SERUM ANTIOXIDANTS AND RISK OF RHEUMATOID-ARTHRITIS

Objectives-Oxygen free radicals have been implicated as mediators of tissue damage in patients with rheumatoid arthritis (RA). Thus it is possible that several micronutrients acting as anti-oxidants and free radical scavengers provide protection against RA. Serum alpha-tocopherol, beta-carotene, and selenium were studied for their associations with the risk of RA. Methods-A case control study was nested within a Finnish cohort of 1419 adult men and women. During a median follow up of 20 years, 14 individuals initially free of arthritis developed RA. Two controls per each incident case were individually matched for sex, age, and municipality. Serum alpha-tocopherol, beta-carotene and selenium concentrations were measured from stored serum samples. An antioxidant index was calculated as the product of the molar concentrations of these three micronutrients. Results-Elevated risks of RA were observed at low levels of alpha-tocopherol, beta-carotene and selenium, but none of the associations were statistically significant. A significant association, however, was observed with a low anti-oxidant index (p for trend = 0.03), the relative risk of RA between the lowest tertile and the higher tertiles of its distribution being 8.3 (95% confidence interval 1.0-71.0). Conclusions-The results of the present study are in line with the hypothesis that a low antioxidant level is a risk factor for RA.