Abnormal BP Patterns May Increase Dementia Risk

Abnormal patterns of blood pressure (BP) in midlife to late life may be associated with subsequent dementia risk, according to new findings published in JAMA.¹

“We found that individuals with high blood pressure in midlife may benefit from targeting their blood pressure to normal levels in later life, as having blood pressure that is too high or too low in late life may further increase dementia risk,” said Keenan Walker, PhD, lead study author and assistant professor of neurology at the Johns Hopkins University School of Medicine, in a press release.²

Dr Walker and colleagues arrived at their conclusion after examining 4761 participants who were enrolled during midlife in the Atherosclerosis Risk in Communities (ARIC) prospective population-based cohort study. Participants were from Washington County, Maryland; Forsyth County, North Carolina; Jackson, Mississippi; and Minneapolis, Minnesota.

Participants’ first visit took place between 1987 and 1989, and 5 follow-up visits took place through 2016 to 2017. Over a period of 24 years between visits 1 and 5, participants’ BP was examined. During visits 5 and 6, detailed neurocognitive evaluation was performed.

Each participant was categorized in 1 of 5 groups based on patterns of normotension, hypertension, and hypotension during visits 1 to 5. Hypertension was defined as a BP higher than 140/90 mm Hg, and hypotension was defined as a BP lower than 90/60 mm Hg.

Results of the study indicated that 516 (11%) of 4761 participants had developed incident dementia between visits 5 and 6. Incidence rates for dementia were:

• 1.31 per 100 person-years for normotension in midlife (n = 833) and late life.
• 1.99 per 100 person-years for midlife normotension and late-life hypertension (n = 1559).
• 2.83 per 100 person-years for midlife and late-life hypertension (n = 1030).
• 2.07 per 100 person-years for midlife normotension and late-life hypotension (n = 927).
• 4.26 per 100 person-years for midlife hypertension and late-life hypotension (n = 389).

Ultimately, the researchers found that midlife and late-life hypertension (hazard ratio [HR] 1.49) and midlife hypertension and late-life hypotension (HR 1.62) were associated with a significantly increased risk of dementia compared with sustained normotension. Sustained hypertension in midlife was associated with dementia risk, regardless of late-life BP (HR 1.41).

Only participants with midlife hypertension and late-life hypotension had an increased risk of mild cognitive impairment (37 affected individuals; odds ratio 1.65) compared with participants with midlife and late-life normotension.

However, the researchers noted, no significant association between BP patterns and late-life cognitive change was observed.

—Christina Vogt

References:

1. Walker KA, Sharrett AR, Wu A, et al. Association of midlife to late-life blood pressure patterns with incident dementia. JAMA. 2019;322(6):535-545. doi:10.1001/jama.2019.10575.
2. Abnormal blood pressure in middle and late life influences dementia risk [press release]. Johns Hopkins Medicine. August 14, 2019. https://www.hopkinsmedicine.org/news/newsroom/news-releases/abnormal-blood-pressure-in-middle-and-late-life-influences-dementia-risk. Accessed August 14, 2019.