Just two servings of red meat a week could increase dementia risk by up to 14 per cent while high cholesterol can lead to a 30 per cent chance of developing the condition, new research has revealed.

New risk factors contributing towards Alzheimer’s disease suggest neurodegeneration and dementia may not be an inevitable sign of ageing, with lifestyle choices playing an even greater role than first thought.

Sight loss in old age has also been added as a risk towards dementia, and was revealed in research led by experts at University College London.

Four years since the Lancet Commission identified 12 commonly known risk factors that contribute towards Alzheimer’s, two more modifiable risk factors have been identified that could maintain brain health for longer.

Speaking at the Alzheimer’s Association International Conference in Philadelphia, experts said almost half of all dementia cases resulted from 14 lifestyle and environmental factors that can be altered to cut the risk of disease.

“Our new report reveals there is much more that can and should be done to reduce the risk of dementia,” said lead author Professor Gill Livingston (UCL Psychiatry).

“We now have stronger evidence that longer exposure to risk has a greater effect and that risks act more strongly in people who are vulnerable.

“Healthy lifestyles that involve regular exercise, not smoking, cognitive activity in midlife, including outside formal education, and avoiding excess alcohol can not only lower dementia risk but may also push back dementia onset.

“So, if people do develop dementia, they are likely to live less years with it.

“This has huge quality of life implications for individuals as well as cost-saving benefits for societies.”

Known risks

Contributing factors towards dementia include brain injury, social isolation, depression, hearing loss and air pollution, as well as modifiable lifestyle factors like obesity, high blood pressure, diabetes, smoking, alcohol and sedentary living.

High cholesterol and sight loss have also now been added to the list of contributing factors in developing dementia.

Dr Tareq Qassem, a consultant in old age psychiatry and mental health lead at Abu Dhabi's Maudsley Health and Al Amal Hospital in Dubai, said risk factors are consistent with what is seen in the Arab world.

“For example, we know obesity causes issues, so that's why there is strong recommendation,” he said.

“And we know that lack of physical exercise or sedentary lifestyle is a major issue – so there is a robust recommendation for that based on very strong evidence.

“Another thing that has fairly strong evidence is hearing aids, which can help with social inclusion.

“With regards to cholesterol, yes there is evidence, and it wouldn't harm if people reduced their cholesterol anyway.

“There is a higher risk of dementia in older age, but it's never too late to engage with cognitive exercise.

“These kinds of illnesses will progress, but treatment is developing that can slow down the progression by 30 per cent, which is significant.”

Research by UAE University, Al Amal Psychiatric Hospital and Mohammed Bin Rashid University of Medicine and Health Sciences found the highest dementia prevalence in the Middle East among those aged more than 60 years was in Lebanon (4.88 per cent).

In Tunisia rates were 4.43 per cent and Algeria, 4.19 per cent, while in the UAE dementia rates are about 1.3 per cent in those aged over 50 and 4.09 per cent in those over 60.

The total direct cost for dementia care in the Arab region was $8.18 billion for those over 50 years old, with indirect costs estimated to range from $2.25 billion to $5.67 billion.

The study highlighted dementia as a growing public health issue in the Arab world, with 1,329,729 individuals affected in 2021 and total costs between $10.43 billion and $13.90 billion.

Improving care

“While ageing is inevitable, dementia is not, and there are steps we can take to reduce the risk,” said Dr Zemer Wang, medical director at DP World’s Aviv Clinic in Dubai, where hyperbaric oxygen therapy is delivered to improve brain health.

“While ageing does increase the likelihood of developing dementia, it's not a guaranteed outcome for everyone.

“The Lancet Commission’s highlights of modifiable risk factors demonstrate that we can control our ageing journey, to a degree.

“Cognitive reserve is like having a mental safety net that can help cushion the brain against the effects of ageing and disease.

“It's built up over a lifetime of engaging in mentally stimulating activities, such as reading, learning new skills, solving puzzles, and even socialising.

“This concept suggests that people who regularly challenge their brains might be better equipped to cope with the changes that come with ageing.”

Results of a widespread study of the diet of more than 130,000 participants tracked across 43 years linked red meat consumption and dementia, and were also announced at the AAI conference.

The Nurses’ Health Study and Health Professionals Follow-Up Study found those who ate processed red meat twice a week had a 14 per cent higher risk of dementia than those who ate fewer than three servings a month.

For every additional daily serving of processed red meat, an extra 1.6 years of cognitive ageing was recorded, including in language and executive function that impacts working memory, flexible thinking and self-control.

“Prevention of Alzheimer’s disease and all other dementia is a major focus, and the Alzheimer’s Association has long encouraged eating a healthier diet – including foods that are less processed – because they’ve been associated with lower the risk of cognitive decline,” said Heather Snyder, the Alzheimer’s Association vice president of medical and scientific relations.

“This large, long-term study provides a specific example of one way to eat healthier.”

Elsewhere, scientists found drugs used to combat diabetes could also hold brain-protection qualities.

GLP-1 agonists drugs such as liraglutide, that act in a similar way to diabetes drug Ozempic, also appear to slow cognitive decline by reducing shrinking in areas of the brain that controls memory, learning and language.

Clinical data reported at AAIC suggested liraglutide may be beneficial in those with mild Alzheimer’s disease.

Obesity drugs

Before the study began, the brain structure of patients were tested via magnetic resonance imaging (MRI) and they also conducted detailed memory tests. These tests were then repeated at the end of the study to compare results.

Trials showed that after a year of treatment, subjects given the drug saw cognitive decline reduced by up to 18 per cent compared to those given a placebo.

“The slower loss of brain volume suggests liraglutide protects the brain, much like statins protect the heart,” said Dr Paul Edison, a Professor of science from Imperial College London who led the trial of 204 patients with mild Alzheimer’s who received daily injections for a year.

“While further research is needed, liraglutide may work through various mechanisms, such as reducing inflammation in the brain, lowering insulin resistance and the toxic effects of Alzheimer’s biomarkers amyloid-beta and tau, and improving how the brain’s nerve cells communicate.”