Almost half of dementia cases can be prevented or delayed by addressing health issues such as vision and hearing loss along with depression, researchers said, offering potential relief as cases of the condition continue to rise.

Wearing head protection in contact sports and controlling levels of cholesterol, a blood fat that’s also been linked to dementia, are among 14 actions that should be encouraged by health officials and doctors to slow growth of the condition in the population, according to a report in the Lancet medical journal.

Dementia is the seventh-leading global cause of death among older people, and the number of people affected is expected to almost triple by 2050 with annual costs upwards of $1 trillion. While rates are falling in some high-income nations, those in lower and middle-income countries are rising quickly with no cure in sight, the researchers said.

"It is vital that we redouble preventive efforts towards those who need them most," Gill Livingston, a dementia specialist at University College London and lead author of the report, said in a statement. "Governments must reduce risk inequalities by making healthy lifestyles as achievable as possible for everyone."

Recently approved drugs, Leqembi from Eisai Co. and Kisunla from Eli Lilly & Co., have been shown to slow the progress of Alzheimer’s disease, one of the most common forms of dementia. Results of a study released Tuesday at a conference in Philadelphia suggested that Novo Nordisk A/S’s diabetes drug Victoza may have a similar effect.

Shingles vaccines may also slow down the condition, according to another study published in the journal Nature Medicine that linked GSK Plc’s Shingrix to later dementia onset. Focusing on prevention and delay would push back the day that such drugs would even be needed.

Inadequately treated vision loss was linked to 2% of dementia cases, while high cholesterol levels alone were associated with 7%.

Wildfires

Exposure to smoke from wildfires was also found to raise dementia risk in seniors, especially among Black and Asian people, according to a separate study conducted in California that was presented at the Philadelphia conference. Implementing strict clean-air policies would also help forestall dementia, Livingston said, and future research may show that low-emission zones in the UK have reduced burden of dementia.

Addressing the collective risk factors, which also include physical brain injury and excess alcohol use, would help England alone save some £4 billion in health and related costs annually, another study published in Lancet Healthy Longevity found. The potential benefits for lower-income countries are even greater, the authors said, particularly where policies like public smoking bans are not already in place.

Other beneficial measures would include making bicycle helmets compulsory for children, raising cigarette prices by 10% and reducing the sugar and salt content of food sold in stores and restaurants.

"If we can support people to reduce their dementia risk and address the societal change needed," said Fiona Carragher, director of research at the Alzheimer’s Society, a UK based advocacy group, "this could mean potentially hundreds of thousands fewer people in the UK will go on to develop dementia."