Nearly half of dementia cases can be prevented or delayed, research shows

Nearly half of dementia cases worldwide could be prevented or slowed, a study has found. Experts cited 14 risk factors.

The number of people with dementia worldwide is expected to almost triple to 153 million by 2050, and researchers warn this poses a rapidly growing threat to health and social care systems. Global health and social costs related to dementia exceed $1 trillion (£780 billion) a year, the study found.

However, a seismic report states published by the Lancet27 of the world’s leading dementia experts concluded that many more cases could be prevented or delayed than previously thought.

By addressing 14 modifiable risk factors, starting in childhood and continuing throughout life, 45% of dementia cases could be prevented or delayed, even as people live longer. Lancet Commission on Dementia said. The findings were presented at the Alzheimer’s Association International Conference in the US.

In an interview with the Guardian, the study’s lead researcher, Prof Gill Livingston, said it was becoming increasingly clear that millions of people could and should do much more to reduce their risk of dementia.

Livingston said at the conference in Philadelphia: “Many people around the world believe that dementia is inevitable, but it is not. Our report concludes that you can greatly increase your chances of not developing dementia or delaying its onset.

“It is also important to emphasise that while we now have stronger evidence that longer exposure to risks has a greater effect… it is never too early or too late to take action.”

People at all stages of life, from children to the elderly, can take steps to reduce their risk of developing the disease – which has no cure – or at least ward it off until later in life, added Livingston of University College London.

Based on the most recent available evidence, the report adds two risk factors that are associated with 9% of dementia cases. About 7% of cases are linked to high low-density lipoprotein, or “bad,” cholesterol in middle age from around age 40, while 2% of cases are attributable to untreated vision loss in later life.

These new risk factors add to the 12 identified by the Lancet Commission in 2020, which together account for about 36% of dementia cases, Livingston said.

These include lower educational attainment, hearing problems, high blood pressure, smoking, obesity, depression, physical inactivity, diabetes, excessive alcohol consumption, traumatic brain injury, air pollution and social isolation.

In the report, the experts wrote: “The potential for prevention is high and overall, almost half of dementias could theoretically be prevented by eliminating these 14 risk factors. These findings offer hope.”

Livingston said there is also emerging evidence showing that reducing the risk of dementia not only leads to more healthy years of life, but also to a shorter time that people with dementia are sick.

“A healthy lifestyle that includes regular exercise, not smoking, cognitive activity in midlife – including outside formal education – and avoiding excessive alcohol consumption may not only reduce the risk of dementia but may also delay the onset of dementia,” she said.

This meant that those who developed dementia lived shorter lives with it, Livingston said, adding: “This has huge implications for the quality of life of individuals and also offers cost-saving benefits to society.”

Livingston said one of the easiest things people can do to reduce their risk of dementia is to incorporate some movement into their day if they are primarily sedentary. That could be a walk or even some seated exercise.

To reduce the risk of dementia throughout life, the Lancet Commission made 13 recommendations. These included making hearing aids available to people with hearing loss, reducing exposure to harmful noise, and detecting and treating high cholesterol from about age 40.

Other recommendations include that screening and treatment for visual impairment should be accessible to all, that children should receive a good education and that they should be cognitively active in middle age.

In a separate study published in the journal Lancet Healthy Longevity Together with the Commission, researchers have mapped the economic impact of implementing some of these recommendations, using England as an example.

They found that public health interventions addressing the risk factors could save £4 billion by reducing the number of dementia cases and helping people live longer, healthier lives.

Fiona Carragher, head of policy and research at the Alzheimer’s Society, which part-funded the research, said: “Some risk factors for dementia, such as alcohol use and exercise, can be managed by changing your lifestyle, but many need to be addressed at a societal level.

“Social isolation, educational inequality, and air pollution are beyond the control of individuals and require public health interventions and concerted action by government and industry.”

Dr Susan Kohlhaas, director of research at Alzheimer’s Research UK, which co-funded the study, warned that age and genetics remain the biggest risk factors for dementia.

But she said the finding that several other health and lifestyle factors played a role was “good news” because it presented a “huge opportunity” for people and governments to take preventative action to reduce the devastating impact of dementia on society and loved ones in the future.