August 13, 2019

expert reaction to two studies looking at blood pressure and dementia

Research, published in two separate papers in JAMA, reports on the connection between high blood pressure and dementia risk.

Dr Jana Voigt, Head of Research, Alzheimer’s Research UK, said:

Comment on ‘Association of Midlife to Late-Life Blood Pressure Patterns With Incident Dementia’:

“The association between blood pressure and dementia risk is complex. Research is increasingly pointing to midlife as the time to act, with high blood pressure at this time associated with the greatest risk of the condition.

“This new study suggests that it’s not only sustained high blood pressure from midlife into later life that could affect dementia risk, but the way blood pressure changes as we age too.

“It’s difficult to draw full conclusions from the research as some key control groups are missing. Researchers will need to confirm these findings in future studies and consider how they may relate to dementia risk reduction guidelines. The World Health Organisation currently recommends the management of high blood pressure to reduce the risk of dementia and these guidelines would only change if there was sufficient evidence of other strategies benefiting people.

“Maintaining a healthy blood pressure throughout our lives is important for many aspects of our health. While most people are aware that factors like blood pressure can impact the health of our heart, people are less likely to know the things that can affect the health of our brains. As well as keeping our blood pressure in check, the best current evidence suggests that not smoking, only drinking within the recommended limits, staying mentally and physically active, eating a balanced diet, and keeping cholesterol levels in check can all help to keep our brains healthy as we age.”

Comment on ‘Association of Intensive vs Standard Blood Pressure Control With Cerebral White Matter Lesions’:

“We know having high blood pressure is a risk factor for dementia, as well as many other health conditions, and that controlling it can have wide-ranging benefits.

“In this well-conducted study, intensively treating blood pressure had a small but positive affect on brain changes associated with diseases like Alzheimer’s. While some previous research suggests that intensively treating high blood pressure could help to limit the rate of memory and thinking decline, this study didn’t follow participants to look for long-term benefits on brain health. Longer-term studies that relate brain changes to memory and thinking skills will be needed to show whether intensive high blood pressure treatment could reduce the risk of dementia.

“The NHS advises that blood pressure should not be above 120/80mmHg and that those over 40 should have their blood pressure checked regularly. Anyone with any concerns about their blood pressure should speak to their GP.

“There is good evidence that what’s good for the heart is also good for the brain. Maintaining good vascular health is one of the key things people can do to reduce their risk of dementia. As well as maintaining a healthy blood pressure, the best current evidence suggests that not smoking, drinking within recommended guidelines, staying mentally and physically active, eating a balanced diet, and keeping cholesterol levels in check can all help to keep our brains healthy as we age.”

Prof Masud Husain, Professor of Neurology, University of Oxford, said:

Comment on ‘Association of Midlife to Late-Life Blood Pressure Patterns With Incident Dementia’:

“This study, performed on a large sample of people followed up over 24 years, adds to accumulating evidence that high blood pressure in your 50s can have a negative impact on memory and cognitive function in later life. Exactly how high blood pressure has its effects on the brain is not answered by this research but, together with other recent findings, the results suggest that tighter control of blood pressure might be very important in reducing the risks of later dementia. However, this has still to be proven because this was an observational study, not a clinical trial.”

Comment on ‘Association of Intensive vs Standard Blood Pressure Control With Cerebral White Matter Lesions’:

“The results of this research were from a clinical trial in which blood pressure was tightly controlled. A small sample of the participants had MRI brain scans at the start and after 4 years. The findings suggest that changes in white mater signal – one of the consequences of high blood pressure in the brain – are reduced in people with tight control of blood pressure. But the results have to be taken with extreme caution, given the relatively small sample size. Moreover, it is difficult to make any conclusions about the impact of these white matter changes on cognitive function from the data presented here.”

Dr James Pickett, Head of Research, Alzheimer’s Society, said:

“While we’ve known for a long time that high blood pressure may be associated with an increased risk of dementia – particularly vascular dementia. This relatively small but thorough study goes beyond what we have seen before, showing that intensively lowering blood pressure well below the limit at which we diagnose hypertension could help maintain brain health.

“What this study doesn’t show is how many of these individuals went on to develop dementia. Researchers have had varied success in showing how best to prevent and treat vascular dementia, which is why current research, supported by Alzheimer’s Society, including the LACI-1 trial, is digging into this. Further studies, which include any harms associated with intensive blood pressure treatments are required before national guidelines are changed.

“The number of people in the UK with dementia is set to rise to one million by 2021 so it’s imperative we understand how best we can take control of our health, including our blood pressure, and reduce our risk of developing dementia. What’s good for the heart is good for the head and maintaining a healthy blood pressure is part of this, so turn off the Netflix and get out for a walk in the fresh air.”

Prof Robert Howard, Professor of Old Age Psychiatry, University College London (UCL), said:

“We have no treatments that can halt or slow the progression of dementia, current drug treatments offer only very modest symptom improvements, and there are no immediate prospects of this situation changing. Consequently, prevention of the development of dementia has become the most promising way to tackle the disease. We have already seen reductions in the age-specific incidence of dementia in the last 10 years that are probably due to improvements in population cardiovascular health and smoking cessation.

“Management of midlife hypertension is the strongest contender for further dementia prevention. Exercise, following a healthier diet and increased social participation have also been advocated. The Atherosclerosis Risk in Communities study provides powerful further evidence for the importance of midlife hypertension as a potentially modifiable risk for dementia. The field now needs to move from demonstration of statistical associations between risk factors and dementia development to randomized clinical trials within which we can directly test whether changing these risk factors can prevent dementia. At the moment, scrupulous control of midlife hypertension remains the best evidenced way for anyone to prevent later dementia development.”

‘Association of Midlife to Late-Life Blood Pressure Patterns With Incident Dementia’ by Walker et al. and ‘Association of Intensive vs Standard Blood Pressure Control With Cerebral White Matter Lesions’ by Nasrallah et al were published in JAMA at 16:00 UK time on Tuesday 13^th August. 

DOI: 10.1001/jama.2019.10575

DOI: 10.1001/jama.2019.10551

Declared interests

Prof Masud Husain: “I don’t have any conflict of interest”

Dr James Pickett: “No conflicts of interest”

Prof Rob Howard: “I am a Trustee of ARUK.”