Midlife and Late Life Blood Pressure Tied to Dementia Risk
AUGUST 14, 2019
Keenan Walker, PhD
In a prospective cohort study, a team led by Keenan A. Walker, PhD, Department of Neurology, Johns Hopkins University School of Medicine, are hoping to identify the association of midlife to late-life blood pressure patterns with subsequent dementia, mild cognitive impairment, and cognitive decline.
The team examined 4761 patients with 24-years of follow-up and blood pressure measurements at midlife and late life, finding those with midlife and late-life hypertension (HR, 1.49) and those with midlife hypertension and late-life hypotension (HR, 1.62) had a higher risk for incident dementia compared with those who remained normotensive.
Investigators believe the link between late-life blood pressure and cognition is due to the presence and chronicity of past hypertension, where late-life declines in blood pressure following prolonged hypertension could be tied to poor cognitive outcomes.
The team used the Atherosclerosis Risk in Communities prospective population-based cohort study, which included 4761 participants during their midlife who had their first visit between 1987-1989, with 6 follow-ups occurring through 2016-2017 in Washington County, Maryland; Forsyth County, North Carolina; Jackson, Mississippi; and Minneapolis, Minnesota.
Blood pressure was measured and examined over 24 years during 5 in-person between visits 1-5 (2011-2013).
During visits 5-6, each participant received a detailed neurocognitive evaluation.
The 5 groups were based on longitudinal patterns of normotensions, hypertension (>140/90 mm Hg), and hypotensions (<90/60 mm Hg) at visits 1-5.
The primary outcome was dementia onset after the fifth visit, with a secondary outcome of mild cognitive impairment after the sixth visit based on the neurocognitive evaluation.
Between visit 5-6, there were 516 incident dementia cases with the incidence rate for participants with normotension in midlife and late life 1.31 (95% CI, 1.00-1.72 per 100 person-years).
The incident rate for midlife normotension and late-life hypertension was 1.99 (95% CI, 1.69-2.32 per 100 person-years) and 2.83 (95% CI, 2.40-3.35 per 100 person-years) for midlife and late-life hypertension.
The incident rate for midlife normotension and late-life hypotension was 2.07 (95% CI, 1.68-2.54 per 100 person-years) and 4.26 (95% CI, 3.40-5.32 per 100 person-years) for midlife hypertension and late-life hypotension.
“Participants in the midlife and late-life hypertension group (HR, 1.49 [95% CI,1.06-2.08]) and in the midlife hypertension and late-life hypotension group (HR, 1.62 [95% CI, 1.11-2.37]) had significantly increased risk of subsequent dementia compared with those who remained normotensive,” the authors wrote.
Regardless of late-life blood pressure, sustained hypertension in midlife is linked to dementia risk (HR, 1.41 [95% CI, 1.17-1.71]).
Only the participants with midlife hypertensions and late-life hypotension had a higher risk of mild cognitive impairment (37 affected individuals (odds ratio, 1.65 [95% CI, 1.01-2.69]) when compared with those with normotensive in midlife and late-life and there was no significant association of blood pressure patterns with late-life cognitive change.
“In this community-based cohort with long-term follow-up, sustained hypertension in midlife to late life and a pattern of midlife hypertension and late-life hypotension, compared with midlife and late-life normal BP, were associated with increased risk for subsequent dementia,” the authors wrote.
The study, “Association of Midlife to Late-Life Blood Pressure Patterns With Incident Dementia,” was published online in JAMA.