EPHX1 and chronic obstructive pulmonary disease: In the overall comparisons with the putative normal EPHX1 enzyme activity, the extremely slow EPHX1 enzyme activity (OR, 1.77; 95% CI, 1.23–2.55) and slow EPHX1 enzyme activity (OR, 1.44; 95% CI, 1.13–1.85) increased the COPD risk significantly, while the fast EPHX1 enzyme activity did not affect the COPD risk (OR, 1.03; 95% CI, 0.87–1.21; Table III and Fig. 3).