Aim: To investigate factors associated with low bone mineral density (BMD) in type-1 diabetic (T1D) patients.
Patients and methods: One hundred and seventy-five eugonadal T1D patients (age 32.8±8.4 years, diabetes duration 13.0±8.4 years) were studied. Body mass index (BMI), daily insulin dose (DID), age at diagnosis (AgeD), presence of diabetic complications, glomerular filtration rate (GFR), HbA1c, and BMD at lumbar spine (LS) and femur (F) by dual X-ray absorptiometry (as Z-score) were determined. Patients were categorized on the basis of LS- and F-BMD ≤ (low BMD) or >−1.0.
Results: As compared with T1D patients without low LS-BMD, those with low LS-BMD (n=46, 26.3%) had lower BMI (22.3±3.4 vs 24.4±3.7 kg/m2, P=0.005) and higher DID (0.9±0.3 vs 0.7±0.2 U/kg, P=0.0001). As compared with T1D patients without low F-BMD, those with low F-BMD (n=58, 33.1%) had lower BMI (23.0±3.3 vs 24.5±3.8 kg/m2, P=0.013), AgeD (17.3±8.7 vs 21.0±9.2 years, P=0.013) and GFR (88.1±31.3 vs 101.8±31.3 ml/min, P=0.007), and higher DID (0.8±0.3 vs 0.7±0.2 U/kg, P=0.006) and HbA1c (8.6±1.1 vs 8.2±1.2%, P=0.05). The diabetic complications were not associated with low BMD. The LS-BMD was independently associated with age (β=0.193, P=0.049), BMI (β=0.187, P=0.022), DID (β=−0.177, P=0.025), while F-BMD with GFR (β=0.170, P=0.03). The cut-off values of these factors for predicting low BMD at any site were determined (age 33.5 years, BMI 23.5 kg/m2, DID 0.67 U/kg, GFR 88.8 ml/min) and in each patient the presence/absence of each risk factor and a total risk factors score for low BMD (RFSc) was calculated by summing the number of present risk factors. The RFSc of 0 showed a negative predictive value of 81.8% and the RFSc of 4 a positive predictive value of 63.4%, for low BMD respectively.
Conclusion: In T1D patients, low LS-BMD is associated with young age, low BMI and high DID, while low F-BMD with low GFR.
30 Apr - 04 May 2011
European Society of Endocrinology