While early research focused on cures, scientists are now taking aim at modifiable risks such as hearing, education and smoking.
Improving hearing, education access and stopping smoking are likely to be key to preventing dementia on a population-wide scale, say researchers, who are calling for increased investment in protective factors.
“When I first started working in dementia, we were looking for medication to try and cure it, and nobody thought that it was possibly preventable,” said Professor Gill Livingston told audiences at this years’ Australian Dementia Forum.
“And some people still think that way, but mostly people have moved on,” said the UK psychiatrist, who leads the Lancet standing committee on dementia prevention, intervention and care.
Although the precise number of Australians living with dementia is unknown, Dementia Australia places it around 470,000 people, and says it is the second leading cause of death in the country.
“We would not suggest in any other illness that we do not try and prevent it,” Professor Livingston said. “Forty per cent [of the population attributable fraction of dementia] is potentially preventable just with 12 risk factors.” PAF is the proportion of cases in a population that can be attributed to a given exposure.
Research had found some people with dementia neuropathology remained asymptomatic, which suggested that there existed external influences such as lifestyle factors that protected against dementia-associated cognitive decline, she added. One well-known example was cognitive reserve.
Education was an important protective factor from early life, as it increased cognitive reserve. But Professor Livingston said that in later life hobbies could be just as important.
“It becomes difficult to work out after the age of 20, because people who have more higher education tend to seek out cognitively stimulating pastimes and it’s difficult to know whether it’s the education or the continued cognitive stimulation,” she said.
“Hearing, education and smoking have the highest population attributable fraction, accounting for 20%,” she added.
Peripheral hearing loss was considered to be one of the key determining factors in dementia, and one which was easily modified on an individual level.
“[Studies] found, uniformly, that people who used hearing aids were protected from [the] excess risk of dementia and mild cognitive impairment [found] in self-reported hearing loss and objectively measured hearing loss,” Professor Livingston said.
She said that she would like to see policy changes which encouraged hearing aid use and decreased noise pollution.
“Prevention is much more important than cure,” Professor Livingston said.
Meanwhile, it was important not to overlook the role that the neurotoxins in smoking and inhaling second-hand smoke had in cardiovascular pathology.
In places where smoking rates have increased – such as south Asia, the Middle East and Africa – there were increasing or stable numbers of people with dementia.
Professor Livingston also called for population-level changes, particularly in countries with vulnerable populations.
“It’s about changes in policy because culture, poverty and inequality are obstacles to end drivers for the need for change,” she said.
“Those who are the most deprived need change the most and they will derive the most benefit.
“We need to think beyond promoting individual life and begin to improve circumstances in which people live: make it easier for people to exercise, make it more possible for them to live in low-pollution places and [they will] be less likely to develop dementia.”
Ultimately, Professor Livingston said she thought that while a cure for dementia was highly desirable, most resources should be put toward prevention.
“Can we prevent dementia? Probably not all of it, but we can prevent a great deal of it.”
The Australian Dementia Forum 2021 was held virtually over May 31 and June 1.
