Univariate ORs (CIs) for the association of clinical predictors and the frequency of bone marrow oedema (BME) (in sacroiliac joints (SIJ) and spine) and fatty lesions (FL) (in spine)
| Parameter | BME SIJ | BME spine | FL spine |
| Age (per 10 years increase), years | 1.19 (0.88 to 1.62) | 1.33 (1.02 to 1.72) | 1.73 (1.32 to 2.27) |
| Sex (male vs female) | 1.14 (0.79 to 1.66) | 0.86 (0.63 to 1.18) | 1.27 (0.89 to 1.82) |
| BMI<25 (reference), kg/m2 | N/A | N/A | N/A |
| BMI (25–30 vs reference) | 1.46 (0.96 to 2.21) | 1.31 (0.93 to 1.86) | 1.48 (1.00 to 2.19) |
| BMI (>30 vs reference) | 1.61 (0.98 to 2.65) | 1.09 (0.71 to 1.68) | 3.27 (1.76 to 6.07) |
| Smoking (ever vs never) | 1.25 (0.84 to 1.84) | 1.06 (0.77 to 1.47) | 1.00 (0.69 to 1.44) |
| Back pain last 3 months (yes vs no) | 1.32 (0.90 to 1.93) | 1.00 (0.73 to 1.37) | 0.91 (0.63 to 1.31) |
| HLA-B27 (pos. vs neg.) | 1.27 (0.68 to 2.36) | 1.15 (0.66 to 1.99) | 1.14 (0.58 to 2.24) |
| hsCRP (>0.5 vs <0.5), mg/dL | 0.96 (0.46 to 2.03) | 0.83 (0.43 to 1.58) | 1.13 (0.54 to 2.37) |
| Physical activity (none=reference) | N/A | N/A | N/A |
| >2 hours vs none | 0.79 (0.47 to 1.35) | 0.88 (0.55 to 1.39) | 1.30 (0.75 to 2.26) |
| 1–2 hours vs none | 0.73 (0.45 to 1.20) | 0.89 (0.58 to 1.36) | 1.01 (0.62 to 1.63) |
| <1 hour vs none | 0.64 (0.38 to 1.08) | 0.85 (0.55 to 1.32) | 0.97 (0.59 to 1.59) |
BMI, body mass index; HLA-B27, human leucocyte antigen-B27; hsCRP, high-sensitivity C reactive protein; N/A, not applicable; neg., negative; pos., positive.