A new study has found that younger generations have larger brains, and they’re continuing to get larger, possibly lowering the chance of general age-related dementia. The study, done by researchers at the American academic health center UC Davis Health and published in the medical journal JAMA Neurology, discovered that participants born in the 1970s had 6.6% greater brain volumes and nearly 15% larger brain surface area than those born in the 1930s.
The study’s lead author, Charles DeCarli, is a professor of neurology and director of the UC Davis Alzheimer’s Disease Research Center.
He said: “The decade someone is born appears to impact brain size and potentially long-term brain health.
“Genetics plays a major role in determining brain size, but our findings indicate external influences – such as health, social, cultural, and educational factors – may also play a role.
“Larger brain structures like those observed in our study may reflect improved brain development and improved brain health.
“A larger brain structure represents a larger brain reserve and may buffer the late-life effects of age-related brain diseases like Alzheimer’s and related dementias.”
The brain volume saw consistent increases, decade by decade
MRI scans of participants born during the 1930s through the 1970s were taken between 1999 and 2019.
A total of 3,226 participants, 53% female, and 47% male, had an average age of 57 at the time of their MRI.
The results revealed consistent increases in various brain areas.
The brain volume saw consistent increases decade by decade: participants born in the 1930s had an average volume of 1,234 ml, but those born in the 1970s had an average volume of 1,321 ml, a 6.6% increase.
Cortical surface area, which measures the surface of the brain, increased even more significantly: participants born in the 1970s had an average surface area of 2,104 cm2 compared to 2,056 cm2 for participants born in the 1930s, representing an almost 15% rise.
The researchers discovered that white matter, grey matter, and the hippocampus (a brain area important in learning and memory) all grew in size between the two groups.
