New risk score strongly predicts dementia chances

A new dementia risk score, which draws on 11 mostly modifiable risk factors, identifies people at risk - from mid-life onwards - of developing the disease within the next 14 years, suggests a new study.

The findings are from a large long-term study published in the open access journal BMJ Mental Health, which shows that the UK Biobank Dementia Risk Score (UKBDRS) outperformed three other widely used risk scores.

40% of cases could be averted

Up to 50 million people worldwide are thought to be living with dementia, with numbers projected to triple by 2050.

But targeting key risk factors, several of which involve lifestyle, could potentially avert around 40% of cases.

Various risk scores have been devised to try and predict a person’s chances of developing dementia while preventive measures are still possible.

But these scores have proved unreliable across different age groups and geographies, and some rely on expensive and invasive tests.

To try and get round these issues, the researchers 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 (the UK Biobank study) and one for validating it (Whitehall II). 

11 dementia risk factors identified

The researchers produced 11 predictive factors for any type of dementia:

• age
• education
• history of diabetes
• history of or current depression
• history of stroke
• parental dementia
• economic disadvantage (Townsend deprivation index) 
• high blood pressure 
• high cholesterol 
• living alone
• male sex. 

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. It was also added to the risk score (UKBDRS-APOE). 

Within 14 years, 3813 (nearly 2%) and 93 (just over 3%) participants developed dementia in the UK Biobank and Whitehall II groups, respectively.  

"Things we can do to help reduce our risk"

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 these are expensive and/or time intensive they may not always be available.  

“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,” suggested lead author Dr Raihaan Patel. 

“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,” said lead co-author associate Professor Sana Suri.

“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 explains: “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.”  

The researchers also acknowledge various limitations to their research. The classification of dementia differed between the two groups as did the demographics, lifestyle, and health of the participants.  

“There are many steps we would need to take before we can use this risk score in clinical practice,” added Dr Patel. 

"The UK's most accurate dementia risk calculator"

Dr Richard Oakley, Associate Director of Research and Innovation at Alzheimer’s Society, said: 

This Alzheimer’s Society-funded research is in its early stages but it’s exciting as it gives us the UK’s most accurate dementia risk calculator.

"While it’s still under development we hope it will soon help identify people in mid-life who are at greater risk of developing dementia so they can make changes to their lifestyle to try to reduce that risk. 
 
"As a rule of thumb for everyone what’s good for the heart is good for the head, and taking care of your cardiovascular health could help reduce your risk of getting dementia.

"Eating a balanced diet, avoiding smoking and heavy drinking, and exercising regularly can all help."