Although type 2 diabetes mellitus (DM) patients have normal or increased BMD as determined by DXA, risk of fracture is greater in DM than non-DM. This paradox has led to investigation of deficits in skeletal microarchitecture that may be responsible for increased fracture risk in DM. We conducted a community-based study of women and men to compare bone microarchitecture by DM status. Participants included 627 members (367 women, 260 men) of the Framingham Osteoporosis Study, mean age 65 yrs (range, 45-84). We defined DM as fasting glucose (FG) ≥126 mg/dl or use of DM medication and pre-DM as FG=100-125 mg/dl. Bone microarchitecture and density of the tibia and radius were measured by HR-pQCT (XtremeCT, SCANCO). Linear regression was used to calculate means (± SEs) for HR-pQCT bone indices according to DM status, adjusted for age, sex, and weight. 71 (40 men, 31 women) cohort members had DM (11%). At the tibia, persons with DM had significantly higher cortical porosity (11.17%±0.38 vs. 10.03%±0.13, p<0.01) and lower cortical vBMD (796.74±8.02 vs. 814.00±2.76, p=0.04) compared with non-DM. In contrast, trabecular vBMD and trabecular number were higher in DM, although differences were not statistically significant. Further, cortical porosity in the tibia was highest in DM (11.19%±0.38), intermediate in pre-DM (10.10%±0.19), and lowest in the non-DM group (9.95%±0.18); trend, p=0.02. HR-pQCT measures at the radius were not associated with DM. Results were similar when stratified by sex. In this community-based study, we found that women and men with DM had deficits in cortical bone at the tibia. To reduce the burden of skeletal fragility in DM, it will be important to determine whether deficits in cortical bone explain increased fracture risk observed in older adults with DM.
Disclosure: The authors declared no competing interests. This work was supported by National Institutes for Health, National Institute for Arthritis and Musculoskeletal and Skin Disorders, R01 AR061445R01.