Enrollment procedure
The process for participation in this study was as follows. First, the study content, conditions for participation, and request for participation were sent via e-mail; second, willingness to participate was confirmed by e-mail replies; third, those who confirmed their participation were randomly assigned by the computer to either the intervention or the control group in a prospective manner and stratified by country, sex, and age. Ineligible individuals were excluded from participation at the beginning of this study.The respondents registered online before participating in this study. The participants accessed the questionnaire site by accepting an e-mail invitation. The online system objectively determined the eligibility of those who accessed the website based on their background information provided at registration. Only those who met the inclusion criteria of this study could complete our questionnaire; the criteria were explained, and the questionnaire was made available after the participants provided their consent.The online system was set up to equally and randomly allocate participants (1:1) to either the intervention group or the control group stratified by sex (male vs. female) and age (18–29, 30–39, 40–49, 50–59, over 60). After a participant answered all questions, the system ensured that the participant could not repeat the program. The online system was closed when the required sample size was reached. We asked the participants to respond to the questions based on their current knowledge and not to search for answers elsewhere. The individuals received a gift certificate for one British pound sterling, one US dollar or one Australian dollar from the 