pubmed:abstractText |
The possibility that oral contraceptives offer a protective effect against the development of rheumatoid arthritis is still contentious. Of the 17 studies investigating this association, 11 have found a protective effect, and 6 have not. These differences are probably attributable to either selection or information biases in a subset of studies, although the exact reason is unknown. To overcome the methodological problems inherent in the design of previous studies, we have conducted a population-based case-control study.
|