A major new study has indicated that millions of dementia cases could potentially be prevented or delayed by mitigating a range of risk factors such as smoking and air pollution. However, experts caution that these measures have their limitations.
Dementia, a debilitating condition that progressively impairs memory, cognitive abilities, language, and independence, currently affects over 55 million people globally. The most prevalent cause of dementia is Alzheimer’s disease, but it can result from various conditions.
Published in The Lancet journal on Wednesday, the extensive review of available evidence underscores a significant potential for prevention in the battle against dementia. This study builds on a 2020 report by an international team of researchers, which estimated that 40% of dementia cases were associated with 12 risk factors. These factors included lower levels of education, hearing problems, high blood pressure, smoking, obesity, depression, physical inactivity, diabetes, excessive drinking, traumatic brain injury, air pollution, and social isolation.
The latest update adds two more risk factors to the list: vision loss and high cholesterol. The study suggests that nearly half of all dementia cases could theoretically be prevented by addressing these 14 risk factors.
EU Turns Down New Drug
Despite decades of research and billions of dollars invested, a cure or highly effective treatment for dementia remains elusive. However, since early last year, two Alzheimer’s treatments—Biogen’s lecanemab and Eli Lilly’s donanemab—have been approved in the United States. These drugs target the buildup of two proteins, tau and amyloid beta, which are believed to play a crucial role in the progression of the disease. While these drugs offer modest benefits, they also come with severe side effects and high costs.
In contrast to the U.S., the European Union’s medicine watchdog recently declined to approve lecanemab and is still evaluating donanemab. Some researchers hope these drugs will pave the way for more effective treatments in the future, but others advocate for a stronger focus on prevention.
Masud Husain, a neurologist at the UK’s University of Oxford, emphasized that addressing risk factors would be more cost-effective than developing high-tech treatments, which have so far shown limited impact on those with established dementia.
The Lancet study has been well-received by experts, although some argue that the notion of preventing nearly half of all dementia cases requires a balanced perspective. The study’s authors acknowledged that it is not proven that the risk factors directly cause dementia. For instance, depression could be a consequence of dementia rather than a cause.
Moreover, distinguishing between risk factors can be challenging, as some may be intrinsically linked, such as depression and isolation or smoking and high blood pressure. Addressing societal issues like these has historically proven difficult.
The study outlines recommendations ranging from personal actions, such as wearing helmets while cycling, to governmental initiatives, such as improving access to education. However, Charles Marshall, a neurologist at Queen Mary University of London, pointed out that existing public health programs already aim to reduce smoking and hypertension, questioning the feasibility of further reductions.
Tara Spires-Jones, a neuroscientist at the University of Edinburgh, stressed the importance of not blaming individuals with dementia for their condition. She noted that many dementia cases are beyond people’s control, influenced by genetic factors and childhood opportunities for education.
While the potential for preventing or delaying dementia through lifestyle and societal changes is promising, it is clear that not all cases can be avoided. The findings highlight the need for a comprehensive approach that includes both preventive measures and continued efforts to develop effective treatments.
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