Weight Loss Surgery Adds Years to Life

There's no doubt that stomach-stapling surgery leads to dramatic weight loss. But new research shows that the procedure might also add years to life.

As the number of obese people in the U.S. has soared, so has the popularity of the surgery. In fact, East Carolina University researchers estimated that the number of people undergoing weight-loss surgery increased from 40,000 in 2001 to 86,000 this year and will reach 140,000 next year.

Past research has shown that gastric bypass improves diabetes, high blood pressure, and other diseases related to excess fat. But the effect on a person's lifespan has been unknown, until now To answer that question, researchers at New Hampshire's Dartmouth-Hitchcock Medical Center first looked at data from previous research that showed how much a weight an average person loses after having the surgery. Then they looked at the average life expectancies of people at various heights and weights. In this way, they could estimate how much the change in weight caused by surgery would affect patients' life span.

The results suggest that most people eligible for the surgery would benefit, says lead researcher G. Darby Pope, MD, surgery resident at Dartmouth-Hitchcock. "By undergoing the surgery, they will gain life years," he said. Pope presented the study this week at a meeting of the American College of Surgeons in San Francisco.

People with a BMI -- a measure of obesity that takes both height and weight into account -- over 25 are considered overweight. But according to U.S. government guidelines, patients should have a BMI of at least 40, or a BMI of 35 with a related serious disease, to be eligible for gastric bypass surgery. Most such patients are more than 100 pounds overweight.

The results varied according to the patients' age, gender, and body mass index (BMI). According to the researchers, a woman with a BMI of 45 at age 40 would gain three years of life. A man of similar age and size could expect to gain 3.9 years.

These results are better than those obtained by heart disease surgery, Pope said. But he cautioned that no one should interpret these findings literally. The actual effects of the gastric bypass surgery will vary a lot from one individual to another.

Questions about the benefits of gastric bypass surgery will be answered with more certainty by studies now under way on large groups of patients, Pope says.

The surgery is getting more popular not only because more people are obese, but also because surgeons have improved their techniques. In earlier weight-loss surgery, doctors routed the digestive track past much of the intestines, resulting in malnutrition. In the kind of surgery in the Dartmouth-Hitchcock study, most of the stomach is stapled shut so that food can only enter a small pouch at the top. A branch of the intestines is connected to this pouch. (The unused part of the stomach is connected to this branch downstream in order to drain its fluids.)

Patients vomit if they overeat, but feel full with much less food. Typically, they lose about three-quarters of their excess weight in the first year, then gradually gain some back. After ten years or more, most carry about half the excess weight they had before the surgery, says Pope.

Patients must take nutritional supplements for the rest of their lives, and there is a chance of dying from complications of the surgery. But Pope and his colleagues took this risk of complications into account in their study and the results suggest that the risk of death from the procedure are much less than the risk of death from obesity.