Previous research from 2011 put the estimate at one in two cases, but this new study takes into account overlapping risk factors. Alzheimer's Research UK said age was still the biggest risk factor.
Writing in The Lancet Neurology, the Cambridge team analyzed population-based data to work out the main seven risk factors for Alzheimer's disease. Examples include diabetes, mid-life hypertension, mid-life obesity, physical inactivity, depression, and smoking.
They worked out that a third of Alzheimer's cases could be linked to lifestyle factors that could be modified, such as lack of exercise and smoking. The researchers then looked at how reducing these factors could affect the number of future Alzheimer's cases.
Current estimates suggest that more than 106 million people worldwide will be living with Alzheimer's by 2050 - more than three times the number affected in 2010.
Of the seven risk factors, the largest proportion of cases of Alzheimer's in the US, UK and the rest of Europe can be attributed to physical inactivity. The study says about a third of the adult population in these countries are physically inactive.
Physical inactivity is also linked to increased risks of other health problems, such as cancers and cardiovascular diseases.
reporter
Park Sae-jin
swatchsjp@ajunews.com
