Weight changes and obesity predict impaired resting and endothelium-dependent myocardial blood flow in postmenopausal women



Background: Obesity has been associated with impaired endothelial function, but the influence of lifetime weight patterns on endothelial function has not been studied.

Hypothesis: We hypothesized that coronary vascular reactivity would be diminished in postmenopausal women with a history of obesity and frequent weight swings.

Methods: We performed dynamic N-13 ammonia positron emission tomography in 18 postmenopausal women with cardiac risk factors. Myocardial blood flow (MBF) was measured at rest, after the cold pressor test (CPT), and after adenosine infusion in order to determine baseline and endothelium-dependent and -independent flows, respectively. Myocardial blood flow was corrected for cardiac work by normalizing to the rate-pressure product. Weight history was obtained by standardized questionnaire.

Results: Normalized rest (n-rest) MBF correlated negatively with current weight (r=-0.52, p= 0.026) and weight at age 18 (r = −0.47, p = 0.047). Normalized CPT (n-CPT) MBF correlated inversely with current weight (r = −0.55, p = 0.018), weight at age 18 (r= −0.605, p = 0.008), and highest weight (r = −0.62, p = 0.006). Higher waist circumference predicted lower n-rest MBF (r= −0.52, p = 0.028) and n-CPT MBF (r = −0.48, p = 0.04). The same association was found with hip circumference (r = −0.52, p = 0.028; r = −0.49, p = 0.038, respectively), whereas higher body mass index (BMI) predicted lower n-CPT MBF (r =-0.53, p = 0.02). Women with at least four significant weight swings had lower MBF during rest, CPT, and n-CPT (0.88 vs. 1.19 ml/g/min, p = 0.008; 0.76 vs. 1.23 ml/g/min, p< 0.001; 0.74 vs. 1.10 ml/g/ min, p = 0.009, respectively).

Conclusions: Increased waist and hip circumference, weight, and frequent weight swings are associated with impaired resting and endothelium-dependent MBF in postmenopausal women. These data suggest that lifetime weight patterns may influence cardiovascular risk in women.