Systolic blood pressure tracking over 25 to 30 years and cognitive performance in older adults

Abstract

Objective - To determine the extent to which individual changes in systolic blood pressure (SBP) over a 30-year interval are associated with differential neuropsychological outcomes in old age. Methods - Seven hundred seventeen survivors from the Western Collaborative Group Study, a longitudinal study of cardiovascular risk factors now in its 38th year of follow-up, with blood pressures measured in middle age (mean=45 years) and in old age (mean=75 years) and neuropsychological tests administered at follow- up were included in this analysis. Participants were grouped according to 30- year change in SBP (increased, decreased, or 'normal'). Analyses focused on comparisons of neuropsychological performance of 'high SBP trackers' (ie, those with persistent SBP≥140 mm Hg throughout adult life) and of SBP 'decreasers' with the performance of those whose SBP was either stable or changed in an expected way over time. Results - Only 7.5% of participants had elevated SBP in middle age, but 43.8% of participants had elevated SBP in old age. After adjustment for age, education, depression, clinically defined stroke, and use of antihypertensive medications and after exclusion of individuals with impaired cognitive performance at follow-up, high SBP trackers, 5.0% (n=36), performed consistently less well than the 'normal' SBP subgroups on a composite measure of verbal learning and memory (P=0.04). When compared with the 'normal' SBP subgroup, the SBP decreasers, 5.3% (n= 38), performed less well on speeded performance (P=0.03). Conclusions - There is a relatively small group of people who maintain elevated SBP throughout their adult lives. These persons are at increased risk for reduced verbal learning and memory function. There is also a group of individuals who experience a decrease in SBP and who are at risk for decreased psychomotor speed. Delineation of these 2 SBP subgroups may lead to further clarification of the effects of SBP on neurobehavioral function in older adults.