In developed countries such as the USA, where cigarette smoking has been widely prevalent for many decades, tobacco is now responsible for about one-third of all cancer deaths, including 90% of the lung cancer deaths and 10-15% of the other cancer deaths. In middle age the proportions are even higher, with tobacco accounting for fully half of all male and a quarter of all female US cancer deaths at ages 0-69. The age-standardized cancer death rates from tobacco have reached their peak in US males, but are still increasing in US females. (There is no good evidence for any other increase in US cancer mortality rates during the past few decades over and above the changes that could plausibly be attributed to tobacco.) In addition, tobacco kills even more people by other diseases than by cancer, and is now responsible for about one-third of all US deaths in middle age. Elsewhere, the epidemic is generally at an earlier stage, but is evolving. For example, current male mortality from tobacco is oniy three-quarters as great in Spain or Portugal as in the USA, but is still increasing rapidly. Among Spanish and Portuguese women a strange situation exists. Few older women have been persistent cigarette smokers, so at present few are dying from the effects of tobacco. Nowadays, however, about half of the young women become cigarette smokers, and if they persist in the habit then about half will eventually be killed by it. Thus, although the epidemic of death from tobacco may soon be approaching its maximum in men, it is only just beginning in Spanish and Portuguese women. Turning from the world as a whole to the individual, about half of all persistent cigarette smokers are eventually killed by their habit, but stopping works remarkably well. Even in middle age, those who stop before they have incurable lung cancer or some other serious disease avoid most of their subsequent risk of death from tobacco, and for those who stop before middle age the benefits are even greater. A billion people now smoke: hundreds of millions of them will be killed by their habit, but if even a moderate proportion of those who now smoke can manage to escape the habit, many tens of millions of premature deaths will be avoided
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