Almost half of dementia cases globally could be prevented or delayed, according to the latest study published in The Lancet.
Dementia is a term for several diseases that affect memory, thinking, and the ability to perform daily activities, according to WHO.
The illness gets worse over time. It mainly affects older people but not all people will get it as they age. It is characterised by symptoms such as confusion, difficulty with communication, problem-solving, and judgement.
Dementia is a leading cause of disability and death globally.
The research, conducted by 27 leading dementia experts, identifies 14 modifiable risk factors that, if addressed, could prevent or delay 45% of dementia cases.
According to the research, the number of people living with dementia is expected to nearly triple to 153 million by 2050, which poses a threat to global health and social care systems.
Global health and social costs linked to dementia exceed $1tn (£780bn) a year, the research shows.
However, addressing risk factors that begin in childhood and continue throughout life has the potential to prevent or delay 45% of dementia cases, even as people live longer lives, according to the Lancet Commission on dementia.
The results were presented at the Alzheimer’s Association international conference in the United States.
“The potential for prevention is high and, overall, nearly half of dementias could theoretically be prevented by eliminating these 14 risk factors. These findings provide hope,” the lead author of the research, Prof Gill Livingston, told Guardian UK in an interview.
The study identifies two new risk factors, high low-density lipoprotein (bad) cholesterol in midlife and untreated vision loss in later life, which are associated with 9% of dementia cases.
These factors are in addition to the 12 previously identified risk factors by the Lancet Commission in 2020, which together account for approximately 36% of dementia cases.
It includes lower levels of education, hearing impairment, high blood pressure, smoking, obesity, depression, physical inactivity, diabetes, excessive alcohol consumption, traumatic brain injury, air pollution and social isolation.
“Many people around the world believe dementia is inevitable, but it’s not. Our report concludes that you can hugely increase the chances of not developing dementia or pushing back its onset,” Livingston noted.
“It’s also important to stress that while we now have stronger evidence that longer exposure to risk has a greater effect… it’s never too early or too late to take action.”
To reduce dementia risk throughout one’s life, the Lancet Commission made 13 recommendations,, including making hearing aids available for those with hearing loss reducing harmful noise exposure, and detecting and treating high cholesterol from about the age of 40.
Other recommendations include making screening and treatment for vision impairment accessible for all, providing children with good-quality education and being cognitively active in midlife.
Livingston also disclosed that new evidence showed that reducing the risks of dementia not only increased years of healthy life but also reduced the time people who developed dementia spent in ill health.
“Healthy lifestyles that involve regular exercise, not smoking, cognitive activity in midlife – including outside formal education – and avoiding excess alcohol cannot only lower dementia risk but may also push back dementia onset,” she said.
This meant that those who developed dementia lived with it for a shorter period of time, Livingston said, adding: “This has huge quality-of-life implications for individuals as well as cost-saving benefits for societies.”
One of the easiest things people could do to prevent their risk of dementia, according to her, was fit some exercise into their day if they are mainly sedentary, be that a walk or even seated exercises.
Meanwhile, Fiona Carragher, the chief policy and research officer at Alzheimer’s Society, which part-funded the study, said: “Some dementia risk factors, such as alcohol consumption and physical exercise, can be managed by changing your lifestyle but many must be addressed on a societal level.
“Social isolation, education inequalities and air pollution are beyond individuals’ control and require public health interventions and joint action between government and industry.”
While Dr Susan Kohlhaas, the executive director of research at Alzheimer’s Research UK, which helped fund the research, warned that age and genetics remained the biggest risk factors for dementia.
But Kohlhaas, however, said that the finding that there were several other health and lifestyle factors at play was “good news” because it provided a “huge opportunity” for people and governments to put in place preventive measures to lessen the devastating impact of dementia on society and loved ones in the future.
Currently, more than 55 million people have dementia worldwide, over 60% of whom live in low- and middle-income countries. Every year, there are nearly 10 million new cases.
Dementia is currently the seventh leading cause of death and one of the major causes of disability and dependency among older people globally, according to WHO.
