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·
Most lung cancer (80-90% in industrialised
countries) is due to smoking.
·
Smoking is the main tobacco type causing mouth cancer.
(Alcohol use is also a cause.) In Sweden where
snuff use predominates in men, snuff does not cause mouth cancer.
·
The evidence for nasal snuff causing nasal
cancer is “insufficient” according to International Agency
for Research on Cancer. If common it would show up under nasopharyngeal
cancer.
·
We compare New Zealand, where snuffs are not
sold, with three countries where snuff has been popular for many many years - Sweden (oral snuff in men) and Lesotho
and South Africa (nasal snuff in women), and the new case cancer rates
for lung, mouth and nasopharynx.
Figures 1 and 2
show that
·
Smoking, not total tobacco use, best predicts
total cancer rates in lung, and mouth.
·
Smoking,
and not snuff or total tobacco use, is the best predictor of oral cancer.
·
Smoking
prevalence in the past is the best guide to the combined cancer rate for
these sites
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Fig. 1.
Prevalence of tobacco use by type used:
NZ, Sweden, and Lesotho; S.
African Black women
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Fig 2.
Main Tobacco-related cancer incidences by site 2002
NZ, Sweden, and Lesotho; and
S. African Black women.
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Lesotho and Black S. African women smoke the least, use nasal snuff the
most, and have the lowest cancer incidence rates at these three cancer
sites.
Tobacco use is as common among Lesotho women as is tobacco smoking by NZ women, yet Lesotho women, using nasal snuff, have a combined rate of cancer at the
main sites for tobacco caused cancers one sixth that of NZ women
(Figure 2).
Swedish
men smoked just as much as NZ men in 1981 but they also used snuff. By
2002 more snuffed than smoked, and their lung and mouth cancer rates
were less than in NZ men.
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Lesotho and Black S. African women
have by far the lowest combined rates of cancers at the main sites for
tobacco caused cancers. Only 1 to 4 % smoke, even though 17-29% of them
use in tobacco – mostly as nasal snuff.
The message is clear- smoking is more
dangerous than snuff.
New Zealand males tend to smoke, avoid
snuff and have a much lower prevalence of tobacco use in total than
Swedish men. Despite their low tobacco use, they have a higher rate of
both lung cancer and oral cancer than Swedish men. In 2002 fewer
Swedish men smoked, many using snuff instead.
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|
New Zealand: 1981 Census smoking
prevalence. Tobacco Statistics 2000. Cancer Society of NZ.
Sweden 1981: www.statveca.com
Lesotho,1992: Tobacco or Health, a global status report. WHO 1997. http://www.cdc.gov/tobacco/who/lesotho.htm
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Based on Table 2 below. Cancer incidence
data: Globocan 2002 http://www.dep-iarc.fr
Age standardised to a world population.
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Whatever the risk of cancer from traditional
snuffs from Africa and India, import
controls based on nitrosamine content can bar these products from sale.
See www.smokeless.org.nz/snuffregulations.htm
Low nitrosamine snuffs are now available from Sweden and the United
States.
Full disclosure of nitrosamine levels with
random independent testing at the manufacturer’s expense, can
ensure carcinogens are kept to low levels.
Cigarettes before combustion have very low toxicity,
but once lit, the high temperatures create toxic gases in the smoke,
which cannot be adequately filtered by any known filter.
Figure 3. Cancer incidence at sites
exposed to smoke and snuffs as a proportion of total cancers
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Most tobacco cancers are due to smoking,
and most are lung cancers.
Tobacco
cancer incidence makes up only 2 to 3 % of total cancers in Black
Southern African women.
This is because very few of these women
smoke. (See Table1).
Nasal snuff is a popular substitute for
smoking among these women.
In contrast, in New Zealand many women smoke, and
tobacco cancers account for 8% of all cancers in women.
Most
tobacco cancers are lung cancers which carry a very high mortality
rate, so tobacco as a cause of cancer deaths is more important than
these percentages might indicate.
Data from Table 2.
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Lesotho Women
have traditionally used nasal snuff, but the risk of nasopharyngeal
cancer is still less than 1 per 100,000 women per year. Only 1% smoke, and they have by far the lowest incidence of
tobacco cancers, 4 per 100,000 per year. Lesotho men may
have recently taken up smoking, as their lung cancer rate is low.
South Africa. 4% of Black women
smoke, 13% using smokeless tobacco. Smoking is taboo for these women, and
use of snuff is less taboo. They avoid lung cancer; and the total tobacco
cancer rate is low. A third of South African men smoke, and lung cancer
is expected to rise further.
New Zealand and Sweden NZ men have the
highest tobacco cancer rate (42 per 100,000 per year), much greater than
26 per 100,000 for Swedish men. NZ women have now reduced their smoking
below that of Swedish women, but due to past smoking have a cancer rate
of 25 per 100,000, higher than for Swedish women.
Table 1. Smoking and
snuff prevalence – Sweden, New Zealand, Maori, Lesotho; S. Africa.
|
Percentages
exposed to each type of tobacco
|
Smoking
A
|
Oral
Snuff
B
|
Nasal
snuff
C
|
Any
tobacco use
A+B+C
|
% of
tobacco users who smoke
A/(A+B+C)
|
|
Sweden
– men 1981
|
34
|
13
|
0
|
47
|
72
|
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Sweden
– women 1981
|
27
|
0.3
|
0
|
27
|
99
|
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NZ European – men 1981
|
33
|
0
|
0
|
33
|
100
|
|
NZ European – women 1981
|
27
|
0
|
0
|
27
|
100
|
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NZ Maori men 1981
|
53
|
0
|
0
|
53
|
100
|
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NZ Maori women 1981
|
58
|
0
|
0
|
58
|
100
|
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Lesotho men
1992
|
38.5
|
8.7
|
1.0
|
48
|
80
|
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S. African Black women 1998
|
4.2
|
3**
|
10**
|
17
|
24
|
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Lesotho women
1992
|
1.0
|
1.8
|
26.5
|
29
|
3
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New Zealand: Tobacco Statistics 2000.
Cancer Society of NZ. 1981 Census data:35% of all
men and 29% of all women smoked.
Sweden Tobacco use: www.statveca.com
Lesotho,1992 data: Tobacco or Health, a global status report. WHO 1997. http://www.cdc.gov/tobacco/who/lesotho.htm
**Total smokeless use 12.6%, of which
“most” is nasal snuff.
New Zealanders consume all their tobacco as
smoking tobacco, 99% in the form of cigarettes.
Table 2. Cancer
incidence at sites exposed to smoke and snuffs as a proportion of total
cancer
|
Percentages
exposed to each type of tobacco
|
All
cancer
All
|
Lung
cancer
A
|
Oral
cancer
B
|
Naso-pharyngeal cancer
C
|
Lung +
oral + naso-pharyngeal
A+B+C
|
These three cancers as % of all cancer
(A+B+C)/All
|
|
NZ
– men 2002
|
363
|
37
|
5.6
|
0
|
42
|
12
|
|
Sweden men
2002
|
278
|
21
|
4.5
|
0
|
26
|
9
|
|
NZ women 2002
|
299
|
21
|
3
|
0.3
|
25
|
8
|
|
NZ Maori women 2002
|
292
|
53
|
0.8
|
0.7
|
54
|
19
|
|
Swedish women 2002
|
299
|
14
|
3
|
0.2
|
17
|
7
|
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S. African Black men
|
224##
|
9*
|
9#
|
2##
|
20
|
9
|
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Lesotho men
2002
|
162
|
12
|
3
|
0
|
15
|
9
|
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S. African Black women 1998
|
168##
|
2*
|
1.75#
|
0.4##
|
4
|
2
|
|
Lesotho women
2002
|
132
|
1
|
2
|
0.7
|
4
|
3
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* Mqoqi N. et al. Incidence of histologically diagnosed
cancer in South Africa 1998-99. National Cancer Registry of SA. 2004.
#Hille JJ et al. J
Dent Assoc S Afr 1996 51: 771-6.
## Rate for the total population, of which
Blacks form the majority.
Note:1) Oral
cancer is mainly due to smoking, partly to alcohol. http://www.smokeless.org.nz/mouthcancer.htm
2) For Lesotho,
earliest available tobacco use data is from 1992. Whereas smoking had probably
been lower before this date, nasal snuff use had been a common
traditional practice.
3) For South
Africa, tobacco use data refers to
1998, whereas the recent cancer rates are due to tobacco use over the
previous several decades.
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