Impact of a countywide smoke-free workplace law on emergency department visits for respiratory diseases: A retrospective cohort study

Background: With the goal of reducing exposure to secondhand smoke, the state of Minnesota (MN), enacted a smoke-free law (i.e., Freedom to Breathe Act) in all workplaces, restaurants, and bars in 2007. This retrospective cohort study analyzes emergency department (ED) visits in Olmsted County, MN, for chronic obstructive pulmonary disease (COPD) and asthma over a five-year period to assess changes after enactment of the smoke-free law. Methods: We calculated the rates of ED visits in Olmsted County, MN, with a primary diagnosis of COPD and asthma in the five-year period from January 1, 2005 to December 31, 2009. Analyses were performed using segmented Poisson regression to assess whether ED visit rates declined following enactment of the smoke free law after adjusting for potential underlying temporal trends in ED visit rates during this time period. Results: Using segmented Poisson regression analyses, a significant reduction was detected in asthma-related ED visits (RR 0.814, p < 0.001) but not for COPD-related ED visits following the enactment of the smoke-free law. The reduction in asthma related ED visits was observed in both adults (RR 0.840, p = 0.015) and children (RR 0.751, p = 0.015). Conclusions: In Olmsted County, MN, asthma-related ED visits declined significantly after enactment of a smoke-free law. These results add to the body of literature supporting community health benefits of smoke-free policies in public environments and their potential to reduce health care costs.