Estimated prevalence and trends in smoking among adolescents in South Korea, 2005-2021: a nationwide serial study.

"Declarations Conflict of interestNo financial or non-financial benefits have been received or will be received from any party related directly or indirectly to the subject of the article. Ethical approvalThe KYRBS data were anonymous and the study protocol was approved by the Korean Centers for Disease Control and Prevention Agency (KCDA) and Institutional Review Board of Sejong University (SJU-HR-E-2020-003). Informed written consent was obtained from all participants at enrollment. Conflict of interest No financial or non-financial benefits have been received or will be received from any party related directly or indirectly to the subject of the article."

"Funding This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HV22C0233) and the National Research Foundation of Korea (NRF) grant funded by the Korea government (NRF2021R1I1A2059735). The funders had no role in study design, data collection, data analysis, data interpretation, or writing of the report."