Weight-loss surgery can sharply reduce the risk of diabetes in very obese people, a new study finds. The study included more than 3,400 obese people. Just under half of them had so-called bariatric surgery to help weight loss. These procedures reduce the size of the stomach, bypass part of the colon or both. The other people in the study did not have surgery. They just received usual care and advice on weight loss. Nobody had diabetes when the study began. Within 10 years, 110 people in the surgery group developed diabetes. This compares with 392 people in the other group. The diabetes rate was 78% lower for those who had surgery. Two studies released this year showed that weight-loss surgery could reverse diabetes. This study showed that it also could help prevent the disease. But experts quoted by the Associated Press (AP) disagreed on whether surgery should be widely used for that purpose. AP wrote about the study August 23.

By Robert H. Shmerling, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

The rising U.S. diabetes rate is a major health concern. But that shouldn't be surprising. Most diabetes is related to obesity, and the obesity rate has been rising rapidly for years.

We know how to reverse this problem. Avoiding obesity and losing excess weight can prevent many cases of type 2 diabetes. But weight loss programs often don't succeed. Many people lose weight, but most quickly regain it.

Surgery to help obese men and women lose weight is called bariatric surgery. These procedures make the stomach smaller or bypass parts of the digestive tract.

Bariatric surgery has a higher success rate than most other methods of weight loss. But it also comes with risks. They include:

• Infection, bleeding or a reaction to anesthesia (as with any surgery)
• Leaks or blockages in the digestive tract
• Long-lasting diarrhea
• Excessive weight loss or problems with absorbing nutrients

These problems usually can be treated. The risks may be worth taking for many who are suffering with medical problems related to obesity. These include diabetes, high blood pressure and arthritis.

A new study finds that bariatric surgery may lower the risk of diabetes as well as help people lose weight. The study included more than 3,400 obese people. Those who had bariatric surgery:

• Lost an average of 68 pounds during the year after surgery
• Usually kept the weight off -- The average weight loss 15 years after surgery was 44 pounds.
• Developed diabetes at just one-fourth the rate of those who did not have surgery

This study also showed a low success rate for weight loss in the non-surgery group. Those who sought professional help to lose weight but did not have surgery lost an average of only 1.3 pounds.

Side effects and complications were common in this study. Nearly 15% had at least one major complication from surgery. About 3% needed a second operation within 3 months. Three of those who had surgery died within 90 days. That’s a rate of about 1 in 500.

Still, this new research suggests that bariatric surgery may be an acceptably safe and effective way to reduce the risk of diabetes among people who are very obese.

What Changes Can I Make Now?

If you're very obese, talk to your doctor about ways to lose weight, including surgery. Bariatric surgery may be recommended in cases of morbid obesity. This is defined as any of the following:

• Having a body mass index (BMI) of 40 or higher
• Having a BMI of 35 or higher with medical problems related to obesity (such as diabetes or high blood pressure)
• Weighing at least 100 pounds over ideal body weight

Bariatric surgery is not for everyone. Poor candidates include those who:

• Can't tolerate the surgery because of other medical problems (such as severe heart disease)
• Have active drug addiction or alcoholism
• Can't cooperate with recommended lifestyle changes after surgery
• Have unstable psychiatric disease or an active eating disorder
• Are only mildly obese -- The benefits of bariatric surgery may not be enough to balance the risks for this group.

After bariatric surgery, remember that you have an important role to play in your surgery's success. Follow up with your doctors and heed their advice about nutrition and lifestyle. For example:

• Eat small meals to avoid discomfort.
• Let your doctors know if you have stomach pain, blood in the stool or shortness of breath.
• Avoid high-sugar meals. Especially watch out for sugary sodas or fruit juices. They may cause nausea and diarrhea.
• Have your vitamin levels checked and take supplements as prescribed. For example, iron, vitamin B12 and vitamin D are often recommended because they are poorly absorbed after bariatric surgery.

To lose weight and improve your health, make a commitment to exercise. The medical benefits include cardiovascular fitness and improved mood.

What Can I Expect Looking to the Future?

You can expect researchers and surgeons to explore new techniques and procedures. As a result, bariatric surgery should become more and more safe and effective.

But you can also expect other weight loss programs to play an important role in addressing the obesity epidemic. I hope that we'll develop better ways to predict who will benefit most from these programs and who will do well with surgery.