The Impact of the Danish National Smoking Ban From 2007 on the Incidence of Eight Smoking-related Diseases: A Nationwide Register-based Interrupted Time Series Analysis

Abstract

Background: Previous research has documented the effect of comprehensive smoking bans on preventing various adverse health outcomes in the years post-ban. In 2007, Denmark implemented a national smoking ban that prohibited indoor smoking in workplaces and public settings, although only partial restrictions applied in specific premises such as small bars, one-person offices, and in psychiatric units. We tested the hypothesis that the implementation of the national smoking ban was associated with a decrease in incidence of smoking-related morbidity in the Danish population compared to the pre-ban period.

Methods: Interrupted time series analyses including the entire Danish population (≥30 years) was conducted. Information of hospitalizations and cause-specific mortality due to acute myocardial infarction, heart failure, hemorrhagic stroke, ischemic stroke, chronic obstructive pulmonary disease, cancer in bronchus and lung, cancer in lip, mouth, oral cavity, and pharynx, and bladder cancer were obtained from population-based registers. Poisson regression models accounting for seasonal variations and secular trends quantified immediate changes in incidence rates occurring at the time of the smoking ban as well as changes in the post-ban trend compared to pre-ban levels.

Results: Overall, we observed no consistent declines in incidence of cardiovascular diseases, chronic obstructive pulmonary disease, or the specific types of cancer in the post-ban period compared with the pre-ban period.

Conclusion: No consistent reduction in incidence of smoking-related diseases was observed after the smoking ban was introduced in Denmark. This probably reflects that the Danish smoking ban included several exemptions, resulting in a less comprehensive ban compared to those introduced in other countries.

Implications: In this study, we found that the Danish national smoking ban from 2007 did not consistently reduced the incidence of eight smoking-related outcomes in the post-ban period compared to pre-ban levels. We argue that due to the exemptions in the smoking ban, which for example allowed smoking in specific premises of the care and nursing sector, in one-person offices, and small bars, the ban was not sufficiently comprehensive to influence smoking behavior and thereof the incidence of smoking-related morbidity. Our findings highlight the importance of introducing comprehensive legislative measures to yield largest health benefits at a population level.