By Dugowson, Carin E., et al.
1992, University of Washington Fred Hutchinson Cancer Research Center, Seattle, WA.

There is controversy about whether silicone breast implants are associated with an increased risk for autoimmune disease. As part of a prospective case-control study of risk for rheumatoid arthritis (RA), we recruited 349 women with new-onset RA and 1456 similarly aged control women. The controls were recruited cooperatively with a breast cancer study and for that reason all were asked about breast implants. To help determine if implants are a risk factor for RA, we sent questionnaires to the RA cases about the history of breast implants prior to their reference date. For cases, this was the date of the first physician visit for what was ultimately diagnosed as RA; for controls, this was a date randomly chosen from the distribution of reference dates for cases.

Questionnaires were returned by 300 eligible cases (86%). The following present the age-adjusted risk.

                   Cases N (%)   Controls N (%)     OR(95% CI)


No implant
before
reference date     299           1444               Reference
                  (99.7)        (99.2)

Implant
prior to
reference 
date               1              12             	  0.41
                  (0.3)          (0.8)             (0.05-3.13)