Date : 21 Sep 2009
Strongly enforced legislation to restrict smoking produces rapid and substantial reductions in community rates of heart attack, according to a meta-analysis published today in Circulation, the journal of the American Heart Association.(1) The analysis pooled 13 studies from regions in North America, Italy, Scotland and Ireland and, despite their geographical range, found a consistent reduced risk of hospitalisation for heart attack (acute myocardial infarction, AMI) of 17% (ie, a relative risk for AMI of 0.83) at 12 months following implementation of the law. The investigators added that this benefit "grows with time", reaching a gain of "about 36%" in three years.
The study was designed to determine the "consistent" effect of smoking bans on AMI rates in communities, and was therefore concerned with both the direct and second-hand effects of smoking. Several studies have shown that the effects of second-hand smoke on many biological mediators associated with AMI risk occur rapidly and are nearly as large as those from direct smoking. For example, a study reported last year showed that passive exposure to second-hand smoke in as short a time as 24 hours led to "sustained vascular injury" characterised by reduced endothelial function and activity of endothelial progenitor cells.(2) According to the American Heart Association's Heart Disease and Stroke Statistics 2009 Update, non-smokers exposed to second-hand smoke at home or at work have a 25-30% increased risk of developing heart disease.
Since the first smoking bans were introduced (the first in Europe was in 2004 in Ireland) there have been many reports showing a decline in hospital admissions for AMI following implementation. Indeed, such laws are the best current examples of a clear association between prevention policies and cardiovascular disease. In Europe reduced AMI rates following smoking bans have been reported from France (15% decrease), Italy (11.2%), and Ireland (11%).