Elevated BMI is associated with decreased blood flow in the prefrontal cortex using SPECT imaging in healthy adults.

ABSTRACT:

Context: Obesity is a risk factor for stroke and neurodegenerative disease. Excess body fat has been linked to impaired glucose metabolism, insulin resistance and impulsivity and may be a precursor to decline in attention and executive cognitive function.

Objective: To investigate the effects of high body mass index on regional cerebral blood flow (rCBF) using SPECT imaging in healthy brain subjects.

Design, setting, and participants: We used SPECT imaging data and analyzed changes in rCBF from 16 adult men and 20 adult women recruited from the community as part of a healthy brain study conducted at the Amen Clinics Inc., a private medical facility, from May 2008 to May 2010. Participants in the study were screened for neurological and psychiatric conditions, concussion history and substance use and excluded based on any conditions known to affect brain function. An additional inclusion criterion for the study was scoring normal on the Connor’s Continuous Performance Test (C-CPT II), an assessment of attention. Subjects were categorized as normal or overweight according to body mass index (BMI). We used a 2 sample t-test to determine the effects of BMI on rCBF. Subjects were matched for age and gender. Main outcome measure: Changes in rCBF in normal and overweight adults. Normal was defined as a BMI of 24.9 or lower. Overweight was defined as a BMI of 25.0 or higher.

Results: Higher BMI in healthy individuals is associated with decreased rCBF in Broadmann Areas 8, 9, 10, 11, 32 and 44, brain regions involved in attention, reasoning and executive function (P<0.05, FEW).

Conclusion(s): We found an elevated BMI is associated with decreased rCBF in the prefrontal cortex of a healthy, middle-aged cohort. These findings indicate that elevated BMI may be a risk factor for impaired executive function and planning, issues associated with the prefrontal cortex.