The Prevalence of Excessive Daytime Sleepiness Among Clinical Year Medical Students and Its Impact on Academic Performance
Article information
Abstract
Objective
Excessive daytime sleepiness (EDS) is commonly found in medical students and affects academic performance. The primary objective was to study the prevalence of EDS in 4th–6th year medical students of Srinakharinwirot University, Thailand. The secondary objective was to investigate the relationship between EDS and grade point average (GPA).
Methods
The cross-sectional study was taken by 196 medical students of Srinakharinwirot University using a questionnaire collected with Google Forms. The data were collected from June 17 to November 26, 2021, and the information was composed of age, sex, GPA, summarizing the lesson into short notes, Epworth Sleepiness Scale, Pittsburg Sleep Quality Index, sleep duration, caffeine drink, energy drink, and lesson review duration.
Results
Our study found that the prevalence of EDS was 73.98%. In the high EDS group, they had poor sleep quality 80.69%. In addition, the factors consisted of the female sex (odds ratio [OR]: 0.426, p=0.017, 95% confidence interval [CI]: 0. 238–0.761) had statistically significant in good GPA. However, the study did not show a correlation between EDS and GPA (OR: 1.073, p=0.957, 95% CI: 0.491–2.119). Furthermore, sleep quality, sleep duration, amount of caffeine drink, amount of energy drink, and lesson review duration were not associated with GPA.
Conclusion
Most medical students had EDS, but it was not associated with grade point average. Female gender had correlation with the good academic performance (good GPA).
INTRODUCTION
Excessive daytime sleepiness (EDS) is a common condition found in medical students and personnel of the public health system in Thailand and abroad. The mentioned condition affected operational errors in hospitals which will lead to hazards to public health personnel and patients. Moreover, this also has a negative effect on medical students’ academic performance resulting in a mental state of the students which may cause mental health problems such as depression and burnout, and it also has an influence on academic performance and medical operations.
At present, according to worldwide academic reports, the main factors that cause EDS are sleep quality and sleep deprivation [1-6]. The two factors also resulted in depression of patients with such condition that may lead to unpleasant academic performance of the medical students. According to previous studies, the experiments were conducted with a sleep quality measuring device called the Epworth Sleepiness Scale (ESS). From the study results, it was discovered that the participants who had high scores of ESS, which indicated poor sleep quality, more than 78% of the participants with lower standard scores had EDS [7]. In addition, from the experiment results, it was found that 63% of the medical students with high scores of ESS had EDS conditions. The previous studies revealed that the prevalence of EDS among medical personnel and the medical students with high score of ESS may have relation to academic and operational performance in hospitals [3,7-11].
However, the confounding variables such as student’s academic year, sex, short note making, amount of caffeine drink per week, amount of energy drink per week, and lesson review duration (that affected to sleep deprivation) including the number of participants in those research studies were not controlled. For this reason, previous researchers suggested that further additional research should be continued to obtain the most reliable conclusions.
In addition, there were a few experiments conducted to search for the relationship between academic performance and EDS in Thailand so the data which will be used for international comparison is still insufficient. Moreover, it may not be used as a representative of a country to draw conclusions and assess the level of the problem when compared to other countries in the world.
Therefore, the primary objective was to study the prevalence of EDS in 4th–6th year medical students of Srinakharinwirot University, Thailand. The secondary objective aimed to investigate the relationship between EDS and grade point average (GPA).
METHODS
Ethical statement
The present study was approved by the Ethics Committee of Srinakharinwirot University, Thailand (SWUEC-141/2564E) and informed consent was obtained from the participants.
Participants
Inclusion criteria were 4th, 5th, and 6th-year medical students of Srinakharinwirot University and age equal to or above 18 years old. The exclusion criteria were medical students who were diagnosed with depression and refused to answer the questionnaires.
Procedures
This study was a cross-sectional study that the data had been collected by Google Form questionnaire from June 17, 2021 to November 26, 2021. The collected data was composed of 2 parts: 1) personal data (sex, age) and 2) research data (GPA, assessment of EDS, sleep quality, consumption of caffeine and energy drinks, sleep duration, duration of lesson review, and late class attendance). The researchers were interested in studying the relationship between EDS and the academic performance of the medical students, and other confounding variables that may affect research results, such as academic performance, consumption of caffeine and energy drinks, sleep duration, etc., were also studied. Moreover, ESS and the Thai-Pittsburgh Sleep Quality Index (Thai-PSQI) [12] were used as the criteria for EDS assessment. The criteria were divided into 4 groups: 1) the group that had ESS ≥10 (excessive sleepiness condition during the day); 2) the group which had ESS <10; 3) the group which had PSQI ≥5 (excessive sleepiness condition during the day); and 4) the group which had PSQI <5. As for other criteria, the sample group was divided by academic performance that the group with GPA ≥3.25 was considered to have good academic performance, and the other group with GPA <3.25 was considered to have poor academic performance. For consumption of caffeine and energy drinks criteria, the sample group was divided by the number of drinks per day (0, 1–2, 3–4, >4 glasses per day). The sample group with sleep duration criteria can be grouped as <5, 5–7, >7 hours per day.
Statistical analysis
When all data were collected, statistical analyses were performed using SPSS software (version 28.0.1; IBM Corp., Armonk, NY, USA).
Descriptive statistics were applied to nominal or ordinal scales, and data were shown in the form of percentage or frequency. The data which was interval or ratio scale presented as the mean value and dispersion. The dispersion test was implemented with Kolmogorov-Smirnov test. If it was normally distributed, it would be represented by mean±standard deviation (SD). However, if it was not normally distributed, it would be represented by median (interquartile range).
Inferential statistics were applied using bivariate analysis according to the description of variables. Chi-square test was used with nominal or ordinal scale variables. As for interval or ratio scale variables, the dispersion test was implemented with Kolmogorov– Smirnov test. If it was normally distributed, it would be analyzed by an independent t-test. However, if it was not normally distributed, it would be analyzed using the Mann–Whitney U test. The obtained variables then would be tested with a colinearity test, and multivariate analysis was used to analyze with multiple logistic regression. The odds ratio (OR) was used to determine the strength of association. The significance level of pvalue was determined at <0.05.
Sample size estimation
The sample size was calculated by Stata version 17.0 (Stata-Corp., College Station, TX, USA). The sample size estimation for this research was conducted with two independent groups of people.
In independent proportion, the set value of α was 0.05 and β was 0.2 which required 80% power. The value of Zα was 1.96 and Zβ was 0.84. The proportion of the medical students with EDS with poor grades was 70% (0.7) and the proportion of the medical students without EDS with poor grades was 50% (0.5). The amount of people without EDS/amount of people with EDS was 0.4/0.6=0.67. The authors also calculated for a 10% drop-out rate. Thus, the calculated sample size was 196 people in the present study.
RESULTS
The average age of the medical students is 22.622±1.381 years. Most of them are female students (53.06%) studying in 5th year (65.82%). In addition, most medical students have good academic performance (3.299±0.301). They consume caffeine drinks of more than 4 glasses per week; however, they never drink energy drinks. Lesson content summary and lesson review have been done for 2 hours per day. According to the survey of sleep duration and sleep quality, it was found that most medical students had a sleep duration of 5–7 hours, and the sleep quality (PSQI) was at a poor level. From the assessment of daytime sleepiness level, it was discovered that most of them had EDS (73.98%) as illustrated in Table 1. In the high EDS group, they had poor sleep quality 80.69%.
Characteristics of study participants
According to the research results, female gender had a statistically significant correlation with the good academic performance (good GPA) of medical students (OR: 0.426, p=0.017, 95% CI: 0.238–0.761). However, the study did not show a correlation between EDS and GPA (OR: 1.073, p=0.957, 95% CI: 0.491–2.119). Furthermore, sleep quality, sleep duration, amount of caffeine drink, amount of energy drink, and lesson review duration were not correlated with the academic performance of the medical students (Table 2). In addition, the results of the present study also found that the quality of sleep was not related to daytime sleepiness (Table 3).
The factors affecting the study of medical students
The relationship between sleep quality and excessive daytime sleepiness
DISCUSSION
According to the study results of the factors affecting academic performance of 4th–6th year medical student by measuring from cumulative GPA throughout the course of clinical studies, it was discovered that female students were at risk of poor academic performance less than male students with statistical significance. In other words, female medical students would be able to reduce the likelihood of poor academic performance by 53.5% which is inconsistent with the results of previous studies by Abdulghani et al. [11] which indicated that female medical students were more likely to be at risk of getting poor grades than male students. In addition, the results of the current study also found that lesson content summaries can reduce the likelihood of having poor grades by 53.4%. This is because the summary of the lesson content is the process of processing, collecting, compiling, and linking knowledge that had been learned according to one’s own understanding. This process, therefore, provides students a greater understanding of the content than review only. Moreover, the summary of the lesson content also helps to promote creativity and encourage students to think further about how to apply what they have learned or how to solve problems. And most importantly, it also saves time on reviewing content and increases relaxation time for themselves. Although drinking caffeine and energy drinks can help the medical students stay awake from exhaustion during study and work duration and while reading and reviewing lesson content before going to bed or nearly exam period, these factors were not related to the academic performance of medical students which is consistent with the results of previous studies by Khan et al. [13] from the research results, it was also discovered that 94% of the medical students consumed caffeine drinks. However, from 32% of them, it was not found that there was statistical significance to encourage them to have better academic results. In addition, the results of the current study also found that there was no correlation between lesson review duration and poor academic performance of medical students that it was inconsistent with the research by Yogendra and Andrew [14], which suggested that the more time spent studying and reviewing the lessons, the better the academic results. According to the assessment of daytime sleepiness and sleep quality of medical students, it was found that most of them (more than 70%) had EDS and poor sleep quality which was consistent with the results of previous research stud-ies [2,4]. The previous studies suggested that EDS and poor sleep quality affected classroom learning, activeness, and reading concentration as well as inefficient hospital operations [3,7,10,11]; however, it was found from the present study that sleep quality and daytime sleepiness were not correlated with medical students’ learning. This was because studying in the faculty of medicine from the pre-clinical period resulted to the problem of sleep duration and exhaustion of medical students on a regular basis. Therefore, they must adjust themselves to get used to it including searching for the study method that is most appropriate for them to achieve academic success. Furthermore, from the present study, it was also discovered that poor sleep quality increased the risk of daytime sleepiness with no statistical significance that is inconsistent with the findings of previous studies by Lawson et al. [7] which indicated that EDS can be caused by poor sleep quality.
For research limitations, the sample population in this study was only 4th–6th year medical students of Srinakharinwirot University that teaching and learning including grading for good and poor academic performance used different criteria from other research studies. Moreover, the sampling population may have confounding factors that the researchers had not anticipated or could not control such as field of study, accommodation and dormmate, etc. This may be affected to the research results. In addition, some people in the sample group may not understand some questions in the questionnaire; therefore, inaccurate answers may have occurred. However, the researchers had explanations for all doubts while answering the questionnaire in order to receive the most accurate data.
In summary from the results of this research, it can be concluded that most of the medical students had poor sleep quality and EDS. Female medical students can reduce the risk of poor academic performance. However, it was found that sleep quality and daytime sleepiness were not correlated with medical students’ learning and this result was different from the previous studies [3,7,10,11]. Advising medical students to improve sleep quality and reduce EDS is important.
Notes
The authors have no potential conflicts of interest to disclose.
Availability of Data and Material
The datasets generated or analyzed during the study are available from the corresponding author on reasonable request.
Author Contributions
Conceptualization: Pichaya Petborom. Data curation: all authors. Formal analysis: all authors. Funding acquisition: Pichaya Petborom. Investigation: all authors. Methodology: all authors. Supervision: Pichaya Petborom. Validation: all authors. Writing—original draft: Jinawit Wiwatwicha, Kittamej Laokannak, Jarukit Chaichomlert, Natthanan Ranida, Kittaphat Khamfung. Writing—review & editing: Pichaya Petborom.
Funding Statement
This work was fully supported by a research grant from Faculty of Medicine, Srinakharinwirot University.
Acknowledgements
I would like to thank Assistant Professor DR. Kittipong Kongsomboon, Ph.D., the Head of Epidemiology Unit of Medicine Faculty at Srinakarinwirot University and, DR. Kitsarawut Kwanchari, Ph.D, who are the dignitaries that provide consultants on the calculation and analysis of various statistical data in this research. I as well am grateful for all the research staff and international relations staff in the Faculty of Medicine at Srinakarinwirot University that helped coordinating and are also important part to make this research completed.