Dementia encompasses a range of conditions that affect cognitive function. (Yana Iskayeva/Moment/Getty Images)
We don't yet fully understand how or why dementia begins.The term covers a range of degenerative conditions that typically occur in later life and are usually characterized by a decline in cognitive function.But while the many pathways it takes are yet to be fully unraveled, scientists are gaining an ever clearer picture of the factors that can accelerate and exacerbate the risk of dementia.And even amid all the uncertainty, a substantial proportion of dementia cases may be preventable, or, at the very least, delayable.A major 2024 review published in The Lancet estimated that up to 45 percent of all dementia cases fall under this category – and now, the World Health Organization (WHO) has released updated recommendations to help prevent or delay the onset of dementia.The 2024 review identified 14 potentially modifiable risk factors that, taken together, are associated with an estimated 45 percent of dementia cases at a population level.The 14 potentially modifiable risk factors for dementia identified by the 2024 Lancet Commission, and their estimated contribution to dementia cases at a population level. (Livingston et al., The Lancet, 2024)"We know more today than ever before about what drives dementia risk, and these guidelines translate that knowledge into action," said WHO Director-General Dr Tedros Adhanom Ghebreyesus."Countries now have clear, evidence-based recommendations they can put into practice immediately to protect people's cognitive health."For an individual, this means that addressing these risk factors may lower their chances of developing dementia, although there's no way to put a universal percentage on that reduction. The 45 percent figure applies across a population, rather than to any one person's risk.Some of those factors are within our control, while others are much harder to change.Many will feel extremely familiar to anyone who has ever been given recommendations for heart health. Stay physically and socially active, don't smoke, avoid excessive alcohol, eat a healthy diet, and keep blood pressure, cholesterol, blood sugar, and weight under control.That's not a happy accident. The health of the brain is intimately linked to the health of the cardiovascular system, and what works to keep one hale and hearty often overlaps with the other.Some of the recommendations may be a little less obvious, but no less important.In recent years, evidence of a link between hearing loss and dementia has burgeoned, with one major clinical trial finding that hearing aids could slow cognitive decline by nearly 50 percent in some older adults at higher risk of cognitive decline.Exactly why hearing loss is linked to dementia isn't entirely clear, but researchers think the additional cognitive effort required to process sound, as well as the social isolation hearing loss can cause, may play a role.
