Background: Associations between vaccinations, particularly hepatitis B, and onset of rheumatoid arthritis (RA) have been reported, but examined in few large-scale studies.
Method: Onset of RA cases and dates of vaccination against hepatitis B, tetanus, and influenza were identified in a retrospective chart review of approximately 1 million Kaiser Permanente Northern California members ages 15-59 years from 1997 through 1999. In a cohort analysis, rates of new-onset RA were compared between vaccinated and unvaccinated within 90, 180, and 365 days. In a case-control analysis, rates of vaccination during exposure intervals (90, 180, 365, and 730 days) were compared between cases and controls using conditional logistic regression.
Results: 378 RA cases were included in the cohort analysis; 37 additional cases were included in the case-control analysis. In the cohort analysis the relative risks of RA onset within 90, 180, or 365 days of hepatitis B vaccination were not significant (R.R.=1.44, p=0.53; R.R.=1.67, p=0.22; R.R.=1.23, p=0.59 respectively). We found a possible association between RA and influenza vaccine in the previous 180 and 365 days in the cohort analysis (R.R=1.36, p=0.03; R.R.=1.34, p=0.01 respectively), but in the case-control analysis, cases were no more likely than controls to have received any of the three vaccines.
Conclusions: In this large retrospective study we found no statistically significant association between exposure to hepatitis B vaccine and onset of RA. A possible association between RA and influenza vaccination in the cohort study was not borne out in the larger case-control analysis.
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