Just Cutting Back on Smoking May Not Boost Lifespan
Quitting entirely is only way to extend longevity, study contends
The researchers found no difference overall in death rates between those who smoked and those who only cut down. In one of the studies, they found a lifespan benefit for those who cut down, but only among those who smoked 21 or more cigarettes per day. In the United States, that would be about a pack-a-day habit.
"These inconclusive results support the view that reducing cigarette consumption should not be promoted as a means of reducing mortality, although it may have a valuable role as a step toward smoking cessation," the researchers wrote.
The lead author of the study, public-health researcher Carole Hart at the University of Glasgow, in Scotland, declined to comment on the study. The two other study authors did not respond to a request for comment.
It remains clear that quitting itself is a good idea. The study found that smokers who quit were 25 percent to 34 percent less likely to die over the period of the research.
"Quit between ages 25 and 34 and save 10 years of life; between 35 and 44, save nine years; quit between 45 and 54, gain six years; quit between 55 and 64, gain four years," UCSF's Schroeder said.
If that's the case, why might cutting down not help much, if it all? "Many of the immediate effects come from reduced cardiovascular disease, which is sensitive to very low smoking exposure," he said. "The benefit from cancer risk reduction is not apparent for many years."
Schroeder cautioned, however, that cutting down still has benefits. "The main, and possibly only, benefit from reducing cigarette intake -- as opposed to stopping -- is that it makes it easier to quit subsequently," he said. "It also reduces the exposure of others to secondhand smoke."
The study was published online July 3 in the American Journal of Epidemiology.