A Retrospective Cohort Study

Charles H. Hennekens, MD, DrPH; I-Min Lee, MBSS, ScD; Nancy R. Cook, ScD; Patricia R. Hebert, PhD; Elizabeth W. Karlson, MD; Fran LaMotte; JoAnn E. Manson, MD, DrPH; Julie E. Buring, ScD

Objective: To evaluate the association of breast implants with connective-tissue diseases.

Design and Participants: Retrospective cohort study of 39,5543 female health professionals who completed mailed questionnaires for potential participation in the Women's Health Study. A total of 10,830 women reported breast implants and 11,805 reported connective-tissue diseases between 1962 and 1991. Cox proportional hazards regression models were used in analyses.

Main Outcome Measure: Self-reported connective-tissue diseases.

Results: Compared with women who did not report breast implants, the relative risk (RR) of the combined end point of any connective-tissue disease among those who reported breast implants was 1.24 (95% confidence interval, 1.08 to 1.41. P=.0015). With respect to the individual diseases, the finding for other connective-tissue diseases (including mixed) was statistically significant (P=.017), the findings for rheumatoid arthritis, Sjogren's syndrome, dermatomyositis or polymyositis, or scleroderma were of borderline statistical significance (.05 P .10), and the finding for systemic lupus erythematosus was not statistically significant (P=.44). There were no clear trends in RR with increasing duration of breast implants.

Conclusion: These self-reported data from female health professionals are compatible with prior reports from other cohort studies that exclude a large hazard, but do suggest small increased risks of connective-tissue diseases among women with breast implants. The very large sample size makes chance an unlikely explanation for the results, but bias due to differential overreporting of connective-tissue diseases or selective participation be affected women with breast implants remains a plausible alternative explanation. The major contribution of this and other observational analytic studies has been to exclude large risks of connective-tissue diseases following breast implants.

-JAMA, February 28, 1996-Vol 275, No.8