Effects of smoke-free air law on acute myocardial infarction hospitalization in Indianapolis and Marion County, Indiana

Anne M Weaver,Dennis P Watson,Katelin Rupp,Yi Wang

doi:10.1186/s12889-018-5153-y

Abstract

BackgroundA comprehensive smoke-free air law was enacted on June 1, 2012 in most of Marion County, Indiana, including all of the City of Indianapolis. We evaluated changes in acute myocardial infarction (AMI) admission rates in Indianapolis and Marion County before compared to after the law.MethodsWe collected AMI admissions from five Marion County hospitals between May 2007 and December 2014. We used Poisson regression to evaluate the overall effects of the law on monthly AMI hospitalizations, adjusting for month, seasonality, meteorology, air pollution, and hospital utilization. We tested the interactions between the law and AMI risk factors on monthly AMI admission rates to identify subpopulations for which the effects might be stronger.ResultsMonthly AMI admissions declined 20% (95% CI 14–25%) in Marion County and 25% (95% CI 20–29%) in Indianapolis after the law was implemented. We observed decreases among never (21%, 95% CI 13–29%), former (28%, 95% CI 21–34%), and current smokers (26%, 95% CI 11–38%); Medicaid beneficiaries (19%, 95% CI 9–29%) and non-beneficiaries (26%, 95% CI 20–31%). We observed decreases among those with a history of diabetes (Yes: 22%, 95% CI 14–29%; No: 25%, 95% CI 18–31%), congestive heart failure (Yes: 23%, 95% CI 16–30%; No: 24%, 95% CI 17–31%), and hypertension (Yes: 23%, 95% CI 17–28%: No: 26%, 95% CI 15–36%).ConclusionsWe observed decreases in AMI admissions comparable with previous studies. We identified subpopulations who benefitted from the law, such as former and current smokers, and those without comorbidities such as congestive heart failure and hypertension.

Highlights

A comprehensive smoke-free air law was enacted on June 1, 2012 in most of Marion County, Indiana, including all of the City of Indianapolis
We modeled sex-specific monthly acute myocardial infarction (AMI) admission rates by using natural logarithms of estimated sexand age-specific population of Marion County as a model offset when modeling sex; natural logarithms of race- and age-specific population counts as an offset when modeling race; and natural logarithms of sex, race- and age-specific population counts as an offset when modeling sex and race
Those aged 75 years and over had the highest age-specific incidence of AMI both before and after the ban (105.3 and 90.7 per 100,000, respectively); incidence of AMI decreased among those 65–74 and 75 years and older. Current smokers, those of other/unknown race, those who were not Medicaid beneficiaries, those who were not diabetic, those with primary diagnosis of AMI, and those who lived within Indianapolis city limits

Summary

Introduction

A comprehensive smoke-free air law was enacted on June 1, 2012 in most of Marion County, Indiana, including all of the City of Indianapolis. A number of previous studies have reported a decrease in incidence of AMI after smoke-free legislation implementation in the United States, Europe, and Canada [3,4,5,6,7,8,9,10,11,12,13,14,15]. In 2006, the city of Indianapolis implemented an ordinance prohibiting smoking in most restaurants and workplaces [16] This law covers most of Marion County, Indiana, with the exception of the cities of Beech Grove, Lawrence, and Southport, and the Town of Speedway. The 2012 amendment prohibited the use of electronic cigarettes

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