Comparative Assessment of Motor Nerve Conduction Velocity among Non-Diabetic, Diabetic Non-Smoker and Sub Groups of Diabetic Smoker.

ABSTRACT

Background: Neuropathy is one of the most common complications affecting individuals with diabetes mellitus. The best evidence indicates that the etiology of neuropathy is multifactorial and is a key area of current research. Hence, this study was undertaken to test the hypothesis of alteration in MNCV (motor nerve conduction velocity) of nerves before the actual manifestation of neuropathy in type II diabetic patients and also to analyze the effect of smoking on MNCV in diabetic subjects. Methods: In the present study, 120 diagnosed diabetics were taken as cases while 30 non diabetic healthy subjects were taken as controls. Case group was divided into diabetic non-smokers and diabetic smokers. Diabetic smokers were further subdivided into light, moderate and heavy smokers, according to smoking index. After detailed history and physical examination MNCV of median and ulnar nerve in upper limb and common peroneal nerve in lower limb was performed. Result: The MNCV of median and ulnar nerves in upper limb showed no significant bilateral decreased in diabetic non-smokers and subgroup of diabetic smokers when compared with control. However, there was a significant bilateral decrease in MNCV of common peroneal nerves in the lower limb of diabetic heavy smokers when compared with control. A negative, but statistically non-significant correlation was found between MNCV and smoking index. The decrease in MNCV was dependent on smoking index by 3%, 1%, 1%, 1%, 3% and 1% in median nerve (right), median nerve (left), ulnar nerve (right), ulnar nerve (left), common peroneal nerve (right) and common peroneal nerve (left) respectively. Conclusion: The present study indicates that MNCV is more resistant to hyperglycemia induced local metabolic and microvascular changes. However, the coalition of diabetes and smoking can augment their effects many folds and can lead to motor neuropathy, reiterating the fact that smoking itself is an independent risk factor for diabetic neuropathy.