Socio-demographic information
Participants were asked to report their age, sex, academic level, father’s education level, father’s occupation, mother’s education level, mother’s occupation, monthly family income, family size, living with whom and religious status. The study divided participants into three age groups: 13–14, 15–16, and 17–18. Monthly household income was divided into four categories: <30,000 Bangladeshi Taka (BDT), 50,000-100,000 BDT, and 100,000 BDT or above. Family size was divided into three categories: 1–4, 5–8, and > 8.
Health-related behaviors
The present study investigated dietary behaviors (breakfast, vegetables, and fruits intakes), physical activity, screen-based sedentary behavior (screen time), sleep risk behavior, and substance use (i.e., smoking, marijuana, alcohol). Health-related behaviors (excluding substance use) were recorded for 7 days to reduce memory recall bias.
Dietary behaviors
Dietary behaviors were assessed in three domains: breakfast intake, vegetables intake, and fruits intake. Breakfast intake was assessed by asking the question, “During the past 7 days, did you take your breakfast daily?” with responses: 1= yes and 2= no. Skipping breakfast was defined missing breakfast at least one day before seven days of the survey. Vegetable intake was assessed by the question, “During the past 7 days, how many times per day did you usually eat vegetables?” and fruits intake by the question, “During the past 7 days, how many times per day did you usually eat fruits?”. Inadequate vegetables intake was defined as having <3 times/day and inadequate fruits intake was defined as having <2 times/day (El-ammari et al., 2019; Ziaei et al., 2019).
Physical activity and Screen-based sedentary behavior
The present study measured leisure time physical activity by asking, “During the past 7 days, on how many days were you physically active (moderate to vigorous-intensity physical activity) for a total of at least 60 minutes per day?” and allowed response options: 1 = 0 days to 8 = 7 days. Insufficient physical activity was defined as “less than the WHO recommended of 60 minutes of moderate to vigorous physical activity per day.” (WHO, 2018d). Screen-based sedentary behavior was defined as spending 2 or more hours of screen-related activities each day while not in school/college or doing homework (Al-haifi et al., 2016).
Sleep risk behavior
The participants were asked to report their sleep and waking times for the last seven days, divided into weekdays and weekends. Sleep duration was estimated by subtracting sleep onset from wakeup (Min et al., 2018). Combining weekday and weekend sleep durations with weights of 6/7 and 1/7 yielded the mean daily sleep duration. Sleep risk was defined as less than 7 hours per day or more than 11 hours per day on average (Mewton et al., 2019).
Substance use
Participants were asked “During the past 7 days, how many cigarettes did you smoke per day?” Currently smoking was defined smoking ≥1 cigarettes per day. Participants were asked if they had ever used marijuana or alcohol. Both questions had the response options: 1 = yes, 2 = no.
Academic performance and truancy
Academic performance was evaluated by the last exam results and classified as follows: good (GPA 4.50-5), medium (GPA 3.50-4.50), and bad (GPA 3.5). Truancy was measured by ‘In the previous 30 days, how many days did you miss school/college without permission (from parents or teachers)?’ and defied as having 3 or more days of unexcused absences from school/college.
Co-occurring health risk behaviors
In the present study, co-occurring health risk behaviors were defined as five or more risk behaviors.
Data analysis
Data were analyzed using the Statistical Package for the Social Sciences (SPSS) software for windows, version 22.0 (IBM SPSS Statistics, New York, United States). Data analysis involved descriptive statistics as well as inferential statistics. Descriptive analysis like frequency, percentage, mean and standard deviation was carried out. The information was presented using frequency tables and figures. Chi-square test (χ2) was used to compare the differences between groups. The logistic regression analysis was performed to determine the factors predicting co-occurring health risk behaviors and reported as an odds ratio (OR) with 95% confidence interval (CI), and the directions of relationship among all examined health risk behaviors were investigated applying Pearson correlation analyses. The association of variables was considered statistically significant if the p-value was less than or equal to 0.05.