{"id":3198212,"date":"2024-03-26T10:42:10","date_gmt":"2024-03-26T14:42:10","guid":{"rendered":"https:\/\/www.futurity.org\/?p=3198212"},"modified":"2024-03-27T08:32:13","modified_gmt":"2024-03-27T12:32:13","slug":"bigger-brains-dementia-alzheimers-3198212","status":"publish","type":"post","link":"https:\/\/www.futurity.org\/bigger-brains-dementia-alzheimers-3198212\/","title":{"rendered":"Human brains are getting bigger"},"content":{"rendered":"
Brain size has steadily increased for people born after the 1930s, according to a new study.<\/p>\n
Study participants born in the 1970s had 6.6% larger brain volumes and almost 15% larger brain surface area than those born in the 1930s.<\/p>\n
The researchers hypothesize the increased brain size may lead to an increased brain reserve, potentially reducing the overall risk of age-related dementias.<\/p>\n
“The decade someone is born appears to impact brain size and potentially long-term brain health,” says Charles DeCarli, professor of neurology and director of the University of California, Davis Alzheimer’s Disease Research Center and first author of the study published in JAMA Neurology<\/a><\/em>.<\/p>\n “Genetics plays a major role in determining brain size, but our findings indicate external influences\u2014such as health, social, cultural, and educational factors\u2014may also play a role.”<\/p>\n The researchers used brain magnetic resonance imaging (MRIs) from participants in the Framingham Heart Study (FHS). The community-based study was launched in 1948 in Framingham, Massachusetts, to analyze patterns of cardiovascular and other diseases. The original cohort consisted of 5,209 men and women between the ages of 30 and 62. The research has continued for 75 years and now includes second and third generations of participants.<\/p>\n The MRIs were conducted between 1999 and 2019 with FHS participants born during the 1930s through the 1970s. The brain study consisted of 3,226 participants (53% female, 47% male) with an average age of about 57 at the time of the MRI.<\/p>\n The study compared the MRIs of people born in the 1930s to those born in the 1970s. It found gradual but consistent increases in several brain structures. For example, a measure that looked at brain volume<\/a> (intracranial volume) showed steady increases decade by decade. For participants born in the 1930s, the average volume was 1,234 milliliters, but for those born in the 1970s, the volume was 1,321 milliliters, or about 6.6% greater volume.<\/p>\n Cortical surface area\u2014a measure of the brain’s surface\u2014showed an even greater increase decade by decade. Participants born in the 1970s had an average surface area of 2,104 square centimeters compared to 2,056 square centimeters for participants born in the 1930s\u2014almost a 15% increase in volume.<\/p>\n The researchers found brain structures such as white matter, gray matter, and hippocampus<\/a> (a brain region involved in learning and memory) also increased in size when comparing participants born in the 1930s to those born in the 1970s.<\/p>\n According to the Alzheimer’s Association, approximately 7 million Americans are currently living with Alzheimer’s disease. That number is expected to rise to 11.2 million by 2040.<\/p>\n Although the numbers are rising with America’s aging population, the incidence of Alzheimer’s\u2014the percentage of the population affected by the disease\u2014is decreasing. A previous study found a 20% reduction in the incidence of dementia per decade since the 1970s. Improved brain health and size may be one reason why.<\/p>\nDecades of brain size growth<\/h3>\n
Alzheimer’s disease buffer?<\/h3>\n