Purpose: In an exploratory case-control study of a private insurance-claims database, Greenland and Finkle (Ann Epidemiol. 1996;6:530-540) observed associations of certain prosthetic nonbreast implants with certain connective-tissue and neurologic conditions. We wished to test these associations using the same design with new data.
Methods: We examined these associations in a case-control analysis of Medicare claims data. To control for possible confounding effects of surgery, our analysis examined nonimplant surgeries of severity similar to implant surgeries.
Results: We again found associations of silicone and metal implants with connective-tissue and neurologic conditions, but we also found similar associations of carpal-tunnel surgery with those conditions.
Conclusions: Possible explanations for these findings include confounding by presurgical conditions. Therefore, we recommend further studies be done in which such conditions can be measured and controlled.