Fig. 1

Flow chart of the study participants. Among 41,837 participants were recruited, 41,121 participants were linked to the Korea Central Cancer Registry. We excluded 1,754 participants for having an incomplete questionnaire, 2,100 participants due to a previous diagnosis of any cancer, 18,110 female participants, 5,780 participants who lacked information on individual characteristics, and 6 participants aged < 20. In total, we had 13,371 participants for final analysis