why are women more exposed than men?

Today in France, 900,000 people suffer from Alzheimer's disease, the fourth leading cause of death in the country, and 60% of patients are women. Around the world, the same trend is observed. On July 9, for the first time, a gender badysis of the last decade's research into this form of dementia has been published. The work, done by the International Women's Brain Project (WBP), was published in the journal Nature .

Several risk factors stand out, note the WBP researchers. First, age. In fact, the older we get, the more likely we are to develop Alzheimer's disease, or women live longer than men, an average of six years longer in France. "In fact, at 70 years the number of women affected is twice that of men, and from age 80 the ratio rises to about two-thirds, in agreement with the figures for Australia and the USA. This is a general observation, "notes André Nieoullon, professor of neuroscience at the University of Aix-Marseille, interviewed by Atlantico .

Depression is another risk factor: this psychological disease is related to Alzheimer's or women are more sensitive. In France, for two men affected by a depressive episode, there are between 3 and 4 women.

The drop in estrogen levels at menopause could weaken the brain

Another hypothesis put forward: complications pregnancy that can lead to dementia years later. Finally, while Alzheimer's disease is detectable in the brain using the levels of two biomarkers, scientists have noted that these levels are not the same depending on the bad, with women's brains tending to decline more. quick. Thus "biomarkers can have different values ​​in men and women." We may need to adjust biochemical and neuropsychological biomarkers according to the bad of the patient, "says Maria Teresa Ferretti, researcher in biomedicine at the University of Zurich specialized in Alzheimer's disease, a member of WBP

The more rapid progression of the disease in women could be explained by "the presence of estrogen in women whose effect is 'protective' on the body and, in particular, the brain, so the drop in estrogen levels at menopause could result in the loss of these protective effects on the brain and so it would be more vulnerable than men to this neurodegenerative disease that affects cognition ", explains André Nieoullon

" Some data – sometimes questionable and contested – have reported beneficial effects hormone replacement therapy following menopause, including in terms of 'prevention' of Alzheimer's disease, or even in women with slowing its progression, "he adds.

Studies on Alzheimer's 'do not include enough women in their panel

But Alzheimer's disease is incurable for now, and, for WBP researchers, medication searches fail because they lack financial resources and do not include enough of women in the experiments. "As women are more affected by the disease, it is necessary to investigate the specific differences between men and women," says Antonella Santuccione-Chadha, a physicist specializing in disease and co-founder of WBP.

For Maria Teresa Ferretti, it is essential to make "more specific prevention by bad to give more information on the risk factors that concern women". But thanks to the studies carried out in recent years, "we can make new hypotheses and find new ways to improve the treatment of patients," she said, however, "

Because everything is not lost. Indeed, in the United Kingdom, new cases of Alzheimer's have decreased by 20% over the last twenty years, mostly among men over 65 years of age. For André Nieoullon, this could be explained by the beneficial impact of the campaigns of prevention against tobacco and heart problems, very important risk factors in the disease.

"This result is quite considerable and leads to the conclusion that if researchers still do not know the causes and treatments of Alzheimer's disease, which could only represent 2/3 of all dementia states and cognitive impairment, then in any case the situation would improve. nevertheless, not by the discovery of a specific drug still expected but by the prevention and management of badociated pathologies that represent real risk factors for the functioning of the brain, "he concludes.