One in three cases of dementia worldwide could be prevented by acting on nine risk factors throughout life, according to research.

The study by 24 international experts found that early intervention and care, as well as modifying lifestyle choices can slow and even prevent the disease occurring in later life for many.

Better education in early life, tackling hearing loss early, treating high blood pressure and obesity in mid-life alone could prevent 20% of dementia cases, the study found.

Treating depression, exercising, not smoking, being sociable and controlling diabetes would cut a further 15%.

Tacking all nine factors effectively could cut cases of dementia by as much as 35%.

Life-course model of contribution of modifiable risk factors to dementia
Image: The Lancet

The study points out that, while most cases are diagnosed in later life – generally symptoms such as confusion appear in the over 65s – brain changes occur many years before, and risk factors should be addressed throughout life, not just in old age.

The clear message from the study is that dementia for many is not an inevitable consequence of ageing. Lifestyle can decrease, or increase, a person’s risk.

Some causes of dementia are genetic, the study points out, and these are not currently modifiable.

“Nonetheless, delaying dementia for some years for even a small percentage of people would be an enormous achievement and would enable many more people to reach the end of life without developing dementia,” the authors say.

“Many people present to services with mild cognitive impairment, a risk state for dementia, which occurs in up to a fifth of people aged older than 65 years, and this state provides an opportunity for more targeted interventions.

“We have itemised interventions that can transform the lives of people with dementia and their families; maximising cognition, decreasing distressing associated symptoms, reducing crises, and improving quality of life. Timely diagnosis is a prerequisite to receiving these interventions.”

Describing the disease as “the greatest global challenge for health and social care in the 21st century”, the report reveals there were approximately 47 million sufferers in 2015.

The cost of caring for this rapidly increasing number of sufferers was estimated to be $818 billion in that same year.

And the number of sufferers is rising rapidly, especially in low and middle-income countries.

According to Alzheimer’s Disease International, the number of sufferers globally is close to 70 million in 2017; this number will almost double every 20 years. By 2030, there will be 75 million people with the disease, and 131.5 million by 2050.

Much of the increase will be in developing countries, and already 58% of people with dementia live in low and middle-income countries. By 2050 this proportion will have risen to 68%.

Image: Alzheimer’s Disease International

There are over 9.9 million new cases of dementia each year worldwide, equivalent to one new case every 3 seconds.