Study design and tools
This cross-sectional study was conducted in three administrative divisions (Dhaka, Chittagong, and Sylhet) of Bangladesh during the months of January to April of 2018. Young’s 20-item Internet Addiction Scale was used to determine the presence or absence of addiction. A validated Bengali version of the instrument  and questionnaire was used to collect information from respondents which were pretested among 5% of the sample population prior to data collection. This widely used instrument has been scientifically analyzed to state an ambiguous psychometric factor structure: salience, lack of control, negligence, time management, etc. Because of the strong correlation among these psychometric factors, it has been considered a robust tool for this study.
To assess behavioral factors, questions were included about the use of internet (length of use, frequency of use, device for use, presence of computer in residence, type of software or application use, type of internet service use, purpose of internet use) and community variables (internet use of friends or colleagues, influence of surrounding people on internet use, influence of surrounding people on internet use). The sociodemographic factors included age, sex, occupation, arrangement of accommodation, area of residence, monthly family income, and personality type. Students were asked to answer questions about family variables (supervision of parents during internet use, problems in family relation, internet use of family members). Cut-off points were marked to categorize the presence of internet addiction. If a respondent got 20–49 points at the scale of 100 points, he was considered an average on-line user. On the other hand, a respondent who scored ≥ 50 points was considered as internet addicted [15, 16].
To estimate the sample size, a single population proportion formula was used. Several previous studies conducted in various locations found the prevalence of internet addiction was around 18% [17, 18]. Considering those reference, the required sample size was n = 227 when the allowable error was 5%. Using a design effect 2, the final sample size was 454.
Sampling and data collection
A multistage clustered sampling was used. From the 3 administrative divisions, 28 districts were targeted, from which three districts (1 from each division) were randomly selected. From each district, two subdistricts were chosen randomly, and finally, households were conveniently selected for data collection. A total of 454 participants were selected (247 males and 207 females). The participants were young adults, internet users, aged between 19 and 35 years. They were categorized according to age, 318 individuals in group A (age 19–24 years) and 136 individuals in group B (age 25–35 years). A Bengali version of questionnaire was filled up by the participants, the first part of which consisted of socio-demographic information and the second part included Young’s 20-item internet addiction test. Participants who did not want to participate were excluded from this study.
Data were checked for completeness and consistency. IBM SPSS version 23 statistical package software was used for data management and analysis. Various descriptive statistics like frequencies and proportions were calculated. Degrees of association between the outcome variable and independent variables were determined by the chi-square test. Variables that showed significant association in chi-square analysis were subjected to multiple logistic regression analyses to explore the strength of association. Results with p values of < 0.05 were considered to be statistically significant.
Ethics approval and consent to participate
Ethical approval for this research protocol was obtained from the Ethics Review Committee of North South University prior to data collection (no. 0013/2018). The aims of the investigation and the nature of the study were fully explained to the participants, who gave informed written consent before participation.