Type 2 diabetes and fractures: more information is needed

Excerpt

Type 2 diabetes mellitus (T2D) is an exceedingly common chronic metabolic disorder that has an enormous impact on public health. Currently, T2D affects over 366 million adults worldwide and is projected to reach 552 million by 2030 [1]. Until recently, the list of target organs affected by T2D did not include the skeleton. Yet there is now substantial evidence that older adults with T2D have a higher risk of sustaining a hip (RR = 1.7) or any clinical (RR = 1.2) fracture [2], morbidities that have important ramifications given the epidemic rates of this disease. Surprisingly, despite the increased fracture risk, bone mineral density (BMD) by dual energy X-ray absorptiometry (DXA) is generally higher in those with T2D [3]. In an analysis of three large prospective cohorts, BMD reliably predicted fracture risk in T2D, yet diabetics fractured at a T score that was higher by 0.6 than that of controls [4]. Similarly, two recent reports have shown that for a given fracture risk assessment (FRAX) probability, the risk of fracture among individuals with diabetes is higher than the risk in non-diabetics [4, 5]. Thus, although BMD and FRAX are able to predict fractures in T2D, both underestimate the actual fracture risk. This minimization may be partly explained by more frequent trauma, as diabetes is associated with an increased frequency of falls. However, even in studies of diabetes and fracture that control for fall frequency, diabetes remains independently associated with increased fracture risk [6]. Thus, the paradox of increased fracture risk with high bone density remains unresolved. Because BMD and FRAX are central to fracture prediction, a consequence of this paradox is a lack of suitable methods to predict fracture risk in older adults with T2D. …