Bone ultrasonography in type 1 and type 2 diabetes: correlations with neuropathic and angiopathic complications

ltered glucose metabolism has marked harmful effects on bone metabolism, having important consequences in terms of reduced bone mass and increased fracture risk. This study set out to explore, in patients affected by type 1 (DM1) and type 2 diabetes (DM2), possible relationships between ultrasonography parameters, indices of metabolic control and parameters indicating complications of diabetes, particularly neuropathy and angiopathy. We studied a total of 265 patients (145 males and 120 females), affected by DM1 (51 patients, 23 males and 28 females) or DM2 (214 patients, 122 males and 92 females), consecutively referred from general medicine to a specialist diabetes centre. Anthropometric and serological parameters were evaluated in all the patients, including lipid profile and glycated haemoglobin (HbA1C). The function of sensory nerve fibres was evaluated by determination of vibration perception threshold (VPT); this was measured at the medial malleolus and hallux by means of a biotesiometer. Autonomic function was evaluated clinically using tests that included beat-to-beat HRV, deep breathing, expiration-to-inspiration ratio, heart rate response to standing, systolic blood pressure response to standing, and the cough test. In addition, all the subjects were assessed using a device for ultrasound assessment of the heel bone (Sahara, Hologic), thereby obtaining speed of sound (SOS), broadband ultrasound attenuation (BUA) and QUI measurements. As expected, in all patients a significant inverse relation (p<0.001) was found between ultrasound parameters and age. QUI and BUA were positively correlated with BMI and waist circumference. In women with DM2, QUI and BUA showed a close correlation with BMI, waist circumference and % body fat (measured using the Tanita BIA technique). In all the patients we observed a significant correlation between BUA, HDL cholesterol, creatinine, uric acid and HbA1C. Still considering the whole population, SOS was found to be significantly correlated with the VPT of the malleolus (p<0.05), and hallux (p<0.001) and positively correlated with the deep breathing (p<0.05) and lying to standing tests (p<0.01). In men with DM1 there also emerged a close correlation between ultrasonography parameters, particularly QUI and SOS, and VPT, deep breathing, lying to standing and the cough test. Furthermore, in the men, QUI and SOS showed an inverse correlation with carotid intima thickness; this correlation was stronger when considering only the men with DM1. On the basis of these results, we can conclude that the complications of diabetes, such as peripheral and autonomic neuropathy and micro and macroangiopathy, are associated with reduced ultrasound parameter values. Bone ultrasound can provide useful information for assessing the bone status of diabetic patients and may represent a further method for evaluating the extent of neurological damage in diabetic patients.