The effects of body mass index on cerebral blood flow velocity

Abstract

Objective-Obesity is a risk factor for cerebrovascular disease. We aimed to determine the effects of high body mass index (BMI) on cerebral blood flow regulation in patients with type-2 diabetes mellitus, hypertension, and stroke.Methods-We analyzed data from 90 controls, 30 diabetics, 45 hypertensives, and 32 ischemic stroke patients who underwent transcranial Doppler for evaluation of blood flow velocities (BFV) in the middle cerebral arteries (MCA) and cerebrovascular resistance (CVR) during supine rest and head-up tilt. This study was a cross -sectional analysis. We used a structural equation multiple indicators modeling to determine the effects of BMI and other background variables (age, sex, race, smoking, alcohol use, and systolic blood pressure) on cerebral BFV.Results-Higher BMI (p=0.02) and age (p=0.004) were associated with lower mean BFV during baseline, independent of diagnosis of diabetes mellitus, hypertension or stroke, and after adjusting for all background variables and vessel diameters. Men, especially those with stroke, had a lower mean BFV than women (p = 0.01). CVR increased with BMI (p=0.001) at baseline and during headup tilt (p=0.02), and was elevated in obese subjects (p=0.004) compared to normal weight subjects across all groups.Interpretation-High BMI is associated with a reduction in cerebral BFV and increased CVR. These findings indicate that obesity can adversely affect cerebral blood flow and resistance in cerebrovascular bed, independent of diagnosis of type-2 diabetes, hypertension or stroke. Obesity may contribute to cerebromicrovascular disease, and affect clinical functional outcomes of older population.

Framingham Cardiovascular Risk Profile Correlates with Impaired Hippocampal and Cortical Vasoreactivity to Hypercapnia

“…Multiple imaging modalities corroborate the relationship between vascular risk factors and deficits in resting cerebral blood flow (CBF) (Claus et al, 1996;Novak et al, 2006;Selim et al, 2008;Beason-Held et al, 2007). Similarly, atherosclerosis risk factors impair vascular response to hypercapnia (Groschel et al, 2007;Settakis et al, 2003), as evidenced by Doppler studies.…”

“…Although many reports substantiate the link between risks for atherosclerosis and blood flow at a global cerebral or lobar level (Claus et al, 1996;Novak et al, 2006;Selim et al, 2008;Groschel et al, 2007;Settakis et al, 2003), there is only a limited information about the influence of these factors on CBF in structures directly related to memory function. Hippocampus is a major anatomical substrate of memory (Eichenbaum, 2004;Shapiro, 2001), and its structural and functional abnormalities predict Alzheimer's disease (AD) (Glodzik-Sobanska et al, 2005;Mosconi, 2005).…”

Physical exercise and executive functions in preadolescent children, adolescents and young adults: a meta-analysis

“…A recent meta-analysis showed that children and adolescents with obesity had cognitive deficits that were most prominent for executive functions 103. This may be explained by decreased levels of CBF in predominantly prefrontal brain areas 104 105. Therefore, physical exercise may provide a promising intervention for executive function deficits of children with obesity, possibly by prolonged enhancement of CBF in the frontal brain regions.…”

The Effects of Obesity on the Cerebral Vasculature

“…The detrimental effects of obesity on the cerebral vasculature are striking, with several studies showing that obese patients, or patients with an elevated body mass index (BMI), have reduced cerebral blood flow [1–3]. Here we will describe some potential mechanisms and possible ramifications of reduced cerebral perfusion in obesity.…”