Tobacco and Public Health - TCSC Indonesia

414
TOBACCO USE AND RISK OF ORAL CANCER
Zheng et al. (1997) reported a case–control study of tongue cancer in Beijing, China.
They found a significantly increased risk of tongue cancer among ex-smokers
(OR = 2.2, 95% CI 1.1–4.6), and among current smokers (OR = 2.7, 95% CI 1.3–5.9).
The risk also increased with increasing tobacco smoking, as reflected by both cigarette
equivalents smoked per day and lifetime pack-years of tobacco smoking. Quitting
smoking was associated with a significant risk reduction for tongue cancer.
In a case–control study in Uruguay, De Stefani et al. (1998) reported an increased risk
of squamous-cell carcinoma of the oral cavity and pharynx for ever-smokers (OR =
7.4, 95% CI 3.7–14.8), current smokers (OR = 10.5, 95% CI 5.2–21.3), and former
smokers (OR = 4.5, 95% CI 2.2–9.2). The risk increases with the increasing intensity of
smoking, smoking duration, and pack-years of smoking. An OR of 13.4 (95% CI
6.5–27.9) was observed for heavy smokers (more than 62 pack-years). Analyses by type
of tobacco products showed that risk was higher for black tobacco smokers (OR = 10.2,
95% CI 5.0–20.5) than for blond tobacco smokers (OR = 4.5, 95% CI 2.2–9.2).
A study from Brazil by Schlecht et al. (1999) investigated the relationship between
different types of tobacco smoking and oral cancer risk. The study found that smokers
of non-filter cigarettes had an OR of 6.9 (95% CI 4.1–11.8), and smokers of filter cigarettes
had an OR of 6.2 (3.9–10.0). Smokers of more than 40 pack-years of commercial
cigarettes had an OR of 8.0 (95% CI 4.6–13.8), and smokers of more than 40 packyears
of black tobacco had an OR of 7.0 (95% CI 4.2–11.5). Current smokers were
found to have an alcohol-adjusted RR of 8.1 (95% CI 4.9–13.4) compared to never
smokers. As observed in other studies, smoking cessation resulted in a significant risk
reduction, decreasing nearly to the levels of never smokers after 20 years of abstention.
Franceschi et al. (1999) also reported a dose-dependent relationship between
cigarette smoking per day and oral cancer risk. The alcohol-adjusted OR was 3.3 (95%
CI 1.5–7.2) for smoking 1–14 cigarettes daily, 7.7 (95% CI 3.8–15.4) for smoking
15–24 cigarettes daily, and 10.7 (95% CI 5.0–22.8) for smoking 25 or more
cigarettes daily. Similarly, a dose–response relationship was observed for daily cigarette
smoking by Moreno-Lopez et al. (2000) in Spain. The study reported that the alcoholadjusted
OR was 3.1 (95% CI 1.4–6.7) for smoking 1–20 cigarettes/day, and 8.3 (95%
CI 3.4–20.4) for smoking more than 20 cigarettes daily.
A study in the south of Greece by Zavras et al. (2001) also reported a significantly
increased risk of oral cancer among current smokers (OR = 3.0, 95% CI 1.4–6.6).
No increased risk, however, was observed for former smokers (OR = 0.9, 95%
CI 0.4–2.1). A strong dose–response relationship was observed for pack-years of
tobacco smoking (P trend = 0.01). For those who had more than 50 pack-years of
tobacco smoking, the alcohol-adjusted OR was 3.3 (95% CI 1.3–8.5) when compared
to never smokers.
In a study from north-eastern Italy, Talamini et al. (2000) reported an OR of
2.4 (95% CI 1.0–5.8) for former smokers compared to never smokers. Among
current smokers, risk increased with increasing number of cigarettes smoked