Risk factors for hip fracture in Japanese elderly women with osteoporosis: applicability of biochemical markers in bone turnover.

Aim: The purpose of this study was to investigate risk factors for hip fracture in 169 Japanese elderly women.

Methods: Patients were divided into three groups: 53 patients had osteoporosis with hip fractures (FX-G), 59 patients had osteoporosis without hip fractures (NFX-G) and 57 patients had low back pain with neither osteoporosis nor hip fracture (NOP-G). Bone mineral density (BMD) of lumbar spine, bone-specific alkaline phosphatase (BAP) and deoxypyridinoline (DPD) were compared among the three groups.

Results: The mean BMD of FX-G and NFX-G was lower than that of NOP-G, but there was no significant difference between FX-G and NFX-G. Although the mean BAP of FX-G was similar to that of NOP-G, both were lower than NFX-G (P < 0.05). However, the mean DPD of FX-G was higher than the other groups (P < 0.05, vs NFX-G, P < 0.001, vs NOP-G). The percentage of patients who showed BAP levels less than 35 IU/L and DPD levels of 7.5 nmoL/mmol-Cr or more, was highest in FX-G (72.7%). This percentage was lower for NFX-G (30.9%) and NOP-G (16.4%). The odds ratio of hip fracture occurring was 5.77 (95% confidence interval, 2.25-14.66).

Conclusion: Bone turnover consisting of increase in bone resorption and decrease in bone formation apart from BMD of lumbar spine resulted in a higher incidence of hip fracture for Japanese elderly women with osteoporosis.