Smoking shortens life by a decade, concludes 50-year study.

Up to two-thirds of those who smoke cigarettes will eventually be killed by their habit, but those who give up by the age of 30 will avoid almost all the risk, according to a study of British doctors which has now been running for 50 years. The study, Mortality in relation to smoking: 50 year's observations on male British doctors, published in the BMJ (2004;328:1519-28) shows that, on average, cigarette smokers die about 10 years younger than non-smokers. While the life expectancy of non-smokers has been increasing steadily since 1900, that of smokers has been progressively decreasing due to earlier and more intensive use of cigarettes. Quitting works, however: stopping at age 60, 50, 40 or 30 adds, respectively about 3, 6, 9 or 10 years to a person's life expectancy. Sir Richard Doll, lead author of the study and emeritus professor of medicine at the University of Oxford told the Bulletin: For countries where smoking has yet to take hold, the most important thing to do is to stop it doing so, and have the governments prevent the promotion of tobacco. But in countries where many people smoke but have not been smoking for very long, the message is that the way to save lives in the first half of this century will be by getting people to stop, rather than by stopping people from starting. This new report provides critical new information and convincingly shows that the risks for persistent cigarette smoking are actually substantially larger than had previously been suspected, wrote Meir Stampfer of the Department of Epidemiology at Harvard School of Public Health in Boston, US, in an editorial accompanying the paper in the BMJ. Stampfer describes the study, which was led by Doll, along with Sir Richard Peto of the Clinical Trial Service Unit and Epidemiological Studies Unit at the Radcliffe Infirmary, Oxford, England, and co authors Jillian Boreham and Isabelle Sutherland, as a stunning achievement. Doll, now 91, set out in 1951, with Bradford Hill and other colleagues, to recruit British doctors to the study. They chose doctors because they thought doctors would describe their own smoking habits accurately, and because they would be easy to trace through the UK medical register, so long as they continued to practise. In addition, they thought that as doctors would be likely to have access to good medical care, their causes of death would be relatively accurately documented. …