Background:
Beyond the amount of adiposity, the pattern of fat distribution has a profound influence on cardiometabolic risk.Thus, the considerable sex differences with regard to body fat distribution could contribute to the prevalence of the metabolic syndrome (MetS) and, ultimately cardiovascular disease. The present study aimed to comprehensively investigate sex differences in various cardiometabolic risk factors in predominantly very obese men and women. The specialty of the present unique study is the consideration of natural sex differences in body composition and fat distribution, as well as important gender differences in lifestyle factors.
Methods: In this cross-sectional analysis, 432 persons (n=356 severely obese, mean BMI 41±8 kg/m2, intending to participate in a medical weight loss program and 76 non-obese, mean BMI 25±3 kg/m2), were included. Adjustments were done by age, body fat and composition parameters, alcohol consumption, smoking, the amount of healthy food intake and physical activity.
Results: Percent fat mass and the fat mass/lean mass ratio were significantly higher in females than in males, regardless of increasing obesity categories, from normal weight to obesity grade III. In contrast, markers of abdominal obesity, such as waist circumference and waist-to hip ratio were higher in men than in women, despite similar BMI. The prevalence of the MetS was higher in obese men than in women (67.6% vs. 45.0%, p<0.0001), particularly in younger individuals <40 years of age (72.5% vs. 36.8%, p<0.0001), but “healthy obesity” was more common in women that in men (15.6% vs. 4.1%, p<0.0001). After multivariate adjustments including natural differences in body fat distribution, true sex differences could be observed for HDL-cholesterol (p<0.001), triglycerides (p<0.001), fasting glucose (p=0.002), insulin and HOMA-IR levels (p<0.001), the liver enzymes ALAT and ASAT (p<0.001), adiponectin (p<0.001), MMP-9 (p=0.002), and sE-Selectin (p=0.005). In contrast, seemingly sex differences in others, such as crude leptin levels (68±4 in obese women vs. 33±2 µg/L in obese men, p<0.0001), completely disappeared after accounting for differences in body fat distribution (52±4 vs. 55±6, p=0.740). Moreover, the higher risk of having MetS in obese men was linked to differences in parameters of abdominal obesity as well as adiponectin levels.
Conclusions: Different body fat distribution patterns, particularly abdominal (visceral) adiposity, adiponectin and additional factors, e.g. sex hormones, contribute to sex differences in cardiometabolic risk factors and to the prevalence of the MetS.