According to the World Health Organization, some 55 million people globally suffer from Alzheimer’s disease or dementia. With 10 million new cases diagnosed annually, dementia has become the seventh leading cause of death worldwide, and those numbers are only likely to grow as life expectancy continues to increase.
Thus far, treatments for Alzheimer’s and other forms of dementia have shown little effect—likely because significant changes to the brain occur long before the actual appearance of the symptoms. The focus for researchers, then, has been to identify populations at high risk with an eye toward uncovering the underlying mechanisms of the disease and developing ways to address them.
One of those underlying mechanisms is midlife obesity, which has previously been associated with greater dementia risk later in life. Hoping to build on this previous research, a team led by researchers from Tel Aviv University in Israel and Rutgers University in New Jersey set out to examine the association between abdominal fat deposits and cognitive functioning among people at high risk of dementia, and then to determine whether those associations differed between males and females. Their results were published in the journal Obesity.
The researchers examined subjects from the Israel Registry for Alzheimer’s Prevention (IRAP) cohort study, which follows cognitively asymptomatic middle-aged (aged 40-65 at baseline) offspring of Alzheimer’s patients. Of the 420 participants in the study, 204 agreed to undergo abdominal MRI scans to assess abdominal fat deposits. Participants also underwent a comprehensive battery of neuropsychological tests—including tests of episodic memory, executive function, and working memory. Additionally, 142 of the participants also underwent a structural volumetric brain MRI scan.
Statistical analysis showed that higher levels of pancreatic fat were associated with lower episodic memory function in male, but not female, participants. The brain MRIs also revealed an association between high levels of pancreatic fat and lower brain volume in males.
“In middle-aged males at high Alzheimer’s disease risk—but not females—higher pancreatic fat was associated with lower cognition and brain volumes, suggesting a potential sex-specific link between distinct abdominal fat with brain health,” said lead researcher Michal Schnaider Beeri, PhD of the Rutgers Institute for Health, Health Care Policy and Aging Research.
Conclusions
In addition to highlighting the importance of investigating the interrelationships of fat depots, brain aging, and cognition in the context of sex differences, the results also point out a potential flaw in earlier research. Specifically, these results challenge the conventional use of body mass index (BMI) as the primary measure for assessing obesity-related cognitive risks, the researchers said, noting that BMI poorly represents body fat distribution and does not necessarily account for sex differences.
“Our findings indicate stronger correlations compared to the relationships between BMI and cognition, suggesting that abdominal fat, rather than BMI, is a risk factor for lower cognitive functioning and higher dementia risk,” said lead author Sapir Golan Shekhtman. These findings should open new avenues for targeted interventions and further exploration of sex-specific approaches in understanding and mitigating the impact of abdominal fat on brain health, Shekhtman noted.
