A causal relationship between smoking and cardiovascular death is well established. But, for those patients who successfully stop smoking, are the detrimental effects fully reversible? And if so, how quickly do the benefits become apparent?
A total of 104 519 patients from the Nurses’ Health Study were followed up between 1980 and 2004, during which 12 483 deaths occurred. Of these, 4485 (35.9%) were people who had never smoked, 3602 (28.9%) were current smokers and 4396 (35.2%) were past smokers. As expected, a relationship was found between the risk of death and the number of cigarettes a day; however, this trend was found to be less pronounced for vascular disease, suggesting that even a few cigarettes may account for most of the associated increase in vascular risk. Similarly, the age at which a participant started smoking seemed to have less of an influence on the risk of death from vascular causes than it did for other diseases such as lung disease.
In examining cessation, the authors looked at outcomes at 5-year intervals. Sixty-one per cent of the full benefit of quitting for reduced death from coronary heart disease and 42% of the benefit for reduced cerebrovascular death was seen within 5 years of stopping smoking. In contrast, the excess mortality risk associated with respiratory disease took 30 years to decline to that of someone who had never smoked.
Although the study was performed exclusively in women, the authors feel their results are also applicable to men who have a similar smoking profile. The message remains that it is never too early to stop smoking, but as an added incentive cardiologists might mention that vascular benefits are among the earliest to become apparent.
Kenfield SA, Stampfer MJ, Rosner BA, et al. Smoking and smoking cessation in relation to mortality in women. JAMA 2008;299:2037-47.