The aim of this study was to evaluate whether tea or coffee consumption is associated with an increased risk of older-onset rheumatoid arthritis (RA) using the Women's Health Initiative Observational Study.
The Women's Health Initiative Observational Study is a longitudinal prospective cohort study conducted from 1993 to 1998. There were 76,853 women who completed a self-administered questionnaire about their daily consumption of tea and coffee. One hundred eighty-five women self-reported and validated incident cases of RA were observed after 3 years of observation. Multivariable Cox proportional hazards models were performed to assess the relationship between consumption habits and disease incidence. Trend tests were calculated using categorical variables modeled as a continuous variable without collapsing.
There was no increase in the hazard ratio for incident RA in those participants who drank coffee compared with those who did not. The amount of coffee consumed and the method of preparation (caffeinated/decaffeinated; filtered/unfiltered) also did not alter the risk of incident RA. There was a positive association of incident RA and caffeinated tea consumption in the trend test (p = 0.03). When assessing any caffeinated tea consumption versus no tea consumption, the hazard ratio for incident RA was 1.40 (confidence interval, 1.01–1.93; p = 0.04).
In a large prospective cohort of older women, there was no association between coffee consumption and incident RA. A small association between daily caffeinated, nonherbal tea consumption and incident RA was found.
From the *MedStar Washington Hospital Center, Washington, DC;
†National Institute of Nursing Research, Bethesda, MD;
‡Fred Hutchinson Cancer Research Center, Seattle, WA;
§National Institute of Environmental Health Science, Research Triangle Park, NC; and
∥Medstar Health Research Institute and Georgetown/Howard Universities Center for Clinical and Translational Sciences, Washington, DC.
The Women's Health Initiative (WHI) program is funded by the National Heart, Lung, and Blood Institute, National Institutes of Health, and the US Department of Health and Human Services, through contracts HHSN268201600018C, HHSN268201600001C, HHSN268201600002C, HHSN268201600003C, and HHSN268201600004C.
This research was supported (in part) by the intramural research program of the National Institutes of Health, National Institute of Nursing Research.
All participants provided written informed consent. Institutional review board (IRB) approval was obtained from each of the participating study centers and from the Fred Hutchinson Cancer Research Center, which currently serves as the IRB of record for the WHI. Federalwide assurance number is 00001920, and the registration numbers for each of the IRBs are as follows: Fred Hutchinson Cancer Research Center IRB registration no. Com A (00000021), Com B (00000022), Com C (00005619), Com D (00009831). The original protocol and consents were approved by all 40 IRBs of the participating WHI sites.
The authors declare no conflict of interest.
Correspondence: Diman Lamichhane, MD, Division of Rheumatology, MedStar Washington Hospital Center, 110 Irving St NW, Washington, DC 20010. E-mail: firstname.lastname@example.org.