Double-blind intervention trial on modulation of ozone effects on pulmonary function by antioxidant supplements

The aim of this study was to investigate whether the acute effects of ozone on lung function could be modulated by antioxidant vitamin supplementation in a placebo-controlled study. Lung function was measured in Dutch bicycli sts (n = 38) before and after each training session on a number of occasion s (n = 380) during the summer of 1996, The vitamin group (n = 20) received 100 mg of vitamin E and 500 mg of vitamin C daily for 15 weeks. The average ozone concentration during exercise was 77 mu g/m(3) (range, 14-186 mu g/m (3)). After exclusion of subjects with insufficient compliance from the ana lysis, a difference in ozone exposure of 100 mu g/m(3) decreased forced exp iratory volume in I second (FEV,) 95 mi (95% confidence interval (CI) -265 to -53) in the placebo group and 1 mi (95% CI -94 to 132) in the vitamin gr oup; for forced vital capacity, the change was -125 mi (95% CI -384 to -36) in the placebo group and -42 mi (95% CI -130 to 35) in the vitamin group. The differences in ozone effect on lung function between the groups were st atistically significant. The results suggest that supplementation with the antioxidant vitamins C and E confers partial protection against the acute e ffects of ozone on FEV, and forced vital capacity in cyclists.