“It is not clear why this imbalance exists.” A large study has found a difference between the brains of women and men in old age
Elderly couple. Photo: Yuri Arcurs | Dreamstime.com
Scientists have found that brain aging is more accelerated in men than in women. In a recent study, researchers explain why men lose brain volume faster with age, regardless of whether they have Alzheimer's or not, reports News.ro.
In 2021, 57 million people worldwide were suffering from dementia, and every year almost 10 million new cases are registered. Dementia is caused by a series of diseases and injuries that affect the brain. Alzheimer's disease is the most common form of dementia and may be responsible for approximately 60–70% of cases.
In the United States alone, more than seven million Americans are affected by Alzheimer's, and estimates show that by 2050, the number of cases will approach 13 million, according to the Alzheimer's Association.
The risk is higher in women, but the effects are more severe in men
The lifetime risk of developing the disease at age 45 is one in five for women and one in ten for men.
The new study, recently published in the journal Proceedings of the National Academy of Sciences – PNAS, shows that, although women are more often diagnosed with Alzheimer's disease, men's brains suffer a faster reduction in volume with age.
This finding provides new insight into how biological differences between the sexes can influence the brain aging process.
The study analyzed more than 12,000 MRI brain images from nearly 5,000 people between the ages of 17 and 95. The researchers found that as they age, men lose brain volume faster and in more regions than women. The affected areas were especially those responsible for memory, emotions and sensory processing.
In contrast, a slight expansion of the cerebral ventricles – the fluid-filled spaces inside the brain – was observed in women, suggesting a different evolution of brain aging.
“Our results show that men show a more pronounced structural decline in several brain regions, which means that normal aging does not explain the difference in the frequency of Alzheimer's disease between the sexes,” said the study's lead author, Anne Ravndal, from the University of Oslo (Norway), quoted in a statement.
“It is not clear why this imbalance exists”
She added that the results point to other possible causes, such as differences in life expectancy, diagnosis or biological factors not yet fully understood.
One of the theories considered by specialists is that the higher prevalence of the disease in women is explained by the fact that they live, on average, longer than men, and age is the main risk factor for dementia. However, this explanation does not seem to be sufficient, according to the authors of the new study.
“It is not clear why this imbalance exists. Longevity has been considered an explanation, because age is a strong risk factor for dementia. But now we see that it does not explain everything, so we are looking at a variety of other factors, both biological and social or cultural,” emphasized researcher Paola Gilsanz, from the Kaiser Permanente Northern California Division of Research, in an article previously published by the Alzheimer's Association.
Alzheimer's remains a complex disease, influenced by numerous genetic, hormonal and lifestyle factors, and the recent study provides a new research direction for understanding gender differences in brain aging and dementia risk.
Photo: Yuri Arcurs | Dreamstime.com
