Tobacco use among older Korean men: a classification and regression tree analysis.

Background: Tobacco use among older adults remains a pressing public health concern in South Korea, particularly among men. Despite the decline in tobacco use rates with age, a range of sociodemographic, psychological, and behavioral factors persist to influence tobacco use behaviors. However, prior studies have primarily relied on linear modeling approaches, which may overlook indirect associations. This study addressed this gap using classification and regression tree (CART) analysis to identify hierarchical and interactive patterns among factors associated with tobacco use. Methods: We analyzed data from the 2023 Korea Community Health Survey, which included 34,924 Korean men aged ≥65 years. Using CART analysis, we identified distinct subgroups and patterns across multiple predictors of tobacco use behavior, including demographic factors, lifestyle characteristics, and chronic health conditions. Results: CART analysis identified age as the strongest predictor of tobacco use. Men aged ≤72.5 years had higher tobacco use rates, especially those with low social engagement (24.8%). Younger men with higher social activity and aged ≤67.5 years had the lowest rate (12.9%). Among men ≥72.5 years, alcohol use was the key predictor. Non-drinkers had the lowest tobacco use rate (9.3%), whereas drinkers aged ≤78.5 years showed elevated rates (22.0%), suggesting persistent risk even in later life. Conclusion: These findings underscore the importance of promoting social engagement and reducing alcohol use to decrease tobacco use among older men, particularly those under 73 years of age.