A recent study published in Radiology, the journal of the Radiological Society of North America (RSNA), suggests that the impact of obesity on brain health may be influenced by both the amount and location of fat in the body.
Researchers from The Affiliated Hospital of Xuzhou Medical University in China identified two previously unrecognized types of fat distribution using MRI scans. These are "pancreatic predominant," which involves a high concentration of fat in the pancreas, and "skinny fat," characterized by a high overall fat burden despite not matching typical obesity patterns.
"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," said Dr. Kai Liu, associate professor at The Affiliated Hospital's Department of Radiology. "The data-driven classification unexpectedly discovered two previously undefined fat distribution types that deserve greater attention."
The study analyzed data from 25,997 individuals included in the UK Biobank database. This resource contains anonymized medical imaging along with physical measurements and other health-related information. By examining these records, researchers compared patterns of body fat with outcomes related to brain health.
According to the findings, both "pancreatic-predominant" and "skinny fat" profiles were linked to significant gray matter loss, faster brain aging, cognitive decline, and an increased risk for neurological diseases. These associations were observed in men and women, though some differences existed between sexes.
People classified as having a "pancreatic-predominant" profile had about 30 percent proton density fat fraction—a precise MRI measure—within their pancreas. Unlike those with high liver fat content ("fatty liver"), these individuals did not show elevated liver fat levels. Dr. Liu emphasized this point: "In our daily radiology practice, we often diagnose 'fatty liver.' But from the perspectives of brain structure, cognitive impairment and neurological disease risk, increased pancreatic fat should be recognized as a potentially higher-risk imaging phenotype than fatty liver."
The "skinny fat" group exhibited elevated total body fat almost everywhere except in the liver and pancreas. This type was mostly seen as abdominal obesity but did not correspond with high BMI rankings typically associated with obesity. As Dr. Liu explained: "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. 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."
While this research focused on links between different patterns of body fat and risks to brain health and cognition, Dr. Liu noted that further investigation is needed into how these patterns might affect cardiovascular or metabolic conditions.
Dr. Liu summarized: "Brain health is not just a matter of how much fat you have, but also where it goes."
The study was conducted by Dr. Liu along with Miao Yu, M.D., Libin Yao, M.D., Sanjeev Shahi, M.M., Yingqianxi Xu, M.M., Meizi Li, M.M., Qingtong Zheng, M.M., Di Ma, M.M., Qi Zhang, M.M., Dan Wang, B.M., Yang Wu, B.M., Xiao Zhou B.M., Haitao Ge Ph.D., Chunfeng Hu M.D., and Yanjia Deng M.D., Ph.D.
