The effects of body mass index on cerebral blood flow velocity.
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 head-up tilt (P = 0.02), and was elevated in obese subjects (P = 0.004) compared to normal weight subjects across all groups.


CONCLUSIONS
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 the cerebrovascular bed, independent of diagnosis of type-2 diabetes, hypertension or stroke. Obesity may contribute to cerebromicrovascular disease, and affect clinical functional outcomes of the older population.
Selim
Magdy
M
Dept. of Neurology, Stroke Division, Beth Israel Deaconess Medical Center, Boston, MA, USA.
Jones
Richard
R
Novak
Peter
P
Zhao
Peng
P
Novak
Vera
V
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D002560:Cerebrovascular Circulation / Q000502:physiology*; D054022:Cerebrum / Q000098:blood supply; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging; D009765:Obesity / Q000150:complications / Q000503:physiopathology*; D020521:Stroke / Q000209:etiology / Q000503:physiopathology; D017585:Ultrasonography, Doppler, Transcranial; D014655:Vascular Resistance / Q000502:physiology