THE EFFECTS OF AGE AND DIABETES-MELLITUS ON NERVE FUNCTION

Objective: This project evaluated the association of age and vibratory thresholds (assessment modality of large sensory nerve fibers) in sub jects with and without diabetes mellitus. Design: Cross-sectional stud y. Setting: Medical Research Institute of Delaware. Participants: Indi viduals with non-insulin-dependent diabetes mellitus and non-diabetic control subjects. Measurements: Vibratory thresholds were examined in four age groups (ie, <45 yrs, 45-54 yrs, 55-64 yrs, greater-than-or-eq ual-to 65 yrs). The independent association of age, duration of diabet es, height, gender, glycemic control, and smoking history were analyze d in terms of their relationship to vibratory thresholds. Main Results : Vibratory thresholds increased with age for both control and diabeti c subjects. Comparing controls with diabetic subjects in the same age categorizes revealed significant differences for vibratory thresholds only in the greater-than-or-equal-to 65 year old age group. Modeling w ith vibratory thresholds as the dependent variable showed that age and male gender were independently associated with vibratory thresholds f or the controls and explained the majority of the variability (R2 = 0. 79). Age, duration of diabetes, and height were independently associat ed with vibratory thresholds for the diabetic subjects but explained m uch less of the variability (R2 = 0.39). Conclusion: The results sugge st an acceleration of the natural aging process for large sensory nerv e fiber function in diabetic subjects. Thus, young diabetic subjects m ay be at a risk of lower extremity complications as a result of injuri es similar to that of older non-diabetic individuals.