Implant Study Finds Little Autoimmune Disease Risk

Silicone breast implants, which have been the subject of heated controversy and multimillion-dollar lawsuits, do not pose a significant risk of connective tissue diseases, Harvard researchers report today.

In the largest study to date, encompassing nearly 400,000 female health professionals, the team found a 24% increase in the risk of such autoimmune diseases, including rheumatoid arthritis, polymyositis, scleroderma and Sjogren’s syndrome.

But that number is somewhat deceiving, according to the authors. The normal incidence of these diseases is very small--an average of 1.14 cases per 1,000 women. The increased risk thus translates into a barely significant number of cases caused by the implants--one extra case for every 3,000 women who had them--the team reports in the Journal of the American Medical Assn.

The increased risk was so small, they said, it could not be statistically distinguished from no risk at all. That finding is in line with earlier, smaller studies of implants.

“Considering all available evidence, women with breast implants should be reassured that there is no large risk of connective tissue disease,” said the study’s lead author, Dr. Charles Hennekens.

Both sides in the ongoing controversy found comfort and support in the study.

“This is very good news for women with implants in that it extends a series of studies that have now consistently shown no large risk of connective diseases associated with having a breast implant,” said Dr. Andrew G. Bodner, vice president of medical and legal affairs for Bristol-Meyers Squibb Co., a former manufacturer of the implants.

But critics of breast implants argue that even the small increased risk shown in the new study is important because previous studies had shown none. Even though the normal incidence of the diseases is very low, a 24% increase in risk would represent 5,400 new cases of the disorders over 20 years among the estimated 1 million women who have such implants, according to Dr. Sidney M. Wolfe of the Public Citizen Health Research Group in Washington.

“That’s a lot of cases,” he said. “It significantly adds to my concern about this problem.”

“The spin [Harvard researchers] are putting on this is that it provides reassuring evidence against a large hazard,” said Stephen Sheller of the Philadelphia law firm Sheller, Ludwig & Beadey. “To the contrary, it provides grave evidence that there are much more serious problems than even the plaintiffs’ lawyers realized. It confirms that implants cause diseases we weren’t even making a point of.”

Lawyers have charged that the implants cause what they call an “atypical immune disease,” a broad mix of symptoms that do not fit neatly into the definition of any specific disease. “By examining only the link with classical connective tissue diseases, the study omits perhaps the biggest risk of all,” said Woodbridge, N.J.-based attorney Chris Placitella of Wilentz, Goldman & Spitzer.

Placitella and Sheller represent women suing breast implant manufacturers.

The two sides could also not agree on the impact the study will have on the ongoing and future lawsuits against silicone implant manufacturers.

Bodner suggested that the study is “something that juries will respond to.” He said that jury verdicts recently have increasingly favored the defendants, and this trend “should make women consider very seriously” the current settlement offer from manufacturers.

“As the scientific evidence accumulates, it will be more and more difficult to persuade juries that there is a cause-and-effect relationship [between implants and disease] because there is none,” he added.

Critics also found a number of problems with the study, beginning with the fact that it was partially funded by Dow-Corning Corp., a former maker of the implants. According to Hennekens, Dow-Corning provided $1.3 million of the $18.3-million cost of the study, part of the Women’s Health Study, which is examining a large number of other health questions as well. The National Institutes of Health contributed the rest. Sheller, however, charges that Dow-Corning has contributed $10 million to the Hennekens team.

The study has a number of serious problems, said epidemiologist Otto Wong of Applied Health Sciences in San Mateo. Wong’s own analysis of implant studies, to be published in March, shows no increased risk, and he believes Hennekens overstates the risks.

One major problem is that the Harvard team sent out 1.7 million questionnaires and had only 460,000 returned, a very low response rate, Wong and others said. “When you get such a low participation rate, we don’t know if the sample is biased or not,” Wong said.

The fact that women were enrolled at the height of the breast implant scare leads him to believe that it is biased toward inclusion of women with problems, which would overstate the risk.

Critics say that another weakness of the study was that the Harvard team also excluded about 30% of the enrolled women with both connective tissue diseases and implants because they didn’t know whether the disease was present before the implant. That exclusion could reduce the perceived risk. Hennekens “had $18 million,” Sheller said. “Why didn’t he just call them?” and ask the date of diagnosis.

And finally, Hennekens acknowledges critics’ charges that the researchers did not distinguish between silicone implants and saline implants, which account for about 20% of all breast implants and are generally conceded to be harmless. That could also lead to an understating of the risks.

The Harvard team is beginning the second phase of the study, in which they will go back to talk to the participants and examine their medical records.