Obesity and metabolic complications: contribution of dehydroepiandrosterone and other steroid hormones

Obesity is a heterogeneous condition and not every obese patient is at increased risk of cardiovascular diseases (CVD). It is now well established that the regional distribution of body fat is a critical correlate of the metabolic complications of obesity. Studies that have assessed adipose tissue distribution by imaging techniques such as computed tomography have demonstrated the importance of the intra-abdominal (visceral) fat depot as a marker of a cluster of metabolic abnormalities which include glucose intolerance, insulin resistance, hyper-insulinemia, hypertriglyceridemia, elevated number of apo B-carrying lipoproteins as well as hypoalphalipoproteinemia. Although the association between visceral obesity and metabolic complications can hardly be questioned, it has been suggested that it may not necessarily represent a causal relationship. For instance, concomitant alterations in sex steroid levels have been found in both men and women with abdominal (visceral) obesity which have also been reported to be significantly correlated with the insulin resistant-dyslipidemic state found in abdominal obese subjects. In women, abdominal obesity is associated with increased free testosterone concentrations and reduced sex hormone binding globulin (SHBG) levels, whereas in men this condition is associated with reduced testosterone and adrenal C12 steroid (dehydroepiandrosterone, androstenedione, androstene-3 beta, 17 beta-diol) levels as well as decreased SHBG concentrations. These altered steroid and SHBG; levels have been reported to be independent correlates of the metabolic complications of visceral obesity although they cannot solely account for the increased CVD risk found in these patients. In this regard, intervention studies are clearly warranted to better quantity the respective contribution of excess visceral adipose tissue and of the concomitant alterations in sex steroid levels as modulators of metabolic disturbances increasing CVD risk in obesity.