(HealthDay)—Oral contraceptive (OC) use does not appear to be associated with the risk of rheumatoid arthritis (RA), although there is an inverse association between OC use and RA severity, according to a meta-analysis published in the International Journal of Rheumatic Diseases.

In an effort to examine the correlation between OC use and development of RA, Qi Chen, from Changhai Hospital in Shanghai, and colleagues conducted a systematic review and based on observational studies. Data were included for 28 studies, of which 18 were case-control, three nested case-control, and seven cohort.

The researchers found that, compared with never OC users, ever, current, and past OC users had a risk of RA of 0.69 (95 percent confidence interval [CI], 0.53 to 0.89), 0.71 (95 percent CI, 0.48 to 1.06), and 0.67 (95 percent CI, 0.44 to 1.01), respectively, in case-control studies. The corresponding odds ratios were 1.00 (95 percent CI, 0.87 to 1.15), 0.93 (95 percent CI, 0.70 to 1.23), and 0.93 (95 percent CI, 0.78 to 1.12) in prospective studies. OC use was inversely associated with RA severity (odds ratio, 0.41; 95 percent CI, 0.22 to 0.78). The correlation between OC use and RA risk was independent of OC use duration.

"OC use has no protective effect on RA onset, but appears to prevent progression to severe RA," the authors write.