Lung cancer and the smoking habit - case control study

THE PURPOSE of the investigation was to determine the existence of the probable causal associations between cigarette smoking and the development and distribution of lung cancer.

The research was conducted as a case-control study. It included 101 patients with lung cancer (investigated group-IG) and the same number of persons without this malignant disease (control group-CG). The members of both groups were interviewed within the period May 2006-May 2007. Risk analyses were done using unconditional logistic regression, which provides results in the form of a crude odds ratio. The odds ratios and their 95% confidence intervals (CI) were computed.

The habit of cigarette smoking was particularly wide-spread among men with lung cancer (68.8%), while in the CG this percentage was 40.3%. In IG, among the females, current smokers and nonsmokers are represented equally. Smokers and ex-smokers have a 4.05 (95%CI 1.78 < OR < 9.19) times significantly higher risk of becoming ill compared to the non-smokers. The risk of becoming ill increases significantly in smokers who smoke > 20 cigarettes per day (c/d) (p < 0.01) and is 9.33 (95%CI 3.56 < OR < 24.48) compared to nonsmokers. The risk of developing lung cancer is 4.55 (95%CI 1.86 < OR < 11.12) times greater in persons smoking > 15 years (y) > 20 c/d, compared to those who smoke < 15 y < 20 c/d.

Our study supports the statement that cigarette smoking is by far the most important risk factor for lung cancer. Concerted control of smoking appears to be an urgent priority in lung cancer prevention, including efforts to prevent adolescents from starting to smoke.