Table 4

Variables associated with low BMD (Z≤-2) in univariate analysis (N=332)

Low BMDLow lumbar spine BMDLow hip BMD
OR (95% CI)p ValueOR (95% CI)p ValueOR (95% CI)p Value
Age0.98 (0.95 to 1.02)0.3460.99 (0.95 to 1.03)0.4851.00 (0.95 to 1.05)0.955
Gender (male)6.84 (3.00 to 18.48)<0.00019.35 (3.24 to 27.01)<0.000111.29 (2.61 to 48.84)0.001
BMI0.92 (0.84 to 1.00)0.0610.91 (0.83 to 1.01)0.0690.88 (0.77 to 1.00)0.046
BASDAI >401.00 (0.53 to 1.93)0.9941.10 (0.56 to 2.19)0.7780.93 (0.41 to 2.15)0.871
ASDAS1.66 (1.15 to 2.38)0.0061.70 (1.16 to 2.47)0.0061.38 (0.87 to 2.21)0.175
CRP1.04 (1.02 to 1.06)0.00011.04 (1.02 to 1.06)<0.00011.01 (0.99 to 1.04)0.329
ESR1.04 (1.02 to 1.05)<0.00011.04 (1.02 to 1.06)<0.00011.01 (0.99 to 1.03)0.288
HLA-B270.60 (0.28 to 1.18)0.1520.55 (0.26 to 1.17)0.1220.66 (0.26 to 1.63)0.364
ASAS criteria2.25 (0.97 to 5.26)0.0612.32 (0.94 to 5.73)0.0701.57 (0.57 to 4.33)0.385
x-Ray sacroiliitis1.82 (0.92 to 3.53)0.0802.05 (1.02 to 4.13)0.0441.25 (0.52 to 3.03)0.621
Sacroiliac BMO MRI2.50 (1.28 to 4.87)0.0072.72 (1.34 to 5.53)0.0061.25 (0.54 to 2.91)0.608
Spine BMO MRI4.36 (2.18 to 8.72)<0.00015.02 (2.43 to 10.40)<0.00012.55 (1.06 to 6.12)0.037
Dorsal spine BMO MRI3.88 (1.77 to 8.27)0.0014.10 (1.86 to 9.07)0.0011.78 (0.62 to 5.05)0.281
Lumbar spine BMO MRI3.39 (1.52 to 7.54)0.0034.15 (1.83 to 9.38)0.0012.71 (1.00 to 7.34)0.0050
Lean mass1.04 (1.01 to 1.08)0.0231.04 (1.01 to 1.08)0.0181.04 (1.00 to 1.09)0.089
Fat mass0.95 (0.91 to 0.99)0.0170.94 (0.89 to 0.98)0.0060.97 (0.92 to 1.02)0.268
% Fat mass0.95 (0.91 to 0.98)0.0030.94 (0.90 to 0.97)0.0010.93 (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.