Tobacco and Public Health - TCSC Indonesia

DAVID ZARIDZE 439
respectively. The risk of dysplasia also rose with increasing pack-years of smoking.
(Kneller et al. 1993). You et al. (2000) assessed the effect of smoking on progression of
gastric precursor lesions to dysplasia and cancer. Smoking duration for more than
25 years was associated with significant increase in the risk of progression to gastric
cancer and dysplasia (OR = 1.6, 95% CI 1.0–2.1; P for trend = 0.04). The risk was
also increased in those who smoked more than 20 cigarettes/day (OR = 1.4 95%
CI 0.9–2.3).
Few studies have reported on cigar, pipe, or smokeless tobacco use in relation to
stomach cancer. In most recent analyses of CPS II cohort, current smokers of exclusively
cigars had significantly higher stomach cancer mortality than non-users of any
tobacco (OR = 2.29, CI 1.49–3.41) (Chao et al. 2002). In a cohort study of American
men of German and Scandinavian origin regular pipe users were at very high risk
(RR = 4.4, CI 1.84–10.72). Relative risk remained marginally significant after stratification
for pack-years of cigarette smoking (RR = 2.3, CI 0.98–5.22). In case–control studies
reported by Correa et al. (1985), Wu-Williams et al. (1990), and Lagergren et al.
(2000) significant association between cigar and/or pipe smoking and risk of stomach
cancer was observed. In case–control study conducted in India smoking of bidi
(RR = 3.3, CI 1.8–5.67) and chutta (RR = 2.4, CI 1.18–4.93) was associated with statistically
significant increase in the risk of gastric cancer, with dose–response relationship
between intensity and duration of smoking and relative risk (Gajalakshmi and Shanta
1996). Chewing tobacco increased risk of stomach cancer in cohort study reported
from America by Kneller et al. (1991). However after adjusting for cigarette smoking
increase in the risk lost statistical significance. All Swedish studies reported no association
between snus (snuff) dipping and stomach cancer incidence (Hansson et al. 1994;
Ye et al. 1999; Lagergren et al. 2000).
Worldwide, it has been estimated that the smoking-attributable proportion of stomach
cancer is 11% among men and 4% among women in developing countries, and
17% among men and 11% among women in developed countries (Tredaniel et al.
1997). According to Liu et al. (1998) 18% death from stomach cancer in men and 1.8%
in women in China are caused by smoking. The proportion of incident cases of stomach
cancer attributable to smoking has been estimated to be 20% in Poland (Chow
et al. 1999) and 31% in India (Gajalakshmi and Shanta (1996). In US 28% of stomach
cancer death in men and 14% in women are attributable to tobacco smoking (Chao et al.
2002). According to estimates of Siemieticky et al. (1995) smoking causes 35% of incidence
cases of stomach cancer in US. Adding stomach cancer to the list of cancers
caused by smoking would increase the total number of smoking-attributable death by
at least 84 000 per year worldwide (Tredaniel et al. 1997) not accounting for recent
increases in smoking prevalence or the expected rise in stomach cancer incidence due
to ageing in the developing world.
In summary the existing scientific evidence suggest a causal association between
smoking and stomach cancer.