Does Intensive Blood Pressure Control Reduce Dementia?
Intensive lowering of blood pressure (BP) did not significantly reduce dementia risk but did have a measurable impact on mild cognitive impairment (MCI), according to the final, peer-reviewed results from the Systolic Blood Pressure Intervention Trial (SPRINT) Memory and Cognition in Decreased Hypertension (SPRINT MIND).
SPRINT MIND secondary results are the first to show an intervention that significantly reduces the occurrence of MCI, which is a well-established precursor of dementia. The results were reported January 28, 2019 in the Journal of the American Medical Association.
SPRINT MIND was an integral aspect of the initial design for SPRINT, a large, randomized clinical trial of intensive BP lowering on cardiovascular and renal disease; both were funded by the National Institutes of Health.
The participants in SPRINT were adults 50 years and older at high risk for cardiovascular disease. Results of the SPRINT trial, which ended early, showed that intensive BP control, (systolic BP target of <120 mmHg), compared to a standard target of <140 mmHg, reduced cardiovascular events and overall mortality.
Between November 2010 and March 2013 more than 9,300 participants were randomized to the two target groups with nearly 4,700 in each group. In August 2015, the SPRINT trial was stopped after 3.3 years of treatment when the major beneficial effects of intensive BP management on mortality and cardiovascular disease were discovered. Assessment for development of dementia and MCI continued for the full planned 5 years.
SPRINT MIND aimed to address whether intensive BP control would also reduce the risk of developing dementia and cognitive impairment over the ensuing 5 years. Cognitive assessments were given to participants who had high BP but no history of stroke or diabetes at the start of the trial, and over 91% had at least one follow up. Participants were classified into one of three categories: no cognitive impairment, MCI, or probable dementia.
The SPRINT MIND Research Group noted the primary results of this analysis found no statistically significant difference between standard and intensive treatment in the proportion of participants who were diagnosed with dementia. The study, however, had fewer cases of dementia than expected. Nevertheless, the secondary results suggested the intensive treatment reduced the risk of MCI and the combined risk of MCI and dementia.
Due to the success of the SPRINT trial on the cardiovascular outcomes, the study intervention was stopped early; as a result, participants were treated for a shorter period than originally planned. The authors concluded the shorter time and the unexpected fewer cases of dementia may have made it difficult to determine the role of intensive BP control on dementia.
The authors emphasized this is the first randomized clinical trial demonstrating that an intervention significantly reduces the occurrence of MCI, which is an established risk factor and often a precursor for dementia. An important conclusion from this research is that the intensive lowering of systolic BP to <120 mmHg target, which reduces the risk of cardiovascular events and mortality, is safe for the brain.
These results also emphasize the connection between vascular health and the brain. In 2016, the NIH launched the Mind Your Risks campaign to make the public more aware of the link. For more on that visit mindyourrisks.nih.gov
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