Researchers from Sweden and Finland have created a dementia-risk test for middle-aged adults, and say the test can be used to help spot risk factors that people can change before dementia starts.
Participants were first studied when they were 39-64 years old (average age: 50) and didn't have dementia.
The researchers noted factors including: age, years of education, body mass index, blood pressure, total cholesterol level, smoking status, physical inactivity and status of the APOE gene, which may indicate genetic risk for Alzheimer's disease.
The researchers say they have identified risk predictors in middle age that could help to identify people more likely to suffer dementia in later life and as with heart disease and other illnesses, lifestyle factors are the key to preventing the risk of Alzheimer's disease and other forms of dementia.
The factors include education, raised blood pressure, high cholesterol levels, obesity and lack of exercise - the same risk factors for heart disease and strokes.
Miia Kivipelto, the lead researcher, says the news is positive news because it opens up totally new avenues for intervention and prevention of dementia.
Dementia or Alzheimer's disease, is the leading cause of dementia in the elderly, for which there is no cure, therefore any means of primary prevention is important.
An estimated 12 million people worldwide suffer from Alzheimer's disease and the numbers are expected to rise as the population ages.
Although dementia becomes more common with age it is not a normal part of the aging process.
Kivipelto and her team analyzed data from a study of 1,409 people who were assessed for signs of dementia in midlife and 20 years later.
They studied several factors to develop their risk predictor and found the four percent of people in the study who developed dementia had the highest risk score for the six risk predictors 20 years earlier.
Kivipelto says it is never too early to prevent dementia.
The study is published in The Lancet medical journal.