Endocrine Abstracts

Background: Impaired bone geometry and/or aberrant bone matrix formation may underlie the increased fracture risk observed in patients with type 1 diabetes mellitus (T1DM). Although reduced areal and volumetric bone mineral density (aBMD, vBMD) have been observed in pediatric and adolescent T1DM patients, few studies have confirmed these observations in adults. Moreover, data on bone geometry in T1DM remain scarce.

Objective: To compare areal and volumetric bone parameters and cortical bone geometry in adult T1DM patients and gender- and age-matched controls.

Methods: In 64 adult T1DM patients (39 men, 41.1±8.1 years) and 63 controls, areal and volumetric bone parameters and bone geometry were assessed using DXA and pQCT (radius: 4% and 66% regions).

Results: Median diabetes duration was 23.1 years, with a mean HbA1c of 63±5 mmol/mol over the last 10 years. In age-, height-, weight- and gender-adjusted analyses, T1DM was associated with lower aBMD and bone mineral content at the total hip (−5.14%, P=0.011 and −6.72%, P=0.013) and femoral neck (−7.43%, P=0.003 and −9.04%, P<0.001) and with lower femoral neck bone area (−2.82%, P=0.014). Cortical vBMD was higher in T1DM patients as compared to controls (+2.06%, P=0.004), but total vBMD was lower (−5.19%, P=0.020) and T1DM patients showed a cortical bone size deficit with smaller cortical thickness (−6.21%, P=0.035) and trends towards lower cortical area (−4.64%, P=0.060) and increased endosteal circumference (+5.29%, P=0.074). Furthermore, T1DM was associated with lower trabecular vBMD and higher trabecular area (−9.00% and +7.62%, P=0.013). Except for trabecular area, which was higher in male but not female T1DM patients as compared to controls, no major interactions between health status and gender were observed.

Conclusion: Besides decreased aBMD and trabecular vBMD, adult T1DM patients present with a cortical bone size deficit characterized by lower cortical thickness and higher endosteal circumference. This might contribute to the higher fracture risk observed in diabetic patients.