The government proposed on Wednesday expanding Medicare coverage of weight-loss surgery for the disabled, but eliminating coverage of such surgery for the elderly.

The Centers for Medicare and Medicaid Services said gastric bypass and other weight-loss surgeries may help people with extreme obesity. That is why the agency is proposing to make it easier for the disabled to get the surgery.

Currently, Medicare covers the cost if the surgery is recommended to treat other health problems. The proposed expansion would allow for the treatment of obesity before associated health problems set in.

"While the best proven treatment is a nutritious diet and regular exercise ... some beneficiaries may significantly reduce their health risks through surgery," said Mark McClellan, the agency's administrator.

But recent medical studies also have shown that weight-loss surgery poses greater risks for the elderly, the agency said in explaining its proposal that Medicare not cover such operations for those beneficiaries.

About 8,000 Medicare beneficiaries had weight-loss surgery covered through the program in 2004. About three-quarters of those procedures were for the disabled and one-quarter were for the elderly. Overall, the government paid about $13,000 per procedure, agency officials said.

Last month, a study in the Journal of the American Medical Association showed that the death rates after weight-loss surgery for patients age 65 and older were two to three times higher than they were for younger people.

The study tracked 16,155 Medicare patients who had obesity surgery. About 13 percent of men and 6 percent of women 65 to 74 died within a year of the surgery. In patients 75 and older, half of the men and 40 percent of the women died within the year.

The proposal is not final and the agency is seeking public comment on how much to expand coverage for the disabled and how much to curtail it for the elderly.

With obesity becoming more of a problem in the country, doctors and others are looking closely at weight-loss surgery for the elderly because it can improve health conditions such as diabetes and heart trouble.

A JAMA editorial said even if Medicare patients do face higher risks, they should not be denied obesity surgery.