New insights into the true nature of the obesity paradox and the lower cardiovascular risk.

Obesity is considered a major risk factor for cardiovascular disease, hypertension, and diabetes by National and International Committees. For this reason, they advocate weight loss and prevention of obesity. However, several studies in patients with established coronary artery disease (CAD), congestive heart failure, and hypertension have shown an inverse relationship between obesity and mortality, the so called "obesity paradox," whereas other studies have not shown such a relationship. In studies showing the obesity paradox (OP), body mass index (BMI) was used, almost exclusively as an index of obesity, although is a poor discriminator of total body fatness. Recent studies using better indices of obesity such as waist circumference (WC) and waist to hip ratio (WHR) have shown that high WC and WHR were directly and positively associated with higher event rate and total mortality in these patients. Because the OP could convey the wrong message in obese patients, the validity and true nature of the OP will be examined in this concise review. A Medline search of the English literature was performed between 2000 and September 2012, and 46 pertinent articles were selected for this review. The majority of these studies do not support an OP and those that do have used almost exclusively BMI as an index of obesity. Therefore, based on recent studies using other indices of body fat distribution, such as WC and WHR, besides BMI, the true existence of OP has been questioned and needs to be confirmed by future studies.