Risk of fracture according to history of ankylosing spondylitis
| Fracture type | Ankylosing spondylitis | No of cases | No of controls | Crude OR (95% CI) | Adjusted OR* (95% CI) |
| Any | No | 231436 | 231362 | Reference | Reference |
| Yes | 416 | 342 | 1.22 (1.05 to 1.40) | 1.02 (0.88 to 1.18) | |
| Radius/ulna | No | 44138 | 44119 | Reference | Reference |
| Yes | 82 | 63 | 1.30 (0.94 to 0.81) | 1.21 (0.87 to 1.69) | |
| Hip | No | 14362 | 14363 | Reference | Reference |
| Yes | 25 | 26 | 0.96 (0.56 to 1.67) | 0.77 (0.43 to 1.37) | |
| Vertebral | No | 8701 | 8678 | Reference | Reference |
| Yes | 34 | 11 | 3.08 (1.56 to 6.08) | 3.26 (1.51 to 7.02) |
*Adjusted for medications and illnesses associated with risk of fracture (as outlined in the Methods section), and smoking and body mass index when known.
CI, confidence interval; OR, odds ratio.