Major Finding: Among women aged 50-79 years who drink tea, the odds ratio for incident RA was 1.40, compared with women who do not drink tea.
Data Source: Epidemiologic study based on self-reported tea drinking among 76,643 in the Women's Health Initiative
Disclosures: The study was funded by NIH. Dr. Collins reported having no disclosures.
Tea drinking slightly increased the risk of rheumatoid arthritis in older women, a new finding at odds with earlier studies showing it has no, or even a protective, effect.
Among women who drink tea, the study found the odds ratio for incident rheumatoid arthritis (RA) was 1.40, compared with women who do not drink tea, with a 95% confidence interval (CI) of 1.01-1.93 and a P value of .04.
The results come from the Women's Health Initiative observational study (WHI-OS), which includes 76,643 women aged 50-79 years.
The women filled out a dietary habit questionnaire at enrollment. Three years later, 185 had developed RA; the tea-drinking habits of those women were analyzed and compared to their RA-free peers.
The odds ratio increased with increasing consumption, with a P value of .03. Among women drinking four or more cups per day, the odds ratio of developing RA was 1.78, though only seven women who developed RA said they drank that much tea, and the finding was not statistically significant.
“I'm not saying anyone should stop drinking tea,” noted lead investigator Dr. Christopher Collins, of the Washington Hospital Center, and the Georgetown University School of Medicine.
The effects of tea drinking on the risk of RA were modest, the incidence of RA in the study low, and the WHI-OS dietary questionnaire vague on the question of tea drinking, asking women only if they drank tea, and if so, how many cups a day.
It did not ask what kind of tea they drank, though black tea accounts for 85% of tea drunk in the United States, Dr. Collins reported.
He presented the findings at a June meeting of the European League Against Rheumatism. They were published in a recent supplement to the Annals of the Rheumatic Diseases (2010;69[Suppl. 3]:350).
The findings contradict results of two earlier epidemiological studies; one that found tea drinking protected against RA, the other that it had no effect (Arthritis Rheum. 2002;46:83-91 and Arthritis Rheum. 2003;48:3055-60).
If tea does increase the risk of RA, the flavanoids present in the beverage offer a possible mechanism, according to Dr. Collins. Flavanoid consumption has been linked with RA risk (Am. J. Clin. Nutr. 2002;76:560-8).
Tea drinking slightly increased RA risk in older women.
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