Abdominal obesity:: the most prevalent cause of the metabolic syndrome and related cardiometabolic risk

Abdominal obesity, due to intra-abdominal adiposity, drives the progression of multiple cardiometabolic risk factors independently of body mass index. This occurs both through altered secretion of adipocyte-derived biologically active substances (adipokines), including free fatty acids, adiponectin, interleukin-6, tumour necrosis factor alpha, and plasminogen activator inhibitor-1, and through exacerbation of insulin resistance and associated cardiometabolic risk factors. The prevalence of abdominal obesity is increasing in western populations, due to a combination of low physical activity and high-energy diets, and also in developing countries, where it is associated with the urbanization of populations. The measurement of waist circumference, together with an additional comorbidity, readily identifies the presence of increased cardiometabolic risk associated with abdominal obesity. For example, > 80% men with waist circumference >= 90 cm and triglycerides (TG) >= 2 mmol/L were found to have an atherogenic triad of elevated apolipoprotein B, fasting hyperinsulinaemia, and small, dense LDL, which had been strongly associated with adverse cardiovascular outcomes in a previous observational study. Accordingly, measurement of waist circumference should become a standard component of cardiovascular risk evaluation in routine clinical practice. Lifestyle modification remains the initial intervention of choice for this population, with pharmacological modulation of risk factors where this is insufficiently effective. Looking ahead, the initial results of randomized trials with rimonabant, the first CB1 receptor blocker, indicate the potential of correcting overactivation of the endogenous endocannabinoid system for simultaneous improvement of multiple cardiometabolic risk factors.