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Title: Impact of a national smoking ban on hospital admission for acute coronary syndromes

Authors: E Cronin, P Kearney, P Kearney, P Sullivan, I Perry

Reference: Clin Cardiol 2012; 35(4):205-209 (open access) http://bit.ly/IPPySD

Reviewer: Robert Goldberg, PhD, Contributing editor, ProCor; Professor of Medicine and Epidemiology, Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA

Reviewer comments: Smoking is a long and well-established risk factor for respiratory disease, CHD, and several cancers. In Ireland, as in many other developed countries, use of tobacco products is the leading cause of preventable deaths in adults.

Smoking bans have been increasingly used in public areas and workplaces to reduce the harmful effects of passive or secondhand smoke in the general population and in targeted at risk groups. These public policy measures have, in general, been shown to be effective not only in reducing exposure to the harmful effects of secondhand smoke but on the occurrence of acute coronary events. While a number of prior studies have examined the effects of total or partial smoking bans on the incidence rates of the acute coronary syndromes (ACS), few studies have been prospective in nature or have analyzed the effects of these bans from a more generalizable population-based perspective.

On 29 March 2004, a national ban on smoking in public places and workplaces was introduced in Ireland. This landmark act by a willing legislature represented the thoughtful actions of the first nation in the world to completely ban smoking in this setting. Using data from a population-based registry of patients admitted to all hospitals in southwest Ireland in the year before the smoking ban (2003), and for several years thereafter (through 2007), the authors found a significant reduction (12%) in hospital admissions for an ACS in the year following implementation of the smoking ban with a similar magnitude of reduction in hospital admissions for ACS in the two years after the ban. The results of this longitudinal study suggest that a ban on smoking in public places can have both a relatively rapid effect on the occurrence rates of ACS as well as a more long lasting effect over several years.

The results of this investigation and prior studies in this area suggest that banning smoking in public places can have considerable beneficial effects on the health of the general public and on the prevention of acute coronary events. These results argue for the more widespread adoption by local communities, states, and regions for public anti-smoking to "clean the air", reduce the magnitude of ACS in the general population, and have likely other beneficial effects on measurable and immeasurable indices of population health and quality of life.

Purpose of study: To examine the association between a national ban on smoking in the workplace and admissions for an acute coronary syndrome

Location of study: Cork, Ireland

Study design: Longitudinal

Results: The authors examined data from the CHAIR (Coronary Heart Attack Ireland Register) population-based investigation. This is a prospective registry of all patients admitted with a suspect or confirmed ACS to eight acute care hospitals in the southwest portion of Ireland. Patients with a discharge diagnosis of ST elevation MI (STEMI), non-ST-elevation MI (NSTEMI), or unstable angina were included in the present analyses. Data for the present investigation were limited to adult residents of Cork and Kerry counties (2006 census estimate = 620,000) admitted to six of the eight hospitals participating in this population-based registry between the years 2003-2007; the data from two hospitals were excluded due to data collection or operational concerns.

Approximately two-thirds of patients hospitalized with an ACS were male, the mean age of this study sample was approximately 69 years, and approximately one-third were current smokers at the time of initiation of the CHAIR registry in 2003.

In the baseline study year of 2003-2004, there were 1216 admissions for ACS to participating Cork and Kerry county hospitals. This translated to an ACS rate of 206/100,000 population with rates of STEMI, NSTEMI, and unstable angina of 47, 99, and 59, respectively. In the year after the ban in the mid-2000's, there was a 12% decline in the rate of admissions for ACS (178/100,000). There was no change in the rate of admissions for ACS in the following year that was followed by a further 13% reduction in hospital admissions for ACS in 2006/2007 (final rate = 149/100,000). The hospital admission rates (per 100,000) were 34, 75, and 41 for patients with a discharge diagnosis of STEMI, NSTEMI, and unstable angina, respectively in this year.

Reductions in hospital admission for ACS between 2003/2004 and 2006/2007 were observed in men and in women across the different ACS categories examined. In addition, there were no significant changes in the number of total deaths, or deaths attributed to circulatory causes, during the years under study.