Exposure to second hand smoke and 10-year (2002–2012) incidence of cardiovascular disease in never smokers: The ATTICA cohort study

Background: Despite WHO Framework Convention of Tobacco Control (FCTC) adoption, effective implementation of national smoking bans remains pending in several countries. This study quantified the association of second hand smoke (SHS) exposure and 10-year cardiovascular disease (CVD) among never smokers in such settings. Methods: In 2001–2002, a sample of 1514 males and 1528 females (range: 18–89 years old) were randomly selected in Greece. Frequency and duration of SHS exposure (i.e. exposure extending >30 min/day) within the home and/or workplace were assessed by interview. Following a 10-year follow-up period (2002–2012), incidence of non-fatal and fatal CVD (ICD-10) was evaluated among n = 2020 participants. The analytic study sample consisted of all never smokers (n = 910). Results: Despite national smoking ban implementation (2009), 44.6% (n = 406) of never smokers reported SHS exposure. While SHS exposed never smokers exhibited a more favorable profile of CVD-related risk factors at baseline, they subsequently developed similar 10-year CVD incidence rates, at a younger mean age (p = 0.001), than their non-exposed counterparts. Following adjustment for several lifestyle and clinical factors, SHS exposed never smokers exhibited a two-fold elevated 10-year CVD risk (adj. HR: 2.04, 95% CI: 1.43–2.92), particularly among women (adj. HR: 2.45, 95% CI: 1.45–4.06). SHS exposure accounted for 32% excess Population Attributable Risk (PAR) for 10-year CVD events in never smokers, with highest rates (PAR: 52%) being among those exposed in the workplace. Conclusion: The prevention of SHS associated CVD and related healthcare costs mandates additional strategies for securing the effective implementation of comprehensive WHO FCTC based national smoking bans.