Researchers at the National Cancer Institute (NCI), part of the National Institutes of Health, found no convincing evidence that breast implants have an effect on the development of subsequent connective tissue disorders (CTDs). The results were reported in the October 1, 2004 issue of the American Journal of Epidemiology.
The researchers used data from one of the largest studies on the long-term health effects of breast implants. A large number of patients reported CTDs, but when their records were examined by two board-certified rheumatologists, few cases were considered likely.
In 1992, the U.S. Congress asked the National Institutes of Health to investigate the long-term safety of breast implants. Scientists at NCI, led by Louise Brinton, Ph.D. in the Division of Cancer Epidemiology and Genetics, examined the medical records of 13,500 women who had cosmetic breast implant surgery before 1989 and 4,000 women similar in age who had other types of plastic surgery. Although it was not the original intent of the study, the available information provided investigators with an opportunity to study the risk of CTDs in this population.
For some time, there has been uncertainty regarding whether breast implants might be associated with the development of certain CTDs. Most of the previous studies on this issue had small sample sizes, limited time to follow the clinical outcomes of the women after their surgeries, and imprecise information on either implant status or disease outcomes. This study included a large population of women with breast implants, detailed information on their implants, patients' answers to questions about their disease experience and other health characteristics, and long-term follow-up of up to 13 years.
Four major CTDs (rheumatoid arthritis, systemic lupus erythematosus, scleroderma, and Sjögren's syndrome) were more commonly reported by breast implant patients, with an approximate two-fold increase in risk. Attempts were made to review the medical records for three of these conditions where there were elevations in reported risks both before and after 1992, the time when breast implants were deemed investigational by the U.S. Food and Drug Administration. Only 30 percent to 40 percent of the medical records could be obtained. When these records were blindly reviewed by two expert rheumatologists, only 17 percent to 30 percent of the diagnoses were considered 'likely.' When only likely diagnoses were considered, the excess risk of CTDs became statistically non-significant, meaning they could have happened by chance. Further, the small number of confirmed cases of scleroderma and Sjogren's syndrome made interpretation of the risks difficult. The researchers also were unable to assess the existence of any new CTD specific to implant patients.
To further clarify the relationship of implants to the risk of CTDs, future research should include clinical examinations of patients using defined diagnostic criteria for these disorders. Given the rarity of conditions such as scleroderma and Sjögren's syndrome, a study would need to be very large to fully clarify the association between breast implants and these disorders.