Impact of smoking and quitting on cardiovascular outcomes and risk advancement periods among older adults

Abstract

Smoking is an established risk factor for cardiovascular events, such as myocardial infarction, stroke and cardiovascular death. However, most pertinent studies primarily relied on middle aged adults. We aimed to provide empirical evidence on the association of smoking with cardiovascular events and the benefits of smoking cessation in people aged 50years or older. In a German population-based cohort study detailed information on lifetime smoking history was obtained from 8,807 individuals aged 50-74years, without previous myocardial infarction (MI) or stroke. Cox proportional hazards regression was applied to estimate the impact of smoking on MI, stroke and cardiovascular death (CVD) as well as on the combined outcome of major cardiovascular events (MI, stroke or CVD). In addition, the impact of smoking and the benefits of smoking cessation were quantified by risk advancement periods (RAP). The cohort included 17.2% current smokers, 31.7% former smokers and 51.1% never smokers. During a mean follow-up of 9.1years, 261 participants experienced a first MI, 456 had a primary stroke and 274 died of cardiovascular reasons. Compared to never smokers, adjusted hazard ratios (95% confidence intervals) of current smokers were 2.25 (1.62-3.12), 2.12 (1.65-2.73) and 2.45 (1.76-3.42) and RAPs were 19.3, 9.8 and 8.4years for MI, stroke and CVD, respectively. Strong dose-response relationships were seen with both current and life-time amount of smoking. Most of the excess risk and risk advancement disappeared within 5years after smoking cessation. Smoking is a strong risk factor for cardiovascular events even at older age. Smoking cessation is highly and rapidly beneficial also at advanced age.