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Bartenders' pulmonary function after establishment of a smoke-free workplace.

To the Editor: The results of the study by Dr Eisner and colleagues 1 addressing the effects of workplace environmental tobacco smoke (ETS) exposure on respiratory symptoms and lung function show a change in both respiratory symptoms and measures of spirometric assessment. Among all study participants, they detected a change in mean forced expiratory volume in 1 second (FEV1) of 0.039 L (95% confidence interval [CI], ˛0.030 to 0.107 L), which was not statistically significant. When the subgroup with complete cessation of workplace ETS was analyzed, a greater and statistically significant increase in FEV1 of 0.142 L (95% CI, 0.020-0.264 L) was noted. While these findings contribute to the authors’ claim of an improvement in lung function after cessation of heavy ETS exposure, the link between statistically significant differences in lung function improvement and its clinical importance may not be that clear. Indeed, in a study of more than 100 patients with chronic obstructive lung disease and a mean FEV1 of 0.975 L, an increase of 0.112 L or 4% of predicted lung function was thought by the majority of patients to represent the minimum clinically noticeable difference. 2 The individuals studied by Eisner et al had a far greater baseline mean FEV1 (3.38 L vs 0.975 L), a far smaller change in the percent of predicted lung function (88.9% to 88.2% [0.7% vs 4% in the study by Redelmeier et al 2 ]), and a far smaller absolute change in FEV1 (0.039 L vs 0.112 L). Therefore, the comparatively small increase in FEV1 found in this study may not represent a clinically important change. Cessation of ETS exposure in the workplace may provide improvements in subjective symptom scores and statistically significant gains in lung function. However, the data provided by Eisner et al do not seem to support a corresponding clinically important gain in lung function.