The paradox of diabetes, obesity and cardiovascular risk

Weight loss to reduce cardiovascular risk is encouraged in both healthy overweight individuals and those at high cardiovascular risk, including patients with diabetes. However, a large body of studies suggest that, in comparison to overweight and even obese subjects, cardiovascular events may be more common among patients who lose weight or who fall into lower body mass index categories. In contrast, other studies confirm the traditional concept that weight loss and maintenance of a healthy body weight is not only associated with improvement in cardiovascular risk factors, such as blood pressure, lipid profile and blood glucose control, but also with a reduction in cardiovascular morbidity and mortality. Possible reasons for the difference in outcomes between these two groups of studies include differences in study design, bias and statistics, the health status of the study participants and differential treatment afforded to different patient groups. This article reviews studies supporting both points of view and describes potential explanations for the observed differences in outcomes according to body weight.