Bone metabolism in postmenopausal women with lumbar spinal stenosis: Analysis of bone mineral density and bone turnover markers

Study Design. A cross-sectional study. Objective. To investigate bone mineral density (BMD) and the change of bone turnover rate in postmenopausal women with lumbar spinal stenosis (LSS). Summary of Background Data. Symptomatic LSS prevents elderly patients from performing daily activities because of back pain and neurogenic claudication. Walking intolerance due to neurologic claudication might have a negative effect on bone metabolism and BMD. However, there has been no study on the relationship between LSS and bone metabolism, especially on bone turnover rate. Methods. Sixty-seven patients were in the LSS group. As a control group, 67 age- and weight-matched subjects were selected. In both groups, BMD, bone turnover markers, vitamin D, severity of knee osteoarthritis, and demographic data were obtained. In the LSS group, walking distance without rest was also recorded. BMD, bone turnover markers, vitamin D, and severity of knee osteoarthritis were compared between the two groups. In the LSS group, the correlation between walking intolerance and bone turnover markers was also analyzed. Results. In the LSS group, urinary N-terminal telopeptide of type I collagen (u-NTx) and alkaline phosphatase were significantly elevated when compared with those of the control group (P < 0.05). However, BMD was significantly low in the control group in all of the measured sites (P < 0.05). In the LSS group, neither bone markers nor BMD were correlated with the extent of walking difficulty. Conclusion. Our study highlights the fact that limited physical activity results in high bone turnover rate in patients with LSS.