The Effects of Caffeinated Beverage Consumption on the Sleep Habits and Lifestyle of Medical Students in Public and Private Medical Universities in Karachi, Pakistan

Objectives: To determine the effects of caffeine consumption on the sleep habits and lifestyle of medical students. Methods: A cross-sectional study was conducted at Jinnah Sindh Medical University (JSMU) and Hamdard College of Medicine. On 422 undergraduate students aged 18-25 years, through random sampling. The duration of the study was from January 2019 to June 2019. The data was collected through self-administered questionnaire which included data regarding sleep habits and lifestyle of medical students. Results: Majority (81.6%) of the students consumed caffeine while only (18.4%) did not. One third of the participants (31.8%) reported caffeine consumption increased their academic performance and (57.3%) reported that it does not. More than half of the participants (63.3%) who consumed caffeine slept during class, whereas (47.2%) never had difficulty in falling asleep during the night. Conclusion: This research concluded that caffeine does have some role on sleep habits of medical students as they tend to have less sleep hours, experience day time dysfunction, average quality of sleep, and falling asleep during class. It has been concluded that caffeine has no effect on eating habits of medical students however, it does increase the screening time, keeping them active.

The ergogenic properties of caffeine also supplement the performance of athletes in physical games. The adverse effects of caffeine are headache, palpitations, anxiety and insomnia. More serious adverse effects include vomiting and abdominal pain, hypokalemia, hallucinations, seizures, arrhythmias and even death (10) . Caffeine dependence may develop among individuals who consume caffeine because of a need to counteract sleep inertia (1) . Along with sleep disruptive effects of caffeine it also enhances the performance of a medical student in academics (11) . The aim of the study is to determine the effects of caffeine consumption on the lifestyle and sleep habits of medical students of public and private medical universities in Karachi.

MATERIAL & METHODS
A cross-sectional survey was conducted in 2019, at one public (Jinnah Sindh Medical University) and one private medical university (Hamdard University) after the approval of IRB. The sample size was calculated through OpenEpi proportion sample size calculator, based on a study according to which, prevalence of energy drinks among medical students in DMC was 39% and in Aga Khan University was 51.9%. Keeping the anticipated frequency of 50% for life style and sleep habits and using 95% confidence interval with bound of error of 5%, sample size came out to be 384. However, considering wasting of 10% for statistical convenience we recruited 422 subjects. The data was collected through random sampling. Students aged 18-25 years, from first to final year MBBS studying in private and public medical universities were included. Students who were having any systemic diseases, taking any medication and females who were pregnant were excluded from the survey. The confidentiality and anonymity of the participants was strictly ensured. Informed consent was signed by all participants. Age, gender, year of education, physical activity, sleep habits were assessed using a standardized questionnaire. Lifestyle variables included are daily routine, total daily screen time, hobbies and physical activity level. Data will be analyzed using SPSS version 23. Mean and standard deviation were calculated for quantitative variables and frequency for categorical variables.

RESULTS:
Majority of the participants (79.4%) were females and (20.6%) were males. Nearly half were between 20-21 years old (44.3%) while (30.6%) were between 22-23 years of age. About (55.9%) belonged to public medical university and (44.1%) belonged to private medical university. Majority lived with their families (86.7%) while only a few resided in hostels (13.3%). (Table: 1) Majority (88.6%) of the students consumed caffeine in any form while only (11.4%) of the students didn't consume caffeine at all. Almost half (43.4%) responded that they sleep between 11-1am followed by (39.8%) by 1-3am during college nights. During weekend (42.7%) sleep between 1-3am, however a significant low (4.3%) were seen to sleep at between 9-11pm. The duration of sleep of nearly half of the participants (46.9%) was less than 6 hours i.e. only (1.4%) were sleeping more than 8 hours. (28.9%) marked that they experienced daytime dysfunction once a week and (28.7%) said twice a week. About half of the population (55.2%) rated their sleep quality average, (16.6%) stated that they find it difficult to fall asleep during weekdays while another (16.6%) throughout the week.
On asking respondents how many times they wake up once they have fallen asleep, (33.9%) marked 1-3 times. Almost half (49.1%) found it hard to stay awake during university hours. About ⅓ i.e. (63.3%) population have fallen asleep during class while (47.2%) never had difficulty in falling asleep during night. (Table. 2)   More than half (52.4%) found no change in their appetite while (21.3%) said caffeine decreases their appetite. Total screen time of more than half (55.2%) of the population is more than 4 hours. Many (63.7%) believed that caffeine keeps them active. About three fourth i.e. (73.5%) participants do not exercise regularly, while (14%) exercise less than 30mins per day. Major (67.5%) number of students didn't participate in any outdoor games while another group said they participated once a week (19.1%). Majority of the participants (95.7%) have never smoked. One third (30.3%) also wanted to cut down on their caffeine consumption. One third of the participants (31.8%) reported caffeine consumption does increase their academic performance and (57.3%) reported that it does not. Half of the participants (52.4%) who consumed caffeine reported that it had no effect on eating habits. (Table. 3).
Majority of the participants consumed tea 61.8%, followed by soft drinks 44.8%, coffee 31.5%, hot chocolate 17.8% and energy drink 8.1% while 7.8% reported of not using any of the beverages at all (Figure 1) Major reason reported for the usage of the drinks was its flavor and as a habit 45%, while another 40% said they regained energy by consumption. More than 1/3 of the participants used it during exams 39.1% and to reduce fatigue 38.2%. Less common reasons included assumption of increased academic performance 31.8%, social gatherings 28.2%, stress 18.7%, and insufficient sleep 17.8%, replace body fluids 3.6%, after workout 1.7% and before training 0.9% (Figure 2) Nearly half of the study participants responded to have moderate levels of stress 45.5% were as severe forms of stress was reported by 11.6% of the participants (Figure 3)