En español | Weight-loss surgery is often pooh-poohed as an easy out for people who aren't able to conquer their weight issues through diet and exercise. But health experts say it shouldn't be so easily dismissed. For one thing, most experts consider bariatric surgery the best way, realistically, for those who are obese (having a body mass index, or BMI, of 30 or more) to lose a sufficient amount of weight and keep it off. For another, research, including a study released this month, suggests the health benefits of bariatric surgery go beyond the weight loss itself.
The new study builds on research published last year in JAMA that looked at obese patients with type 2 diabetes who lost weight through one of two means: bariatric surgery or lifestyle changes such as diet and exercise. In that study, tracking participants for up to eight years, Cleveland Clinic researchers found that those who lost weight with the help of surgery lowered their risk of major cardiovascular events — like heart attack, heart failure, atrial fibrillation and stroke — by 39 percent, and deaths from any cause by 41 percent, compared to the nonsurgical group.
Returning to the same group of patients in a study published this month in the Annals of Surgery, the researchers found even greater health benefits of bariatric surgery compared to traditional weight loss methods. For example, those who had surgery needed to lose only about 10 percent of their weight to see reduced cardiovascular risk and improved life expectancy. By comparison, those who lost weight without the help of surgery required about a 20 percent loss to see similar health benefits.
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As the researchers explained, the health benefits of weight loss kick in faster for obese people with type 2 diabetes who lose through bariatric surgery than they do for people who lose weight through lifestyle changes.
"Even after adjusting for the amount of weight loss, the effect of bariatric surgery was still there and persisted,” says Ali Aminian, M.D., director of the Cleveland Clinic's Bariatric and Metabolic Institute and lead author of the study. “That tells us that the positive effects of bariatric surgery on cardiovascular health and mortality isn't just about the weight loss.”
Other benefits — better diabetes, blood pressure and lipid control — also kick in after surgery in particular, he adds.
Possible metabolic benefits from surgery
Although the reasons aren't entirely clear, Aminian points to one possibility. “When we remove part of the stomach or bypass part of the gastrointestinal tract , neurohormonal changes appear in the body and the composition of bacteria in the gastrointestinal tract alters,” he says. “So all of these changes that happen with these surgical procedures can have some metabolic benefits. That's probably why we see these health benefits in a lower threshold of the weight loss compared with the nonsurgical group."
The study, which doesn't prove cause and effect, isn't conclusive. “There's no question that weight loss surgery is an important option for people with obesity, particularly those with type 2 diabetes who are at high risk for cardiovascular disease,” says Robert Eckel, M.D., president of medicine and science at the American Diabetes Association (ADA).
Otherwise, he says, “it's hard to lose a fair amount of weight and keep it off long term. But the benefit of surgery really is the amount of weight loss and the maintenance of that weight loss. This study is suggesting there may be other mechanisms besides the weight loss, but that remains to be proven.”
In any case, no one's suggesting weight loss surgery as an across-the-board Rx for anyone with diabetes and a BMI over 30. The ADA says metabolic surgery should be recommended as a treatment option for people with type 2 diabetes who have a BMI over 40, or a BMI over 35 and high blood glucose that isn't adequately controlled by lifestyle and medication. The ADA says it may also be an option for those with a BMI of 30-plus who are unable to lose weight through nonsurgical means.