Obesity is associated with several other disorders including type 2 diabetes. With increasing degrees of obesity, the risk of developing type 2 diabetes is also increased. This results partly due to the emergence of insulin resistance with increasing adiposity. As the world has witnessed the worsening of the obesity epidemic, so too has the rate of type 2 diabetes worsened. We have previously discussed that the rate of diabetes has more than doubled in the last 30 years. There are currently 285 million people with type 2 diabetes in the world, and with the worsening obesity epidemic the number of people with type 2 diabetes is expected to reach 439 million by the year 2030. We have previously discussed the finding that bariatric surgery can reverse type 2 diabetes in some patients, and allow them to completely stop their diabetic medications altogether. Lifestyle modifications such as dieting, weight loss, and exercise has been shown to prevent the occurrence of type 2 diabetes in individuals with pre-diabetes or glucose intolerance. Although bariatric surgery has been shown to lessen the severity of diabetes and even reverse the disease in some individuals, bariatric surgery has never been shown to prevent the occurrence of type 2 diabetes in pre-diabetics.
Researchers, led by Dr. Lars Sjorstrom of the University of Gothenburg in Sweden, have shown that bariatric surgery can prevent the occurrence of type 2 diabetes in obese patients with pre-diabetes. The results of their study were published online in the New England Journal of Medicine. The researchers performed a prospective, nonrandomized controlled study involving a subset of data from study participants enrolled in the Swedish Obese Subjects (SOS) trial. The analysis included 1,658 individuals who had bariatric surgery and 1,771 individuals in the control group. The study participants were followed for a 15 year period and it was found that those who had impaired glucose tolerance and underwent bariatric surgery had an 87% lower incidence of type 2 diabetes when compared to the control obese group who did not have the surgery. Type 2 diabetes was diagnosed in 392 study participants in the control group and in 110 study participants in the bariatric surgery group, which corresponds to an incidence rate of 28.4 cases per 1000 person-years and 6.8 cases per 1000 person-years, respectively. Study participants in the bariatric surgery group had a maximal mean weight loss of 68 pounds after one year and 44 pounds after 15 years. In the control group that did not have bariatric surgery, weight that was gained or lost never exceeded 6 or 7 pounds.
The authors wrote, “The results of this analysis show that bariatric surgery, as compared with usual care, reduces the long-term incidence of type 2 diabetes by 78% in obese patients. This risk reduction was achieved despite a less favorable risk profile in the surgery group at baseline. Among patients with impaired fasting glucose, bariatric surgery reduced the risk by 87%, and type 2 diabetes did not develop in approximately 10 of 13 obese patients who underwent bariatric surgery. This risk reduction is at least twice as large as that observed with lifestyle interventions in moderately obese, pre-diabetic persons”.
The study authors concluded, “Bariatric surgery appears to be markedly more efficient than usual care in the prevention of type 2 diabetes in obese persons”.
In an accompanying commentary, Dr. Danny O. Jacobs writes, “The long-term findings of the SOS study are both provocative and exciting — especially the findings that suggest that bariatric surgery may prevent the conversion of abnormalities in glucose metabolism to frank diabetes”.
This study is remarkable because it is the first to show that weight loss through bariatric surgery can prevent the onset of diabetes in patient that are at risk of developing the disease. In addition, this study points out the extremely strong impact that obesity has on the development of type 2 diabetes. Bariatric surgery is not a good option for all obese patients, but in those that meet the criteria, it has health benefits that go beyond the immediate weight loss. The prevention of type 2 diabetes can forestall other health problems that result from uncontrolled blood glucose such as heart disease, stroke, and peripheral arterial disease.
Lena M.S. Carlsson et al. “Bariatric Surgery and Prevention of Type2 Diabetes in Swedish Obese Subjects” New Engl J Med 2012; 367: 695-704.