Response to Letter Regarding Article, “Effect of the Italian Smoking Ban on Population Rates of Acute Coronary Events”
We thank Drs Gasparrini and Gorini for their interest in our work.1 They suggested that we test for a nonlinear time trend in the occurrence of coronary events. We did so for the reference period (2000 to 2004) before the smoking ban. A quadratic term gives a better fit to the model than a linear term among 35- to 64-year-old individuals (likelihood ratio test probability value, 0.024) and among 65- to 74-year-old individuals (likelihood ratio test probability value, 0.005). The introduction of troponin as a diagnostic tool may be one explanation for the first increase in coronary events.2
As Drs Gasparrini and Gorini suggested, we performed a sensitivity analysis excluding the first 2 years of the reference period (2000 and 2001). The results are very similar to those presented in our article1: We found a decrease in acute coronary events for those aged 35 to 64 years, with a relative risk of 0.89 (95% confidence interval, 0.85 to 0.94) in 2005 compared with 2002 to 2004, as well as for those aged 65 to 74 years, with a relative risk of 0.90 (95% confidence interval, 0.86 to 0.95) in 2005 compared with 2002 to 2004.
We were not surprised by the size of the effect reported in our study, as it was plausible on the basis of a theoretical calculation we did report in the published article and of the emerging literature in the field.3 In addition, the evidence of an immediate effect of environmental tobacco exposure on the cardiovascular system is already overwhelming.4,5
Cesaroni G, Forastiere F, Agabiti N, Valente P, Zuccaro P, Perucci CA. Effect of the Italian smoking ban on population rates of acute coronary events. Circulation. 2008; 117: 1183–1188.
Sanfilippo FM, Hobbs MS, Knuiman MW, Hung J. Impact of new biomarkers of myocardial damage on trends in myocardial infarction hospital admission rates from population-based administrative data. Am J Epidemiol. 2008; 168: 225–233.
Barnoya J, Glantz SA. Cardiovascular effects of secondhand smoke: nearly as large as smoking. Circulation. 2005; 111: 2684–2698.
Heiss C, Amabile N, Lee AC, Real WM, Schick SF, Lao D, Wong ML, Jahn S, Angeli FS, Minasi P, Springer ML, Hammond SK, Glantz SA, Grossman W, Balmes JR, Yeghiazarians Y. Brief secondhand smoke exposure depresses endothelial progenitor cells activity and endothelial function: sustained vascular injury and blunted nitric oxide production. J Am Coll Cardiol. 2008; 51: 1760–1771.