Cardiovascular risk, obesity, and myocardial blood flow in postmenopausal women.
BACKGROUND
This study was designed to determine whether overweight or obese status is independently associated with myocardial flow reserve (MFR), an established predictor of cardiovascular mortality, in a group of postmenopausal women with no previous cardiovascular disease. Postmenopausal women are the largest group of overweight and physically inactive individuals in the United States. Increased body mass index (BMI) is consistently associated with increased cardiovascular mortality in this population. Whether this is because of obesity itself or the accompanying increase in cardiovascular risk factors (CRFs) remains controversial.


METHODS
We examined the relationship of myocardial blood flow (MBF), coronary vascular resistance, and MFR to BMI in 60 postmenopausal women with no coronary heart disease. Subjects underwent dynamic N-13 ammonia positron emission tomography for the measurement of MBF and MFR. Baseline demographics, CRF, and hemodynamic parameters were recorded for each subject. Datasets were divided into 3 groups according to BMI: normal (18 to 24), overweight (25 to 29), and obese (>or=30).


RESULTS
The overweight and obese groups showed significantly higher resting MBF and lower MFR than the normal-weight group (both P < .001), even after adjusting for CRF. A further analysis of subjects without any CRF (n = 35) showed that the MFR remained significantly lower in the obese compared with normal-weight subjects (P = .05). Levels of known markers of vascular inflammation (high-sensitivity C-reactive protein and homocysteine) and high-density lipoprotein cholesterol levels correlated with declining MFR.


CONCLUSIONS
These findings provide a mechanistic link between obesity and coronary heart disease in this population.
Motivala
Apurva A
AA
Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Rose
Patricia A
PA
Kim
H Myra
HM
Smith
Yolanda R
YR
Bartnik
Catherine
C
Brook
Robert D
RD
Muzik
Otto
O
Duvernoy
Claire S
CS
D000368:Aged; D003324:Coronary Artery Disease / Q000150:complications* / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000000981:diagnostic imaging*; D017698:Postmenopause; D015995:Prevalence; D011877:Radionuclide Imaging; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors