Study Blows Smoke on Lung Cancer Causes

Do smokers who reduce, but don’t quit smoking, reduce their risk of smoking-related disease? Reminiscent of past allegations of tobacco industry lying, the anti-tobacco industry apparently doesn’t want smokers to know the truth.

The situation recalls George Orwell’s book "Animal Farm" in which the leaders of the animal revolt against their human masters gradually took to acting, well, just like the humans they deposed.

“Smokers who cut back the number of cigarettes they smoke may not be reducing the cancer-causing chemicals in their bodies as much as they hoped,” reported the Washington Post this week.

The Post report was spurred by a study conducted by University of Minnesota “researchers” and published in the Jan. 21 issue of the Journal of the National Cancer Institute.

The researchers studied a group of 153 smokers who reduced their smoking by 25 percent during the first two weeks of the study, by 50 percent during weeks 2-4 and by 75 percent during weeks 4-26.

At weeks 4, 6, 8, 12 and 26 of the study, the researchers tested urine samples of the smokers for the presence of NNAL (search) and NNAL-Gluc (search), byproducts of a compound in cigarette smoke called “NNK” that may (or may not) play a role in the development of lung cancer.

As the smokers reduced the number of cigarettes smoked per day, statistically significant reductions in the levels of urinary NNAL and NNAL-Gluc were reported by the researchers.

“However, the observed decreases were generally modest, always proportionally less than the reductions in cigarettes smoked per day, and sometimes transient,” noted the researchers. Reducing the number of cigarettes smoked per day, whether by 50 percent or by 75 percent, reportedly only reduced urinary levels of NNAL and NNAL-Gluc by about 30 percent.

The researchers suggested that the comparatively small reduction in urinary levels of NNAL and NNAL-Gluc compared to the reduction in cigarettes smoked per day may be due to the smokers’ “compensation” ― that is, dragging longer and harder on every cigarette.

“The results indicate that some smokers may benefit from reduced smoking, but for most the effects are modest,” concluded the researchers.

The University of Minnesota group, led by anti-tobacco activist-researcher Stephen Hecht (search), thereby teed up the study for its real purpose ― a broader attack on the notion of “harm reduction” with respect to tobacco use.

Harm reduction (search) is a strategy to reduce the incidence of smoking-related heath effects by getting smokers to smoke less, smoke “safer” cigarettes or transition to “safer” products such as smokeless tobacco (search).

Though harm reduction would seem to be a reasonable approach toward reducing the risk of smoking-related health effects ― at least for those who insist on meddling in the personal health and private lives of others ― anti-tobacco extremists oppose it. Their public posture is that harm reduction doesn’t work.

The University of Minnesota study was accompanied by a Journal of the National Cancer Institute editorial hailing its results and concluding that there are “certainly insufficient data to support the practice of encouraging smokers to pursue reduced smoking as a harm reduction strategy.”

That statement is demonstrably false.

Anyone who knows anything about the research on smoking and health ― and presumably that would include the authors of the study and editorial ― knows that the risk of smoking-related disease increases with the number of cigarettes smoked.

A good summary of such studies is presented in the U.S. Environmental Protection Agency’s 1993 report on secondhand smoke.

In trying to link secondhand smoke with lung cancer based on data concerning smoking and lung cancer, the EPA wrote, “A gradient of increasing risk for lung cancer mortality with increasing number of cigarettes smoked per day was established in [each of eight major studies].”

In an American Cancer Society study of over one million persons, for example, less-than-a-pack-per-day smokers had less than half the lung cancer risk of two-pack-per-day smokers. People who smoked 1-9 cigarettes per day had about half the lung cancer risk of people who smoked 10-19 cigarettes per day.

There is no question that fewer cigarettes smoked per day reduces lung cancer risk.

The University of Minnesota study does not change this fact for at least two reasons: (1) the researchers did not study the impact of reduced smoking on health and so cannot claim that it has no effect on health; and (2) what they did study (urinary levels of the NNK metabolites) may not even be biologically related to cancer risk in smokers and so may be utterly meaningless in terms of health consequences.

The condemnation of harm reduction on the basis of this study is so unjustified as to be blatantly dishonest. Lying to smokers about the health effects of smoking less is simply despicable ― and isn’t that one of the anti-tobacco activists’ primary criticisms of the tobacco industry?

Many people are going to smoke no matter what. Rather than accept and work within this reality to reduce the consequences of such smoking, the anti-tobacco industry is taking an “our way (tobacco prohibition) or the highway (more smoking-related disease)” approach.

It’s a disturbing attitude that seems to be driven more by a blind hatred of the tobacco industry than concern for the health of smokers.

Steven Milloy is the publisher of, an adjunct scholar at the Cato Institute and the author of Junk Science Judo: Self-Defense Against Health Scares and Scams (Cato Institute, 2001).

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