The survey contained 58 questions. To define smoking status, students were first asked if they had ever smoked. If yes, they were defined as ‘ever smokers’. Ever smokers were further asked if they had smoked ≥100 cigarettes in their lifetime. Next, all were asked if they were currently smoking. If yes, they were defined as ‘current smokers’, regardless of how many cigarettes they had smoked. Current smokers were further asked if they smoked every day (defined as ‘daily smokers’) or only on some days (defined as ‘occasional smokers’). Daily smokers were asked the number of cigarettes smoked per day. Occasional smokers were asked how many days in the last week they had smoked.