14 Risk Factors Could Reduce Dementia Cases by 45 Percent

Nearly half of dementia cases may be postponed or prevented entirely by tackling 14 potential risk factors, among them vision loss and raised cholesterol.

This is the central conclusion of a new study that our colleagues and we published in The Lancet.

Dementia is a fast-growing worldwide issue, currently affecting an estimated 57 million people globally; that total is projected to reach 153 million worldwide by 2050. While dementia prevalence is falling in high-income countries, it is still rising in low- and middle-income countries.

The third updated report from the Lancet Commission on Dementia delivers encouraging news alongside a clear call to action. Policymakers, clinicians, individuals and families can take an ambitious approach to prevention and lower dementia risk. For people living with dementia and those who care for them, evidence-based methods can also support quality of life.

The latest report reaffirms the 12 potentially modifiable risk factors identified in its 2017 and 2020 reports. It also presents fresh evidence for two further modifiable factors: vision loss and high concentrations of low-density lipoprotein (LDL) cholesterol, commonly known as "bad" cholesterol.

Our review of the published evidence concluded that tackling all 14 modifiable risk factors together could reduce dementia prevalence worldwide by 45 percent. The potential reduction could be even greater in low- and middle-income countries, as well as among lower-income people in wealthier countries, because these groups experience higher rates of dementia, health inequalities and risk factors.

The report also suggests that reducing these 14 risks could extend the number of years spent in good health and shorten the period of poor health for people with dementia.

In addition, it references clinical trials indicating that non-drug interventions - including activities adapted to a person's interests and abilities - can lessen dementia-related symptoms and enhance quality of life.

We are a general internist and an applied sociologist and intervention scientist whose work examines memory and wellbeing in older adults. Alongside 25 other internationally recognised dementia specialists, led by psychiatry professor Dr Gill Livingston, we closely assessed the evidence to develop recommendations on prevention, intervention and care.

Why dementia prevention matters

The swift expansion of ageing populations around the world reflects improvements in public and personal health across the life course. However, as there is no cure for dementia, the report underlines both the value of prevention and the need to protect quality of life for people diagnosed with dementia.

In the new report, our team set out an ambitious dementia prevention programme that could operate at individual, community and policy levels, from early life through midlife and later life.

The 14 modifiable dementia risk factors

The main recommendations are:

• During early life, improve general education.
• In midlife, tackle hearing loss, high LDL cholesterol, depression, traumatic brain injury, physical inactivity, diabetes, smoking, hypertension, obesity and excessive alcohol consumption.
• In later life, reduce social isolation, air pollution and vision loss.

Taken together, these measures account for the Lancet Commission on Dementia's estimate that 45 percent of dementia risk could be reduced. A substantial body of newer research also indicates that addressing risk factors, including air pollution exposure, is associated with better cognition and is likely to lower dementia risk.

Healthier years of life and dementia care

New findings indicate that, in high-income countries, lowering dementia risk may mean more years in good health, more years without dementia and a shorter period of ill health among those who develop dementia.

What is still unknown

The estimated 45 percent reduction in dementia risk across the global population is calculated on the assumption that risk factors cause dementia and can be removed. It illustrates why dementia prevention is vital and the difference it could make to individuals and families.

The commission stressed that further research is required to find additional risk factors, assess risk-factor changes through clinical trials, inform public-health initiatives, and identify and evaluate ways to introduce and expand evidence-based programmes that support people with dementia and carers.

The updated report is having an international impact on public health and research and is being shared widely. It provides guidance for clinicians and policymakers while identifying new avenues for research.

The Research Brief provides a short overview of engaging academic research.

Eric B. Larson, Affiliate Professor of Medicine, UW School of Medicine, University of Washington and Laura Gitlin, Dean Emerita and Distinguished Professor of Nursing and Health, Drexel University

This article has been republished from The Conversation under a Creative Commons licence. Read the original article.