Osteoporosis in patients with ankylosing spondylitis / 中国实用内科杂志

ABSTRACT

Objectives To study the frequency and risk factors of osteoporosis,and the relationship between bone turnover makers and bone mineral density (BMD) in patients with ankylosing spondylitis (AS).Methods BMD in the spine and femoral neck was measured with dual-energy x-ray absorptiometry (DEXA) in 30 AS patients. Enzyme linked immunoassay was used to measure serum bone gla protein (BGP), bone-specific alkalin phosphtase (BAP), and urine deoxypyridinoline crosslinks (D Pyr).Results The patients in early stage lost the bone mass already.They had lower volume of BMD in both hip and spines than that of controls. But in the later stage,the BMD of spines was higher than that of the control group because of the calcification of the surrounding tissues of the spine.While even the BMD of femoral neck was still lower than that of normal subjects. Osteoporosis was observed in 6 patients, osteopenia in 10. Osteoporosis in AS correlated negatively with the disease duration, ESR, CRP, and X ray grades. The reduction in BMD in premenopausal women with early AS was slighter than that in men. The BMD had no significant differences in HLA B 27 (+) patients and HLA B 27 (-)patients. BGP and BAP which reflect bone formation had no differences in AS patients and controls. D Pyr which reflects bone resorption was significantly increased compared with controls.Conclusions Osteoporosis in AS is common and may be related to disease duration and severity. A significant increase in bone resorption is observed in AS with osteoporosis.