ABSTRACT
Objectives: Tobacco smoking is the strongest risk factor for lung cancer. As the strength of association of smoking and lung cancer in Sri Lanka has not been estimated, a study was conducted to estimate the risk of lung cancer among adult male smokers in the Colombo District. Methods: A case control study was carried out among 62 newly diagnosed male lung cancer patients from the Colombo District presenting to National Cancer Institute, Maharagama. Four controls per case were randomly selected from the same Grama Niladhari area matching the age of the cases within 10 years. Absence of lung cancer was clinically confirmed in the controls. Information on smoking, other potential risk factors and confounders were obtained using an interviewer-administered questionnaire. Univariate analysis and logistic regression identified the risk factors. Results: After adjustment for confounding variables, ever smokers odds of having lung cancer compared to never smokers OR 10.74 (95% CI 3.54-32.59) . Lower educ ation level (OR=5.61, 95% CI 2.37-13.28), ever exposed to X-rays (OR=2.81, 95% CI 1.14-6.94) and a family history of any cancer (OR=2.83, 95% CI 1.09-7.30) were other significant risk factors. The population attributable risk percent (PAR%) showed that 84.04% of the male lung cancer cases are attributed to smoking. Conclusions: Smoking and exposure to X-rays were risk factor for lung cancer among adult males in the Colombo District.