By Peter Russell
WebMD Health News
Reviewed by Sheena Meredith, MD
July 14, 2014 -- About one-third of Alzheimer's disease cases are preventable, according to research by the University of Cambridge, England.
The study identifies seven risk factors, with lack of exercise topping the list.
A previous study published in 2011 suggested as many as half of cases of Alzheimer's disease could be prevented, but the researchers of the new study say these earlier findings are likely to be less accurate because they did not take into account overlapping risk factors.
Soaring Number of Cases
Current estimates suggest that by 2050, more than 106.2 million people worldwide will be living with Alzheimer's -- a huge increase from the 30.8 million people affected by the disease in 2010.
Researchers analyzed population-based data to work out the seven top risk factors for developing Alzheimer's disease. These are:
- Lack of exercise
- High blood pressure in middle age
- Obesity in middle age
- Low education
The team then looked at how reducing each of these factors would cut the number of cases of the disease.
The results varied according to whether they looked at the U.K., US., Europe, or the world as a whole.
Cutting Risk Factors
The researchers estimated that by reducing the relative risk posed by each lifestyle factor by just 10%, nearly 9 million cases of dementia could be prevented by 2050.
Worldwide, low education was identified as the main risk factor, followed by smoking and lack of exercise.
The research is published in the journal Lancet Neurology.
A Healthier Old Age
Study researcher Carol Brayne, MD, from the Institute of Public Health at the University of Cambridge, says in a statement: "Although there is no single way to prevent dementia, we may be able to take steps to reduce our risk of developing dementia at older ages. We know what many of these factors are, and that they are often linked.
"Simply tackling physical inactivity, for example, will reduce levels of obesity, hypertension, and diabetes, and prevent some people from developing dementia as well as allowing a healthier old age in general -- it's a win-win situation."
Commenting on the research, Doug Brown, PhD, director of research and development at the Alzheimer's Society in the U.K., says: "This valuable study adds to a growing body of evidence strongly suggesting that simple lifestyle changes can help lower our risk of developing dementia.
"With 106 million people on this planet expected to be living with the condition by 2050, the prospect of preventing up to 1 in 3 cases of Alzheimer's disease is something we cannot ignore. We must now carefully consider how this new evidence influences public health messaging for dementia risk," he says in a statement.
"In the meantime, we already know that what is good for your heart is good for your head and there are simple things you can start doing now to reduce your risk of developing dementia. Regular exercise is a good place to start as well as avoiding smoking and eating a Mediterranean diet."
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