*2.4. Health-Related Factors*

Hours of sleep per day were measured on a self-perception scale, indicating the number of hours the student sleep per day. The quality of the parcipants' last sleep was measured using a Likert scale, where 1 means very poor sleep quality and 10 means very good sleep quality. Average number of steps per day in the last week was measured on a self-perception scale, indicating the number of steps the student had taken in the last week. Nutritional habits were analyzed using an adapted previously used questionnaire. The first 2 questions were related to eating habits. The rest of questions to the consumption frequency of different food groups, including fish, vegetables, legumes, meat, fast food, soft drinks, in which answers ranged from "less than two per week" to "seven or more per week." For oral health, a previously used questionnaire consisting of 4 items related to oral health was used. For the first question ("How many times a day do you brush your teeth?"), the answers ranged from "none" to "more than four per day." For the question "Do you smoke?", answers ranged from "no" to "more than five cigarettes per day." The rest of questions were answered by "yes," "sometimes," or "no." Physical activity habits were measured with a questionnaire used in line with previous research. We evaluated the psychophysiological stress response in high psychologically demanding contexts using a questionnaire which included the items: "Did you do any physical activity in the last 7 days?", "If so, time in minutes of cyclic and/or aerobic activity (cycling, treadmill, Zumba) adding up all the sessions of the 7 days", "If so, time in minutes of activity with self-loads (sit-ups, push-ups, squats...) or weights (gym machines, weights...) adding up all the sessions of the 7 days."

#### *2.5. Statistical Analysis*

Statistical analyses were analyzed using the Statistical Package for the Social Sciences (SPSS) version 24.0 (SPSS Inc., Chicago, IL, USA). Descriptive statistics (mean and standard deviation) were calculated for each variable. Kolmogorov–Smirnov tests were performed to analyze normality and homogeneity of each variable. To analyze gender differences in sociodemographic, academic, and psychological variables, an independent T test was conducted. To analyze gender differences in economic, health-related, and oral health variables, the Chi-square test was used. The level of significance was set at *p* ≤ 0.05.
