Dr Gupta’s letter suggests that the reduction in lung cancer in both
Sweden and Connecticut is highly likely to be due to a reduction in
smoking in both places. This is entirely unsurprising, and as far as
Sweden is concerned is precisely what we suggested in the original paper
he referred to:
“There has been a larger drop in male daily smoking (from 40% in 1976
to 15% in 2002) than female daily smoking (34% in...
Dr Gupta’s letter suggests that the reduction in lung cancer in both
Sweden and Connecticut is highly likely to be due to a reduction in
smoking in both places. This is entirely unsurprising, and as far as
Sweden is concerned is precisely what we suggested in the original paper
he referred to:
“There has been a larger drop in male daily smoking (from 40% in 1976
to 15% in 2002) than female daily smoking (34% in 1976 to 20% in 2002) in
Sweden, with a substantial proportion (around 30%) of male ex-smokers
using snus when quitting smoking. Over the same time period, rates of lung
cancer and myocardial infarction have dropped significantly faster among
Swedish men than women and remain at low levels as compared with other
developed countries with a long history of tobacco use.” (p349,
abstract)1.
The idea that smoking and lung cancer rates may fall to a similar or
greater degree in other places is entirely irrelevant to whether or not
snus played a role in smoking reduction in Swedish men. Indeed, in the
original paper we stated clearly that:
“Both within and outside Sweden, smoking is primarily influenced by
factors other than availability of smokeless tobacco (for example, real
price of cigarettes, health education, smoke-free air policies, industry
marketing, etc).” (p357)1
It is therefore entirely unsurprising that these types of factors
will have influenced smoking and lung cancer rates in the United States
and every other country, regardless of whether or not snus is available. A
key point in our original paper that distinguished Sweden from other
countries was that smoking rates WITHIN that country have fallen
significantly faster in men than women, and that this appeared to be
related to the fact that men in Sweden use snus much more than women. So
although these comparisons between one country in Europe and a state in
the US are almost entirely irrelevant to the question of the effect of
snus use on lung cancer rates in Sweden, the more appropriate comparison
(if one wanted to make one) would be of the difference in decline of lung
cancer rates between men and women in Sweden as compared to changes in
that difference in the US. It is not clear whether the data presented in
Dr Gupta’s letter was for men, women or both.
Since the publication of our original paper there have been
subsequent publications that have confirmed that in Sweden, men who start
using snus are less likely to become daily smokers, that men who smoke and
then start using snus are more likely to stop smoking, and that a higher
proportion of men than women in Sweden have quit smoking, with the
difference largely attributable to snus use2,3. It had previously been
suggested that the men who quit smoking in Sweden are not the same ones
who start using snus (and that snus use is therefore not involved in men
quitting smoking)4. However, studies have now verified that in fact a
sizeable proportion (26-29%) of Swedish men who quit smoking use snus as a
smoking cessation aid2,5.
It is now crystal clear that their transfer of nicotine dependence
onto snus has accelerated the rate of decline of smoking among Swedish men
in substantial numbers. That transfer from an extremely harmful form of
tobacco use (cigarette smoking) to a much less harmful form (snus) has
contributed to a reduction in the rate of smoking-caused diseases in
Swedish men.
1. Foulds J, Ramstrom L, Burke M, Fagerstrom K. The effect of
smokeless tobacco (snus) on public health in Sweden. Tobacco Control 2003;
12:349-59.
2. Ramström LM, Foulds J. The role of snus (smokeless tobacco) in
initiation and cessation of tobacco smoking in Sweden. Tobacco Control
2006 Jun;15(3):210-4.Pdf available at:
http://www.tobaccoprogram.org/staffarticles.htm
3. Furberg Furberg H, Bulik C, Lerman C, et al. Is Swedish snus associated
with smoking initiation or smoking cessation? Tob Control.2005; 14:422-
424.
4. Tomar SL, Connolly GN, Wilkenfeld J, Henningfield JE. Declining smoking
in Sweden: Is Swedish Match getting the credit for Swedish tobacco
control’s efforts? Tobacco Control2003; 12:368-59
5. Gilljam H, Galanti MR. Role of snus (oral moist snuff) in smoking
cessation and smoking reduction in Sweden. Addiction 2003;98:1183-9.
Dr Gupta’s comparison of trends in lung cancer mortality and smoking
prevalence in Sweden and Connecticut purports to undermine the claim that
increasing snus use in Sweden has contributed to declining lung cancer
rates there.
Dr Gupta argues that some factor other than snus must have been at
work because the ratio of lung cancers between Sweden and Connecticut has
remained constant despite the large differenc...
Dr Gupta’s comparison of trends in lung cancer mortality and smoking
prevalence in Sweden and Connecticut purports to undermine the claim that
increasing snus use in Sweden has contributed to declining lung cancer
rates there.
Dr Gupta argues that some factor other than snus must have been at
work because the ratio of lung cancers between Sweden and Connecticut has
remained constant despite the large difference in snus use between the two
places. He identifies this “other factor” as a declining cigarette smoking
prevalence that he attributes to tobacco control policies.
We agree that a decline in cigarette smoking in both countries
explains the lung cancer trends but we don’t see how this rules out a role
for snus. This is exactly the mechanism by which proponents of snus would
claim that snus use reduces smoking prevalence, namely, that population
smoking prevalence declines because existing smokers switch to snus and
new tobacco users use snus rather than cigarettes (Ramström and Foulds
2006).
The fact that smoking prevalence declined in Connecticut as a result
of more traditional tobacco control policies simply shows that there is
more than one way to reduce smoking prevalence. The fact that the decline
in cigarette smoking over the time period examined was greater in Sweden (
-13%) than in Connecticut (-8%) supports the hypothesis that the addition
of snus to more conventional tobacco control policies has increased the
decline in smoking prevalence.
We concede that the comparison does not prove that snus was
responsible for the decline in lung cancer rates in Sweden, but it is much
more supportive of the claims for snus than Dr Gupta allows.
Yours sincerely
Coral Gartner and Wayne Hall
References
Ramström, L. M. and J. Foulds (2006). "Role of snus in initiation and
cessation of tobacco smoking in Sweden." Tobacco Control 15(3): 210-214.
Some tobacco control community members believe that advocating the
use of snus, a form of Swedish smokeless tobacco said to be less harmful
than cigarettes, would prove an effective harm reduction strategy against
tobacco related diseases. One important basis for such a claim is the
fact that snus is widely used in Sweden (23% men used snus daily in 2002),
where the incidence of cancer caused by tob...
Some tobacco control community members believe that advocating the
use of snus, a form of Swedish smokeless tobacco said to be less harmful
than cigarettes, would prove an effective harm reduction strategy against
tobacco related diseases. One important basis for such a claim is the
fact that snus is widely used in Sweden (23% men used snus daily in 2002),
where the incidence of cancer caused by tobacco is relatively low, and the
observation that the Swedish are switching from smoked tobacco to snus.
One way of looking at this claim of harm reduction through the use of snus
is to compare tobacco related cancer rates in Sweden to those in the state
of Connecticut, where use of any kind of smokeless tobacco including snus
has been consistently rare.
The table below provides a comparison of age adjusted incidence rates
for Sweden and Connecticut. As the data show, the incidence of tobacco
related cancer is much lower in Sweden, about one half that of
Connecticut. Trend data for Sweden seemingly provide further supportive
evidence to the harm reduction hypothesis, as a dramatic increase in snus
use in Sweden (0.4 kg/person in 1970 to 0.9kg/person in 2000) coincides
with a decreasing cigarette consumption (1.1kg/person in 1970 to
0.6kg/person in 2000) resulting in a decrease of tobacco related cancer
from 97.8 per 100,000 in 1966-1970 to 56.7 per 100,000 in 1993-1997.1,
However, if snus has a harm reduction effect, the incidence of
tobacco related cancers should not only decline in Sweden as snus use
increases, but it should decrease more in Sweden than in Connecticut,
where the consumption of smokeless tobacco has remained <1% over 1990s.
However, the data below demonstrate that the ratio of the incidence of
tobacco related cancer in Sweden and Connecticut has remained constant at
about 0.5 since 1973, and the same ratio for lung cancer has been stable
at about 0.4 since1960. Rather than snus causing the decrease in tobacco
related cancer in Sweden, these data suggest that another factor was
responsible in reducing cancer incidence in both Sweden and Connecticut.
That factor is likely to be the decline in cigarette use, which fell in
men from about 28% to 15% (Sweden) and 26.7% to 18.7% (Connecticut) from
1985-2003.1,3 During the period of 1970s to 1990s, both populations were
exposed to smoking reduction strategies such as increased awareness of
health risks, increased prices, a change in social norms regarding tobacco
use, etc but both places did not have an increase in snus use. Thus, the
data do not seem to support the hypothesis that the decrease in tobacco
related cancers in Sweden is due to increasing use of snus.
References
1. Foulds, J., Ramstrom, L., Burke, M., Fogerstrom K. Effect of
Smokeless tobacco (snus) on smoking and public health in Sweden. Tobacco
Control, 2003; 12:349–359.
2. Cancer Incidence in Five Continents. Vol. I-VIII. Lyon:
International Agency for Research on Cancer.
3. CDC. State System: State Tobacco Activities tracking and
evaluation system. Tobacco Use Supplement to the Current Population
Survey. 2006. Available at http://apps.nccd.cdc.gov/statesystem/. Accessed
January 17, 2007.
Reduction as a permanent solution may give people false expectations
Thanks to Dr. John R Hughes for his interesting remarks of 20 January 2007
to our article (TC 15:472-480). We have the following comments:
1. Dr. Hughes states that our main finding (no health benefit from
reducing cigarettes) has not been found in the few prior prospective
studies of this topic. This is not correct. Based on a large study
population in C...
Reduction as a permanent solution may give people false expectations
Thanks to Dr. John R Hughes for his interesting remarks of 20 January 2007
to our article (TC 15:472-480). We have the following comments:
1. Dr. Hughes states that our main finding (no health benefit from
reducing cigarettes) has not been found in the few prior prospective
studies of this topic. This is not correct. Based on a large study
population in Copenhagen, Dr. Nina S Godtfredsen and co-workers have
reported the same results in a series of publications, references given in
our article. Dr Hughes’ remarks imply that there may be other prospective
studies that give other results. We have not been able to find other
prospective studies that take up this problem.
2. Our article reports on results from three examinations; for the
majority of participants the interval between the examinations was five
years. A subgroup of the study population was nominated ‘sustained
reducers’. They were heavy cigarette smokers at the first examination, had
reduced their daily cigarette consumption by at least 50 % at the second
examination, and had remained as ‘reducers’ at the third examination.
Their mean consumption at the three examinations was 23.6 – 10.0 – 10.4
cigarettes per day (table 6 in our article).
Dr Hughes states that “the question at each follow-up did not ask about
smoking since the last follow-up”. This is correct, and we agree with Dr
Hughes that it is unknown what the rate of smoking really was between
follow-ups in sustained reducers. The sustained reducers had, however, a
mean daily consumption that was almost the same at the second and third
examination, and in our opinion, the most reasonable explanation is that
their daily cigarette consumption had stabilised at a consumption level
which actually was at least 50% lower than at the first examination. We
also underline that at the second examination, reducers had a serum
thiocyanate level that was lower than in heavy smokers, and close to the
serum thiocyanate level in moderate smokers (table 3 in our article).
3. Dr Hughes states that reduction actually increases motivation to quit.
In our paper, we state explicitly:”Undoubtedly, reduction in consumption
may have a place as a temporary measure in systematic smoking cessation”.
Our conclusion that advising reduction may give people false expectations,
refer to reduction as a permanent solution. We think that the results of
our study and of those of the Copenhagen Study, with study populations of
more than 70 000 persons together, give a sound basis for this conclusion.
Age Tverdal,
Professor
Norwegian Institute of Public Health,
Oslo
Kjell Bjartveit
Director Emeritus
National Health Screening Service
Oslo
The recent study by Tverdal and Bjartveit (TC 15:472-480, 2006) that
found no health benefit from reducing cigarettes had several assets not
found in the few prior prospective studies of this topic; e.g. the
reducers had reduced by over 50% and several outcomes were measured.
I would, however, like to make two comments. First, one asset of the
study was the examination of "sustained reducers;" i.e., those who...
The recent study by Tverdal and Bjartveit (TC 15:472-480, 2006) that
found no health benefit from reducing cigarettes had several assets not
found in the few prior prospective studies of this topic; e.g. the
reducers had reduced by over 50% and several outcomes were measured.
I would, however, like to make two comments. First, one asset of the
study was the examination of "sustained reducers;" i.e., those who
reported reduction at two consecutive examination. Although this
estimation of sustained reduction is superior to that in prior studies,
the question at each follow-up did not appear to ask about smoking since
the last follow-up but rather asked about smoking at the current time;
thus, in actuality, it is unknown what the rate of smoking really was
between follow-ups in "sustained reducers." As a result, there is still
the possibility that these results are false positives. Having said that,
I do believe the burden of proof is on those who believe reduction is
helpful to provide more rigorous tests.
Second, the concluding sentence of the abstract states advising
reduction may "give people false expectations." While this may be true to
some extent, advising reduction does not appear to undermine motivation to
quit but actually increases motivation to quit. Dr Carpenter and I
published a review paper of 19 studies (that did not come out until after
this current study was submitted). None of these studies suggested
reduction undermined motivation to stop smoking. Instead, 16 of the 19
found smoking reduction increased the probability of future cessation.
(NTR 8:739-749, 2006). Thus, I believe smoking reduction can be beneficial
to smokers if they see reduction not as an end itself but as way to
quitting. In fact, surveys suggest this is exactly how the large majority
of smokers see reduction (Hughes et al, NTR, in press)
Dr Gupta’s letter suggests that the reduction in lung cancer in both Sweden and Connecticut is highly likely to be due to a reduction in smoking in both places. This is entirely unsurprising, and as far as Sweden is concerned is precisely what we suggested in the original paper he referred to:
“There has been a larger drop in male daily smoking (from 40% in 1976 to 15% in 2002) than female daily smoking (34% in...
Dr Gupta’s comparison of trends in lung cancer mortality and smoking prevalence in Sweden and Connecticut purports to undermine the claim that increasing snus use in Sweden has contributed to declining lung cancer rates there.
Dr Gupta argues that some factor other than snus must have been at work because the ratio of lung cancers between Sweden and Connecticut has remained constant despite the large differenc...
Dear Editor
Some tobacco control community members believe that advocating the use of snus, a form of Swedish smokeless tobacco said to be less harmful than cigarettes, would prove an effective harm reduction strategy against tobacco related diseases. One important basis for such a claim is the fact that snus is widely used in Sweden (23% men used snus daily in 2002), where the incidence of cancer caused by tob...
Reduction as a permanent solution may give people false expectations Thanks to Dr. John R Hughes for his interesting remarks of 20 January 2007 to our article (TC 15:472-480). We have the following comments: 1. Dr. Hughes states that our main finding (no health benefit from reducing cigarettes) has not been found in the few prior prospective studies of this topic. This is not correct. Based on a large study population in C...
The recent study by Tverdal and Bjartveit (TC 15:472-480, 2006) that found no health benefit from reducing cigarettes had several assets not found in the few prior prospective studies of this topic; e.g. the reducers had reduced by over 50% and several outcomes were measured.
I would, however, like to make two comments. First, one asset of the study was the examination of "sustained reducers;" i.e., those who...
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