title: Comorbid type 2 diabetes mellitus and hypertension exacerbates cognitive decline: evidence from a longitudinal study.
abstract: BACKGROUND
  diabetes and hypertension are two highly prevalent diseases in the old population. They are highly related such that comorbidity is common.
  
  
  OBJECTIVE
  to examine (i) the independent impact of the respective diseases on cognitive decline in very old age and (ii) the interactive impact of the two diseases on cognitive decline.
  
  
  METHODS
  258 individuals (mean age = 83 years), all non-demented at baseline. Of these, 128 individuals (non-cases) were free from diabetes and hypertension, 92 individuals had a diagnosis of hypertension, 16 had a type 2 diabetes mellitus diagnosis without hypertension, and 22 had comorbid diabetes and hypertension.
  
  
  METHODS
  a population-based longitudinal study of ageing (The OCTO-Twin Study), including four measurement occasions 2 years apart. The Mini-Mental State Examination was used to measure general cognitive function. Data were analysed using SAS Proc Mixed multilevel modelling.
  
  
  RESULTS
  longitudinal trajectories indicated a steeper decline in cognitive function related to diabetes but not related to hypertension. However, the results indicated greatest cognitive decline among persons with comorbid diabetes and hypertension.
  
  
  CONCLUSIONS
  it is concluded that comorbidity of diabetes and hypertension produce a pronounced cognitive decline. This finding emphasises the importance of prevention and treatment of those highly prevalent diseases in the old population.
authors.affiliation: Department of Psychology, Göteborg University, Göteborg, Sweden. Linda.Hassing@psy.gu.se
authors.forename: Linda B
authors.initials: LB
authors.lastname: Hassing
authors.forename: Scott M
authors.initials: SM
authors.lastname: Hofer
authors.forename: Sven E
authors.initials: SE
authors.lastname: Nilsson
authors.forename: Stig
authors.initials: S
authors.lastname: Berg
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Pedersen
authors.forename: Gerald
authors.initials: G
authors.lastname: McClearn
authors.forename: Boo
authors.initials: B
authors.lastname: Johansson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003071:Cognition / Q000502:physiology*; D003704:Dementia / Q000209:etiology; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000523:psychology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000523:psychology*; D008137:Longitudinal Studies; D008297:Male