Large Amounts of Tea Linked to Arthritis in Women

ROMEWomen who drink tea have an increased risk of developing rheumatoid arthritis (RA) compared with those who drink none, according to a study presented at EULAR 2010, the Annual Congress of the European League Against Rheumatism. Further results from the same study showed no correlation between the amount of coffee consumption and RA incidence.

Results of the U.S. based longitudinal cohort study involving 76,643 women showed a positive association of incident RA in tea drinkers with an increasing Hazard Ratio (HR) observed alongside tea consumption (p=0.03). Consuming any amount of tea carried a significant risk of developing RA (HR 1.40 (95%CI 1.01-1.93) p=0.04) and women who drank 4 cups of tea per day had an increased risk of developing RA compared to those who drank none (HR 1.78 (95%CI 0.83-3.82)).

An analysis of the method of preparation of coffee (filtered vs. unfiltered) and presence or lack of caffeine in the beverage did not show any significant associations with RA or Systemic Lupus Erythematosus (SLE, an autoimmune disease in which the immune system harms the body's own healthy cells and tissues) (RA: filtered p=0.08, unfiltered p=0.38, SLE: filtered p=0.74, unfiltered p=0.97). No increase was shown in the risk of developing RA in participants who drank coffee compared to those that did not (RA: HR 1.09 (95%CI 0.77-1.54 p=0.63).

Data on women aged 50-79 were taken from the Womens Health Initiative Observational Study database where participants completed a self-administered questionnaire providing information on daily consumption of coffee and tea. The relationships between drinking tea and coffee and the risk of RA or SLE were assessed in age-adjusted models and in multivariate Cox proportional hazard models (a statustical approach to estimating survival data). At three years follow up, the diagnosis of incident RA was determined using self-reporting and respondents feedback on use of disease modifying anti-rheumatic drugs (DMARDS). The variables studied in the RA population were also investigated in women with SLE, but no significant associations were found.