Impact of smoke-free ordinance strength on smoking prevalence and lung cancer incidence.
6578 Background: Smoke-free ordinances (SFO) have been shown to decrease the prevalence of cardiovascular and pulmonary disease, but there is limited data on the impact of such policies on lung cancer incidence. We investigated the relationship between strength of county-level SFO with smoking prevalence and lung cancer incidence in Indiana. Methods: Following IRB approval, we queried the Indiana State Cancer Registry and Indiana Tobacco Prevention and Cessation Commission’s policy database between 1995 and 2016. County-level characteristics included population, income, poverty, education, race/ethnicity, sex, and rurality. Lung cancer diagnosis and stage were also collected. Using generalized estimating equations (GEE) with robust standard errors and accounting for the clustering effect at county level, we performed multivariable analyses of smoking prevalence and age-adjusted lung cancer rates with respect to the strength of smoke-free ordinances at the county level over time. Results: Indiana consists of 92 counties, 24 of which had SFO by 2011. In 2012, Indiana enacted a law mandating at least a moderate state-wide SFO. From 1995 to 2016, 110,935 Indiana residents were diagnosed with lung cancer. Indiana also had an average age-adjusted yearly lung cancer incidence of 76.8 per 100,000 population and average yearly smoking prevalence of 25% during this time. Smoking prevalence was 1.2% (95% CI [-1.88, -0.52]) lower in counties with comprehensive or moderate SFO compared with those with weak or no SFO. Counties that had comprehensive or moderate SFO had an 8.36 (95% CI [-11.45, -5.27]) decrease in new lung cancer diagnosis per 100,000 population per year compared with counties that had weak or no SFO. Conclusions: Stronger municipal smoke-free air ordinances are associated with decreased smoking prevalence and fewer new lung cancer cases. Strengthening smoke-free ordinances is paramount to decreasing lung cancer incidence.