New "calculator" identifies 14-year dementia risk from 50 onwards
Researchers have developed a new risk 'calculator' that identifies people in midlife at risk of developing dementia in the next 14 years, outperforming existing scores. Moreover, it's based on 11 key risk factors, many of them modifiable.
With our aging population, it’s projected that the number of dementia cases will triple by 2050, making prevention crucial. It’s known that a number of modifiable risk factors may reduce or prevent dementia, so a prognostic model that takes into account these factors should help with the early identification of at-risk individuals.
A new study led by researchers at the University of Oxford has designed a novel test to predict 14-year risk for all forms of dementia based on 11 predictive factors, most relating to lifestyle.
Existing tests used to predict a person’s dementia risk vary in the factors they assess. Because these risk scores are often developed in a single population, such as those of the UK or the US, they may not perform well in other populations. Additionally, because the risk factors associated with dementia may vary across the lifespan, models for elderly people may not apply to people in midlife.
The researchers addressed these limitations using data from two groups of 50- to 73-year-olds participating in two large studies. They obtained data from 220,762 individuals from the UK Biobank Study and 2,934 from the Whitehall II study to develop a score specific to a midlife population.
They compiled a list of 28 risk and protective factors associated with dementia to which they applied a statistical method called LASSO regression to identify and discard the least relevant factors. This produced 11 predictive factors for all types of dementia that the researchers called the UK Biobank Dementia Risk Score (UKBDRS). The 11 factors are age, education, history of diabetes, history of or current depression, history of stroke, parental dementia, economic disadvantage, high blood pressure, high cholesterol, living alone, and being male.
To the score the researchers also added the APOE4 gene, which is involved in producing a protein that helps carry cholesterol and other fat types in the bloodstream and is a known dementia risk factor.
The predictive values of UKBDRS with and without the APOE4 gene were compared with that of age alone, and with three other widely used risk scores: Australian National University’s Alzheimer’s Disease Risk Index (ANU-ADRI), the Cardiovascular Risk Factors, Aging and Incidence of Dementia (CAIDE) score, and the Dementia Risk Score (DRS). UKBDRS with APOE4 produced the highest predictive score, closely followed by the UKBDRS without APOE4, then age alone, and then DRS, CAIDE, and ANU-ADRI.
Using the novel scoring system, individuals can also be classified as low- or high-risk. The researchers say the addition of cognitive tests, brain scans, and blood tests for biomarkers of neurodegeneration could make the UKBDRS more accurate, noting that these tests can be expensive and/or time-intensive and may not always be available.
“Therefore, 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,” said Raihaan Patel, corresponding author of the study.
The researchers point out that the UKBDRS provides information about risk and cannot predict that someone will definitely develop dementia.
“It’s important to remember that this risk score only tells us about our chances of developing dementia; it doesn’t represent a definite outcome,” said Sana Suri, a study co-author. “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.”
The researchers acknowledge some limitations to the study, namely that the classification of dementia differed between the UK Biobank and Whitehall II studies, as did the demographics, lifestyle, and health of the participants. There were substantially fewer women in the Whitehall II study, and the majority of participants across both studies were white and less likely to live in lower socioeconomic areas.
“There are many steps we would need to take before we can use this risk score in clinical practice,” Patel said. “It’s well known that dementia risk, onset, and prevalence vary by race, ethnicity and socioeconomic 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.”
The study was published in the journal BMJ Mental Health.