Factors associated to the sleep quality of medical students

1.Doutoranda, Programa de Pós Graduação em Enfermagem e Biociências (PPGENFBIO). Docente no Departamento de Ciências Fisiológicas (DCF), Universidade Federal do Estado do Rio de Janeiro (UNIRIO). Rio de Janeiro-RJ, Brasil. ORCID: https://orcid.org/0000-0002-4202-7514 2.Doutora, Departamento de Ciências Fisiológicas (DCF), Universidade Federal do Estado do Rio de Janeiro (UNIRIO). Rio de Janeiro-RJ, Brasil. ORCID: https://orcid.org/0000-0002-6371-3409 3.Doutoranda, Programa de Pós Graduação em Enfermagem e Biociências (PPGENFBIO). Universidade Federal do Estados do Rio de Janeiro (UNIRIO). Rio de Janeiro-RJ, Brasil. ORCID: https://orcid.org/00000002-2125-1437 4.Graduando da Escola de Medicina e Cirurgia (EMC), Universidade Federal do Estado do Rio de Janeiro (UNIRIO). Rio de Janeiro-RJ, Brasil. ORCID: https://orcid.org/0000-0002-6979-3075 5.Doutor, Laboratório de Fisiologia e Fisiopatologia Translacional, Faculdade de Medicina de Teresópolis, Centro Universitário Serra dos Órgãos (UNIFESO). Departamento de Fisiologia e Fisiopatologia, Faculdade de Medicina de Petrópolis (UNIFASE). Petrópolis-RJ, Brasil. ORCID: https://orcid.org/0000-0001-90988005 6.Doutor,Universidade Federal Fluminense (UFF). Rio das Ostras-RJ, Brasil. ORCID: https://orcid.org/0000-0001-8371-628X 7.Doutor, Departamento de Ciências Fisiológicas (DCF), Universidade Federal do Estado do Rio de Janeiro (UNIRIO), Rio de Janeiro-RJ, Brasil. ORCID: https://orcid.org/0000-0002-9462-4564 8.Doutor, Escola de Enfermagem Alfredo Pinto (EEAP). Universidade Federal do Estado do Rio de Janeiro (UNIRIO). Rio de Janeiro-RJ, Brasil. ORCID: https://orcid.org/0000-0002-9725-4626 9.Doutora, Departamento de Matemática Universidade Federal do Estado do Rio de Janeiro (UNIRIO). Rio de Janeiro-RJ, Brasil. ORCID: https://orcid.org/0000-0003-0977-5921 10.Doutor, Departamento de Enfermagem Fundamental, Escola de Enfermagem Alfredo Pinto (EEAP), Universidade Federal do Estado do Rio de Janeiro (UNIRIO). Rio de Janeiro-RJ, Brasil. ORCID: https://orcid.org/0000-0002-4327-6272


INTRODUCTION
Sleep is a fundamental biological function for the wellbeing and good functioning of the human organism 1 .
Changes in sleep stages can trigger significant disturbances in body metabolism, unpredictable lapses in attention, and decreased performance in daily activities 2,3 .
Sociodemographic and pathophysiological factors, such as age, sex, smoking, excessive alcohol consumption, use of drugs, irregular lifestyle, as well as a reduction in the number of sleep hours, can cause stress and sleep deprivation, in addition to excessive daytime sleepiness, significantly compromising the quality of life of individuals 3 .
Studies have shown that the behavior adopted by Brazilian university students, such as irregular sleep time, prolonged naps during daytime, use of alcohol before bed, studying or accessing the internet in bed, everyday habits in this population, classified them as bad sleepers, making them prone to disruption of the circadian cycle and deterioration of sleep quality [3][4][5] .
Among medical students, it has been found that they often consider sleep quality being secondary in the context of fulfilling their academic activities, which do not allow them to sleep properly 6,7 . One study identified insufficient sleep and sleep disorders as complaints common among these undergraduates, which can result in negative impacts on their cognitive, physical, and mental performance 8 . The analysis of the sleep of medical students from Saudi Arabia showed a close relationship between insufficient sleep of these individuals and high scores for depression, anxiety, and stress 9 . Thus, both studies emphasized the close relationship between quality sleep and the well-being of these students.
Medical students have a rigorous demand for studies, a full-time curricular load, extracurricular activities that, added to the lack of time for family and social activities and the stress of good academic performance, make them vulnerable to sleep disorders 10,11 .
Hence, medical students' sleep has been subjectively assessed through standardized research instruments developed to analyze the quality of sleep (the Pittsburgh Sleep Quality Index -PSQI) and daytime sleepiness (the Epworth Sleepiness Scale -ESS) 12,13 .
For these reasons, it is important that more studies address adequate sleep-wake patterns aiming at the wellbeing, comfort, healthy academic performance, and quality of life of these future health professionals.
The objective was to identify the factors associated with the sleep quality of medical students from the subjective indices of PSQI and ESS.

Sample
Here is an observational and analytical study with a quantitative approach. The target population of this research consisted of 813 medical students between the first and the tenth semesters in 2019. As inclusion criteria, all students regularly enrolled, from the first to the tenth semesters in the medical course of a public university in Rio de Janeiro, aged 18 years or over, who signed the free and informed consent form. Students from the last two semesters were excluded due to anticipation of graduation. Thus, 131 participants were eligible for the study.

RESULTS
The sample consisted of 131 students (16.11% of the target population) who agreed to participate in the study.
The data presented in Table 1  reported having a chronic disease.    (Table 4).
In the assessment of sleep quality through the PSQI, 73.28% of the participants had a poor-quality classification.
Regarding the use of alcoholic beverages, 80% of students who reported consuming alcohol and 64.3% of those who did not consume it slept with poor quality. Regarding the use of medication that could interfere with sleep, 78.6% of the students who reported using some medication and 48.9% of those who did not use these drugs presented poor sleep quality. In both cases, the differences were significant. Table 5 shows that 82.4% of students who took less than 30 minutes and 67.5% of those who spent more time getting home had poor sleep quality. In the analysis of the body mass index, 81% of students classified as obese and 67.5% of students with a normal index exhibited poor sleep quality. There were no significant differences.

DISCUSSION
For some years, excessive daytime sleepiness and poor sleep quality have been increasingly reported in the university population due to its high prevalence 15 . In this study, most participants (60.31%) had scores considered pathological for daytime sleepiness, with a predominance of females (69.6%), corroborating the study of EDS in university students, with prevalence ranging between 24% and 39%. In the sample, 36.3% had EDS, the majority being women 15 . Although the results can be alarming, it is noteworthy that they are inferior to other studies.
Another study points out that these students represent a population prone to sleep-related issues because they have inadequate sleep habits, as a rule, caused by excessive activities 16 . In Taiwan In this research, 61.9% of students classified as obese and 75% of those who had increased waist circumference measurements exhibited EDS, confirmed by results found in Nutrition students in Chile in a study whose author established an association between fewer hours of sleep and risk of obesity. The author warns of short sleep duration, increased intake of carbohydrates and fats, and little protein 20 .
Sleep duration was associated with increased body fat, waist circumference, and BMI in graduate nursing students, and the author warns of overweight and obesity 21 .
It is noteworthy that many students live alone, and the natural tendency is to consume food of quicker preparation or easy access, which is not always healthy. In addition, many reported not practicing physical exercise or doing it without regularity. The association between obesity and EDS may be indicative of inadequate quantity and quality of sleep 22 .
Concerning chronic non-communicable diseases, 30.53% of those assessed had some condition, among which 67.5% have EDS. Although an ordination was not carried out, the prevalence was higher than the findings of an author who distributed them among patients with diabetes (2%), hypertension (1%), cholesterolemia (1%), and heart disease (1%), justifying the results due to the low age of most participants, in which a high prevalence of these diseases is unexpected 23 . The other demographic and behavioral factors assessed in this study did not have significant associations with EDS.
The sleep quality of 73.28% of the students appraised over the PSQI had high scores, indicating poor quality. In this investigation, most students (80%) who reported drinking alcohol showed reduced sleep quality. This association was statistically significant. These findings are substantiated by a study in which 20.1% of the participants who consumed alcohol had poor sleep quality 24 . The association was not established in another study since changes in sleep quality caused by alcohol usually occur long-term, even if the individual has already stopped consumption for prolonged periods 23 .
The excessive consumption of alcohol and the poor quality of sleep of university students has been the scope of studies for many ingest alcoholic beverages as a strategy to relieve stress and anxiety 13,25 . Although alcohol is seen as a sleep-inducing substance, its excessive intake is related to insufficient or reduced sleep quality 23,24,26 , which can result in drowsiness during academic activities in addition to emotional and motor impacts 24 .
Regarding the use of any medication that interferes with sleep, the majority (78.6%) of consumer students had poor sleep quality. In some studies, the prevalence of consumption of sleep-inducing drugs among medical students was considered high (11%) 27 . These are results above those found in other populations (6.9% and 7.1%).
The authors attributed the excessive use of sedative drugs to the need for the student to replace the sleeping period with study or other activities 27,28 .
The time spent by students in their return home from college, as well as the need to fulfill their tasks, could delay their retreat to bed, thus leading to sleep deprivation. There was no statistically significant difference between students who spent more or less time getting home, but the majority (82.4%) of those who took more than thirty minutes to arrive exhibited worse sleep quality.
The anthropometric analysis of this research revealed that the studied population was healthy, an expected occurrence since most participants were aged between 18-25 years, however, more than half of students with normal metabolic parameters were classified by the PSQI as having poor sleep quality.
In a study carried out with medical students with a mean age of 22 years, there was no relationship between metabolic data and sleep variables in this population. The author attributes this to the effects of poor sleep quality on the metabolic profile occurring in the long term 24 .
Although the media, in its most diverse modalities, draws society's attention to the importance of good sleep quality for human health, it is essential to highlight that some medical students will not be able to meet the recommendations for a healthy life, considering the number of commitments and responsibilities that they assume throughout their lives 25 .
Medical students become exposed to intense and varied levels of stress during their academic course since their entry into an environment different from that experienced in high school, often associated with family separation due to approval in universities far from their home, and, in the final stage, the prospect of entering the professional field 26,29 .
These situations can generate irritability, anxiety, and, consequently, EDS and poor sleep quality 22,23 .
This research addressed important aspects of sleep quality and excessive daytime sleepiness and their connection with factors that can interfere with sleep, with likely harmful effects on the health of medical students during the academic period.

CONCLUSIONS
The present study concludes that the high prevalence of excessive daytime sleepiness found in most medical students is predominant in females and in those with noncommunicable chronic diseases. In addition, the poor sleep quality observed among the students can be associated with demographic and behavioral factors, such as drinking alcohol and medications that interfere with sleep.
The present study has several strengths, including the sample being composed of medical students who will be future health professionals. Another strength is its longitudinal design, which allows determining the action of time on the studied variables. As a limitation of the present study, there is a lack of discrimination against non-