# Alcohol dependence trajectories and smoking cessation among Korean men who smoke: A secondary data analysis from the Korean longitudinal study of aging dataset

## TL;DR

This study shows that long-term patterns of alcohol dependence in Korean men are linked to lower chances of quitting smoking, especially in younger individuals.

## Contribution

The study identifies distinct alcohol dependence trajectories and their impact on smoking cessation among Korean men using longitudinal data.

## Key findings

- Three alcohol dependence trajectories were identified: stable low, decreasing, and increasing.
- Men with increasing or decreasing alcohol dependence were less likely to quit smoking than those with stable low dependence.
- Current smokers were more likely to belong to the increasing alcohol dependence trajectory.

## Abstract

Alcohol dependence may hinder smoking cessation, yet few studies have examined how long-term patterns of alcohol use influence quit outcomes. This study assessed how alcohol dependence trajectories affect smoking cessation among Korean men who smoke.

We performed a secondary analysis using waves 1–7 (2006–2018) of the Korean Longitudinal Study of Aging (KLoSA). Latent class growth analysis (LCGA) identified alcohol dependence trajectories among 2356 men aged ≥45 years who participated in at least three consecutive waves. Multinomial logistic regression (n=1959) was used to assess predictors of trajectory class membership, and Cox proportional hazards models (n=1122) were used to evaluate the association between class membership and smoking cessation. Statistical significance was set at a two-sided p<0.05.

Three alcohol dependence trajectories were identified: stable low (80.7%), decreasing (14.3%), and increasing (5.0%). Participants in the decreasing (adjusted hazard ratio, AHR=0.77; 95% CI: 0.63–0.95) and increasing (AHR=0.60; 95% CI: 0.42–0.86) groups were less likely to quit smoking than the stable low group. Multinomial regression showed that, compared to non-smokers, both former smokers (AOR=1.83; 95% CI: 1.24–2.70) and current smokers (AOR=2.23; 95% CI: 1.60–3.09) were associated with higher odds of belonging to the decreasing trajectory. Only current smoking was significantly associated with the increasing trajectory (AOR=2.28; 95% CI: 1.36–3.84). In stratified analyses, the inverse association between increasing trajectory and quitting was significant only in those aged 45–54 years. Sensitivity analyses using weighted and complete-case data confirmed the robustness of the findings.

Alcohol dependence trajectories were significantly associated with smoking cessation outcomes, especially among younger individuals. Smoking status was also a significant predictor of trajectory class membership, with current smokers more likely to belong to the increasing trajectory. Integrated interventions addressing both behaviors may improve cessation outcomes in high-risk groups.