A relationship between connective-tissue diseases and silicone breast implants has been the focus of controversy since the early 1990s. The issue has not been fully resolved, despite the publication of three meta-analyses that failed to demonstrate an increased risk of connective-tissue disease from breast implants. Since 1996, eight studies on this topic have been published. In addition, none of the earlier meta-analyses dealt specifically with silicone-gel–filled breast implants. To revisit this issue, Janowsky and colleagues performed a comprehensive series of meta-analyses that included more recent data.
The authors obtained the results of all studies cited in the three previous meta-analyses along with other reviews. They also researched MEDLINE, Toxline, Current Contents and Dissertation Abstracts Online for literature published through May 1998. The searches were limited to English-language studies of human subjects. To be included, the studies had to use an internal comparison group and provide numbers for the construction of two-by-two tables to establish categories of disease and implants. Specific diseases included were rheumatoid arthritis, systemic lupus erythematosus, scleroderma or systemic sclerosis, Sjögren's syndrome, dermatomyositis, polymyositis, undifferentiated connective-tissue disease and mixed connective-tissue disease.
The authors identified nine cohort studies, nine case-control studies and two cross-sectional studies in their meta-analyses. Most of the studies were performed in the United States, with one from Canada, one from Australia and three from Europe. The authors conducted the analysis with the use of an adjusted and unadjusted statistical technique. In addition, they reviewed the data by restricting the analysis to patients who received only silicone-gel implants. Lastly, they estimated the number of new cases of a connective-tissue disease that could possibly be attributed to a breast implant.
The authors note that after review of data using several statistical methods, there is no evidence of an increased risk of any specific connective-tissue disease, all definite connective-tissue diseases combined or other autoimmune conditions associated with the use of breast implants, including nonsilicone and silicone implants. This is in keeping with the findings of the three previously published meta-analyses. They further conclude that the elimination of breast implants would not decrease the incidence of the above-noted rheumatic diseases.