MRI findings link fat distribution to risk of cognitive decline
Not all fat is created equal, and some specific types carry more neurological consequences than others, according to new research.
Published in Radiology, the flagship journal of RSNA, the new data offer details on how different types of fat distribution patterns affect overall brain health. Researchers compared MRI measurements to patients’ health histories, disease biomarkers and answers to lifestyle questions to determine whether certain imaging findings put individuals at greater risk of cognitive disease processes.
“Our work leveraged MRI’s ability to quantify fat in various body compartments, especially internal organs, to create a classification system that’s data-driven instead of subjective,” explains Kai Liu, M.D., Ph.D., an associate professor in department of radiology at the Affiliated Hospital of Xuzhou Medical University in China. “The data-driven classification unexpectedly discovered two previously undefined fat distribution types that deserve greater attention.”
The two types of fat Liu is referring to are “pancreatic predominant” and “skinny fat." The pancreatic predominant type refers to instances of abnormally high concentrations of fat throughout the pancreas, while “skinny fat” describes higher internal fat burden in or around organs in individuals who do not meet standard obesity criteria.
Researchers analyzed data from nearly 26,000 individuals in the UK Biobank database, which contains MRI exams in addition to information on patients’ medical histories and bloodwork, to compare how each distribution type affects cognitive health.
Individuals with the pancreatic dominant distribution type displayed fat accumulation in up to 30% of the pancreas, which Liu warned is “about two to three times higher than that of other fat distribution categories, and it can be up to six times higher than that of lean individuals with low overall fat.” These individuals also tended to have higher BMI and overall body fat load, though they did not display higher accumulations of liver fat, which is a distinguishing feature.
Individuals with “skinny fat” characteristics showed higher fat burden in almost all areas other than the pancreas and liver. However, the accumulation of fat was most pronounced in the abdominal area.
“Most notably, this type does not fit the traditional image of a very obese person, as its actual average BMI ranks only fourth among all categories,” says Liu. “The increase is perhaps more in fat proportion. Therefore, if one feature best summarizes this profile, I think, it would be an elevated weight-to-muscle ratio, especially in male individuals.”
In terms of how these findings affect brain health, researchers found significant associations between both fat distribution types and widespread gray matter atrophy, accelerated brain aging, markers of cognitive decline and increased risk of neurological disease. These findings, the team suggested, could be used when stratifying an individual’s risk of future cognitive decline.
Read more from the study here.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She began covering the medical imaging industry for Innovate Healthcare in 2021.