Health Outcomes among Heated Tobacco Product Users, Combustible Cigarette Users, and Quitters: a Cohort Study

This study aimed to investigate the health effects of heated tobacco product (HTP) and combustible cigarette (CC) use, as well as cessation, by tracking health outcomes using a prospective cohort design. A total of 750 males were included, comprising 250 HTP users, 250 age-matched (± 2 years) CC users, and 250 quitters. The HTP user group was selected from individuals who underwent a health examination between 2021 and 2022. The CC user group was randomly selected from the same age range and examination period. Participants were provided with information on the health hazards of smoking and were advised on smoking cessation for both CCs and HTPs. A follow-up test was conducted 2 years (18 ± 8 months) later. Peak expiratory flow and peak expiratory flow percentage were significantly lower in CC users than in HTP users or quitters. Erythrocyte sedimentation rate and total cholesterol were significantly lower in quitters than in the HTP and CC user groups. Alpha-fetoprotein levels were significantly lower in quitters than in HTP and CC users, whereas carbohydrate antigen 19-9 levels were significantly higher in quitters than in the other two groups. Differences in respiratory function, inflammatory markers, and cancer markers were observed among HTP users, CC users, and quitters. Therefore, ongoing longitudinal follow-up is required.