Low-Tar Cigarettes: Evidence Doesn't Indicate Benefit to Public Health
Millions of Americans smoke "low-tar," "mild," or
"light" cigarettes, believing those cigarettes to be less harmful
than other cigarettes. In a new monograph from the National Cancer Institute
(NCI) titled Risks Associated with Smoking Cigarettes with Low Machine-Measured
Yields of Tar and Nicotine*, national
scientific experts conclude that evidence does not indicate a benefit to public
health from changes in cigarette design and manufacturing over the last 50
years.
"This report was made possible by the work and cooperation of scientists
throughout the country," said Scott Leischow, Ph.D., chief of the NCI
Tobacco Control Research Branch. "The monograph clearly demonstrates that
people who switch to low-tar or light cigarettes from regular cigarettes are
likely to inhale the same amount of cancer-causing toxins and they remain at
high risk for developing smoking-related cancers and other diseases." This
monograph is the 13th volume in NCI's Smoking and Tobacco Control
Monograph Series, which began in 1991.
Public Health Effects
Epidemiologic studies (studies that examine the relationship of risk factors to
health and disease) in the late 1960s and 1970s found that smokers of lower-tar
or filtered cigarettes had somewhat lower lung cancer risks than smokers of
other cigarettes. This finding was particularly noteworthy because smokers in
these studies had been smoking the reduced-yield cigarettes for only a
relatively short period of time. It was predicted that as more smokers used
lower yield products for longer periods of time, a greater benefit would occur
and national lung cancer death rates would fall.
Unfortunately, these reductions have not been seen. Even as the popularity of
lower- yield cigarettes grew - 97 percent of the cigarettes now sold in the
United States are filtered cigarettes - lung cancer rates continued to rise
until the early 1990s. The monograph demonstrates that the overall decline that
has been seen since the 1990s can be attributed to the decrease in smoking
prevalence, and not to changes in cigarette design.
The new monograph reviews published literature on death rates in the U.S. and
the United Kingdom which also demonstrated an increase - rather than a decrease
- in smoking risks over a period when machine-measured yields of tar and
nicotine were declining. Two studies conducted by the American Cancer Society
more than 20 years apart found that, despite the large reduction in
machine-measured tar yield over this period, smokers in the later study had an
increased risk of lung cancer. This increase was seen even when differences in
the number of cigarettes smoked per day and duration of smoking were factored
into the analysis. The monograph clearly demonstrates that the expected
reduction in lung cancer risk offered by the early epidemiologic studies has
not been seen in national lung cancer death rate trends.
Surveys have indicated that among the estimated 47 million adults who smoke in
the United States, people who are most concerned about smoking risks or are
most interested in quitting use brands labeled "light" or
"ultra-light." Unfortunately, the monograph finds that choosing
lower-yield cigarettes is not likely to reduce tar intake and resulting disease
risks. Furthermore, marketing and promotion of reduced yield products may delay
genuine attempts to quit. There is no evidence that switching to light or
ultra-light cigarettes actually assists smokers in quitting.
According to David M. Burns, M.D., senior scientific editor of the monograph and
a professor at the University of California, San Diego School of Medicine,
"The take-home message of this report is that the only proven way to
reduce the disease risks associated with smoking is to quit."
New Testing Method Needed
Currently, measurements of tar, nicotine, and carbon monoxide are obtained by
machine measurement using the Federal Trade Commission (FTC) testing method.
However, studies now show that the FTC method does not appropriately mimic
human smoking behavior. The monograph concludes that: "Measurements of tar and
nicotine yields using the FTC method do not offer smokers meaningful
information on the amount of tar and nicotine they will receive from a
cigarette. The measurements also do not offer meaningful information on the
relative amounts of tar and nicotine exposure likely to be received from
smoking different brands of cigarettes."
According to Leischow, "There is an urgent need to develop new approaches
to testing that offer meaningful information. Smokers should not believe that
the tar and nicotine levels listed on a pack of cigarettes are what they are
actually inhaling."
The FTC has asked the Department of Health and Human Services (DHHS) for
guidance to improve its testing method for tar and nicotine. NCI and other DHHS
agencies will convene a working group to review and synthesize the science on
this issue and to determine what changes should be made to the testing method
to correct the limitations identified in the monograph.
Smokers Compensate
The monograph describes several reasons why the levels of tar and nicotine
measured by the FTC method do not reflect actual tar and nicotine delivery to
the smoker. The filters in low-tar/low-nicotine cigarettes often include vent
holes which, when open, allow air to enter and dilute the smoke. However, many
smokers cover these holes with their lips and fingers. In contrast, when tested
by a machine, the holes are unobstructed, and artificially low measurements of
tar and nicotine are obtained. In addition, smokers who switch to low-tar or
low-nicotine cigarettes from regular cigarettes "compensate" for the
lower nicotine level by inhaling more deeply; taking larger, more rapid, or
more frequent puffs; or by increasing the number of cigarettes smoked per day.
As a result, smokers cancel out any potential benefit of smoking a
"low-tar" cigarette.
The monograph describes the advertising and promotional strategies used by the
tobacco industry to market lower-yield cigarettes. It concludes that these
strategies were intended to reassure smokers and to prevent them from quitting,
and that they led consumers to perceive filtered and low-tar products as safer
alternatives to regular cigarettes. The monograph also cites internal tobacco
industry documents that demonstrate the industry's early knowledge of the
discrepancy between the FTC machine-measured yields of tar and nicotine and
what the smoker actually inhales.
Future Research
The authors note that continued research, as well as tracking of the diseases
caused by smoking, is necessary to determine the disease risks associated with
recently introduced "reduced exposure" cigarettes or cigarette-like
products. Further study on the health risks of individuals who have smoked only
"low-yield," "ultra-low-yield," and
"low-carcinogen" cigarettes is also needed.
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*The senior scientific editor of the monograph is David M. Burns, M.D.
(University of California, San Diego), and the co-scientific editor is Neal L.
Benowitz, M.D. (University of California, San Francisco). ###
To view a series of Questions and Answers related to this monograph, please
visit http://www.cancer.gov/cancertopics/factsheet/monograph13qa
.For more information about Risks Associated with Smoking Cigarettes
with Low Machine-Measured Yields of Tar and Nicotine and to view the
complete monograph online, please visit
http://cancercontrol.cancer.gov/tcrb/monographs/.
To order a copy of the monograph, please call NCI's Cancer Information Service
at 1-800-4-CANCER (1-800-422-6237) or visit NCI's Publications Locator Web site
at http://www.cancer.gov/publications
To learn about the monograph series and tobacco control programs at the NCI,
please visit NCI's Tobacco Control Research Branch at
http://cancercontrol.cancer.gov/tcrb.
To learn about tobacco control programs at the Office on Smoking and Health
(OSH) at the Centers for Disease Control and Prevention, visit OSH's Web site
at http://www.cdc.gov/tobacco.
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