Cumulative Burden of Lifestyle Risk Factors on Cancer in Older Korean Men: A Nationwide Retrospective Cohort Study

Background/Objectives: Cancer prevalence is increasing globally due to aging populations. Certain lifestyles are associated with cancer; however, the long-term combined effects of lifestyle factors on cancer has not been investigated. This study aimed to investigate the cumulative effect of lifestyle risk factors over 8 years on cancer in older Korean men. Methods: We assessed 64,756 men aged >= 65 years at the baseline year (2008-2009) using data from the National Health Insurance Service-Senior Cohort. Lifestyle factors, including smoking status, alcohol consumption, and physical activity, were evaluated over four consecutive phases (2002-2003, 2004-2005, 2006-2007, and 2008-2009) of health check-ups, and each participant's overall lifestyle risk score was calculated after considering the value of a single poor lifestyle factor in each phase as 1, with a cumulative score ranging between 0 and 12. According to the lifestyle risk scores, the hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazard regression analysis. Results: Of the 64,756 men, 13,130 cases of cancer developed. The risk of cancer increased as the number of poor lifestyle factors and lifestyle risk score increased from the baseline year during the four phases. Compared to a score of 0-2, the HRs for cancer were 1.10 (0.98-1.23), 1.54 (1.37-1.73), and 1.72 (1.48-1.99) for scores of 3-5, 6-8, and 9-12, respectively. Conclusions: The risk of cancer increased as the cumulative burden of poor lifestyle habits over 8 years increased. Therefore, practicing and maintaining healthy lifestyles is crucial to preventing cancer in older Korean men.