A large health data analysis by the Korea Medical Institute (KMI) examined the effects of traditional cigarettes, e-cigarettes, and dual use and their impact on higher rates of metabolic syndrome and declining lung function. The study, part of KMI’s “Health Big Data Series,” analyzed medical check-up data from about 3 million individuals screened at eight centers across South Korea and compared health outcomes by smoking type and cumulative exposure measured in pack-years, a metric defined by the National Cancer Institute.
Among men, metabolic syndrome prevalence increased from 21.5% in non-smokers to 29.9% in current smokers, reaching 31.2% among conventional cigarette users and 30.8% among dual users. Among women, overall prevalence was 10.7% among non-smokers and 12.6% among current smokers. By smoking type, the rate reached 15.8% among conventional cigarette users and 12.1% among dual users.
Risks also rose with cumulative exposure, climbing to 36% among men with more than 20 pack-years of smoking and 22% for women. Lung function impairment was recorded in 23.4% of men and 21.5% of women, rising sharply among heavy smokers. The study also found smoking patterns shifting, with the share of male lifetime non-smokers rising from 36.7% in 2022 to 39.7% in 2025, while e-cigarette-only use increased from 7.8% to 10%. Researchers noted the findings are based on anonymized screening data and may not fully represent the national population.
