Diabetic polyneuropathy is a risk factor for decline of lower extremity strength in patients with type 2 diabetes

AIMS/INTRODUCTION The present study elucidated the effect of diabetic polyneuropathy (DPN) on lower extremity strength in a wide age range of type 2 diabetes patients. MATERIALS AND METHODS Participants (n = 1,442) were divided into three age groups (30-49 years, 50-69 years and 70-87 years), and comparisons were made separately for each sex. Lower extremity strength was measured in terms of knee extension force (KEF) with a hand-held dynamometer. KEF was compared according to the presence or absence of DPN. Furthermore, the effect of DPN on KEF with other diabetic complications (diabetic retinopathy and diabetic nephropathy), diabetes status (diabetes duration and glycated hemoglobin) and habitual behavior (regular exercise, smoking and drinking behaviors) as explanatory variables was analyzed using multiple regression analysis in several models. RESULTS The frequency of DPN differed among age groups, ranging from 14.3 to 49.6%, and increasing with age. There was no significant difference in KEF between patients aged 30-49 years with and without DPN. However, among both men and women aged 50-69 years and 70-87 years, patients with DPN showed significantly diminished KEF (11.0-12.9% and 11.9-16.6%, respectively) compared with those without DPN (P < 0.01-0.001). In women aged 50-69 years and 70-87 years, and in men aged 50-69 years, DPN was a significant explanatory variable for KEF in all multiple regression analysis models. CONCLUSION DPN might reinforce a KEF decline in middle-aged and elderly type 2 diabetes patients.