Association of Nerve Conduction Velocity with Total Body Fat Mass and Body Mass Index in Type 2 Diabetes Mellitus

Introduction: There is a close association between obesity and type 2 diabetes as well as its complications. Obesity related changes in nerve conduction assume paramount importance in diabetic patients where the nerve functions are already compromised by other metabolic derangements. Aim: To study any existing correlation of the Nerve Conduction Velocity (NCV) with the Total Body Fat Mass (TBFM) and Body Mass Index (BMI) and to identify which is a better predictor of NCV impairment in type 2 diabetics. Materials and Methods: A prospective, cross-sectional study was conducted during April 2018-January 2019 in 90 patients with confirmed diagnosis of Diabetes type 2 of recent onset or not more than 8 years and age between 30 to 60 years. NCV was measured in both upper and lower limbs. Median, ulnar, and posterior tibial nerves were selected for motor nerve conduction study and median, Ulnar and sural nerves were selected for sensory nerve conduction study. Bioelectric Impedance Analysis (BIA) was used to find the TBFM. The correlation of TBFM and BMI with the NCV was assessed by using Pearson's coefficient of linear correlation. Results: Both BMI and TBFM showed negative correlation with the motor and sensory NCV of both sides of the body. BMI had a significant negative correlation with conduction velocity of two sensory nerve viz., right median (r=-0.388) and left sural (r=-0.356) and two motor nerves viz., right median (r=-0.483) and right posterior tibial (r=-0.305) only. However, the TBFM showed a significant negative correlation with the motor conduction velocity of four motor viz., right median (r=-0.602), right posterior tibial (r=-0.455), left median (r=-0.483) and left posterior tibial (r=-0.288) and four sensory nerves viz., right median (r=-0.411), right sural (r=-0.435), left median (r=-0.461) and left sural (r=-0.408). Conclusion: TBFM as assessed by BIA analysis shows a stronger correlation with the NCV as compared to the BMI and should be used clinically along with electrophysiological studies for the risk factor stratification of diabetic peripheral neuropathy in type 2 diabetes patients.