Forget Those Occasional Cigarettes: There Is No Safe Level Of Smoking

There is no safe level of smoking, according to a new study. Even one cigarette a day can shorten your life while quitting later in life can add years. We all know smoking cigarettes is harmful. But some people think if they only have one cigarette per day, or 10 or fewer, they are in the clear for smoking-related diseases including lung cancer and heart disease.

Not so fast, say researchers at the U.S. National Cancer Institute. The investigators conducted the first study looking at the health impact of so-called low-intensity smoking. Dr. Maki Inoue-Choi, an epidemiologist at NCI, led the study. The results were based on questionnaires filled out by smokers taking part in a large, long-term study of more than 290,000 adults being conducted by the National Institutes of Health.

"In our study, we found the kind of smokers who consistently smoke less than one cigarette per day over their lifetime were 1.6 times more likely to die during the study compared to never smokers. And adults who consistently smoked between one and ten cigarettes per day were 1.9 times more likely to die during the study than never smokers," said Inoue-Choi.

The health risks were lower among former low-intensity smokers compared to those who continued to puff away, and the risk of serious illness dropped the earlier someone quit. The results of the research were published in JAMA Internal Medicine. The study, part of NIH's large prospective AARP Diet and Health study, includes adults from 59 to 82. Questionnaires were sent to participants in 2004-2005. Some of the smokers began at age 15 or younger.

During follow-up 10 years later, investigators found smokers who puffed one cigarette or less per day increased their risk of lung cancer by nine percent compared to never smokers. And lung cancer death was 12 times higher among those who indulged in one to 10 cigarettes per day.

There were also increases in early death from other causes. People who smoked between one and 10 cigarettes a day had more than six times the risk of dying from respiratory diseases, like emphysema, than never smokers and about one and half times the risk of succumbing to cardiovascular disease.

Numerous negative health effects of smoking have been researched and described over the years, beginning with the U.S. surgeon general's report in 1964. But the study in the JAMA journal is the first to actually look at the health impacts of low cigarette consumption. Another study involving some 170,000 participants, published recently in the American Journal of Preventive Health, also found it's never too late to quit. The participants were also in the AARP Diet and Health Study.

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Even among those who stopped smoking in their 60's, they were 23 percent less likely to die early compared to those who kept smoking in their 70's, according to lead researcher Sarah Nash. Norman Edelman is a pulmonologist and a senior medical consultant to the American Lung Association. Edelman said both studies were extremely well done and their findings convincing because of their enormous size.

Edelman said he has a large number of patients who say they can't quit. "And you know I can now pull out data from the study we were talking about and say, "No, no, no you can actually prolong your life even if you're well into your 60's and quit," Edelman said the studies show it is never too early and never too late to kick the habit. (VOA/JC)

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