WEDNESDAY, Dec. 4, 2024 (HealthDay News) — Obesity and visceral fat are associated with measures of amyloid burden in the brain among cognitively normal midlife individuals, according to a study presented at the annual meeting of the Radiological Society of North America, held from Dec. 1 to 5 in Chicago.
Mahsa Dolatshahi, M.D., M.P.H., from the Washington University School of Medicine in St. Louis, and colleagues examined the association of magnetic resonance imaging (MRI)-derived abdominal visceral and subcutaneous adipose tissue (VAT and SAT), liver proton-density fat fraction, thigh fat-to-muscle ratio, and insulin resistance with whole-brain amyloid burden among 62 cognitively normal midlife individuals. Participants underwent brain positron emission tomography scan, body MRI, and metabolic assessment. Whole-brain amyloid Centiloids were calculated using dynamic amyloid imaging.
The researchers found that compared with individuals without obesity, individuals with obesity had significantly higher Centiloids. There was a significant association seen for Centiloids with VAT, homeostatic model assessment for insulin resistance (HOMA-IR), SAT, and body mass index (BMI), but no associations with other fat metrics. The effects of BMI on Centiloids were fully mediated by VAT in a mediation analysis. VAT had a significant direct effect on amyloid burden, which was not explained by HOMA-IR.
“Our study showed that higher visceral fat was associated with higher PET levels of the two hallmark pathologic proteins of Alzheimer’s disease — amyloid and tau,” Dolatshahi said in a statement. “To our knowledge, our study is the only one to demonstrate these findings at midlife where our participants are decades out from developing the earliest symptoms of the dementia that results from Alzheimer’s disease.”
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