The growing brain affects human health

People born in the 1970s had a 6.6% increase in brain volume compared to the 1930s generation, which research shows helps reduce the risk of dementia in old age.

Human brain size has increased every decade since at least the 1930s, according to new research published in the journal JAMA Neurology on March 26. Brain growth is likely the result of improving early-life environmental factors and may help reduce the risk of dementia in old age, the team said .

The human brain has grown larger over the decades. (Photo: Orla).

The team of experts reviewed brain magnetic resonance imaging (MRI) images of 3,226 participants in the Framingham Heart Study (FHS). Launched in 1948 in Framingham, Massachusetts, USA, the FHS study includes participants born in every decade since the 1930s and now includes descendants of some of the original group.

When observing MRI images (taken from 1999 - 2019), the research team wanted to compare the brains of people born in the 1930s with people born in the 1970s. They discovered that the average brain volume had increased from 1,234 ml to 1,321 ml over this 40-year period, corresponding to an increase of about 6.6%.

Surprisingly, the participants' brain surface area increased even more: The average cortical surface area of ​​people born in the 1970s was nearly 15% larger than that of people born before that. 40 years, from 2,056cm ² to 2,104cm ² .

Decade of birth appears to influence brain size and possibly long-term brain health, according to study author, neuroscientist Charles DeCarli. "Genetics plays an important role in determining brain size, but our results show that external influences - such as health, social, cultural and educational factors - are also at play. can influence ," DeCarli explains.

Scientists still need to do more research on the exact impact of increased brain size on long-term health. However, the team noted that adult brain volume is an important predictor of cognition in old age. They hypothesize that larger brain volume indicates more brain development and better brain preservation, which may explain the decreasing incidence of dementia. In fact, although the number of people with Alzheimer's disease continues to increase in the United States, the incidence of the disease has decreased over the past few decades.

New research also reveals that the size of the hippocampus - closely related to memory and learning - appears to increase with each decade along with the amount of white and gray matter in the brain. Based on these findings, DeCarli said, larger brain structures (like those observed in the new study) may reflect improved brain development and brain health. good.