title: Cognitive efficiency declines over time in adults with Type 1 diabetes: effects of micro- and macrovascular complications.
abstract: OBJECTIVE
  Mild cognitive dysfunction is not uncommon in adults with Type 1 diabetes, but its pathogenesis remains unclear. Previous cross-sectional studies had suggested that microangiopathy might affect brain integrity and lead to "central neuropathy." To assess the relationship between changes in cognitive performance and the incidence of new micro- and macrovascular complications, 103 young and middle-aged adults (mean age: 40 yrs) with childhood-onset Type 1 diabetes were followed over a 7-year period, and were compared to 57 demographically-similar adults without diabetes.
  
  
  METHODS
  All subjects completed a comprehensive battery of neurocognitive tests on two occasions. Diabetic subjects also received repeated medical assessments to diagnose the onset of clinically significant complications.
  
  
  RESULTS
  Relative to control subjects, diabetic adults showed significant declines on measures of psychomotor efficiency; no between-group differences were evident on learning, memory, or problem-solving tasks. The development of proliferative retinopathy and autonomic neuropathy during the follow-up period predicted decline in psychomotor speed (p<0.01), as did incident macrovascular complications (p<0.05), systolic blood pressure at follow-up (p<0.01), and duration of diabetes (p<0.01).
  
  
  CONCLUSIONS
  This study shows that cognitive efficiency may decline over time in diabetic adults, and that this neurocognitive change may be linked, at least in part, to the occurrence of complications like proliferative retinopathy and elevated blood pressure. Therapeutic interventions that reduce the risk of vascular complications may have a similarly beneficial effect on the brain and reduce the risk of neurocognitive dysfunction in diabetic patients.
authors.affiliation: Western Psychiatric Institute and Clinic, University of Pittsburgh School of Medicine, 3811 O'Hara Street, Pittsburgh, PA 15213, USA. ryancm@msx.upmc.edu
authors.forename: C M
authors.initials: CM
authors.lastname: Ryan
authors.forename: M O
authors.initials: MO
authors.lastname: Geckle
authors.forename: T J
authors.initials: TJ
authors.lastname: Orchard
mesh_terms: D000328:Adult; D017668:Age of Onset; D003072:Cognition Disorders / Q000209:etiology*; D003922:Diabetes Mellitus, Type 1 / Q000523:psychology*; D003925:Diabetic Angiopathies / Q000523:psychology*; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D012016:Reference Values; D012044:Regression Analysis