Study: cutting back doesn't cut toxins in smokers

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Study: cutting back doesn't cut toxins in smokers

Last Updated: 2004-01-21 12:45:00 -0400 (Reuters Health)

By Maggie Fox

WASHINGTON (Reuters) - 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 had hoped, according to a report published on

Tuesday.

The study, published in this week's issue of the Journal of the National

Cancer Institute, suggests that cutting back is not nearly as good for

the health as completely quitting, experts said.

When smokers smoke less, they probably drag longer and harder on every

cigarette, the researchers said. " The results indicate that some smokers

may benefit from reduced smoking, but for most the effects are modest,

probably due to compensation, " they wrote.

The scientists, led by Hecht of the University of Minnesota

Cancer Center, tested 92 smokers over six months.

They looked specifically for the by-products of NNK, one of the

best-known carcinogens in tobacco smoke.

The smokers, who had smoked an average 23.7 cigarettes a day, agreed to

systematically cut back how much they smoked ---- 25 percent fewer in

the first two weeks, 50 percent fewer in the next two weeks and then by

75 percent, or more, if they could.

Urine tests showed that smokers who cut back by 55 percent to 90 percent

reduced NNK by only 27 percent to 51 percent. Even smokers who were able

to cut back to just two cigarettes a day reduced their NNK indicator

levels by only 46 percent.

In a commentary, Leischow and Mirjana Djordjevic of the Tobacco

Control Research Branch at the National Cancer Institute said the study

showed that completely kicking the habit is the only way to escape the

damage done by cigarettes.

Dr. Thun of the American Cancer Society agreed.

" These results support other evidence that when smokers reduce the

amount they smoke or switch to reduced tar cigarettes, they modify the

way they smoke in order to extract more nicotine and tar from each

cigarette, " Thun said in a statement.

" The study complements other lines of evidence that suggest that

quitting smoking is far more beneficial than reducing the number of

cigarettes smoked. At least for lung cancer, the number of years spent

smoking is far more important than the number of cigarettes smoked per

day, " he added.

" Furthermore, even very low amounts of smoking are associated with

substantial increases in the risk of heart attacks. "

Smoking causes 90 percent of all lung cancer cases and is the leading

cause of heart disease, the No. 1 killer in the developed world

The study also showed how hard it is to quit. Six months into the study,

56 percent of the smokers had relapsed and were back to a pack a day or

more.

SOURCE: Journal of the National Cancer Institute January 21, 2004.

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