title: Diabetes is associated with postural instability and gait difficulty in Parkinson disease.
abstract: BACKGROUND
  Comorbid diabetes may be associated with more severe motor impairment in Parkinson disease. In normal elderly individuals, diabetes is associated with parkinsonian features, including gait difficulty and rigidity, though not tremor. Whether diabetes contributes to increased motor dysfunction in Parkinson disease by exacerbating nigrostriatal dopaminergic denervation or through intensification of extranigral pathology is unknown.
  
  
  METHODS
  We performed a case-control study (n = 39) involving 13 Parkinson disease subjects (age 66.4yrs ± 5.5; duration of disease 6.9yrs ± 4.4) with diabetes and 26 age, gender, and duration-of-disease-matched Parkinson disease controls without diabetes. All subjects underwent [(11)C]dihydrotetrabenazine vesicular monoamine transporter type-2 positron emission tomography imaging to assess striatal dihydrotetrabenazine distribution volume ratio and Unified Parkinson disease rating scale motor examination to determine rigidity, bradykinesia, tremor, and postural instability and gait difficulty subscores. Magnetic resonance imaging scans were analyzed to assess leukoaraiosis burden.
  
  
  RESULTS
  After controlling for nigrostriatal dopaminergic denervation, Parkinson disease subjects with diabetes displayed greater postural instability and gait difficulty subscores (t = 3.81, p = 0.0005). There were no differences in bradykinesia, rigidity, or tremor subscores between cases and controls. The association between diabetes and postural instability and gait difficulty persisted after controlling for comorbid hypertension and body mass index. Leukoaraiosis, distal vibratory sense, and levodopa dose equivalents did not differ significantly between cases and controls.
  
  
  CONCLUSIONS
  Diabetes may contribute to postural instability and gait difficulty in Parkinson disease through mechanisms other than nigrostriatal dopaminergic denervation.
authors: Department of Neurology, University of Michigan, Ann Arbor, MI, USA. vikaskot@med.umich.edu
authors: Vikas
authors: V
authors: Kotagal
authors: Roger L
authors: RL
authors: Albin
authors: Martijn L T M
authors: ML
authors: Müller
authors: Robert A
authors: RA
authors: Koeppe
authors: Kirk A
authors: KA
authors: Frey
authors: Nicolaas I
authors: NI
authors: Bohnen
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D003920:Diabetes Mellitus / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D005260:Female; D005684:Gait / Q000502:physiology*; D020233:Gait Disorders, Neurologic / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D049268:Positron-Emission Tomography / Q000379:methods; D004856:Postural Balance / Q000502:physiology*; D012189:Retrospective Studies