Dementia can be predicted ten years in advance with a simple ‘crystal ball tool’, according to new research.
It combines a blood test with a person’s age and sex to work out their risk of developing the devastating condition.
For instance, women in their 80s who carry a gene linked to the neurological illness are over a third more vulnerable.
And those in their 70s are more than a fifth as likely to be struck down within the next decade. The dangers for male counterparts are almost as high.
The breakthrough could lead to preventing Alzheimer’s disease by prescribing drugs much sooner – and advising lifestyle changes.
A healthy diet – such as eating plenty of oily fish – along with plenty of exercise that boosts blood flow is known to be protective. Quitting smoking also helps.
Professor Ruth Frikke-Schmidt, of Copenhagen University, said: “Recently, it was estimated one-third of dementia most likely can be prevented.
“According to the Lancet Commission early intervention for hypertension, smoking, diabetes, obesity, depression and hearing loss may slow or prevent disease development.
“If those individuals at highest risk can be identified, a targeted prevention with risk-factor reduction can be initiated early before disease has developed, thus delaying onset of dementia or preventing it,”
In the UK, dementia has become the number one killer of the elderly above heart disease.
The country is thought to be heading towards a dementia crisis, as millions of people who will be affected by the disease do nothing to prepare for it.
By 2025, more than 13 million people who are at risk of mental incapacity will be unprepared, with no legal or medical plans in place for their future care.
The study published in CMAJ (Canadian Medical Association Journal) looked at data on 104,537 Danish people and linked it to diagnoses of dementia.
Prof Frikke-Schmidt and colleagues found just age, gender and a common mutation called APOE flagged up the most prone people.
The gene carries cholesterol around the body and normal versions also clear proteins from the brain known as beta amyloid.
Variants fail to do this allowing them to form into clumps that destroy neurons and cause memory loss, confusion and other symptoms of dementia.
Among the 3,017 participants who were carriers the ten year dementia risk was ten and eight percent for women and men at 60 to 69 respectively.
This rose to 22 and 19 per cent for 70 to 79 year-olds – and 38 and 33 percent for over 80s.
Prof Frikke-Schmidt said: “The present absolute 10-year risk estimates of dementia by age, sex and common variation in the APOE gene have the potential to identify high-risk individuals for early targeted preventive interventions.”
Dementia currently affects 850,000 people in the UK alone with the figure set to rise to 2 million by 2050 because of the ageing population.
There is no cure. One of the reasons drug trials have so far failed is participants have been diagnosed too late – when medications are unlikely to work.
Earlier this year research showed people with mutated versions of APOE were 12 times more likely to develop Alzheimer’s – the most common form of dementia.
Prof Frikke-Schmidt said: “Dementia is a major cause of disability in older adults worldwide, yet no effective treatment is currently available.
“Reduction of risk factors for dementia may have the potential to delay or prevent development of the disease.
“Age, sex and common variation in the APOE gene identify high-risk individuals with the greatest potential to benefit from targeted interventions to reduce risk factors.
“The apolipoprotein E (APOE) protein is key for metabolising cholesterol and to clear beta-amyloid from the brain in individuals with Alzheimer’s disease.”
She added: “Taken together, the present findings emphasise APOE genotype as an important component in the individual risk assessment of dementia and cerebrovascular disease.”