New research is revealing that obesity surgery does more than simply help patients lose weight; it may also "cure" type 2 diabetes for five years or longer.

In two new studies presented at the annual meeting of the American Society for Metabolic and Bariatric Surgery, researchers have found that both "lap band surgery" and gastric bypass surgery can help eliminate diabetes.

While previous studies have made similar findings, this new research finds that the effects can be long-lasting.

In one study, researchers at New York University School of Medicine looked at 95 morbidly obese patients, with an average BMI (body mass index) of 46, who underwent a temporary form of stomach reduction, called laparoscopic adjustable gastric banding (LAGB).

Five years after the surgery, diabetes in 40 per cent of patients had gone into remission so that they could stop taking medication. An additional 43 per cent of patients saw their diabetes improved so that their blood sugar levels fell and they could reduce their medication use.

"Our study contributes to mounting evidence that demonstrates gastric banding can have a sustained and meaningful effect on diabetes and morbid obesity and that the two diseases are interrelated," said Dr. Christine Ren, co-researcher and associate professor of Surgery at New York University School of Medicine.

Ren noted that those patients who had diabetes for the least amount of time before surgery tended to be more likely to see their condition go into remission.

"We didn't find a substantial difference in remission outcomes for patients who suffered with diabetes for more than six years compared to those who had the disease for a shorter period of time," said Ren.

A second study of 177 obese patients with diabetes who underwent gastric bypass surgery, or stomach stapling, as it's sometimes called, found that 57 per cent of those remained diabetes-free up to 16 years after the procedure.

Once again, those most likely to experience a recurrence of diabetes were those who had type 2 diabetes longer prior to surgery and who had a more severe form in which they were dependent on insulin.

Those who saw their diabetes return were also those who regained the most weight following the surgery.

Study co-author, Dr. James W. Maher, professor of Surgery at Virginia Commonwealth University said these two factors seem to be the primary determinants of long-term diabetes resolution after gastric bypass surgery.

"This study suggests that people with Type 2 diabetes and morbid obesity who get surgery before becoming insulin-dependent have the greatest chance for complete resolution and avoiding the progression of diabetes."

In gastric bypass surgery, the stomach is reduced from the size of a football to golf-ball-size. As well, the upper portion of the small intestine is replaced with the lower part.

Stomach banding, or LABG, involves wrapping a silicone band around the upper part of the stomach to limit the amount of food it can hold.

People who are morbidly obese are generally 100 or more pounds overweight and have a BMI of 40 or more. They also meet the definition if they have a BMI of 35 or more with an obesity-related disease, such as Type 2 diabetes, heart disease or sleep apnea.

The American Diabetes Association recently recommended bariatric surgery be considered for adults with BMI greater than 35 and type 2 diabetes, especially if the diabetes is difficult to control.

Consensus is building in Canada that surgery, not medications, may be the more effective and even more cost-effective solution for obese people with difficult-to-control diabetes, said Dr. Mehran Anvari, a surgeon at St. Joseph's Healthcare in Hamilton, who has also studied the surgery's health benefits

"Type 2 diabetes is not a benign disease and many patients experience significant complications from diabetes that may be worse than potential complications from surgery," he told CTV News.

There are at least a dozen hospitals across Canada that offer bariatric surgery for those with morbid obesity, but the wait for the surgery can stretch five years or longer. Lap band surgery is also available at private clinics across Canada though the costs are not covered by provincial or regional health plans..