Abstract
BACKGROUND: Research indicates major risk factors including smoking, alcohol consumption, obesity and physical inactivity contribute significantly to global disease burden and healthcare costs. However, these studies have challenges, such as increased bias and uncertainty arising from use of population attributable fractions (PAF) and the issue of reverse causality in cross-sectional data. This study aims to evaluate the long-term healthcare costs associated with these behaviors using a longitudinal cohort. METHODS: This longitudinal cohort study used the Korean National Health Insurance Service-National Sample Cohort database (NHIS-NSC 2.0), covering 2002-2019. The cohort included individuals aged 40-69 years who underwent health examinations in 2002-2004 and had no pre-existing risk factor-related diseases. Cumulative healthcare costs during 2010-2019 were analyzed using a generalized linear model with log-link function and gamma distribution, adjusted for other health behaviors and sociodemographic factors. RESULTS: Smoking, alcohol consumption, obesity, and physical inactivity significantly increased healthcare costs for both sexes. Male current smokers incurred 13.8% higher costs than never-smokers, while female smokers spent 18.6% more. Former smokers had lower costs than current smokers, with reductions of 9.9% for males and 13.2% for females. Almost daily alcohol consumption raised costs by 21.4% for males and 31.8% for females. Costs varied by BMI categories, with severe obesity increasing expenditures by 26.9% for males and 46.5% for females compared to normal weight. Overweight status showed contrasting effects between sexes, with a 3.4% decrease in healthcare costs for males but a 7.6% increase for females. Exercising 1-4 times weekly reduced costs by 7.6% for males and 7.4% for females compared to non-exercisers. CONCLUSIONS: The study underscores the economic impact of health risk behaviors and supports the need for targeted public health interventions. The findings highlight the importance of targeted interventions for high-risk groups for reducing healthcare costs.