A cross-sectional observational study was conducted among first year MBBS students in Nil Ratan Sarkar Medical College (NRSMC), a Government Medical College in Kolkata, West Bengal, India, over a period of three months from January 2019-March 2019. After getting the Institutional Ethics Committee clearance, (No/NMC/588) the students were briefed about the purpose and nature of the study; their informed written consent was taken, their confidentiality and anonymity were ensured in all aspects. Out of 250 first year MBBS students only 211 gave consent for participation in the study and hence they were included.

Inclusion criteria: All first year MBBS students who were present during the data collection period and gave written informed consent to participate in the study were included.

Exclusion criteria: Seriously ill students during the study period were excluded.

Study tools were a pre designed pre tested structured self-administered questionnaire, which consisted of information on the sociodemographic profile and lifestyle questions (physical activity and BMI [12]), PQSI scale and the IAT.

The PSQI scale is a self-administered questionnaire used to assess sleep quality in last one month. There are 19 individual items which generates seven subcomponents of sleep quality i.e. sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleep medications and daytime dysfunction. A combined PSQI score is obtained by summing up the subcomponents. PSQI score ranges from 0-21. A score less than or equal to five indicates good sleep quality and scores higher than five indicates poor sleep quality. PSQI score has high internal consistency Cronbach’s alpha of 0.83 and high-test retest reliability of 0.85 (p<0.001) [12,13].

IAT is a 20-item 5-point Likert scale that measures the severity of self-reported compulsive use of the internet. Total internet addiction scores were calculated, scores ranging from 20 to 100. According to Young’s criteria, total IAT scores 20-39 represented “average users” who had complete control over their internet use, scores 40-79 represented “over-users” who had frequent problems due to their internet use, and scores 80-100 represented internet “addicts" who had significant problems because of their internet use [9].

Data was entered in Microsoft Office Excel 2010, was analysed in SPSS Version 23.0 (IBM SPSS Statistics for Windows, Version 23.0. IBM Corp, Armonk, NY). All categorical data were represented in terms of numbers and percentages and continuous data were summarised using the mean and standard deviation. Independent sample t-test was used to study differences in means with respect to categories. A p<0.05 was considered to be statistically significant.

The study questionnaire was administered among 211 undergraduate medical students of first year in the Physiology Department of NRS Medical College, Kolkata, West Bengal, India. Among them 125 (59.2%) were males and 86 (40.8%) were females. A 193 (91.5%) were less than or equal to 20 years age and only 18 (8.5%) were aged more than 20 years. The mean±SD of age was 19.3±0.9 years. As far as Body Mass Index (BMI) was concerned, maximum students (56.4%) had normal BMI (18.5-24.9 kg/m²) [Table/Fig-1].

The study participants were divided into two groups, ones with PSQI ≤5 (n=107, 50.7%) having good sleep quality and others with PSQI >5 having poor sleep quality (n=104, 49.3%). It was seen that students with poor quality of sleep were having high IAT scores compared to ones with good quality of sleep and this finding was statistically significant (p-value <0.001) [Table/Fig-2].

Using IAT the participants were divided into groups: out of which 65.9% were “average users”, 33.2% were “moderate users or possible addicts”, only 2 students were “less than average users” and there were no “addicts” with scoring interval between 80-100 [Table/Fig-3]. The mean scores of PSQI and IAT were tested for probable association with the socio-demographic characteristics of the study participants. The mean IAT score was almost similar for participants aged more than 20 years and for those aged less than and equal to 20 years. Same was the condition among both males and females and these were not significantly associated with internet addiction. On the contrary internet use was significantly higher among participants living on campus (p=0.006) as compared to ones residing off campus. As far as sleep quality was concerned mean PSQI scores were significantly higher among participants who were aged more than 20 years and among those who were involved in “less than 3 times per week physical activity” (p=0.028 and 0.004, respectively) [Table/Fig-4].

In this study, it was seen that 49.3% of the students suffered from poor sleep and remaining 50.7% had normal sleeping pattern. In a study done by Basu M et al., 63.48% undergraduate medical students had poor sleep quality as per PSQI scale [14]. There were several studies done across the country and abroad such as a study done by Priya J et al., which concluded that 67.42% students had poor sleep, study by Ibrahim NK et al., at Saudi Arabia found 70.4% had poor sleep [15,16]. 63.5% by Gassara I et al., at Tunisia, Africa, 62.6% by Shad R et al., at Delhi and 79.3% by Machado-Duque ME at Universidad Tecnológica de Pereira (Columbia) were some other studies which had more or less similar results [17-19]. In a study conducted by Nagori N et al., almost two thirds of the study participants had good sleep qualityand one third had poor sleep quality [20]. Similar was the finding of Chutani A et al., study which revealed that only 23.6% of MBBS students had poor sleep quality [21]. A study among Indian medical students too had reported that two out of ten medical students suffers from poor sleep quality [22]. However, another study reported that 62.6% of the Indian undergraduate students had poor sleep quality. Studies conducted in China and Chile reported that 40-55% of students had poor sleep quality [23-25]. Thus it is seen that there is varied difference in prevalence of good vs. poor sleep quality. In comparison to all studies present study had relatively low percentage of students with sleep abnormalities except Nagori N et al., [20]. A possible reason could be that present study was conducted only among first year medical students who were just introduced to the field of medical science and had just started their career of rigorous studies which in the long run might as well affect their sleep pattern.

According to present study, it was seen that students with poor quality of sleep were having high IAT scores compared to ones with good quality of sleep and this finding was extremely significant. This finding was consistent with other studies like the one done by Nagori N et al., and Cheng SH et al., [20,26]. A study conducted in Turkey also revealed that students with sleep disorder have higher tendency to use internet [27]. Sleep time could be hampered by excessive internet use. Though present study had no ‘addicts’ yet there was a significant association between quality of sleep and IAT scores. Increased screen time in any form was a definite hazard.

This study showed that using IAT, 65.9% of the participants were “average users”, 33.2% were “moderate users or possible addicts”, only 2 students were “less than average users” and there were no “addicts” with scoring interval between 80-100. In a study conducted in Gujarat [20], 9.3% of all participants were considered problematic internet users, which was in contrast to this study. This could be explained by the fact that in their study, the participants were MBBS students, interns and postgraduate students, but in present study participants were only first year medical students. Medical students have to experience high levels of stress which increase as years pass by. A study in Odisha revealed 1.0% of the study population had severe internet addiction whereas 13% were moderate internet addicts [28].

In the present study, internet use was significantly higher among participants living on campus as compared to ones residing off campus. Present study findings were similar to the findings of the study by Awasthi AA and Kaur G, were the mean IAT score was higher in students who lived in a hostel compared with students staying at home with families [22,29]. This finding could be explained by the fact that students who live in hostel or on campus are free from direct parental supervision as compared to the ones who travel from home or are days scholar.

In the present study, PSQI scores were significantly higher among participants who were aged more than 20 years and among those who were involved in “less than 3 times per week physical activity”. In the studies conducted by Awasthi AA et al., and Wolniczak I et al., there was no significant difference in total PSQI scores with regards to demographic characteristics [22,23]. On the contrary, mean PSQI scores were significantly higher in males as compared to females and among participants who were not involved in physical activity. Study done by Giri PA et al., revealed that those who exercise daily had less disturbances in sleep. It can be inferred that regular physical activity improves sleep quality [30].

Limitation of the study was its cross-sectional nature. A longitudinal study could have given a better idea about the temporal associations between the socio-demographic factors if any. This study did not deal with the possible causes of internet addiction among the participants. This study did not deal with parameters of sleep quality (i.e., subjective sleep quality, sleep latency, sleep duration, sleep disturbance, use of sleep medication, and daytime dysfunction) and its associations with internet addiction.

This study showed that almost 50% of the students had poor sleep quality and remaining 50% had good sleep quality and there were no participants who were internet “addicts” though there were some who were moderate addicts. The study also revealed a strong association between sleep quality and internet addiction or use. Medical students are at increased risk to undergo stress and care must be taken to carry out counselling sessions to wave off such stressors. To improve the sleep quality regular exercise and a positive environment is the need of the hour.