No additional effect of a comprehensive smoke-free ordinance on AMI hospitalizations in Lawrence, Kansas

Background: Several recent studies have demonstrated significant decreases in acute myocardial infarction (AMI) hospitalizations following the implementation of local and state smoke-free ordinances. We investigate if the trend in AMI hospitalizations, in residents age 55 years and older, differs before and after the implementation of a 2004 comprehensive smoke-free ordinance in Lawrence, Kansas. We also compare the Lawrence trend to the overall trend statewide, excluding residents of cities with existing smoke-free ordinances.

Methods: Rates of AMI hospitalizations per 100,000 adults age 55 and older were calculated. Relative risk was estimated by comparing AMI hospitalization rates for the three year period preceding and the four year period following implementation. A Poisson regression model was used to evaluate if there was a statistically significant relationship between annual AMI hospitalizations and the smoke-free ordinance, accounting for the already declining AMI hospitalizations in non-ordinance counties in Kansas.

Results: A significant decrease in AMI hospitalization rates among adults age 55 and older was observed before and after ordinance implementation in Lawrence (relative risk: 0.74, 95% CI: 0.63-0.86) and statewide (relative risk: 0.78, 95% CI: 0.76-0.80). Ordinance implementation was not statistically associated with AMI hospitalizations in the regression model.

Conclusions: Between 2001 and 2008, there was a significant decline in AMI hospitalizations among adults age 55 years and older in Lawrence and across the rest of the state. However, contrary to recently published literature, we found no added benefit of the smoke-free ordinance on the secular trend in AMI hospitalizations.