Fracture Risk in Diabetes

Advanced Imaging Reveals Secrets of Increased Fracture Risk in Diabetes
Dateline: San Francisco, Calif.

Thomas Link, M.D., needn’t have worried that he might have to close down an imaging system critical to his work on fragility fractures in people with type 2 diabetes mellitus (T2DM). A grant from the American Recovery and Reinvestment Act (ARRA), has "reinvigorated" his osteoporosis imaging program, allowing him and his team of researchers at the University of California, San Francisco, to better understand why individuals with the T2DM have these fractures, despite the absence of low bone mineral density (BMD). The answer, he says, may be found in bone structure and composition features that his imaging facility identified.
Normal BMD, as measured by a standard imaging procedure called dual x-ray absorptiometry (DXA), does not usually indicate a higher risk for fractures. But when studies showed that women with T2DM had both normal or higher BMD and fractures, Dr. Link decided to investigate further. Using a different imaging modality called high-resolution peripheral quantitative computed tomography (hr-pQCT), he looked at bone structure in a group of elderly women with type 2 diabetes mellitus. This type of imaging system was able to reveal increases in the porosity of cortical bone (an indicator of impaired bone strength) among the T2DM women, as compared with women without the disease. Furthermore, they found a trend toward higher bone marrow fat in the women with diabetes, in particular, in those whose diabetes was not well controlled. Dr. Link now plans to expand his studies and further explore these findings.
Given the project’s success, the scientist is excited about the potential of hr-pQCT to join BMD as a possible bone biomarker for fracture risk. "Finding a strong, noninvasive bone-quality biomarker for fragility fractures in people with diabetes is clearly a major challenge area," says Dr. Link. "Based on our preliminary data, we believe that our novel biomarker may be able to better characterize fracture risk in these patients."