Quitting still best strategy for reducing risks of smoking

  Article date: 2005/10/10,Even a Few Cigarettes a Day are Harmful

Smokers who are serious about reducing the health risks from their habit are better off quitting than just cutting back, two recent studies suggest.

One paper, published in the Journal of the American Medical Association, shows that while heavy smokers can reduce their lung cancer risk by reducing the number of cigarettes they smoke, their risk is still significantly higher than that of nonsmokers or former smokers. These same researchers have also published work showing that cutting back on smoking doesn’t lower the risk of other lung diseases or of heart attacks.

Another report, from Tobacco Control, finds that people who smoke as few as 1-4 cigarettes daily have significantly more risk of dying than nonsmokers do.

"There is no such thing as a safe level of smoking," said Tom Glynn, PhD, director of Cancer Science and Trends at the American Cancer Society. "Reducing smoking can reduce lung cancer risk, but that risk remains high. And even with reduced cigarette consumption, the risk of heart disease and [other] lung disease remains the same."

The authors of the JAMA paper, led by Nina S. Godtfredsen, MD, PhD, of Copenhagen University Hospital and Hvidovre Hospital in Denmark, agree.

"For the present, smoking cessation and not smoking reduction should still be advocated as the ultimate method of reducing harm from smoking," they write.
Big Cutbacks Have Small Benefit

Godtfredsen and her colleagues studied the health records of nearly 20,000 Danish men and women ages 20-93 who had completed a physical examination and questionnaires about their lifestyle, including smoking habits. The participants were followed for as many as 31 years. Godtfredsen and her colleagues specifically compared their self-reported smoking habits to their lung cancer risk.

Heavy smokers were defined as those who smoked 15 or more cigarettes (or grams of tobacco) per day. Light smokers smoked 1-14 cigarettes (or grams of tobacco) per day. "Reducers" were defined as heavy smokers who cut back by 50% or more over the course of the study. "Quitters" were those smokers who stopped smoking during the study. Nonsmokers and former smokers (smokers who had quit before the study began) were also included.

Compared with the heavy smokers, the "reducers" did see their lung cancer risk drop some. But this drop was not proportionate to their smoking reduction. Cutting back by more than half -- from about 20 cigarettes a day to fewer than 10 -- only lowered lung cancer risk by about 27% compared to those who continued to smoke heavily.

Those who quit during the study had a 50% lower lung cancer risk compared to the heavy smokers, while those who quit before the study started (former smokers) had an 83% lower lung cancer risk. But even that risk reduction paled in comparison to the risk for nonsmokers, which was 91% lower than the risk for heavy smokers.
Help Available for Quitting

The paper from Tobacco Control highlights similar risks. In that study, researchers led by Kjell Bjartveit, MD, PhD, MPH, of Norway’s National Health Screening Service, found increasing health risks with increasing numbers of daily cigarettes. And even a few cigarettes a day significantly raised the risk of dying from heart disease and from all causes combined.

The risk of dying from lung cancer was also higher among people who smoked very little, but the difference was statistically significant only for women. That may be because the study didn’t have many men who smoked that little. Nevertheless, the risk of dying of lung cancer was nearly 3 times higher for light-smoking men (1-4 cigarettes per day) than for nonsmoking men. For women, the risk was 5 times greater.

Those findings are important, said Glynn, because new restrictions on public smoking have led many smokers to cut back on how much they smoke.

"By doing so, they often feel that they are sharply reducing or eliminating the health dangers from smoking, but this study shows that this is not the case," he said.

"Compensatory" smoking is likely the reason that cutting back on cigarettes doesn’t have a more positive effect on health, Glynn said. Even when they smoke less, smokers may unconsciously inhale more deeply or smoke the cigarette closer to the filter -- and that keeps the level of harmful substances they take in high.

"Fortunately, smokers now have a variety of medications and treatments they can use to help them stop smoking, even when they smoke fewer than 5 cigarettes a day," Glynn noted.

Counseling has been shown to help smokers kick the habit. The American Cancer Society’s telephone Quitline is available at 1-877-YES-QUIT (1-877-937-7848). Smokers can also talk with their doctors about nicotine replacement products (gums, patches, inhalers) and the antidepressant bupropion (Zyban).

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