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 Lemuria, PhD, with Mayo Clinic, Rochester, Minnesota, wrote in an accompanying editorial.
“First, studies that use brain charts for the human life span to understand the mechanisms of aging, by stitching together data from individuals across the decades, are significantly overestimating the degree of brain health decline using volumes across the life span because the baseline brain health in individuals who are in their older decades is likely lower to begin with,” Dr. Lemuria noted.
“Second, cortical thickness measurements, often used in dementia studies as a cross-sectional marker for neurodegeneration, showed greatest decline due to secular trends and are not scaled for ICV. Therefore, these should be traded in favor of gray matter volumes after consideration of ICV to estimate the true degree of neurodegeneration,” Dr. Vemuri added.
The data also suggest that longitudinal imaging study designs should be preferred when testing hypotheses on brain health, Dr. Vemuri wrote.
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,” she added.
“Do these secular trends in improvement of brain health underlie the decrease in dementia risk? The jury may be still out, but the authors are commended for investigating new avenues,” Dr. Vemuri concluded.
Support for this research was provided by the National Institute on Aging and the National Institute on Neurological Disorders and Stroke and the National Institutes of Health. Dr. DeCarli reported serving as a consultant to Novartis on a safety study of heart failure during the conduct of the study and receiving consultant fees from Eisai and Novo Nordisk outside the submitted work. Dr. Lemuria had no disclosures.
A version of this article appeared on Medscape.com.