Objective: We studied whether sensory function abnormalities are present at diagnosis and whether they develop in the early stages of non-insulin-dependent diabetes (NIDDM).
Research design and methods: Quantitative assessments of vibration sensitivity at the hallux and index fingers, and thermal sensitivity at the hallux were performed at screening (2-h oral glucose tolerance tests) for diabetes in 364 individuals. Twenty-five subjects diagnosed with NIDDM and 25 matched nondiabetic subjects were restudied after an interval of 12-41 mo.
Results: When those with NIDDM (n = 41) or impaired glucose tolerance (IGT) (n = 38) were compared with nondiabetic subjects, there were no significant differences in sensory function indices. However, the vibration threshold and HbA1c were related among those found to be hyperglycemic (IGT and NIDDM combined P less than 0.05; NIDDM alone P less than 0.05). Among diabetic subjects, the vibration threshold and interaction term of height and Hba1c were positively related in a multiple regression analysis (P less than 0.01). There were increments in all sensory thresholds in diabetic patients at follow-up (P less than 0.05 for all). Increments were smaller in control subjects.
Conclusions: These data suggest that although sensory function tends to be normal at diagnosis in NIDDM patients, there appears to be a diminution in sensory function as the disease progresses. An interaction between metabolic factors and height may influence sensory function early in the course of NIDDM.