Coffee consumption and risk of rheumatoid arthritis

Recent reports have suggested an association between consumption of coffee or decaffeinated coffee and the risk of rheumatoid arthritis (RA), although data are sparse and somewhat inconsistent. Furthermore, existing studies measured dietary exposures and potential confounders only at baseline and did not consider possible changes in diet or lifestyle over the followup period. We studied whether coffee, decaffeinated coffee, total coffee, tea, or overall caffeine consumption was associated with the risk of RA, using the Nurses' Health Study, a longitudinal cohort study of 121,701 women.

Information on beverage consumption was assessed with a food frequency questionnaire (FFQ) that was completed every 4 years, from baseline in 1980 through 1998. Among the 83,124 women who completed the FFQ at baseline, the diagnosis of incident RA (between 1980 and 2000) was confirmed in 480 women by a connective tissue disease screening questionnaire and medical record review for American College of Rheumatology criteria. Relationships between intake of various beverages and the risk of RA were assessed in age-adjusted models and in multivariate Cox proportional hazards models including the cumulative average intake of each beverage during the followup period, adjusted for numerous potential confounders. In addition, for direct comparisons with prior reports, multivariate analyses were repeated using only baseline beverage information.

We did not find a significant association between decaffeinated coffee consumption of >/=4 cups/day (compared with no decaffeinated coffee consumption) and subsequent risk of incident RA, in either an adjusted multivariate model (relative risk [RR] 1.1, 95% confidence interval [95% CI] 0.5-2.2) or a multivariate model using only baseline reports of decaffeinated coffee consumption (RR 1.0, 95% CI 0.6-1.7). Similarly, there was no relationship between cumulative caffeinated coffee consumption and RA risk (RR 1.1, 95% CI 0.8-1.6 for >/=4 cups per day versus none) or between tea consumption and RA risk (RR 1.1, 95% CI 0.7-1.8 for >3 cups/day versus none). Total coffee and total caffeine consumption were also not associated with the risk of RA.

In this large, prospective study, we find little evidence of an association between coffee, decaffeinated coffee, or tea consumption and the risk of RA among women.