This section elicited data regarding socio-demographic characteristics, academia-related factors, and lifestyle factors. Data concerning socio-demographic characteristics included age, gender, family's monthly income, marital status, father's education, parents' marital status, birth order, body mass index (BMI), and smoking. The academia-related factors included year of study and self-reported Grade Point Average (GPA). The years of study were grouped into two academic levels (Junior: second and third year; Senior: fourth to sixth year). Lifestyle factors included smoking status, physical exercise, tea consumption, coffee consumption, and energy drink consumption. Smoking status was defined as follows: current smoker is any person who smoked regularly in the past month at the time of responding; ex-smoker, who quit smoking at least 1 month prior to the study; and nonsmoker as someone who has never smoked.