0.41 to 2.15) | 0.871 |
| ASDAS | 1.66 (1.15 to 2.38) | 0.006 | 1.70 (1.16 to 2.47) | 0.006 | 1.38 (0.87 to 2.21) | 0.175 |
| CRP | 1.04 (1.02 to 1.06) | 0.0001 | 1.04 (1.02 to 1.06) | <0.0001 | 1.01 (0.99 to 1.04) | 0.329 |
| ESR | 1.04 (1.02 to 1.05) | <0.0001 | 1.04 (1.02 to 1.06) | <0.0001 | 1.01 (0.99 to 1.03) | 0.288 |
| HLA-B27 | 0.60 (0.28 to 1.18) | 0.152 | 0.55 (0.26 to 1.17) | 0.122 | 0.66 (0.26 to 1.63) | 0.364 |
| ASAS criteria | 2.25 (0.97 to 5.26) | 0.061 | 2.32 (0.94 to 5.73) | 0.070 | 1.57 (0.57 to 4.33) | 0.385 |
| x-Ray sacroiliitis | 1.82 (0.92 to 3.53) | 0.080 | 2.05 (1.02 to 4.13) | 0.044 | 1.25 (0.52 to 3.03) | 0.621 |
| Sacroiliac BMO MRI | 2.50 (1.28 to 4.87) | 0.007 | 2.72 (1.34 to 5.53) | 0.006 | 1.25 (0.54 to 2.91) | 0.608 |
| Spine BMO MRI | 4.36 (2.18 to 8.72) | <0.0001 | 5.02 (2.43 to 10.40) | <0.0001 | 2.55 (1.06 to 6.12) | 0.037 |
| Dorsal spine BMO MRI | 3.88 (1.77 to 8.27) | 0.001 | 4.10 (1.86 to 9.07) | 0.001 | 1.78 (0.62 to 5.05) | 0.281 |
| Lumbar spine BMO MRI | 3.39 (1.52 to 7.54) | 0.003 | 4.15 (1.83 to 9.38) | 0.001 | 2.71 (1.00 to 7.34) | 0.0050 |
| Lean mass | 1.04 (1.01 to 1.08) | 0.023 | 1.04 (1.01 to 1.08) | 0.018 | 1.04 (1.00 to 1.09) | 0.089 |
| Fat mass | 0.95 (0.91 to 0.99) | 0.017 | 0.94 (0.89 to 0.98) | 0.006 | 0.97 (0.92 to 1.02) | 0.268 |
| % Fat mass | 0.95 (0.91 to 0.98) | 0.003 | 0.94 (0.90 to 0.97) | 0.001 | 0.93 (0.88 to 0.98) | 0.004 |
ASAS, Assessment of Spondyloarthritis International Society; ASDAS, ankylosing spondylitis disease activity score; BASDAI, Bath ankylosing spondylitis disease activity index; BMD, bone mineral density; BMI, body mass index; BMO, bone marrow oedema; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate.