Reduction of postexercise FEV
decline by vitamin C. The vertical lines indicate the 95% CI for the three trials that studied the effect of vitamin C administration on EIB and the squares in the middle of the lines indicate the point estimates of the studies. An effect of 100% would indicate full prevention of postexercise FEV1 decline. The diamond shape at the foot indicates the 95% CI for the pooled vitamin C effect: 48% (95% CI: 33% to 64%) reduction in postexercise FEV1 decline. For example, Tecklenburg et al. reported a 12.9% FEV1 decline after placebo, but only a 6.4% decline after the vitamin C period, which corresponds to a 50% reduction in FEV1 decline by vitamin C . This figure is based on data published in .