Tobacco and Public Health - TCSC Indonesia

DAVID ZARIDZE 435
such as sex, age, SES, education, income, diet, namely consumption of fruits and
vegetables, alcohol consumption.
Thirty-one case–control studies reported a statistically significant increase in the risk
of stomach cancer among smokers (Hoey et al. 1981; Correa et al. 1985; Risch et al.
1985; Hu et al. 1988; You et al. 1988; De Stefani et al. 1990; Kato et al. 1990; Lee et al.
1990; Wu-Williams et al. 1990; Dockerti et al. 1991; Saha 1991; Yu and Hsieh
1991; Hoshiyama and Sasaba 1992; Kabat et al. 1993; Hansson et al. 1994; Inoue et al.
1994; Siemiaticky et al. 1995; Yu et al. 1995; Gajalakshmi and Shanta 1996; Ji et al.
1996; Zang et al. 1996; Gammon et al. 1997; De Stefani et al. 1998; Liu et al. 1998;
Chow et al. 1999; Innoue et al. 1999; Ye et al. 1999; Lagergren et al. 2000; Mathew et al.
2000; Zaridze et al. 2000; Wu et al. 2001).
In 10 case–control studies smoking was found not to have any influence on the risk
of stomach cancer (Hanszel et al. 1972, 1976; Armijo et al. 1981; Jedrychowski et al.
1986, 1993; Buatti et al. 1989; Ferraroni et al. 1989; Boeing et al. 1991; Agudo et al.
1992; Gao et al. 1994).
Twenty-one studies have shown statistically significant dose–response trend between
number of cigarettes smoked per day and/or duration of smoking and/or age start
smoking and/or pack-years smoked and the risk of gastric cancer (Hu et al. 1988; You
et al. 1988; De Stefani et al. 1990; Kato et al. 1990; Lee et al. 1990; Wu-Williams et al.
1990; Yu and Hsieh 1991; Kabat et al. 1993; Hansson et al. 1994; Yu et al. 1995;
Gajalakshmi and Shanta 1996; Ji et al. 1996; Zhang et al. 1996; Gammon et al. 1997;
De Stefani et al. 1998; Liu et al. 1998; Ye et al. 1999; Lagergren et al. 2000; Mathew et al.
2000; Zaridze et al. 2000; Wu et al. 2001). For example, a population-based case–
control study from China which included 1124 stomach cancer cases and 1452
community controls (Ji et al. 1996) showed statistically significant dose–response relationship
between numbers of cigarettes smoked per day and risk of stomach cancer
(P for trend = 0.0002), with highest risk observed in men who smoked 20–29 cigarettes
per day (RR = 1.77, 95% CI 1.35–2.33); statistically significant trend in the risk was
observed for duration of smoking (P for trend = 0.002), with highest risk seen in men
who smoked for more than 40 years (RR = 1.64, 95% CI 1.21–2.24) and for cumulative
lifelong exposure to smoking expressed as pack-years smoked (P for trend = 0.0002),
with highest risk estimates in the highest exposure group (RR = 1.68, 95% CI 1.22–2.30).
Statistically significant dose–response relationships between duration of smoking
(P for trend < 0.001), pack-years smoked (P for trend < 0.001), age at start smoking
(P for trend < 0.01), and relative risks of stomach cancer were observed in hospitalbased
case–control study from Uruguay which included 330 male cases and 622
controls drawn from the same hospitals as cases (De Stefani et al. 1998). In the population-based
study in USA (Gammon et al. 1997) statistically significant dose–response
was observed for number of cigarettes smoked per day (P for trend < 0.05), duration of
smoking in years (P for trend < 0.05), and cumulative exposure to tobacco smoke, or
pack-years (P for trend