Colles' fracture of the wrist as an indicator of underlying osteoporosis in postmenopausal women: a prospective study of bone mineral density and bone turnover rate

Abstract

Colles' fracture has been shown to be associated with an increased risk of hip fracture. The incidence of low bone mineral density (BMD) and high bone turnover in such patients is uncertain. The aim of this study was to prospectively assess BMD and bone turnover in a cohort of consecutive postmenopausal Colles' fracture patients. BMD (spine, hip and contralateral radius) was measured by dual-energy X-ray absorptiometry (DXA) within 2 weeks of fracture. Bone turnover was assessed within 4 days by measurement of serum osteocalcin, total alkaline phosphatase (TALP), bone-specific alkaline phosphatase (BSAP) and urine hydroxyproline. We recruited 106 (71%) of 149 consecutive patients. Fifty-one per cent of subjects had a history of previous fracture, and 25% a past history of wrist, hip or vertebral body fracture. The incidence of osteoporosis was 21%, 42% and 22% at the spine, hip and radius respectively. Fifty per cent of subjects had osteoporosis of at least one of these sites. When compared with the values expected for their age the patients were found to have higher BMD than expected at the spine, and slightly lower BMD at the hip and distal radius. Patients aged 65 years or less had lower hip BMD than expected from the age-matched normal range (p < 0.01). Osteocalcin and TALP levels did not differ from the normal ranges, but BSAP and hydroxyproline levels were significantly elevated (p < 0.001), with 37% and 25% of patients having levels above the respective normal ranges. We conclude that osteoporosis is common in patients with Colles' fracture; however, in older patients BMD is not lower than would be expected in the normal population. In patients aged 65 years or less BMD is lower than expected at the hip. Bone turnover rate is high in many such patients. Intervention to prevent future fracture would be appropriate in women aged 65 years or less with Colles' fracture.