An expert commission organised by Lancet assessed the influence of different risk factors for dementia. The nine well-known factors (education, hypertension, hearing impairment, smoking, obesity, depression, physical inactivity, diabetes, low social contact) were supplemented with three new factors: excessive alcohol consumption, brain damage and air pollution. Treating all of these factors would make it possible to delay around 40% of dementias worldwide.
Controlling 12 risk factors would make it possible to prevent or delay this neurodegenerative disease. Among the most important measures: raising the level of education and correcting hearing loss.
Preventing Alzheimer's disease? This challenge has become a measurable prospect. The stakes are enormous. Worldwide, some 50 million people today suffer from this age-related dementia; if nothing is done, there should be 152 million by 2050. The current global cost of this condition is esti
mated at one trillion dollars a year (850 billion euros).
"Alzheimer's disease is not a fatality. Of course, its occurrence cannot be prevented. But we can delay the onset of its symptoms for several years. In the end, people will die from another disease - cancer, cardiovascular disease, etc. - before the cognitive and behavioural problems associated with this dementia manifest themselves," explains Philippe Amouyel, professor of public health and managing director of the Alzheimer's Foundation. These disorders only occur 20 to 30 years after the onset of brain degeneration. We can therefore slow down their development by controlling the factors that accelerate it.
Twelve of these risk factors were examined in a study published on July 30 in the journal The Lancet. The verdict: controlling each of them could prevent or delay up to 40% of Alzheimer's cases - and even more in low- and middle-income countries, where two-thirds of those affected live.
This work, in fact, extends a study published in 2017 in the same journal, which quantified the impact of 9 risk factors. Here, the authors add 3 others: head injuries, air pollution and alcohol abuse.
Blood pressure, alcohol, tobacco...
Let's summarize. In children and young adults, 7.1% of Alzheimer's cases would be prevented or delayed by raising the level of education. Later, between the ages of 45 and 65, 8.2% of Alzheimer's cases would be prevented or delayed by correcting hearing loss; 3.4% by avoiding even minor head trauma; 1.9% by maintaining a systolic blood pressure of 130 mmHg at most; 0.8% by limiting alcohol consumption to 3 glasses a day; 0.7% by combating obesity. Even over the age of 65, action can be taken: by stopping smoking, 5.2% of cases would be prevented or delayed; by treating depression, 3.9%; by combating social isolation, 3.4%; by maintaining physical activity, 1.6%; by treating diabetes, 1.1%; by limiting exposure to air pollution, 2.3%.
By Florence Rossier, full article published in Le Monde on 31 July 2020