Impact of Different Bariatric Surgical Procedures on Insulin Action and β-Cell Function in Type 2 Diabetes

Abstract

The prevalence of obesity appears to have reached a plateau in the U.S. between 2003 and 2007 (1), but the obesity epidemic is still rampant in many other countries—especially in the developing world (2)—in adults as well as children (http://www.who.int/topics/obesity/en/). A recent analysis of a large prospective cohort of individuals 50–71 years old (3) has generated a precise dose-response gradient for the positive association of BMI and relative risk of death independent of other risk factors (especially smoking and preexisting disease, which cause weight loss). Yet, long-term observational studies have generally found that weight loss, whether spontaneous or intentional, is associated with increased, rather than decreased, overall mortality (rev. in 4). Lifestyle intervention (diet and exercise), behavioral management, and drug therapy for obesity deliver a degree of weight loss that is usually modest (and therefore unattractive to patients) and short-lived (6 months to 1 year at best) and carry considerable side effects. Moreover, despite the attenuation of risk factors such as diabetes and dyslipidemia, trial evidence for an effect of these weight-control approaches on reducing cardiovascular disease or mortality is still lacking (rev. in 5). On the other hand, and perhaps as a consequence, surgery for the treatment of severe obesity is gaining increasing favor. The annual U.S. frequency of hospital discharges that included bariatric surgery increased sevenfold (from 3.5 to 24.0 per 100,000) between 1996 and 2002 (6). According to a review of 85,048 morbidly obese patients (7), early (≤30 days) and late (30 days to 2 years) mortality rates for bariatric surgery trend downward (0.28 and 0.35%, respectively). Surgical treatment of massive obesity is being extended to adolescents, seemingly with similar success and risk rates as in adults (8–10). Recently, the 10.9-year follow-up of the Swedish Obese Subjects Study reported a 30% risk reduction for …