Rheumatoid-Factor (Anti-Gammaglobulin) In Women - Effects Of Oral-Contraceptive Use On Its Prevalence

A total of 14,856 women, including 921 pregnant subjects, were tested for rheumatoid factor; 4,562 were using oral contraceptives at the time of testing. The prevalence of rheumatoid factor increased directly with age. The age-adjusted prevalence of rheumatoid factor was lower in oral contraceptive users than in nonusers but this difference was not statistically significant. Rheumatoid factor remained positive in 39% of subjects undergoing retesting after an average interval of 16 months. Those women with higher titers of rheumatoid factor were more likely to remain positive (81%). Of the women having positive tests, 5.4% were identified as having rheumatoid disease.To determine the influence of oral contraceptives (OCs) on the prevalence of the rheumatoid factor, 14,856 18-45 year old women were studied. Of these, 921 were pregnant and 4562 were currently using OCs. 5118 were past users of OCs. The prevalence of rheumatoid factor was directly related to age (p less than .001), being higher in older women. The age-adjusted prevalence of rheumatoid factor among current users of OCs was 25% lower than among others. Among nonusers and former users there was equal prevalence. Among the 921 pregnant women, 9 (1%) were found to have positive tests for rheumatoid factor. Among OC users the rate of positive tests was 1%, but the rate was only .8% among nonusers in the 18-29 age group. Repeat rheumatoid factor studies were done on 7427 women after an average 16-month interval. 882 had discontinued OC use and 481 resumed or started OCs during the interval between tests. Those who had continued, started, or resumed OC use showed a reduction in positive tests while positive tests were increased among those who discontinued OC use. Among the 7427 women, 122 were positive for rheumatoid factor on their 1st test but only 46 (39%) remained positive. 16 women changed from negative to positive. Rheumatic disorders were present in 5.4% of all persons who had positive tests. Only 1 current user was thought to have rheumatic arthritis. Those with high titers of rheumatoid factor remained positive in 81% of cases. Findings indicate that OC use does not induce the formation of the rhematoid factor.