December 12, 2016

expert reaction to study on whether statins may reduce risk of alzheimer’s

Publishing in JAMA Neurology, researchers reported an association between statin use and lower Alzheimer’s disease risk. They reported variation in lowering disease risk across race and ethnicity and type of statin.

Dr Rosa Sancho, Head of Research, Alzheimer’s Research UK, said:

“Although this study highlights a link between statin use and a lower risk of Alzheimer’s, we can’t say from this research that statins can prevent the disease. These types of studies identify important trends, but cannot allow researchers to conclude a causal relationship between statin use and Alzheimer’s risk. This research differs from previous studies in the general population, as it focused on people who already have raised cholesterol, which is itself a known risk factor for Alzheimer’s disease.

“The reasons why sex and ethnicity may influence trends in Alzheimer’s risk are very important to understand, as these factors must be taken into consideration in studies of Alzheimer’s risk. Until there is firm evidence from clinical trials, we would not recommend people take statins for the purpose of preventing Alzheimer’s disease. Cardiovascular risk factors can be associated with poor brain health, so keeping cholesterol in check is important for maintaining a healthy brain as we age. Other ways to keep the brain healthy include regular exercise, eating a balanced diet, maintaining a healthy weight, not smoking and controlling high blood pressure. Those concerned about their cholesterol should talk to their doctor.”

Prof Jane Armitage, Professor of Clinical Trials and Epidemiology, University of Oxford, said:

“This large observational study reports associations between statin use and risk of Alzheimer’s disease in different groups. However, although involving a large number of people, it cannot tell us anything about whether statin use is causing the effects on Alzheimer’s disease. The people prescribed statins are likely to be different in many ways from those not prescribed statins. As a result, conclusions about cause and effect cannot be made despite the authors trying to take account of such differences. In order to find out if statins protect against Alzheimer’s disease randomized studies are needed in which the people who are given a statin are as similar as possible to those who are not. Unfortunately such long-term trials are hard to do. The randomized trials of statins lasting 5-6 years do not suggest that statins protect against cognitive decline.”

Dr Doug Brown, Director of Research and Development at Alzheimer’s Society said:  

“Previous research has attempted to find out whether using statins to lower cholesterol can alter a person’s risk of developing dementia but these studies have produced mixed findings. This new study goes some way towards clearing up this confusion by analysing large amounts of existing data of people who use different types of statins over a long period of time. Their refreshing approach highlights that ‘one size fits all’ is not always a suitable approach to healthcare and this is likely to be the case when it comes to ways people can reduce their risk of dementia. However, their data does not provide direct evidence that statins can influence dementia risk – this question will need to be answered by clinical trials.

“The results found cannot yet be applied to the doctor’s surgery, but could be used to improve the design of clinical trials that can help to answer the complicated questions around statin use and dementia risk.

“Currently there is not enough evidence that statin use can reduce your risk of dementia, but you should keep an eye on your cholesterol levels as keeping them in check will help to combat other conditions such as heart disease and stroke. We advise people to speak to their GP if they have any questions about cholesterol, statin use and dementia risk before making any decisions about their medications.”

Prof John Hardy, Professor of Neuroscience, UCL, said:

“The possible role of statins in Alzheimer prevention has been debated for nearly 20 years.  This paper contributes to that discussion but does not really lead to a definitive answer: rather it suggests, based on health records analysis, that in some groups there is a protection, but in others there are not.  This is a complex outcome and will need more studies to determine whether there is protection or not and who the protection works for.  Prospective, rather than retrospective studies are the most likely way this will be definitively sorted out.”

* ‘Sex and Race Differences in the Association Between Statin Use and the Incidence of Alzheimer Disease’ by Zissimopoulos et al. will be published in JAMA Neurology at 16:00 UK time on Monday 12th December, which is also when the embargo will lift. 

Declared interests

Dr Sancho: None to declare

Prof Armitage: “I have been involved in running large randomized trials of statins and work in the Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU) at the University of Oxford. The CTSU has received research grants from Abbott, AstraZeneca, Bayer, GlaxoSmithKline, Merck, Novartis, Pfizer, Roche, Schering, and Solvay that are governed by University of Oxford contracts that protect its independence, and it has a staff policy of not taking personal payments from industry (with reimbursement sought only for the costs of travel and accommodation to attend scientific meetings).”

Dr Brown: “No interests to declare.”

Prof Hardy: “I consult for Eisai”