Reducing Cigarette Use May Yield Only Modest Benefit
In January 1964, a U.S. Surgeon General’s report acknowledged that smoking causes cancer and other diseases. Since then, the prevalence of tobacco use has been cut in half, but we’re still a long from solving this public health challenge. Currently, there are more than one billion smokers in the world. Furthermore, tobacco smoking is estimated to cause 4-5 million deaths a year worldwide, a number that is projected to increase to 10 million by 2030.
So what’s being done to address this issue? Numerous public health campaigns have focused on getting smokers to quit, but unfortunately, many smokers are unsuccessful. So some health professionals have suggested that if smokers cannot eliminate their use of tobacco, perhaps reducing the number of cigarettes they smoke will at least decrease their risk for lung cancer. This idea makes sense, but will it work?
A new study in the January 21, 2004 issue of the Journal of the National Cancer Institute found that reducing cigarette use reduced levels of carcinogen byproducts in smokers’ urine. However, the reduction in these byproducts was modest and proportionately less than the reductions in cigarettes smoked per day.
About the Study
This study included 92 men and women who smoked 15–45 cigarettes per day for the past year. The participants expressed interest in reducing their cigarette use, but did not intend to quit smoking during the study period.
During the 26-week “reduction phase” of the study, the participants were instructed to reduce the number of cigarettes smoked per day by 25% in weeks 1–2, 50% in weeks 3–4, and 75% in weeks 5–6 and thereafter. Nicotine replacement therapy was available to help participants reduce cigarette use.
The researchers measured the levels of byproducts from lung carcinogens in the participants’ urine (a known marker for lung carcinogen exposure) at the start of the study and five times during the reduction phase. (A carcinogen is a substance found the environment that has been linked to cancer in humans or animals.)
Throughout the study, the participants reported their cigarette use. To verify these self-reports, the researchers measured a urine marker for cigarette use in a subgroup of participants.
At baseline, the participants smoked an average of 24 cigarettes per day. They were divided into the following groups, based on their reduction of cigarette use:
- Group 1 – participants who reduced daily cigarette use by at least 40% during weeks 4–6
- Group 2 – participants who reduced daily cigarette use by at least 40% during weeks 4–12
- Group 3 – participants who reduced daily cigarette use by at least 40% by week four and 70% during weeks 6–12
All of the groups saw a significant reduction in levels of lung carcinogen byproducts at nearly all measurement intervals. These reductions were best in Group 3 participants, who reduced their cigarette use the most. The degree of this reduction, however, was proportionately less than the reduction in cigarette use. For example, at week 12, participants in Group 2 reduced their number of cigarettes per day by 74%, but the carcinogen byproduct level was only reduced by 29%.
How Does This Affect You?
These findings suggest that reduction in cigarette use does lower exposure to lung carcinogens—but only modestly. The researchers speculate that the reason for this discrepancy is that as the participants reduced the number of cigarette they smoked, they compensated by changing their style of smoking, probably by inhaling longer and deeper.
If reducing the amount of cigarettes you smoke won’t help, what about switching to “light” or low tar cigarettes? A study in the January 10, 2004 issue of the British Journal of Medicine found that people who smoked low and very low tar cigarettes were just as likely to die from ]]>lung cancer]]> as people who smoked medium tar cigarettes. People who smoked non-filtered high tar cigarettes were at even higher risk of dying from lung cancer.
These studies reinforce the notion that the best way for smokers to avoid lung cancer and other smoking-related diseases is to quit. This is easier said than done, considering that the average participant in this study tried to quit more than three times. But no matter how tough it is, quitting is worth it. It’s estimated that half of all lifetime smokers will die as a result of their habit.
Smokfree.gov suggests you “START” trying to quit by taking these five steps:
- S = Set a quit date
- T = Tell family, friends, and coworkers that you plan to quit
- A = Anticipate and plan for the challenges you’ll face while quitting
- R = Remove cigarettes and other tobacco products from your home, car, and work
- T = Talk to your doctor about getting help to quit.
Tobacco and Cancer Home Page
National Cancer Institute
Harris JE, Thun MJ, Mondul AM, Calle EE. Cigarette tar yields in relation to mortality from lung cancer in the cancer prevention study II prospective cohort, 1982-8. British Journal of Medicine . 2004;328.
Hecht SS, Murphy SE, Carmella SG, et al. Effects of reduced cigarette smoking on the uptake of a tobacco-specific lung carcinogen. Journal of the National Cancer Institute . 2004;96:107–115.
Leischow SJ, Djordjevic MV. Smoking reduction and tobacco-related cancers: the more things change, the more they stay the same. Journal of the National Cancer Institute . 2004;96:86–87.
Online guide to quitting: preparing to quit: overview of basic steps. Smokefree.gov website. Available at: http://smokefree.gov/guide/basic_steps.html . Accessed January 21, 2004.
Veneis P, Alavanja M, Buffler P, et al. Tobacco and cancer: recent epidemiological evidence. Journal of the National Cancer Institute . 2004;96:99–106
Last reviewed Jan 23, 2004 by ]]>Richard Glickman-Simon, MD]]>
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