Women have significantly more risk factors for Alzheimer’s disease than men, new international study finds, ranging from depression to post-menopausal estrogen drop to complications pregnancy-related.
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. All over the world, the same trend is observed. On July 9, for the first time, a gender analysis of research on this form of dementia over the past decade was published. The work carried out by the international organization Women’s Brain Project (WBP) appeared in the specialist journal Nature.
Several risk factors stand out, note the WBP researchers. First of all, the age. In fact, the older we get, the more risk we have of developing Alzheimer’s disease, but women live longer than men, six years longer on average in France. “In fact, at age 70 the number of women affected is twice that of men, and from age 80 the ratio rises to around two-thirds, in accordance with the figures for Australia and the United States. It is therefore a general observation “, notes André Nieoullon, professor of neurosciences at the University of Aix-Marseille, interviewed by Atlantico.
Depression is another risk factor: this psychological disease is linked to Alzheimer’s disease, but women are more sensitive to it. Indeed, in France, for two men affected by a depressive episode, there are between 3 and 4 women.
Falling estrogen levels during menopause could weaken the brain
Another hypothesis put forward: pregnancy complications that can lead to dementia years later. Finally, while Alzheimer’s disease is detectable in the brain using the levels of two biomarkers, scientists noticed that these levels were not the same depending on gender, with women’s brains tending to decline more. quick. So “biomarkers can have different values in men and women. We might need to adjust biochemical and neuropsychological biomarkers depending on the patient’s sex”, analyzes Maria Teresa Ferretti, biomedical researcher at the University of Zurich specialist in Alzheimer’s disease, member of the WBP.
The more rapid progression of the disease in women is explained in particular by “the presence of estrogen in women, the effect of which would be ‘protective’ on the body and in particular on the brain. Consequently, the drop in levels of Estrogen at menopause could result in the loss of these protective effects on the brain and thus the latter would be more vulnerable than that of men to this neurodegenerative disease which affects cognition “, explains André Nieoullon.
“Some data – sometimes questionable and contested – have reported ‘beneficial’ effects of hormone replacement therapy following menopause, including in terms of ‘prevention’ of Alzheimer’s disease, even in women affected by slowing its evolution, “he adds.
Alzheimer’s studies do not include enough women in their panel
But Alzheimer’s disease is incurable for the moment, and, for the researchers of the WBP, the research of medication fails because it lacks financial resources and does not include enough women in the experiments. “As women are more affected by the disease, we must investigate the specific differences between men and women,” protested Antonella Santuccione-Chadha, a physicist specializing in the disease and co-founder of WBP.
For Maria Teresa Ferretti, it is essential to carry out “prevention more specific by sex in order to provide more information on the risk factors which 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 welcomes however.
Because all is not lost. Indeed, in the United Kingdom, new cases of Alzheimer’s have decreased by 20% over the past twenty years, mainly among men over 65. For André Nieoullon, this could be explained by the beneficial impact of prevention campaigns 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 or the treatments of Alzheimer’s disease, which could only represent 2/3 of all dementia and damage cognitive, then in any case the situation would improve nonetheless, not by the discovery of a specific drug always awaited but by the prevention and the management of associated pathologies which represent real risk factors for the functioning of the brain, ”he concludes.
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