A study published in the New England Journal of Medicine is pointing to another benefit of bariatric surgery: prevention, in addition to the more widely known benefit of that it can reverse type 2 diabetes.

The Swedish study followed patients for a period of 15 years and compared obese patients who underwent surgery with those who did not. None of them had diabetes at the start of the study. More than a decade after surgery, 392 patients in the non-surgical group (28.4%) had developed type-2 diabetes, compared with just 110 (6.8%) in the surgical group.

The results took into account a variety of surgical procedures, including banding, vertical banded gastroplasty and gastric bypass. Men had a BMI of at least 34, women, 38.

Associate Professor of Surgery at University of Chicago Medicine Vivek Prachand told MM&M the findings support what surgeons have already suspected, but this is the first time there’s been “robust enough evidence to be able to say” the surgery has a protective quality. “I think it is a very important additional piece of information for patients and physicians to take into consideration, rather than wait until somebody develops diabetes and say ‘well, we tried.’”

He also noted that the study’s results may be even more significant, in that the Swedish study largely relied on vertical banded gastroplasty, which is not widely used in the US. He said that gastric bypass, which was used in just 12% of the patients in the study, has a greater impact on diabetes than vertical banded gastroplasty or banding.

The findings, however, are not a license to undergo surgery just to lose a few pounds. Prachand said that the surgical requirements the NIH laid out more than twenty years ago still hold—meaning a patient either has to have a BMI of at least 40, or a BMI of at least 35, along with co-morbidities, like diabetes. Further slowing the rush to surgery is that insurers use these weight and health guidelines for coverage.

Prachand does not expect the study’s results to prompt greater numbers of patients who meet these requirements to look into surgery. He said that while about 7% of the US population currently meet the NIH criteria, in the last year fewer than 1% of those people have elected to have surgery

The bariatric surgeon said patients are put off by factors that include blaming themselves for their obesity and the perception that the surgery—whose risk he equates with that of gall bladder surgery—is high. On the provider side, Prachand said physicians, internists and general practitioners can be “overly optimistic that ‘If I just talk with that patient one more time, just to say, you know, you’ve gotta eat right and exercise,’” it will be enough to help patients. He added that as familiar as people may be with how hard it is to lose 5, 10 or 15 pounds, “multiply that by 10, 15 or 20 times and I think that becomes a much more difficult task, but there’s a certain level of denial,” which he says translates into fewer surgeries because the difference in difficulty is not necessarily understood.

Prachand noted that the surgery can also include financial benefits which are often overlooked. “The break-even point in the cost of surgery versus the savings in terms of medications and treatments for diabetes is about two, two-and-a-half-years after surgery.” He said that because most bariatric surgery patients are in their 40s, this means that patients could continue to save money decades after surgery because they will not be paying for diabetes-related care or medications.

The CDC estimates that type-2 diabetes accounts for between 90% and 95% of all diabetes cases, with the remainder falling under type-1 diabetes (gestational diabetes) and to the rarer type of diabetes that is linked to other causes, such as illnesses or infection. The disease affects multiple organs, and is associated with an elevated risk of cancer and heart disease.

The health agency’s latest data shows that medical costs directly related to diabetes hit $116 billion in 2007, and that indirect costs, such as disability, missed work, and death was $58 billion five years ago. The health agency also says diabetics typically have medical costs that outpace patients without diabetes by more than 50%.

“If this wasn’t obesity, say this was breast cancer or Parkinson’s disease or Alzheimer’s and I were to tell you that there’s a treatment that can prevent this from happening, or even if you have the disease could reverse it, yet fewer than 1% who could benefit from it have the procedure, that’s pretty substantial” he said.