Low systolic blood pressure is associated with impaired cognitive function in the oldest old: longitudinal...

The primary aim of the present study was to examine whether there is an association between blood pressure and the risk of subsequent cognitive decline in the oldest old. Various factors associated with blood pressure and cognitive function were considered.

The study comprised 599 individuals of a population-based sample, 199 men (mean age at baseline 82.8 years, range 80-95) and 400 women (mean age at baseline 83.3 years, range 80-100). Cognitive function was evaluated by the Mini Mental State Examination (MMSE). For a subgroup of 385 subjects (130 men, 255 women), data were available on blood pressure and MMSE at baseline and two followups at two-year intervals. Baseline blood pressure was studied in one group with reduced cognition and in another group with intact cognition across the following four years. The association of systolic blood pressure (SBP) with the MMSE score through the follow-up period was analysed controlling for frailty (time to death), age, gender, apoprotein E, homocysteine, hypertension, congestive heart failure, and stroke.

A medical history of arterial hypertension was associated with lower MMSE scores and a higher prevalence of dementia and cognitive decline at baseline. However, intact cognition through the observation period was associated with higher baseline SBP. This relationship also remained when the frailty of aging subjects, indicated by remaining time to death, was taken into account.

Lower SBP in the oldest old is associated with an increased risk of cognitive impairment even after adjustment for compromised vitality. In late life, the risk of cognitive decline needs to be considered in clinical practice.