Pancreatic and ‘Skinny Fat’ Linked to Brain Risks

 I'm sure there is no way you can get this testing and then your competent? doctor will know nothing on how to address it. 

Pancreatic and ‘Skinny Fat’ Linked to Brain Risks

The effect of body fat on brain health may depend not only on the amount of fat an individual has but also on where that fat is stored, new research revealed.

While previous research has established a link between obesity and brain and cognitive health, particularly in people with higher ratios of visceral fat, the current study focused on the risks associated with specific fat distribution patterns, said co-senior author Kai Liu, MD, PhD, associate professor in radiology at the Affiliated Hospital of Xuzhou Medical University in Xuzhou, China.

The study leveraged MRI and latent profile analysis (LPA), a modeling technique used to identify unobserved subgroups (latent profiles) within a population, to quantify fat in various body compartments, especially internal organs. The result was “a classification system that’s data-driven instead of subjective,” Liu told Medscape Medical News.

“The data-driven classification unexpectedly discovered two previously undefined fat distribution types” that carried risks for the brain, he said. One was a pancreatic predominant profile. “This was surprising. Though a small organ with minimal total fat, pancreatic fat played a disproportionately important role in our system and defined the profile with the highest brain risk — a finding that somewhat overturned conventional understanding.”

“The other newly defined high-risk type — ‘skinny fat’ — also surprised us,” he said. “It does not fit the traditional ‘very obese’ image, yet it still showed strong associations with adverse brain outcomes.”

The study was published online in Radiology.

High Pancreatic Fat, Low Liver Fat

The researchers conducted a secondary analysis of prospective data from 25,997 participants (mean age, 55 years; 52% female) in the UK Biobank, including health records and MRI scans of the brain, heart, and abdomen.

Participants were included if they had complete data for BMI and nine MRI-derived fat quantification variables from cardiac and abdominal imaging: hepatic proton density fat fraction, pancreatic proton density fat fraction, abdominal fat ratio, muscle fat infiltration, total abdominal adipose tissue index, weight-to-muscle ratio, abdominal subcutaneous adipose tissue volume, visceral adipose tissue volume, and mean estimated area of pericardial fat.

Differences in brain volume, white matter properties, cognition, and the risk for neurologic disorders were analyzed across profiles and relative to a benchmark lean profile, and analyses were stratified by sex.

LPA identified six profiles of body fat distribution in both sexes. Of these, compared with the lean profile, “pancreatic predominant” and “skinny fat” profiles were most associated with extensive gray matter atrophy, accelerated brain aging, cognitive decline, and an increased risk for neurological disease, according to the authors. The risks were present in both men and women, with small variations between the sexes.

Specifically, individuals with “pancreatic predominant” distribution patterns showed a proton density fat fraction — an MRI marker that provides a precise estimation of fat concentration in tissue — of around 30% in the pancreas.

“This level 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,” Liu said. “Additionally, this group tends to have a higher BMI and overall body fat load.”

Yet these individuals didn’t have significantly more pronounced liver fat than those with other profiles. Thus, high pancreatic fat accompanied by relatively low liver fat emerged as a “distinct, clinically overlooked phenotype,” he said.

“In practice, we routinely diagnose ‘fatty liver,’ but our findings suggest that — from a neurological risk perspective — elevated pancreatic fat should be acknowledged as a potentially higher-risk imaging marker,” he said.

In individuals with the “skinny fat” profile, fat tends to be more concentrated in the abdomen. “This type does not fit the traditional image of a very obese person, as its actual average BMI ranks only fourth among all categories,” he noted. “The increase is perhaps more in fat proportion. Therefore, if one feature best summarizes this profile, it would be an elevated weight-to-muscle ratio, especially in male individuals.”

The study was supported by grants from the National Natural Science Foundation of China, the Construction Project of High Level Hospital of Jiangsu Province, the Qinglan Project of Jiangsu Province of China, and the Key Research and Development Project of Xuzhou. Liu reported having no conflicts.

Marilynn Larkin, MA, is an award-winning medical writer and editor whose work has appeared in numerous publications, including Medscape Medical News and its sister publication MDedge, The Lancet (where she was a contributing editor), and Reuters Health.