Patterns of Regional Cerebral Blood Flow as a Function of Obesity In Adults

AB: Background: While obesity has been shown to be a risk factor for Alzheimer’s Disease, the potential mechanisms underlying this risk may be clarified with better understanding of underlying physiology in obese persons. 

Objective: To identify patterns of cerebral perfusion abnormality in adults as a function of body mass index defined weight categories, including overweight or obese status.   

Methods: A large psychiatric cohort of with 35442 brain scans across 17721 adults (Mean age 40.8 ± 16.2 years, range 18-94 years) were imaged with SPECT during baseline and concentration scans, the latter done after each participant performed the Connors Performance Test II. ANOVA was done to identify patterns of perfusion abnormality in this cohort across Body Mass Index (BMI) designations of under weight (BMI < 18.5), normal weight (BMI = 18.5 to 24.9) overweight (BMI 24.9 to 29.9), obesity (BMI ³ 30) and morbid obesity (BMI ³ 40). This analysis was done for 128 brain regions quantifying SPECT perfusion using the automated anatomical labeling (AAL) atlas.

Results: Across adulthood, higher BMI correlated with decreased perfusion on both resting and concentration brain SPECT scans.  These are seen in virtually all brain regions, including those influenced by AD pathology such as the hippocampus.  

Conclusion:  Greater BMI is associated with cerebral perfusion decreases in both resting and concentration SPECT scans across adulthood.