Experts list 2 new modifiable risk factors for dementia: Cholesterol and eye health

• Reducing the risks of dementia starting as early as childhood could reduce the number of people living with dementia by nearly half, a new report by the Lancet Commission on dementia prevention, intervention, and care says.
• The Lancet Commission outlined 12 risk factors for dementia in 2020 and added two more — high cholesterol after the age of 40 and vision loss — in its report, presented this week at the Alzheimer’s Association International Conference.
• Experts say that governments should prioritize large-scale attempts to reduce these risks, with enormous social and economic benefits to slowing the surge of dementia worldwide.

Preventing the development of dementia can begin as early as childhood, new research says, with 14 risk factors identified that could be a step toward reducing a global trend by nearly half.

At the Alzheimer’s Association International Conference , held between July 28 and August 1 in Philadelphia, the third Lancet Commission on dementia prevention, intervention, and care outlined recommendations for governments to help reduce risk, suggesting that in England, for example, around £4 billion could be saved through large-scale interventions.

The commission reports these conclusions in The Lancet .

What are the 14 risk factors for dementia?

The Lancet Commission in 2020 established 12 of the risk factors that are linked to 40% of all dementia cases. These are:

1. alcohol abuse
2. smoking
3. diabetes
4. obesity
5. high blood pressure
6. air pollution
7. brain injury
8. physical inactivity
9. depression
10. social isolation
11. hearing loss
12. lower levels of education.

The Commission’s new report added high cholesterol after the age of 40 and vision loss as new risk factors to that list, suggesting that they contribute to about 9% of all dementia cases — 7% for high cholesterol and 2% for vision loss.

Dementia is an umbrella-term for several neurodegenerative conditions characterized by symptoms affecting memory, communication, and thinking. Although the likelihood of having dementia increases with age, it is not a normal part of aging.

Types of dementia include:

• Alzheimer’s disease
• vascular dementia
• Lewy body dementia , which may occur with Parkinson’s disease
• frontotemporal dementia
• mixed dementia.

Health policies must tackle dementia risk factors

The current report notes that given a rapidly aging global population, the number of people with dementia is expected to almost triple by 2050, rising from 57 million in 2019 to 153 million.

In lower-income countries, longer life expectancy is causing a surge in dementia, and the economic impact of dementia around the world is estimated to be more than $1 trillion a year.

Andrew Sommerlad, BMBS, PhD , one of the Lancet Commission report’s authors and an associate professor at University College London’s division of Psychiatry and Consultant Old Age Psychiatrist in Islington Memory Service, told Medical News Today that a broad, organized approach by governments around the world would be necessary to combat the expected surge in dementia in the next several decades.

“Many of the known risk factors for dementia can be influenced by health and government policy and this is likely to be the most effective way to support people to make lifestyle changes which they would not otherwise be able to do themselves,” Sommerlad said.

He went on to offer “provision of socially integrated housing, activities and volunteering opportunities in old age“ as examples of beneficial interventions promoted through health policies.

David Merrill, MD, PhD , a board-certified geriatric psychiatrist and director of the Pacific Neuroscience Institute’s Pacific Brain Health Center in Santa Monica, CA, who was not involved in the study, also told MNT that these risk factors for dementia must addressed by public health officials as a matter of priority.

“Keeping modifiable risk-factors for dementia front and center in the discussion of achieving healthy brain development and subsequent aging informs governmental public health initiatives across the lifespan,” Merrill said.

“Taking a stance that improved health across the lifespan leads to higher vitality with aging is one way to get dementia risk reduction taken seriously,” he added.

Social isolation: A key player in dementia

The United States Surgeon General, Vivek H. Murthy, has described the current situation in the States as an “ epidemic of loneliness ,” exacerbated by social media and technology.

Murthy linked social isolation to health issues like substance abuse and obesity.

Similarly, Merrill described social isolation as “the new smoking.” He noted that:

“Everything, from longevity to healthy brain aging, has been tied to the richness of our social connections. Psychiatry, as a field, has practiced using a biopsychosocial model of care for decades, [and] it’s good to see neurologists following our lead in recognizing the importance of social activities in healthy brain aging.”

Sommerlad also emphasized that frequent social contact is essential to reducing the risk of dementia.

“There is consistent evidence that having more frequent social contact with others and lower levels of loneliness are linked to lower dementia risk,“ he told us.

“This is likely to be because social contact in any form is an effective way of exercising our brains to build cognitive reserve, or resilience, against dementia pathology,“ Sommerlad explained.

Furthermore, “[s]ocial contact may also promote healthy behaviors, such as exercise and diet, and reduce stress,” he suggested.

How does alcohol use contribute to dementia?

There are some reports that younger generations, at least in the U.S., are drinking less than their older cohort. But there is also a growing body of evidence that any consumption of alcohol is an increased risk of developing dementia, among other health complications.

“The evidence is building that drinking any amount of alcohol is damaging for dementia risk and general health so reduction over time in the proportion of people drinking or engaging in other risky health behaviors is positive,” Sommerlad told us.

“We also know that some risks have increased over time — for example, obesity levels — so we have to monitor trends and respond to these,” he added.

Merrill echoed this sentiment about alcohol use, pointing out that there are several types of drinking that can result in the same damage to the brain.

“Heavy alcohol use is one modifiable risk factor for dementia. This can be heavy daily use or also periodic episodes of binge drinking. Both are detrimental to the health of the brain with aging,” he said.

“It’s now increasingly accepted that there is no ‘healthy’ amount of alcohol intake for the brain or body, so one would imagine that the trajectory of dementia would improve with less alcohol use,” Merrill advised.