Abdominal Fat and Risk of Alzheimer’s

For some middle-aged people, the amount of fat in the pancreas, liver and abdomen is related to brain volumes and function, according to a Rutgers Health study.

Abdominal fat deposits linked to lower cognitive functioning and brain volumes in middle-aged men at high risk for Alzheimer’s

Aim

A high BMI, which poorly represents specific fat deposits, is related to poorer cognition and increased risk of dementia, with different associations between sexes. This study specifically examined the associations of abdominal fat deposits with cognition and brain volumes and whether sex modifies this association.

Methods

A total of 204 healthy middle-aged offspring of patients with Alzheimer’s dementia (mean age = 59.44, 60% female) underwent abdominal magnetic resonance imaging to quantify hepatic, pancreatic, visceral, and subcutaneous adipose tissue and to evaluate cognition and brain volumes.

Results

Across the entire sample, a higher percentage of liver fat was associated with a lower total gray matter volume (β = −0.17, p < 0.01). Primarily in men, a higher percentage of pancreatic fat was associated with lower global cognition (men: β = −0.27, p = 0.03; women: β = 0.01, p = 0.93) executive function (men: β = −0.27, p = 0.03; women: β = 0.02, p = 0.87), episodic memory (men: β = −0.28, p = 0.03; women: β = 0.07, p = 0.48), and inferior frontal gyrus volume (men: β = −0.28, p = 0.02; women: β = 0.10, p = 0.33).

Visceral and subcutaneous adipose tissue were inversely associated with middle frontal and superior frontal gyrus volumes in men and women.

Conclusions

In middle-aged men at high risk for Alzheimer’s dementia, but not women, higher pancreatic fat was associated with lower cognition and brain volume. These findings suggest a possible sex-specific link between distinct abdominal fat and brain health.

Importance of the study

What is already known?

• Alzheimer’s dementia (AD) research is moving toward identifying high-risk populations to facilitate unraveling the underlying mechanisms and new treatment targets.
   
• Obesity is a risk factor for lower cognitive functioning and higher risk of dementia, with different associations between sexes.
   
• Obesity is often measured by BMI, which poorly represents the distribution of body fat and does not necessarily take into account differences between the sexes.

What does this study add?

• A high BMI was associated with a high percentage of liver and pancreatic fat, but not with a percentage of visceral adipose tissue (VAT). Only in women, a high BMI was associated with a high percentage of subcutaneous adipose tissue (SAT).
   
• Among middle-aged men at high risk for AD, a higher percentage of pancreatic fat was associated with lower cognitive function and lower frontal gyrus volume.
   
• VAT percentage and SAT percentage were inversely associated with middle frontal and superior frontal gyrus volumes in men and women.

How might these results change the direction of research or the focus of clinical practice?

• Abdominal fat deposits, rather than BMI, will be assessed as a risk factor for lower cognitive functioning and higher risk of dementia.
   
• Because, to our knowledge, we are the first to do so, more research is needed on the association between pancreatic fat percentage, cognitive functioning, and brain volumes.
   
• Future investigation of the underlying mechanisms that may explain the observed associations may lead to sex-specific interventions for the promotion of brain health.

Comments

The impact of belly fat on brain health and cognition is generally more pronounced in middle-aged men at high risk for Alzheimer’s disease compared to women, according to Rutgers Health researchers.

In middle-aged people with a family history of Alzheimer’s disease, the amount of fat in their abdominal organs (pancreas, liver and abdominal fat) is related to their brain volumes and cognitive function, according to the study published in the journal Obesity . The study was authored by Sapir Golan Shekhtman, a doctoral student at the Joseph Sagol Neuroscience Center at Sheba Medical Center in Israel, and led by Michal Schnaider Beeri, director of the Herbert and Jacqueline Krieger Klein Alzheimer’s Research Center at the Brain Health Institute. from Rutgers.

The research, carried out on 204 healthy middle-aged children with Alzheimer’s dementia, investigated fat deposits in the pancreas, liver and abdomen measured with MRI.

"In middle-aged men at high risk for Alzheimer’s disease, but not women, higher pancreatic fat was associated with lower cognition and brain volumes, suggesting a possible sex-specific link between distinctive abdominal fat and brain health," said Beeri, who holds the Krieger Klein Chair in Neurodegeneration Research at BHI and a faculty member at Rutgers Institute of Health. Health care policies and research on aging.

Obesity is a risk factor for lower cognitive functioning and higher risk of dementia, with different associations between sexes.

The research results highlight the importance of investigating the interrelationships of fat deposits, brain aging and cognition in the context of sex differences.

Additionally, the study challenges the conventional use of body mass index (BMI) as a primary measure to assess obesity-related cognitive risks. The researchers said BMI poorly represents the distribution of body fat and does not necessarily take into account sex differences.

"Our findings indicate stronger correlations compared to the relationships between BMI and cognition, suggesting that abdominal fat deposits, rather than BMI, are a risk factor for lower cognitive functioning and increased risk of dementia." "Shekhtman said.

These research findings open new avenues for targeted interventions and further exploration of sex-specific methods to understand and mitigate the impact of belly fat on brain health, Shekhtman noted.