Study: Quitting the Only Way to Reduce Risk
Article date: 2004/01/09 – American Cancer Society
Smoking low tar cigarettes – commonly called “light” or “ultra light” – does nothing to lower a smoker’s risk of lung cancer, according to a study by researchers at the Massachusetts Institute of Technology and the American Cancer Society (ACS). People who smoked low tar cigarettes had the same lung cancer risk as those who smoked regular cigarettes, they report in the online edition of the British Medical Journal.
The study is the first to compare lung cancer risk among smokers of low tar cigarettes and regular tar brands, said co-author Michael Thun, MD, vice president of epidemiology and surveillance research at ACS.
“The data underscore that terms like ‘light’ and ‘ultra light’ are misleading because they imply less health risk, but do not correspond to less hazardous cigarettes,” said Thun. “For a smoker, the only sure way to reduce [lung cancer] risk is to quit smoking.”
Unfiltered Cigarettes Worst
Thun and colleagues tracked the smoking habits of nearly 1 million adults (age 30 and older) for 6 years. They compared the type of cigarette smoked with deaths from lung cancer. Cigarettes were categorized based on tar content: very low tar (0-7 mg tar per cigarette), low tar (8-14 mg tar per cigarette), medium tar (15-21 mg per cigarette), or high tar (22 mg or more per cigarette).
As expected, people who never smoked had the lowest risk of lung cancer. Smokers had a substantially higher risk, and there was virtually no difference between those who smoked low or very low tar brands and those who smoked regular cigarettes.
People who smoked the high tar cigarettes, however, had an even higher risk of lung cancer than other smokers, perhaps because all of the high tar brands were unfiltered. All of the low and very low tar cigarettes were filtered, as were 99% of the medium tar cigarettes.
Labels Not Reliable Indicators
The way people smoke may account for the findings, Thun said. The tar and nicotine content listed on cigarette labels is based on measurements from a smoking machine, but studies have shown “there’s a very poor correlation between machine-measured yield and what people are actually taking in,” he explained.
People who smoke lower tar cigarettes don’t necessarily reduce the amount of tar, nicotine, and other chemicals they take into their bodies, because they inhale deeper, hold the drag longer, and puff more often than people who smoke regular cigarettes. They also tend to smoke more cigarettes, and may cover ventilation holes in the filter that are designed to dilute smoke with air.
Although cigarette manufacturers warn that listed tar and nicotine levels can’t predict what an individual smoker will take in, “the natural assumption of someone reading those levels is that they actually communicate something meaningful,” Thun said. “But they don’t.”
According to the US Federal Trade Commission, nearly 89% of cigarettes sold in the United States in 2001 had tar ratings of 15 mg or less. The lowest tar varieties, those with 3 mg or less, accounted for only 1% of the market. Unfiltered high tar cigarettes also account for about 1% of the US market.
The Sooner You Quit, the Better
Smokers in the study who quit substantially reduced their risk of dying of lung cancer, especially if they quit by age 35. These young quitters had a risk similar to that of nonsmokers. But even smokers who kicked the habit later in life – age 55 or older – saw a significant drop in lung cancer risk.
“The lung cancer risk among those who stopped smoking was markedly lower than those who continued to smoke, irrespective of the type of cigarette,” Thun said.
People who smoked low tar cigarettes were more likely to quit than smokers of higher tar brands. Thun said low tar smokers may be more concerned with the health effects of smoking, and thus may be more motivated to give up the habit.
But he warned that lower tar smokes are no substitute for quitting.
“The important thing is that people not see these products as an alternative to quitting,” said Thun. “The only sure way we know to reduce risk is to quit.”