Fifty years after British researchers published the first study firmly linking cigarette smoking to lung cancer, the same scientist following the same group of subjects has reported the most detailed and long-term results ever of the health effects of smoking. His stark conclusion: A life of cigarette smoking will be, on average, 10 years shorter than a life without it.

While the lethal effects of cigarette smoking have long been known, the new study, published yesterday in the British Medical Journal, is the first to quantify the damage over the lifetime of a generation. The effects, the researchers reported, were “much larger than had previously been suspected.”

In the 50-year study of a group of almost 35,000 British doctors who smoked, the pioneering epidemiologist Richard Doll, who is now 91, and his colleagues found that almost half of all persistent cigarette smokers were killed by their habit, and a quarter died before age 70.

The study also found, however, that kicking the cigarette habit has equally dramatic effects. He found, for instance, that someone who stops smoking by age 30 has the same average life expectancy as a nonsmoker, and that someone who stops at 50 will lose four, rather than 10, years of life.

I do my best to get everyone to stop smoking – both patients and friends. My efforts are worthwhile. Smoking cessation, while difficult, has great benefits.

This article only refers to mortality. Cigarette smoking also often decreases quality of life. Chronic obstructive pulmonary disease, coronary artery disease, and congestive heart failure all impair quality of life prior to causing death. I use all this information to encourage smoking cessation.