Researchers investigating one of the health claims against silicone breast implants said they have failed to find any link between the devices and scleroderma, a disease of the skin and internal organs.
"Our data is somewhat preliminary, but we don't feel there is a causal association between having silicone breast implants and having scleroderma," said Dr. Marc C. Hochberg, who presented his findings this week to a conference of the American College of Rheumatology in Atlanta.
The conclusions were reached by comparing women registered with scleroderma centers in Baltimore and Pittsburgh with surveys of the general population.
Scleroderma is a rare condition in which the body's own immune system attacks the skin, arteries, kidneys, lungs, heart and other internal organs.
One of its telltale symptoms is an unusual tightness and thickness of the facial skin. It is twice as common among women than among men.
The disease is extremely rare: About one new case appears among every 10,000 people in the general population.
Researchers found that about 1 percent of 740 women registered with two scleroderma centers had breast implants before they were diagnosed with the disease.
The centers were the Baltimore Scleroderma Center, run jointly by the University of Maryland and Johns Hopkins medical schools, and another at the University of Pittsburgh.
Surveys of the general population by the National Center for Health Statistics have found that about 1 percent of adult women have the breast implants.
If there a link between implants and the disease, one would expect a higher percentage of scleroderma patients to have the silicone implants.
Dr. Hochberg admitted that his study group of scleroderma patients was too small to yield conclusive results. A study involving a larger group is being planned, he said.
Allegations that leaking silicone caused a variety of autoimmune diseases including scleroderma, lupus and rheumatoid arthritis prompted the Food and Drug Administration to greatly restrict the implants' use earlier this year.
For the most part, the implants now are limited to patients who have lost breasts to cancer. Most women having their breasts enlarged for cosmetic reasons are getting implants filled with salt water.
The study in Baltimore and Pittsburgh did not investigate the link between breast implants and any diseases besides scleroderma.