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

Abstract

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 (BMI) defined weight categories, including overweight or obese status.

Methods: A large psychiatric cohort of 35,442 brain scans across 17,721 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 completed the Connors Continuous Performance Test II. ANOVA was done to identify patterns of perfusion abnormality in this cohort across BMI designations of underweight (BMI < 18.5), normal weight (BMI = 18.5 to 24.9), overweight (BMI 24.9 to 29.9), obesity (BMI≥30), and morbid obesity (BMI≥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.

Keywords: Cerebral perfusion; SPECT; obesity.

Fig. 1.

Areas of obesity-related hypoperfusion in brain regions vulnerable to Alzheimer’s disease: temporal lobes.

Fig. 2.

Areas of obesity-related hypoperfusion in brain regions vulnerable to Alzheimer’s disease: parietal lobes.

Fig. 3.

Areas of obesity-related hypoperfusion in brain regions vulnerable to Alzheimer’s disease: hippocampus.

Fig. 4.

Areas of obesity-related hypoperfusion in brain regions vulnerable to Alzheimer’s disease: posterior cingulate.

Fig. 5.

Areas of obesity-related hypoperfusion in brain regions vulnerable to Alzheimer’s disease: precuneus.

Fig. 6.

This figure showed 3-D renderings of resident perfusion averaged across normal BMI (BMI = 23), overweight (BMI = 29), and obese (BMI = 37) men, each 40 years of age.