Cigarette smoking and mortality in the Korean Multi-center Cancer Cohort (KMCC) study

Abstract

Objectives: The aim of this study was to evaluate the association between cigarette smoking and total mortality, cancer mortality and other disease mortalities in Korean adults. Methods: A total of 14161 subjects of the Korean Multi-center Cancer Cohort who were over 40 years of age and who were cancer-free at baseline enrollment reported their lifestyle factors, including the smoking status. The median follow-up time was 6.6 years. During the follow-up period from 1993 to 2005, we identified 1159 cases of mortality, including 260 cancer mortality cases with a total of 91987 person-years, by the national death certificate. Cox proportional hazard regression model was used to estimate the hazard ratio (HR) of cigarette smoking for total mortality, cancer mortality and disease-specific mortality, as adjusted for age, gender, the geographic area and year of enrollment, the alcohol consumption status, the education level and the body mass index (BMI). Results: Cigarette smoking was significantly associated with an increased risk of total mortality, all-cancer mortality and lung cancer mortality (p-trend, <0.01, <0.01, <0.01, respectively). Compared to non-smoking, current smokers were at a higher risk for mortality [HR (95% CI) = 1.3 (1.1 -1.5) for total mortality; HR (95% CI) = 1.6 (1.1-2.2) for all-cancer mortality; HR (95% CI)=3.9 (1.9 - 7.7) for lung cancer mortality]. Conclusions: This study's results suggest that cigarette smoking might be associated with total mortality, all-cancer mortality and especially lung cancer mortality among Korean adults.