Male Brains May Shrink Faster Than Female Brains With Age, New Study Finds
New evidence suggests that male brains may experience a faster rate of shrinkage with age compared to female brains, though researchers caution further study is needed to fully understand the implications.
An analysis of over 4,700 participants with healthy cognitive function, utilizing more than 12,000 brain scans collected over decades from individuals aged 17 to 95, revealed “modest yet systematic sex differences” in neurological tissue loss. The research, published today in PNAS, found that men showed a decline in a greater number of brain regions, including areas of the cortex, as they aged. Women, conversely, exhibited declines in fewer regions and less cortical thinning. This finding could reshape our understanding of age-related cognitive decline and neurological diseases.
Despite women being diagnosed with Alzheimer’s disease at roughly twice the rate of men, the study surprisingly found no initial difference in volume changes to the hippocampus – a brain region crucial for memory and learning. However, women in the study began to show a faster decline in the hippocampus in older age, potentially linked to their longer life expectancy. “If women’s brains declined more, that could have helped explain their higher Alzheimer’s prevalence,” explained co-author Anne Ravndal, a neuroscientist at the University of Oslo in Norway. Researchers controlled for differences in overall brain size between sexes during their analysis.
The study highlights a significant historical bias in neurological research, with a 2019 analysis showing only 5 percent of published studies considered the influence of sex. Researchers emphasize that teasing apart the impact of sex from other genetic and environmental factors remains a complex challenge, and further longitudinal research is essential to determine how these brain volume changes correlate with cognitive function. The team plans to continue investigating these differences and their potential impact on neurological health.
