A significant new study suggests that millions of cases of dementia could be prevented or delayed by addressing various risk factors, including smoking and air pollution, although experts caution that these measures have their limits. Dementia, a condition that gradually erodes memory, cognitive function, language, and independence, currently impacts over 55 million individuals worldwide. It is primarily caused by diseases such as Alzheimer's. A comprehensive review of existing evidence, published in The Lancet, highlights the high potential for prevention in the battle against dementia. This study builds on a 2020 report that identified 12 risk factors linked to 40 percent of dementia cases, including lower education levels, hearing issues, and high blood pressure. The updated research adds vision loss and high cholesterol to the list, suggesting that nearly half of dementia cases could theoretically be prevented by mitigating these 14 factors.
Despite decades of research and substantial investment, no cure or highly effective drug for dementia has been developed. However, two new Alzheimer's treatments, Biogen's lecanemab and Eli Lilly's donanemab, have recently been approved in the United States. These drugs target the accumulation of tau and amyloid beta proteins, key to the disease's progression, but their benefits are modest, side effects are severe, and they are costly. Meanwhile, the European Union has yet to approve these treatments. Some researchers believe these new drugs could lead to more effective therapies, while others advocate for prevention strategies. Masud Husain, a neurologist at the University of Oxford, argues that focusing on risk factors is more cost-effective than pursuing high-tech treatments that have shown limited success.
The Lancet study has been well-received, but some experts caution that the claim of preventing nearly half of dementia cases should be viewed with skepticism. The study authors acknowledge that the direct causation of dementia by these risk factors has not been proven, and some factors may be interconnected, such as depression and isolation. Additionally, many risk factors are societal issues that are challenging to fully address. The study proposes various recommendations from personal actions, like wearing helmets while cycling, to governmental initiatives, 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 existing public health programs. Tara Spires-Jones, a neuroscientist at the University of Edinburgh, emphasizes that we should not blame individuals with dementia for their condition, as many factors are genetic or beyond personal control.
