The Swedish study followed more than 3,400 obese men and women, roughly half of whom had weight loss surgery, for up to 15 years. It found that bariatric surgery reduced the risk of type 2 diabetes by 78 percent – double the effect of diet and exercise alone.
“Weight loss surgery appears to be markedly more efficient than usual care in the prevention of type 2 diabetes in obese persons,” Dr. Lena Carlsson from the University of Gothenburg, Sweden, wrote in the study, published Tuesday in the New England Journal of Medicine.
The bariatric surgery, which shrinks the stomach to hold less food and absorb fewer calories, has previously been shown to help treat diabetes. But this study, funded by the Swedish Research Council, the Swedish Foundation for Strategic Research to Sahlgrenska Center for Cardiovascular and Metabolic Research, the Swedish federal government, the VINNOVA-VINNMER program and the Wenner-Gren Foundations, is the first to suggest it can help prevent the disease.
“Instead of waiting for illness to begin and treat with medications, patients will now have a choice to prevent diabetes,” said Dr. Carson Liu, a obesity surgeon in Los Angeles. “This is a terrific data for decreasing the epidemic of diabetes.”
Some experts say the study could broaden the spectrum when it comes to who qualifies for weight-loss surgery, as most insurance companies currently cover the procedure only in adults who are obese or overweight with weight-related health problems.
“There are data to suggest that weight loss surgery can be safely employed in [non-obese diabetics],” said Dr. John Morton, associate professor of surgery at Stanford University, who has successfully treated diabetic patients with body mass indices — or BMIs — below 35.
“The threshold for metabolic surgery has been 35 for many years, like a brick wall,” said Dr. Philip Schauer, director of the Bariatric and Metabolic Institute (BMI) at the Cleveland Clinic. “But that brick wall is like the Berlin Wall, it’s coming down. Thirty is potentially the new wall.”
Weight loss surgery is thought to cut the risk of diabetes by both reducing weight and changing hormone signaling pathways that control blood sugar levels. After the surgery, blood sugars typically normalize in just a few days — long before the patient starts to lose weight.
But regardless of the mechanism, experts say the results speak for themselves.
“It is indisputable that weight loss surgery addresses weight-related problems better than medical treatments, regardless of the mechanism,” said Dr. Ozanan Meireles, an instructor in surgery at Massachusetts General Hospital. “All patients would certainly benefit from it, either by achieving remission, by decreasing the amount of medications that they take on a daily basis, or by postponing the onset of diabetes in their lifetime.”
Still, experts caution that the decision to go under the knife should not be taken lightly – keeping in mind that weight-loss surgery can, in rare cases, cause infections, blood clots, malnutrition, ulcers, vomiting or diarrhea.
“Surgery still has risks,” said Dr. Jaime Ponce, president of the Gaines-ville Fla.-based American Society for Metabolic & Obesity Surgery. “There is more and more data supporting surgery, but you need to look at it on a case-by-case basis.”
