Prevalence of Low Bone Mineral Density in Younger Versus Older Women With Distal Radius Fractures
Although distal radius fractures (DRFs) are the most common fractures among younger women, few studies have examined bone health in this age group.
We compared bone mineral density (BMD) of younger women (35-50 years) and older women (>50 years) treated for DRFs. Between January 2005 and August 2010, our orthopedic service obtained dual-energy x-ray absorptiometry scans from 128 women with DRFs (47 were 35-50 years old; 81 were older than 50 years).
According to the World Health Organization classification system, 43% of the younger patients were osteopenic, and 6% were osteoporotic. Mean femoral neck BMD was 0.91 for the younger group and 0.80 for the older group (P < .05); t scores were –0.87 and –1.65, respectively (P < .05). The difference in femoral neck z scores between the younger and older patients was not statistically different: –0.69 and –0.67, respectively (P = .92).
A notable proportion of younger patients with DRFs have osteopenia or osteoporosis. The similarity in z scores among younger and older women with DRFs and among patient groups differentiated by mechanism of injury suggests that any younger or older woman with a DRF should have her BMD evaluated and treated as appropriate.
Secondary causes of osteoporosis have been documented in 30% of premenopausal women and 55% of men with vertebral fractures.13-15 Primary osteoporosis results from the normal aging process; secondary osteoporosis results from reversible causes, including medications, gastrointestinal disorders, renal disease, endocrine disorders, and sedentary lifestyle.15,16 When a secondary cause of osteoporosis is identified, treatment can be initiated to increase BMD. As younger patients can reverse bone loss and even increase BMD, it is important to identify reversible causes of osteopenia and osteoporosis in this age group. It is well documented that both younger and older patients with DRFs are at increased risk for subsequent fractures.6 Preventing further bone loss at a younger age may drastically decrease lifetime fracture risk.12,17
Most previous studies of BMD in women were limited to patients with DRFs caused by a low-energy mechanism or by a fall from standing. Current recommendations for BMD testing focus on postmenopausal women who have sustained a fragility or low-energy DRF. When an osteoporotic or osteopenic patient’s distal radius is subjected to a high-energy force, a fracture is likely. Therefore, we expanded our study to include high-energy mechanisms of injury. Our analysis of BMD in patients with DRFs sustained in MVCs indicated that 12% of this group were osteoporotic, and 44% were osteopenic. Forty-three percent of our younger patients with a DRF fractured in a MVC were osteopenic, and 6% were osteoporotic. Among 4 mechanisms of injury for DRFs, there was no statistically significant difference in z scores (P = .22) (Figure 2). This provides evidence that a significant portion of patients with DRFs from both high- and low-energy mechanisms are osteoporotic or osteopenic. Patients with DRFs sustained in MVCs or in falls from heights of more than 6 feet should be referred for BMD evaluation.
Conclusion
A significant proportion of younger patients with DRFs are osteopenic or osteoporotic (43% and 6%, respectively), and their z scores are comparable to those of older patients with DRFs. There was no statistically significant difference in BMD z scores between younger and older patients and no difference in mechanisms of injury. This is evidence that younger patients with DRFs caused by a high- or low-energy mechanism of injury should undergo both DXA scan and BMD evaluation. If osteoporosis or osteopenia can be diagnosed at an earlier age, and if these patients can be properly treated, subsequent fractures could be prevented. The present study provides evidence supporting a simplification of the current recommendations for BMD evaluation: All women with DRFs should undergo bone densitometry.
