Background: A ban on smoking in the workplace was introduced in Ireland on March 29, 2004. As exposure to secondhand smoke has been implicated in the development of coronary disease, this might impact the incidence of acute coronary syndromes (ACS).

Hypothesis: The smoking ban was associated with a decreased rate of hospital admissions for ACS.

Methods: We analyzed data collected in a registry of all patients admitted to hospital with ACS in the southwest of Ireland, catchment population 620 525, from March 2003 until March 2007.

Results: In the year following implementation of the ban, there was a significant 12% reduction in ACS admissions (177.9 vs 205.9/100,000; 95% confidence interval [CI]: 164.0-185.1, P = 0.002). This reduction was due to fewer events occurring among men (281.5 vs 233.5, P = 0.0011) and current smokers (408 vs 302 admissions, P < 0.0001). There was no change in the rate of admissions for ACS in the following year (174.3/100,000; 95% CI: 164.0-185.1, P > 0.1). However, a further 13% reduction was observed between March 2006 and March 2007 (149.2; 95% CI: 139.7-159.2). Variation in admissions with time as a continuous variable also demonstrated a reduction on implementation of the smoking ban.

Conclusion: A national ban on smoking in public places was associated with an early significant decrease in hospital admissions for ACS, suggesting a rapid effect of banning smoking in public places on ACS. A further reduction of similar magnitude 2 years after implementation of the ban is consistent with a longer-term effect that should be further examined in long-term studies.