Studies examining the links between dementia and hypertension in the past have yielded inconclusive results. A study published in JAMA in 2003 did find a link between high and low diastolic blood pressure and an increased risk of cognitive impairment. This study focussed on low blood pressure as a risk factor unlike other studies on high blood pressure. Two of the most recent trials, HOPE-3 and SPRINT MIND, have found separate results regarding high blood pressure as a risk factor: SPRINT MIND found a reduced risk of mild impairment, while HOPE-3 found no significance between high blood pressure and high risk dementia.
The most recent study may provide another piece of the puzzle, having almost 10 times the number of participants this study showed the most definitive results to date, finding that hypertensive treatment can help to lower the risk of cognitive decline.
The relationship between blood pressure and dementia risk is that hypertension can cause cognitive impairment through clotting or bleeding which can lead to stroke, silent strokes, and brain atrophy that can in turn lead to brain shrinkage, according to Dr. Michelle Canavan whoa senior author of the study and is also a consultant geriatrician at Galway University Hospital. Covert silent strokes are a notable cause of dementia as damage to the brain accumulates over time with almost little detection.
“The effect of lowering blood pressure on the brain not only reduces the risk of stroke but also reduces the amount of damage to blood vessels in the brain,” Canavan said. “When brain blood vessels, particularly small blood vessels, are subjected to prolonged high blood pressure levels, they can be damaged causing brain cell death and dysfunction, which can result in slower brain processing and decline in memory over time.”
96,157 participants with a mean age of 60 were involved in this study within 14 randomized and controlled clinical trials, who were followed over a 4 year period. Findings suggest that lowering blood pressure using antihypertensive medications helped to lower the risk of cognitive impairment or decline by 7%.
According to the researchers from the National University of Ireland at Galway increased confidence in this link between hypertension and dementia risk is important because compared to other therapeutic treatments for dementia accepted blood pressure medications such as ACE inhibitors, diuretics or beta blockers are typically more accessible, more affordable, and less invasive; and treating blood pressure may be a way to reduce the need for dementia treatment in the future.
“We would hope to disseminate a simple message from this research: Get your blood pressure checked,” said Canavan. “If it is high, it can be readily treated with lifestyle changes and medications. We would hope that our study will heighten awareness of the importance of controlling blood pressure to maintain brain health, combined with a healthy lifestyle.”
“Prevention of dementia is a major health priority,” said Canavan. “The message from this study is simple: Get your blood pressure checked. If it is high, it can be readily treated with lifestyle changes and medications.”
