The mystery of waning dementia: the proportion of older people affected falls to 30% in 15 years

It is the enigma of waning dementia.

People are living longer, and the risk of dementia increases with age, but more and more studies confirm an apparent paradox: the incidence of Alzheimer's and other similar disorders is plummeting in rich countries.

New work now finds that the proportion of older people with dementia has fallen by 30% in just 15 years in the United States.

The reasons for this collapse are not clear, but the authors mainly point to the higher educational level of citizens.

Other previous studies have suggested that illiterate people have three times the risk of suffering from dementia.

The researchers have analyzed a group of more than 21,000 people over the age of 65, which they consider representative of the United States population.

Their results reveal that the proportion of participants with dementia fell from 12.2% in 2000 to 8.5% in 2016, despite the fact that there is no effective treatment available.

The three authors, led by the economist Peter Hudomiet, belong to the RAND Corporation, one of the main think tanks in the United States.

This is “good news”, Hudomiet applauded in a statement.

The phenomenon is repeated everywhere in rich countries.

A decade ago, the team of the Dutch epidemiologist Monique Breteler detected a surprising drop in incidence in the Netherlands between 1990 and 2005. Scientists associated this drop with the sharp increase in the use of antithrombotic drugs, for the prevention of cardiovascular diseases, and anti-cholesterol drugs.

A couple of years ago, a commission organized by the medical journal

calculated that changing a dozen risk factors can prevent or delay 40% of dementias.

These variables are lack of education, hypertension, hearing impairment, smoking, obesity, depression, physical inactivity, diabetes, social isolation, excessive alcohol consumption, blows to the head and air pollution. .

The new work, published this Monday in the scientific journal

, points directly to the effect of education on the analyzed group.

Women with higher education went from 12% in 2000 to 23% in 2016, while that percentage in men increased from 21% to almost 34%.

Exercising the brain prevents dementia.

The proportion of older people with dementia is very similar in Europe and the United States.

A consortium of scientists, led by researchers at Harvard University, calculated a couple of years ago that the incidence in several European countries - France, the United Kingdom, Iceland, Sweden and the Netherlands - fell by 13% per decade between 1988 and 2015, a rate similar to that observed in the United States.

The new work has detected an even greater decline: 30% in about 15 years.

Alzheimer's and other dementias, however, remain extremely concerning.

Due to the aging of the population, although the percentage of patients is reduced, their absolute number is increasing.

In Spain there are already more than 800,000 people with dementia, especially Alzheimer's, but also other types, such as the so-called LATE encephalopathy, whose traces appear in more than 20% of the brains of people over 80 years of age.

The German psychiatrist Alois Alzheimer described the first case of the disease that bears his name in 1906. She was a 50-year-old woman with memory problems and episodes of aggression and confusion.

More than a century later, the scientific community still does not understand the exact causes of dementia.

And there is also no treatment with confirmed efficacy, despite the usual bombastic announcements from companies.

The latest promising treatment has been lecanemab, with which the US pharmaceutical company Biogen made some 10,000 million euros on the stock market in one day last September, despite not yet having demonstrated its effectiveness.

The first drug authorized in the United States against the supposed causes of Alzheimer's, aducanumab, also from Biogen, has not been the revolution announced.

The drug, approved in 2021, is a monoclonal antibody, based on a molecule obtained from a lucid old man.

The treatment targets amyloid beta proteins, which accumulate between brain cells and appear to be associated with Alzheimer's.

The European Medicines Agency, however, has refused to authorize aducanumab as it found no evidence of its efficacy.

You can follow