Abstract:

Objectives: Osteoporosis is a common complication of ankylosing spondylitis (AS) and various factors may cause a reduction in bone mineral density (BMD). Methods: In this study, the frequency of osteoporosis and the relationship between BMD and disease activity (BASDAI), functional status (BASFI), age, disease duration, body mass index (BMI), calcium, phosphorus, alkaline phosphatase, erythrocyte sedimentation rate, CRP, ferritin, intact parathyroid hormone, sex and thyroid hormones were investigated. Thirty four men with AS (mean age:35.4±10.7; mean disease duration:5.2±5.6 years) were enrolled. Results: The measurement of lumbar spine and/or femoral neck BMD was under -2.5 SD in 13 patients (38.2%). Osteopenia or osteoporosis was detected at lumbar region in 19 patients (55.9%), and at femoral neck in 10 cases (29.4%). The values of BMD T-score were found -1.44±1.76 for lumbar spine, and -0.24±1.35 for femoral neck. Negative correlation was found between DHEA-S and lumbar T-score (r=-0.44, p=0.013) and lumbar Z-score (r=-0.58, p=0.003). Positive correlation was found between lumbar Z-score and estradiol (r=0.45, p=0.029) and homocysteine (r=0.68, p=0.004). For presence of osteoporosis, there was a positive correlation with DHEA-S (r=0.44, p=0.011), and negative correlation with estradiol (r=-0.39, p=0.029). When looking at the correlation between disease activity and osteoporosis, there was only negative correlation between BASFI and femoral neck Z-score (r=-0.47, p=0.027), and positive correlation between BASDAI and the presence of osteoporosis (r=0.40, p=0.025). Conclusion: Osteoporosis is a common complication of young men with AS. Further studies are required to determine the factors that contribute to a reduction of bone density in AS.

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