Antioxidants Showed no Protection Against Lupus, Arthritis

BOSTONBased on incident cases pulled from the Nurses Heath Study, researchers have found antioxidant intake is not associated with risk of either rheumatoid arthritis (RA) or lupus erythematosus. The team from the Division of Rheumatology at Brigham and Women's Hospital, Boston, identified and confirmed incident cases of RA and lupus among 184,643 U.S. women from the Nurses' Health Study and Nurses' Health Study II cohorts (1980-2004). They used semiquantitative food frequency questionnaires to assess intakes of vitamins A, C, and E and alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, lutein, and zeaxanthin from foods and supplements. Using a new method for quantifying the total antioxidant effect of a food based on the reduction of ferric to ferrous iron by antioxidants, the researchers calculated a "ferric-reducing ability of plasma" score for each case. Including cumulative updated total energy-adjusted dietary intakes, the team looked for connections between intake of each nutrient and incident RA and systemic lupus, adjusting for age and confounders and considering Cox proportional hazards models.

Pooling the results as a meta-analysis, the scientists identified 787 incident RA cases and 192 lupus casesonly those with dietary information availablebut these large, prospective cohorts of women did not reveal any association between antioxidant intake and the risk of developing either disease. The results were published online ahead of print in the American Journal of Epidemiology.