Many Dementia Cases Preventable, Not All

AFP/APP

Paris: A major new study reveals that millions of dementia cases could be prevented or delayed by addressing various risk factors such as smoking and air pollution.

However, experts caution that these measures have limitations. Dementia, which progressively diminishes memory, cognitive abilities, language, and independence, currently affects over 55 million people globally. The most common cause of dementia is Alzheimer’s disease.

A comprehensive review published in The Lancet journal on Wednesday highlights the significant potential for prevention in the fight against dementia. This study builds on a 2020 report that identified 12 risk factors linked to 40 percent of dementia cases.

These factors include low education levels, hearing issues, high blood pressure, smoking, obesity, depression, physical inactivity, diabetes, excessive alcohol consumption, traumatic brain injury, air pollution, and social isolation. The latest update introduces two additional risk factors: vision loss and high cholesterol.

The study suggests that nearly half of dementia cases could theoretically be prevented by eliminating these 14 risk factors. Despite decades of research and substantial investment, no cure or truly effective drug for dementia has been developed.

However, since early last year, two Alzheimer’s treatments Biogen’s lecanemab and Eli Lilly’s donanemab have been approved in the US. These drugs target tau and amyloid beta proteins, which are associated with disease progression. Despite their approval, the drugs offer modest benefits, have severe side effects, and are very expensive.

In contrast, the European Union’s medicine watchdog recently rejected lecanemab and is still reviewing donanemab. Some researchers hope these new treatments will pave the way for more effective therapies in the future, while others advocate for a focus on prevention strategies.

Masud Husain, a neurologist at the University of Oxford, argues that addressing risk factors could be more cost-effective than pursuing advanced treatments that have yet to show significant impact on established dementia.

The Lancet study has been well-received by experts who agree on the importance of prevention. However, some caution that the claim that nearly half of all dementia cases could be prevented should be viewed critically. The study’s authors acknowledge that it has not been proven that these risk factors directly cause dementia.

For instance, it is possible that dementia could contribute to conditions like depression rather than the other way around. Moreover, some risk factors are interrelated, such as depression and isolation or smoking and high blood pressure.

Many of the risk factors are deep-rooted societal issues that are challenging to address comprehensively. The study offers recommendations ranging from personal actions, like wearing helmets while cycling, to broader governmental measures, such as enhancing educational access.

Charles Marshall, a neurologist at Queen Mary University of London, questions the feasibility of completely eliminating these risk factors, given the existing public health initiatives to reduce smoking and hypertension.

Tara Spires-Jones, a neuroscientist at the University of Edinburgh, emphasizes that people living with dementia should not be blamed for their condition. Many cases of dementia cannot be prevented due to genetic factors and other uncontrollable circumstances, such as limited educational opportunities during childhood.