Abstract 843: Exaggerated Left Ventricular Adaptive Response to Obesity in Women
Background: There is little information on influence of body composition and fat distribution on magnitude of LV mass in obese men and women. We examined gender differences in those relations, in the presence or absence of obesity.
Methods: From the Strong Heart Study, we selected 2919 participants (1068 men, 501 obese; 1851 women, 1108 obese) without prevalent CV diseases (heart failure, stroke, coronary heart disease) and GFR>30 mL/min/1.73 m2. Fat free mass (FFM) and adipose mass (AM) were estimated by bioelectric impedance. Central adiposity was estimated by waist girth (ATPIII). Echocardiographic LV mass (LVM) was normalized for height2.7 or FFM. Stroke volume (SV) was measured by transaortic Doppler and related to pulse pressure (PP/SV) as an index of arterial stiffness.
Results: Diabetes and hypertension were more prevalent in obese men and women (all p<0.0001). Obesity was central in 94% of men and 99.7% of women. Among non-obese women fat distribution was central in 79%, vs 19% of non-obese men (p<0.0001). The ratio FFM/AM was higher in men than in women, a difference that was increased by obesity (2.18 vs 1.24, all p<0.0001). However, women exhibiting greater values of LVM indices (LVMis) than men by either normalizations (both p<0.0001). Obesity increased LVMis more in women than in men (both p<0.02). These results were confirmed also after controlling for hypertension and diabetes. Variance of LVM was independently associated with age, body composition, and hemodynamic determinants (systolic pressure, SV and PP/SV) in both genders (all 0.06<p<0.0001), but in women it was also related to diabetes and central fat distribution, with a substantial greater effect for age and AM than in men (p<0.0001). In women, residuals of the sex-specific regression models were positively related to fibrinogen levels and urinary albumin/creatinine excretion (both p<0.001).
Conclusions: LV mass increases to an unexpected level in obese women, despite their lower FFM, and appears to be more susceptible to the harmful effects of pathologic stimuli such as diabetes and central adiposity. This findings are consistent with the known greater severity of CV disease in women.