Obesity and type 2 diabetes are strongly associated. It has been shown recently that obesity surgery - gastric bypass, intestinal bypass, gastric banding - cures type 2 diabetes. It might be be safe to presume that surgery for obesity would also prevent it. Last week’s The New England Journal of Medicine has a report from Sweden that demostrates that obesity surgery dramatically prevents the onset of type 2 diabetes in obese people who do not have it yet. (1) So that’s not very surprising.
More interesting were some other observations they made. In the controls who did not get surgery, professional guidance (diet and exercise recommendations) didn’t significantly help prevent diabetes. That’s probably both because this advice is not worth much and also because it’s tough guidance to follow.
There were three surgeries - gastric banding, vertical banded gastroplasty and gastric bypass. Other studies have shown that gastric bypass works better for cure of diabetes than gastric banding. That may be because there is more weight loss with gastric bypass, or because of some other mechanism. Gastric bypass surgery also bypasses the first part of the small intestine and it has been shown that if you divert food from the first part of the small intestine alone, without mangling the stomach, you also cure diabetes. In this study gastric bypass did better than gastric banding and vertical banded gastroplasty but there were not enough patients to show a statistically significant difference.
Finally the benefit of preventing type 2 diabetes did not have any relation to how obese these subjects were. This observation, that degree of obesity does not predict the benefit from these kinds of surgery, has previously been shown with respect to heart disease and stroke and cancer and death. Also it has been shown in prior studies that the cure of diabetes comes before any weight loss. So while obesity and type 2 diabetes seem to be strongly associated, this kind of surgery that causes big weight loss and diabetes cure and prevention may be two different magic bullets at once. As mentioned in an accompanying editorial (2) it would be impractical to suggest that we open the flood gates by doing bariatric surgery to prevent type 2 diabetes but if we could figure out how these magic bullets are working, (and stop talking about diet and exercise) “it is possible that interventions that are even less invasive may accomplish the very desirable goal of decreasing the incidence of type 2 diabetes..”
1. Carlsson LMS et al. Bariatric surgery and prevention of type 2 diabetes in Swedish obese subjects. N Engl J Med 2012;367:695-704.
2. Jacobs DO. Bariatric surgery - from treatment of disease to prevention? N Engl J Med 2012;367:764-5.