Updated

Weight-loss surgery may not help obese middle aged and older men live longer, according to new research that runs counter to earlier findings in younger people.

The results mean doctors should be extra careful when counseling obese patients about their treatment options, Matthew Maciejewski of Durham VA Medical Center in North Carolina and colleagues write in the Journal of the American Medical Association.

In 2009, more than 220,000 Americans had some type of weight loss surgery, at a price of about $20,000 per patient, according to the American Society for Metabolic and Bariatric Surgery.

Experts say surgery is the most enduring way to bring down one's weight, and earlier studies have suggested it will increase life expectancy by up to three years.

At first, the new study did appear to confirm those findings, but the benefit didn't hold up when comparing similar patients who did or did not have surgery.

The researchers looked back at the outcomes of 850 veterans, mostly men over 50 years old, who'd had weight-loss surgery between 2000 and 2006.

Six years after their surgery, about seven percent of the men had died, compared to 15 percent among a comparison group of obese men who didn't have surgery.

But when patients from the two groups were matched closely according to weight, age, race and other factors, the survival gap disappeared.

Previous studies have found that about seven percent of patients having weight-loss surgery experience complications, although most are minor wound problems.

Serious complications — such as massive bleeding or kidney failure — occurred in 2.6 percent of patients in one study from last year.

The new study is the first to compare death rates among heavy middle aged and older men who did or did not have weight-loss surgery, the researchers say, but it did have a number of limitations.

For instance, it's possible that following the patients for longer than six years would have changed the picture in favor of those who had surgery. And, the researchers stress, patients may still want surgery, even if it turns out not to affect their life expectancy, because the weight loss is likely to improve other medical conditions and quality of life.