Systolic Blood Pressure Tracking Over 25 to 30 Years and Cognitive Performance in Older Adults Downloaded from

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 (meanϭ45 years) and in old age (meanϭ75 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 SBPՆ140 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% (nϭ36), performed consistently less well than the "normal" SBP subgroups on a composite measure of verbal learning and memory (Pϭ0.04). When compared with the "normal" SBP subgroup, the SBP decreasers, 5.3% (nϭ38), performed less well on speeded performance (Pϭ0.03). 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. (Stroke. 1998;29:2334-2340.) Key Words: aging Ⅲ blood pressure Ⅲ cognition Ⅲ neuropsychology E levated systolic blood pressure (SBP) is associated with reduced levels of cognitive performance and increased cognitive decline in the majority of investigations of this issue. 18 Although the long-term consequences of elevated midlife SBP for cognitive function now appear indisputable, 1 of the unanswered questions in this area is the extent to which individual differences in SBP tracking throughout adult life result in different neurobehavioral consequences. For example, the functional consequences of persistently elevated SBP over periods of as much as 30 years may be different from those associated with persistently low or moderate levels or those that occur as a result of gradually increasing SBP associated with aging. Under the assumption that the cumulative neurobehavioral consequences of SBP are more severe the longer the interval over which it is elevated, we hypothesized that the high SBP trackers would perform less well on neuropsychological tests taken at the end of the 25-to 30-year observation period than would any of the other tracking subgroups