The most accurate way yet of identifying who will get dementia has been developed by British scientists.
Researchers say the new dementia risk score "strongly predicts" the chances of people over the age of 50 developing the debilitating disease within 14 years.
And they say that having diabetes, depression and high blood pressure can triple the risk of developing the condition.
The system, created by Oxford University researchers following a long term study published in BMJ Mental Health, draws on 11 mostly modifiable risk factors to identify people most at risk from middle age onwards.
The new UK Biobank Dementia Risk Score (UKBDRS) outperformed three other widely used dementia risk scores originally developed in Australia (ANU-ADRI), Finland (CAIDE), and the UK (DRS).
Up to 50 million people worldwide are thought to be living with dementia, with the number projected to triple by 2050.
But scientists say targeting key risk factors, several of which involve lifestyle, could potentially avert around 40 percent of cases.
Several risk scores have been devised to try and predict a person’s chances of developing dementia while preventive measures are still possible.
But those scores have proved unreliable, and some rely on expensive and invasive tests, precluding their use in primary care.
To try and get round those issues, the Oxford team drew on two large groups of 50 to 73-year-olds participating in two long term studies - one group for developing the new risk score (UK Biobank study) and one for validating it (Whitehall II study).
A total of 220,762 people from the UK Biobank study, with an average age just under 60, and 2,934 from the Whitehall II study, average age 57, were included in the final analysis.
The research team compiled a list of 28 established factors associated with a higher or reduced risk of developing dementia, to which they applied a statistical method designed to identify and discard the least relevant factors.
That produced 11 predictive factors for any type of dementia: the UK Biobank Dementia Risk Score (UKBDRS).
The 11 factors were: age, education, history of diabetes, history of/current depression, history of stroke, parental dementia, economic disadvantage, high blood pressure, high cholesterol, living alone and being a man.
The APOE gene, which is involved in the production of a protein that helps carry cholesterol and other types of fat in the bloodstream, is a known risk factor for dementia.
Its carriage was known for 157,090 participants in the UK Biobank study and 2,315 of those in the Whitehall II study and added to the risk score (UKBDRS-APOE).
Within 14 years, nearly two percent of people in the UK Biobank group and just over three percent of participants in the Whitehall II group developed dementia.
The predictive values of UKBDRS with and without APOE were compared with that of age alone; and the three other widely used risk scores.
UKBDRS-APOE produced the highest predictive score, closely followed by the UKBDRS, and then age alone, followed by DRS, CAIDE, and finally ANU-ADRI.
The researchers suggest that the accuracy of their risk score could be further improved by adding cognitive tests, a brain scan, and a blood test for indicators of neurodegeneration.
But as those are expensive or time intensive they may not always be available.
Lead author Raihaan Patel said: "The UKBDRS may best be used as an initial screening tool to stratify people into risk groups, and those identified as high risk could then benefit from the more time intensive follow-up assessments described above for more detailed characterization."
Co-author Sana Suri said: *“It’s important to remember that this risk score only tells us about our chances of developing dementia; it doesn’t represent a definitive outcome.
“The importance of each risk factor varies and given that some of the factors included in the score can be modified or treated, there are things we can all do to help reduce our risk of dementia.”
She added: “While older age, 60 and above, and APOE confer the greatest risk, modifiable factors, such as diabetes, depression, and high blood pressure also have a key role.
"For example, the estimated risk for a person with all of these will be approximately three times higher than that of a person of the same age who doesn't have any.”
Patel, of Oxford's Department of Psychiatry, added: “There are many steps we would need to take before we can use this risk score in clinical practice.
“It’s well known that dementia risk, onset, and prevalence vary by race, ethnicity and socio-economic status.
"Therefore, while the consistent performance of UKBDRS across these two independent groups boosts our confidence in its viability, we need to evaluate it across more diverse groups of people both within and beyond the UK."
Talker
