Regular intake of vitamin E supplements is not associated with a reduction in the risk for rheumatoid arthritis (RA), show results from the Women’s Health Study (WHS).
The WHS, conducted between 1992 and 2004, was a randomized, double-blind, placebo-controlled trial designed to evaluate the benefits and risks of low-dose aspirin and vitamin E in the primary prevention of cardiovascular disease and cancer among female health professionals age 45 years or older throughout the USA.
Knowing that chronic inflammation can affect serum antioxidant vitamin levels in RA patients, Elizabeth Karlson (Brigham and Women Hospital, Boston, Massachusetts, USA) and colleagues used this cohort to investigate the association of vitamin E supplementation and the risk for developing RA.
A total of 39,144 women were included in the study, each took 600 IU of vitamin E every other day. The primary end point, definite RA, was confirmed using a connective tissue disease-screening questionnaire, followed by medical record review for American College of Rheumatology criteria.
During an average follow-up of 10 years, 106 cases of definite RA occurred, 50 in the vitamin E group and 56 in the placebo group. Sixty-four (60%) of the RA cases were rheumatoid factor positive and 42 (40%) were rheumatoid factor negative. There was no significant association between vitamin E and risk of definite RA. There were also no significant risk reductions for either seropositive or seronegative RA.
The researchers describe various other studies that have investigated the link between antioxidant vitamins and the risk for RA and comment: “The WHS adds further information from a randomized controlled trial demonstrating no significant association between vitamin E supplementation and the primary end point, risk for RA.”
These findings have occurred “despite plausible biologic mechanisms, as well as data from some previous observational studies showing that diets high in antioxidants are associated with lower RA risk,” they conclude in the journal Arthritis Care and Research.