Objective: Decrease in bone mineral density (BMD) occurs relatively early and is known to be correlated with disease activity in patients with ankylosing spondylitis (AS). We investigated BMD and its correlation factors in Korean patients with AS. Methods: Fifty patients with AS fulfilling modified New York criteria and age-, sex-, and body mass index-matched 100 normal controls were selected. Medical records were reviewed retrospectively. Lumbar and femur BMD was measured using a dual energy X-ray absorptiometry. Results: Both lumbar and femur BMD in patients with AS were significantly lower than BMD in control group. Although Bath ankylosing spondylitis disease activity index, C-reactive protein and erythrocyte sedimentation rate showed no correlation with BMD, lumbar BMD in patients with high disease activity in terms of inflammatory factors was significantly lower than that in patients with low disease activity. Conclusion: BMD in patients with AS was significantly lower than those in control group. Early detection and appropriate management will be necessary in patients with AS.

Keywords: Ankylosing spondylitis, Bone mineral density