Data were analyzed from the International Health and Behavior Study, an anonymous questionnaire study of health behaviors, attitudes, and risk awareness in university students, which was performed in 24 countries between 1999 and 2001. It was based on the European Health Behavior Survey, a study of 16 483 students from 21 European countries conducted between 1989 and 1991, which was designed to elucidate the wide variation across countries in the prevalence of health behaviors and their associations with beliefs and risk awareness.14 The International Health and Behavior Study was carried out with a network of collaborators in participating countries, and the questionnaire used for data collection was developed in English and then translated and back-translated into 19 languages (Bulgarian, Chinese, Dutch, Flemish, French, German, Greek, Hungarian, Icelandic, Italian, Japanese, Korean, Mandarin, Polish, Portuguese, Romanian, Slovakian, Spanish, and Thai). One university took part in each of 21 countries, and 2 universities took part in the remaining 3 countries. The selection of universities was not random but was designed to compare public universities of similar academic standing in different countries. The same European universities were involved as in the European Health Behavior Survey to analyze trends over time.15 Participants were students aged 17 to 30 years who were not studying medicine or health-related topics. A variety of students were involved, including those studying physical sciences, engineering, social science, languages, geography, history, and economics. Data collection was carried out in classes, and participation rates in most countries were higher than 90%. Students were told that the survey concerned activities related to health and that an international comparison was being performed, but no further details were given. A total of 17465 respondents were included, and the distribution across countries is detailed in Table 1.