title: Reduced Lower-Limb Muscle Strength and Volume in Patients With Type 2 Diabetes in Relation to Neuropathy, Intramuscular Fat, and Vitamin D Levels.
abstract: OBJECTIVE
  Muscle weakness and atrophy of the lower limbs may develop in patients with diabetes, increasing their risk of falls. The underlying basis of these abnormalities has not been fully explained. The aim of this study was to objectively quantify muscle strength and size in patients with type 2 diabetes mellitus (T2DM) in relation to the severity of neuropathy, intramuscular noncontractile tissue (IMNCT), and vitamin D deficiency.
  
  
  METHODS
  Twenty patients with T2DM and 20 healthy control subjects were matched by age, sex, and BMI. Strength and size of knee extensor, flexor, and ankle plantar and dorsiflexor muscles were assessed in relation to the severity of diabetic sensorimotor polyneuropathy (DSPN), amount of IMNCT, and serum 25-hydroxyvitamin D (25OHD) levels.
  
  
  RESULTS
  Compared with control subjects, patients with T2DM had significantly reduced knee extensor strength (P = 0.003) and reduced muscle volume of both knee extensors (P = 0.045) and flexors (P = 0.019). Ankle plantar flexor strength was also significantly reduced (P = 0.001) but without a reduction in ankle plantar flexor (P = 0.23) and dorsiflexor (P = 0.45) muscle volumes. IMNCT was significantly increased in the ankle plantar (P = 0.006) and dorsiflexors (P = 0.005). Patients with DSPN had significantly less knee extensor strength than those without (P = 0.02) but showed no difference in knee extensor volume (P = 0.38) and ankle plantar flexor strength (P = 0.21) or volume (P = 0.96). In patients with <25 nmol/L versus >25 nmol/L 25OHD, no significant differences were found for knee extensor strength and volume (P = 0.32 vs. 0.18) and ankle plantar flexors (P = 0.58 vs. 0.12).
  
  
  CONCLUSIONS
  Patients with T2DM have a significant reduction in proximal and distal leg muscle strength and a proximal but not distal reduction in muscle volume possibly due to greater intramuscular fat accumulation in distal muscles. Proximal but not distal muscle strength is related to the severity of peripheral neuropathy but not IMNCT or 25OHD level.
authors.affiliation: Centre for Endocrinology and Diabetes, Institute of Human Development, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K.
authors.forename: Monirah M
authors.initials: MM
authors.lastname: Almurdhi
authors.affiliation: School of Healthcare Science, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, U.K.
authors.forename: Neil D
authors.initials: ND
authors.lastname: Reeves
authors.affiliation: Centre for Endocrinology and Diabetes, Institute of Human Development, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K.
authors.forename: Frank L
authors.initials: FL
authors.lastname: Bowling
authors.affiliation: Centre for Endocrinology and Diabetes, Institute of Human Development, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K.
authors.forename: Andrew J M
authors.initials: AJ
authors.lastname: Boulton
authors.affiliation: Centre for Endocrinology and Diabetes, Institute of Human Development, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K.
authors.forename: Maria
authors.initials: M
authors.lastname: Jeziorska
authors.affiliation: Centre for Endocrinology and Diabetes, Institute of Human Development, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K. Weill Cornell Medical College, Doha, Qatar ram2045@qatar-med.cornell.edu.
authors.forename: Rayaz A
authors.initials: RA
authors.lastname: Malik
mesh_terms: D050154:Adiposity / Q000502:physiology*; D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000097:blood / Q000503:physiopathology*; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000294:innervation / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D018908:Muscle Weakness / Q000097:blood / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000502:physiology; D009133:Muscular Atrophy / Q000097:blood / Q000503:physiopathology; D016059:Range of Motion, Articular; D014807:Vitamin D; D014808:Vitamin D Deficiency / Q000097:blood / Q000503:physiopathology*
chemical_list: D014807:Vitamin D