Objectives-Oxygen free radicals have been implicated as mediators of t
issue damage in patients with rheumatoid arthritis (RA). Thus it is po
ssible that several micronutrients acting as anti-oxidants and free ra
dical 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 Finn
ish cohort of 1419 adult men and women. During a median follow up of 2
0 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 antioxidan
t index was calculated as the product of the molar concentrations of t
hese three micronutrients. Results-Elevated risks of RA were observed
at low levels of alpha-tocopherol, beta-carotene and selenium, but non
e of the associations were statistically significant. A significant as
sociation, 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 inte
rval 1.0-71.0). Conclusions-The results of the present study are in li
ne with the hypothesis that a low antioxidant level is a risk factor f
or RA.