Factor analysis of thermal and vibration thresholds in young patients withType 1 diabetes mellitus

Aims To identify factors that represent relationships among sets of interre lated thermal and vibration threshold variables and to find clinical correl ates that are significantly associated with these factors. Methods Thermal and vibration perception thresholds were tested in the hand s and feet of Type 1 diabetic patients treated in an outpatient clinic for juvenile-onset diabetes. Factor analysis was used to identify factors that represent relationships among sets of thermal and vibration threshold repre sent variables. Results One hundred and forty-eight patients (47.3% males, median current a ge 22.3 years and median duration of diabetes 11.4 years) were evaluated. T hree factors explained 77% of the total variance: 'hand sensation' factor, underlying cold, warmth and vibration perception thresholds in the hand; 'f oot sensation' factor, underlying the same sensory thresholds in the foot; and 'heat-related pain' factor, underlying heat pain perception threshold i n both limbs. The 'foot sensation' factor was the only factor that signific antly correlated with diabetes-related variables (e.g. duration and cumulat ive glycaemic control of the disease) and concurrent diabetic microangiopat hy. Male sex was associated with higher values of the 'heat-related' factor , while the 'hand sensation' factor did not correlate with any of the study variables. Conclusions The distribution of the various thermal and vibration threshold variables according to the three factors may point at length-dependent mec hanism of axonal degeneration. Cold, warmth and vibration perception thresh olds in the foot may be the only valuable psychophysical parameters in the evaluation of early sensory impairment associated with diabetes.