Joint trajectories of health behaviors and their associations with healthcare utilization and expenditure

Objectives This study identified sex-specific trajectories of key health behaviors among middle-aged and older adults and examined their longitudinal associations with healthcare utilization and expenditure. Methods We analyzed 167,343 Korean adults aged 40–79 years from 2002 to 2019 using the National Health Insurance Service Health Screening Cohort. Group-based multi-trajectory modeling identified joint trajectories of smoking, alcohol consumption, physical activity, and BMI. Associations with healthcare outcomes were assessed using generalized estimating equations stratified by sex and age group. Results Six distinct health behavior trajectories were identified in both sexes. Among men, the higher moderate-risk trajectory showed fewer outpatient visits but longer hospital stays. Among women, the higher severe-risk trajectory was associated with increased expenditures and higher healthcare utilization. Age-stratified analyses revealed stronger associations for severe-risk trajectories in men aged <65 years and lower severe-risk trajectories in those aged ≥65 years. Conclusion Sex- and age-specific behavioral trajectories were differentially associated with healthcare utilization and expenditure, underscoring the importance of multidimensional behavioral patterns in developing preventive strategies to reduce healthcare burdens.