Context: Scotland prohibited smoking in confined public places on March 26, 2006.
Objective: To investigate the association of smoke-free legislation with symptoms, pulmonary function, and markers of inflammation of bar workers.
Design, setting, and participants: This prospective observational study was conducted in Tayside, Scotland from February-June 2006. One hundred five nonasthmatic and asthmatic nonsmoking bar workers were initially enrolled, of whom 77 completed the study per protocol.
Main outcome measures: Respiratory and sensory symptoms, spirometry measurements, serum cotinine levels, peripheral inflammatory cell count, asthma quality-of-life scores, and exhaled nitric oxide levels were evaluated before and after introduction of the smoking ban.
Results: For the per-protocol analysis, the percentage of bar workers with respiratory and sensory symptoms decreased from 79.2% (n = 61) before the smoke-free policy to 53.2% (n = 41) (total change, -26%; 95% confidence interval [CI], -13.8% to -38.1%; P<.001) and 46.8% (n = 38) (-32.5%; 95% CI, -19.8% to -45.2%; P<.001) 1 and 2 months afterward. Forced expiratory volume in the first second increased from 96.6% predicted to 104.8% (change, 8.2%; 95% CI, 3.9% to 12.4%; P<.001) and then 101.7% (change, 5.1%; 95% CI, 2.1% to 8.0%; P = .002), and serum cotinine levels decreased from 5.15 ng/mL to 3.22 ng/mL (change, -1.93 ng/mL; 95% CI, -2.83 to -1.03 ng/mL; P<.001) and then 2.93 ng/mL (-2.22 ng/mL; 95% CI, -3.10 to -1.34 ng/mL; P<.001). The total white blood cell and neutrophil count was reduced from 7610 to 6980 cells/microL at 2 months (-630 cells/muL; 95% CI, -1010 to -260 cells/microL; P = .002) and from 4440 to 4030 cells/microL (-410 cells/microL; 95% CI, -740 to -90 cells/microL; P = .03), respectively. Asthmatic bar workers also had less airway inflammation, with a reduction in exhaled nitric oxide from 34.3 parts per billion (ppb) to 27.4 ppb 1 month after the ban (0.8-fold change; 95% CI, 0.67 to 0.96 ppb; P = .04), and Juniper quality-of-life scores increased from 80.2 to 87.5 points (7.3 points; 95% CI, 0.1 to 14.6 points; P = .049).
Conclusions: Smoke-free legislation was associated with significant early improvements in symptoms, spirometry measurements, and systemic inflammation of bar workers. Asthmatic bar workers also had reduced airway inflammation and improved quality of life.