Comorbid type 2 diabetes mellitus and hypertension exacerbates cognitive decline: evidence from a longitudinal study.
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.
Hassing
Linda B
LB
Department of Psychology, Göteborg University, Göteborg, Sweden. Linda.Hassing@psy.gu.se
Hofer
Scott M
SM
Nilsson
Sven E
SE
Berg
Stig
S
Pedersen
Nancy L
NL
McClearn
Gerald
G
Johansson
Boo
B
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