The authors suggest that the most likely explanation for the results is that people who are trying to cut back by smoking fewer cigarettes per day alter their smoking behavior by inhaling longer and deeper, which is known to alter a smoker's exposure to carcinogens. "The results indicate that some smokers may benefit from reduced smoking, but for most the effects are modest, probably due to compensation," the authors conclude.
In a commentary in the same issue of the Journal, Paolo Vineis, M.D., and his colleagues--a team of epidemiologists who participated in a 2002 working group that prepared a monograph on tobacco smoking and secondhand smoking for the International Agency for Research on Cancer (IARC)--review the evidence for a causal relationship between tobacco use and cancers not previously believed to be associated with smoking, such as cancers of the upper aero-digestive tract, stomach, liver, kidney, uterine cervix, and large bowel, and myeloid leukemia. They also summarize the causal association between cancer and tobacco use other than smoking, such as bidi, cigar, and pipe smoking.
"Although 1 billion people worldwide already smoke and more will start, individuals who stop smoking reduce their smoking-related cancer risks effectively," they write. "A balanced public health strategy is therefore needed that not only prevents young individuals from starting to smoke, but also helps adults stop smoking."
In an accompanying editorial, Scott J. Leischow, Ph.D., and Mirjana Djordjevic, Ph.D., of the Tobacco Control Research Branch at the National Cancer Institute, discuss how
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Contact: Katherine Arnold
jncimedia@oupjournals.org
301-841-1287
Journal of the National Cancer Institute
20-Jan-2004