High blood pressure link to dementia
People with high blood pressure and raised cholesterol levels have a much higher risk of getting Alzheimer's disease as they get older.
Scientists said the discovery was an important weapon in the fight against dementia.
The Finnish scientists said their research could be tailored to help identify and treat people at risk from Alzheimer's, which affects one in five people by the age of 80.
And the Alzheimer's Society said the research provided an important piece of the jigsaw in the fight against the disease.
Dr Richard Harvey, director of research at the Alzheimer's Society, said he hoped the public would take on-board the message that there were some life-style changes they could make now that would cut their risks of getting the disease.
He said high blood pressure and raised cholesterol were linked to vascular disease and that if this caused damage to the brain it could account for the link with Alzheimer's.
"This is an important new piece of research. The results of this study fit together well with the jigsaw puzzle we are fitting together.
"This gives a good public health message that people need to look at their risk factors."
A total of 1,449 people took part in the 10-year-study, which was published in the British Medical Journal.
People were quizzed about their medical history as well as whether they smoked and how much they drank.
And the researchers found that those who had both high cholesterol and high blood pressure were at an even greater risk of getting the disease than those with just one of them.
The report said: "It is important to identify early risk factors for Alzheimer's Disease because the neurodegenerative processes of Alzheimer's disease may begin in midlife.
"Identification of these risk factors may shed some light on the pathophysiology of Alzheimer's disease and also provide new potential avenues for its prevention and treatment.
"As the proportion of elderly people in the population increases, Alzheimer's disease will become an enormous public health problem.
"Interventions that could delay the onset of the disease, even modestly, would therefore have a major impact on public health."
Source: BBC News