Objective: To quantify the effects of smoke-free workplaces on smoking in employees and compare these effects to those achieved through tax increases.
Design: Systematic review with a random effects meta-analysis.
Study selection: 26 studies on the effects of smoke-free workplaces.
Setting: Workplaces in the United States, Australia, Canada, and Germany.
Participants: Employees in unrestricted and totally smoke-free workplaces.
Main outcome measures: Daily cigarette consumption (per smoker and per employee) and smoking prevalence.
Results: Totally smoke-free workplaces are associated with reductions in prevalence of smoking of 3.8% (95% confidence interval 2.8% to 4.7%) and 3.1 (2.4 to 3.8) fewer cigarettes smoked per day per continuing smoker. Combination of the effects of reduced prevalence and lower consumption per continuing smoker yields a mean reduction of 1.3 cigarettes per day per employee, which corresponds to a relative reduction of 29%. To achieve similar reductions the tax on a pack of cigarettes would have to increase from $0.76 to $3.05 (0.78 euro to 3.14 euro) in the United States and from 3.44 pounds sterling to 6.59 pounds sterling (5.32 euro to 10.20 euro) in the United Kingdom. If all workplaces became smoke-free, consumption per capita in the entire population would drop by 4.5% in the United States and 7.6% in the United Kingdom, costing the tobacco industry $1.7 billion and 310 million pounds sterling annually in lost sales. To achieve similar reductions tax per pack would have to increase to $1.11 and 4.26 pounds sterling.
Conclusions: Smoke-free workplaces not only protect non-smokers from the dangers of passive smoking, they also encourage smokers to quit or to reduce consumption.