Report suggests one in three dementia cases may be preventable

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By Philip Tubby | Thursday 20 July 2017

A new report has estimated that a third of dementia cases could potentially be prevented if nine different risk factors could be eliminated.

The Lancet Commission report, which summarises available evidence on risk factors for dementia and models their likely impact on prevalence of the condition, is due to be presented today (Thurs) at the Alzheimer’s Association International Conference 2017 in London.

The Lancet Commission, which was supported by Alzheimer’s Research UK, involved 24 dementia experts from the UK and across the globe. The team brought together existing evidence from a range of studies in an effort to produce a comprehensive overview of research into dementia prevention, diagnosis, treatment and care. As well as outlining established risk factors for dementia, their report also highlights emerging evidence linking hearing loss and social isolation to dementia risk, and calls for more ambitious strategies for dementia prevention.

As part of the review, the researchers modelled the potential impact of eliminating a number of risk factors for dementia, including established risk factors such as hypertension, obesity, smoking, physical inactivity, diabetes, depression, and lack of education in early life. The review also considered growing evidence linking hearing loss in mid-life and social isolation in later life to a higher risk of dementia. For each risk factor, the researchers calculated the potential impact on dementia prevalence if the risk could be completely eliminated. Their results suggest that if nine modifiable risk factors could be removed, the number of people living with dementia could reduce by 35%.

The report identified that the three risk factors with the largest potential impact were hearing loss, low education in early life, and smoking. The analysis suggested that dementia prevalence could potentially be reduced by 9% if hearing loss in mid-life could be eliminated – but the authors caution that evidence in this area is still emerging. A number of theories have been put forward to explain the link between hearing loss and dementia, including the possibility that the same underlying mechanisms could be driving both conditions. Similarly, the researchers point out that many of the risk factors highlighted in the review can be difficult to separate from one another.

Dr David Reynolds, Chief Scientific Officer at Alzheimer’s Research UK, the UK’s leading dementia research charity, said:

“This comprehensive report further underlines the potential impact of action to reduce dementia risk, and the importance of public health policies aimed at helping people reduce their risk of the condition. Prevention strategies must be underpinned by robust evidence and while our understanding of dementia risk is growing, there is still much we need to know about the different risk factors for dementia. Further research is vital to help pinpoint the most effective strategies for reducing dementia risk, which is why Alzheimer’s Research UK is investing at least £2m in our Prevention and Risk Reduction Fund.

“Research into the links between hearing loss and dementia is at an early stage and this review points to a need for further studies to establish the reasons behind this link. It’s not yet clear from the available evidence whether treating hearing loss could help reduce the risk of dementia, and it will be important to see this explored in future research.

“The report recommends more vigorous treatment of high blood pressure, and we would welcome moves to ensure all those who could benefit from blood pressure medication do so. We know that many people who are prescribed these medicines have difficulty sticking with their treatments, and it could be important to examine how these challenges might be addressed. A healthy lifestyle is also important for keeping blood pressure under control, and strategies to help people adopt and stick to healthy habits must form part of our efforts to reduce dementia risk.

“While this report rightly highlights measures we can take to reduce our risk of dementia, it also serves as a reminder that even if every risk factor identified here could be eliminated, we do not yet have a sure-fire way to prevent dementia. Alongside prevention research, we must continue to invest in research to find a life-changing treatment for people with this devastating condition.”

About the author

Philip Tubby