The participants were grouped according to their smoking history. There were those who never smoked and ex-smokers. But among those who began the study as smokers, there were quitters (stopped smoking over the course of the study), moderate smokers (1-14 cigarettes daily), reducers (started the study smoking 15 or more cigarettes but cut that number by half) and heavy smokers (15 or more cigarettes a day).
Over the course of the study, the researchers found that there was no difference in the number of smoking-related deaths between the heavy smokers and the reducers. For women, in fact, the death rate from cancer rose in the group that reduced the number of cigarettes they smoked.
Only the group of men who cut back the number of cigarettes they smoked during the first 15 years of the study saw any improvement in death rates, although it was slight.
Tveral wrote that as a result of his findings, doctors and other health educators should make sure that patients understand that cutting back is not nearly the same as quitting.
“The only safe way out of the risk caused by smoking” is to quit, he says. And while lowering the number of cigarettes you smoke may be one step on the way to a cigarette-free life, “a reduction in consumption does not seem to bring about harm reduction.”