Epidemiological evidence associating secondhand smoke exposure with cardiovascular disease.

The objective of this paper was to review the epidemiological literature examining the association between secondhand smoke (SHS) and cardiovascular disease (CVD). Specifically, we examined the various screening methods available in assessing smoking behaviour and quantifying nicotine absorption. Further, we considered the natural history of those exposed to SHS and the associated risk of CVD. We reviewed routine methods used to assess exposure to SHS; evaluated the utility of subjective screening questions regarding smoking behaviour and examined the efficacy of nicotine and cotinine biomarkers used to quantify SHS exposure in epidemiological and clinical-based research. Self-reporting is practical and cost-effective in identifying smoking behaviour patterns, but is subject to recall bias and underestimation of exposure, especially in the presence of children. Nicotine and cotinine biomarkers have proven valuable in quantifying tobacco smoke absorption and establishing biological plausibility. A combination of SHS self-reported and biomarker evaluation provide the most stringent method of establishing exposure. Sufficient evidence is reported in epidemiological research to support a causal association between SHS exposure and increased risks of CVD morbidity and mortality among both men and women. The risk of developing an acute cardiac syndrome or chronic lifetime coronary events is at least 30%. Similarly, reduction in the incidence of a myocardial infarction decreases by nearly 50% in the absence of SHS. Considering the biological plausibility and dose-response relationship between SHS and CVD, effective interventions that incorporate a comprehensive screening method of behavioral and biological measures of exposure coupled with efficacious treatment should elicit favorable change for at-risk populations.