March 27, 204 -- The size of the human brain has increased over time, a finding that may help explain a reported decline in cases of dementia.
A trends analysis using brain imaging data from a long-running heart study showed an increase in several brain measurements in people born in the 1970s vs those born in the 1930s.
Researchers believe the increased size of the brain will lead to “increased 'reserve' against the diseases of aging, consequently reducing overall risk of dementia," Charles DeCarli, MD, director of the Alzheimer's Disease Research Center and Imaging of Dementia and Aging Laboratory at the University of California at Davis, said.
The study was published online Monday in the journal JAMA Neurology.
Dementia Protection?
An earlier paper from the same study, known as the Framingham Heart Study, suggested cases of dementia are declining. The study is sponsored by the National Heart, Lung and Blood Institute and has been under way since 1948. It is generally used to study multigenerational patterns of cardiovascular and other diseases.
"This difference occurred among persons with at least high school education and was not affected by differences in vascular risk. Our work was stimulated by this finding and the possibility that differences in brain size might be occurring over the three generations of the Framingham Heart Study, which might explain an increased resilience to dementia," said DeCarli.
The findings are likely based, in part, on improved lifestyle and environmental factors, as well as newer evidence that there are things a person can do to lower the risk of dementia, the authors said.
There are limitations to the researcher, however, namely that the Framingham study’s participants are largely white, healthy and well educated and not representative of the borader U.S.
Exciting Work
"If these results are confirmed by others and the observed differences by decade are as large as those reported, it has important implications for aging and dementia studies," Prashanthi Vemuri, PhD, with Mayo Clinic, Rochester, MN, wrote in an accompanying editorial.
Although this work is "exciting and will bring attention to secular trends in brain health, much work is yet to be done to validate and replicate these findings and, more importantly, understand the mechanistic basis of these trends," Vemuri said.
