Obesity is a major risk factor for type 2 diabetes, which is accountable for around 90-95% of diabetes cases in the US. But a new study claims that for obese individuals, weight loss surgery may dramatically reduce this risk.

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Weight loss surgery may reduce the risk of type 2 diabetes in obese individuals by 80%, according to the researchers.

The research team, including Prof. Martin Gulliford of King’s College London in the UK, publish their findings in The Lancet Diabetes & Endocrinology.

Past studies have indicated that weight loss surgery, or bariatric surgery, may be an effective strategy to treat type 2 diabetes in obese patients. But Prof. Gulliford and colleagues note there have been very few studies looking at whether weight loss surgery can prevent the development of diabetes in obese patients. For their study, the team wanted to find out.

They analyzed health records from the UK Clinical Practice Research Datalink and identified 2,167 obese adults without diabetes who had undergone one of three surgical procedures: gastric bypass, gastric banding or sleeve gastrectomy.

Gastric bypass, which involves redirecting the digestive system past the stomach, is the most common weight loss procedure. Gastric banding involves having an inflatable band placed around the top portion of the stomach, creating a smaller stomach, while sleeve gastrectomy involves removal of around 80% of the stomach.

To act as controls, the team also identified 2,167 obese individuals – matched for age, sex, body mass index (BMI) and blood sugar levels – who had not undergone weight loss surgery or had any other obesity-related treatments. Participants were followed for up to 7 years.

The researchers found that 177 of the control participants developed type 2 diabetes during follow-up, compared with only 38 participants who had undergone weight loss surgery.

The team calculated that even after accounting for other factors that influence diabetes among obese individuals – such as smoking, hypertension and high cholesterol – weight loss surgery reduced participants’ risk of type 2 diabetes by 80%.

Commenting on these findings, Prof. Gulliford says:

Our results suggest that bariatric surgery may be a highly effective method of preventing the onset of new diabetes in men and women with severe obesity.

We need to understand how weight loss surgery can be used, together with interventions to increase physical activity and promote healthy eating, as part of an overall diabetes prevention strategy.”

The researchers point out that there are some limitations to their study. For example, they did not include patients who had undergone less common weight loss procedures, such as duodenal switch – surgery that combines gastric bypass and creation of a smaller stomach pouch. Therefore, it is unclear how such procedures would affect type 2 diabetes risk in obese patients.

Furthermore, the team says that patients who underwent weight loss surgery may have been more adherent to diabetes prevention advice – such as adopting a healthy diet and exercise – than control patients. “However,” they add, “we noted that people who received surgery were more likely to be prescribed antihypertensive drugs or statins, which can sometimes be associated with diabetes.”

In an editorial linked to the study, Dr. Jacques Himpens, of Saint Pierre University Hospital in Belgium, says that the findings from Prof. Gulliford and colleagues bring us closer to understanding the effects of bariatric surgery for prevention of type 2 diabetes. However, she notes that “many questions remain unanswered.”

“More evidence is needed to convince endocrinologists about the nature of this effect,” she adds.

In February of this year, Medical News Today reported on a study revealing that although most women who undergo weight loss surgery say they do not regret having the procedure, many of them feel it causes emotional problems.