The Role of Environmental Factors on Sleep Patterns and School Performance in Adolescents

Investigation of the influence of 45-minute pre-sleep social media use on sleep quality and memory consolidation in adolescents

Adolescents devote a significant portion of their time to smartphone usage, often engaging in social media activities. Social media use has previously been linked to diminished sleep quality and reduced sleep durations in correlational studies. In this experimental study, we aimed to investigate the influence of pre-sleep social media use on memory consolidation, subjective arousal and objectively assessed sleep quality in adolescents. We compared the social media condition to two reading conditions, one involving reading a book on a smartphone and the other reading from a physical book in a within-subjects design. Twenty participants between 12 and 14 years engaged in these activities for 45 min before bedtime. Contrary to our expectations, the results indicated that pre-sleep social media use did not have a discernible impact on sleep quality, pre-sleep arousal or memory consolidation. All assessed sleep measures remained consistent across the three conditions. Subjectively, the social media condition was rated less thrilling than the reading conditions. This suggests that, within the confines of this experiment, pre-sleep social media exposure did not significantly disrupt adolescents' sleep or their ability to consolidate memories during sleep. This deviation from previous correlational studies might be explained by a possible impact of mental health factors on media consumption and sleep or the fact that contrary to their daily routines participants had to sleep after our intervention and could not continue to engage in their activities. This highlights the need for further investigations into the complexities of this interaction.

A scientometric review of the association between childhood trauma and sleep

Sleep is a complex state which involves interactions between neurophysiological, psychological and neurochemical processes which in turn have an important impact on brain functioning, immune responses, mental health, and quality of life. The incidence of Adverse Childhood Experiences (ACEs) varies across different countries and have been linked with lifespan sleep disturbances with further effects on people's physical and mental health functioning. This review aims to explore the significance of ACE and its impact on sleep by identifying key documents, thematic trends, and knowledge gaps in the literature. A document co-citation analysis of 882 documents from Scopus was conducted to achieve this goal. Research trends focused on the long-term consequences of childhood adverse events with respect to sleep, with emphasis on the role of type, timing and accumulation of these experiences. A recent study has also taken advantage of machine learning and network analysis for discovering essential factors could offer useful information about adults with history of childhood adversity and sleep problems. The studies show unanimously that ACEs are associated with multiple sleep disturbances/disorders which can persist into adulthood, with consequences for suboptimal cognitive and behavioral functioning. Such neurobiological scars can be associated with an increased risk of mental disorders. Future studies are needed that focus on longitudinal analysis of the relationship between early adversity, sleep, and resilience characteristics in adult populations exploring the use of objective assessment measures as well as neurobiological markers.

Predictors of insomnia among undergraduate students at Hawassa University Sidama, Ethiopia, 2023: a facility-based cross-sectional study

Background

Insomnia is a sleep disorder characterized by difficulty falling asleep, staying asleep, or experiencing poor-quality sleep. People with this problem often have trouble falling asleep at night, wake up frequently during the night, and may wake up too early in the morning and feel tired and not refreshed. This can lead to daytime fatigue, irritability, difficulty concentrating, and impaired functioning in their day-to-day activities. Study is scarce in resource-limited countries such as Ethiopia, particularly concerning the study setting. As a result, this study aimed to assess the prevalence of insomnia and its associated factors among undergraduate students at Hawassa University.

Methods

An institution-based cross-sectional study design was used. A stratified simple random sampling method was used among 398 study participants. The data were collected using a structured self-administered questionnaire. The outcome variable was assessed by the insomnia severity index (ISI). The data were then gathered by using the Kobo toolbox online and then exported into the Statistical Package for Social Sciences version 27 to analyze the data. Data cleaning and screening were conducted exclusively by the investigators. Descriptive statistics like frequency, percentages, and mean were used. Bivariate and multivariate binary regression were performed. In multivariate binary logistic regression, a p-value of<0.05 was identified as a significantly associated factor with the dependent variable.

Results

Among 398 students who participated in the study, 81 (20.4%) experienced insomnia. Being female [adjusted odds ratio (AOR) = 2.98; 95% confidence interval (CI) 1.56-5.69], age (AOR = 3.06; 95% CI 1.11-8.45), mild anxiety symptom (AOR = 4.89; 95% CI 1.56-15.37), and mobile device use ≥30 min just before going to sleep (AOR = 7.81; 95% CI 2.34-26.12) were significantly associated with insomnia.

Conclusion

In this study, the prevalence of insomnia was one-fifth among university students, which is high when compared to another study at the national level. There were significant associations between being female, age, anxiety symptoms, and mobile device use before going to sleep with insomnia. This indicates that there is a need to treat and prevent insomnia in college students, emphasizing the necessity for mental healthcare and ethical technology use.

Actigraphic sleep dimensions and associations with academic functioning among adolescents

STUDY OBJECTIVES

There is mixed evidence regarding associations of sleep duration with academic functioning in adolescents and a lack of research on other sleep dimensions, particularly using objective sleep measures. We examined associations of multiple actigraphic sleep dimensions with academic functioning among adolescents.

METHODS

Data were from the sleep sub-study of the age 15 wave of the Future of Families and Child Wellbeing Study (n = 774-782; 52% female), a national, diverse sample of teens. Adolescents wore wrist-actigraphs for ~1 week and completed a survey reporting academic performance and school-related behavioral problems. Regression models assessed whether average sleep duration, timing, maintenance efficiency, and SD-variability were associated with self-reported academic functioning in cross-sectional analyses adjusted for demographic characteristics, depressive symptoms, and anxious symptoms.

RESULTS

Later sleep timing (hours) and greater sleep variability (SD-hours) were associated with poorer academic outcomes, including sleep onset variability with higher odds of receiving a D or lower (OR = 1.29), sleep onset (β = -.07), sleep offset (β = -.08), and sleep duration variability (β = -.08) with fewer A grades, sleep offset with lower GPA (β = -.07), sleep offset (OR = 1.11), sleep duration variability (OR = 1.31), and sleep onset variability (OR = 1.42) with higher odds of being suspended or expelled in the past 2 years, and sleep duration variability with greater trouble at school (β = .13). Sleep duration, sleep maintenance efficiency, and sleep regularity index were not associated with academic functioning.

CONCLUSIONS

Later sleep timing and greater sleep variability are risk factors for certain academic problems among adolescents. Promoting sufficient, regular sleep timing across the week may improve adolescent academic functioning.

Circadian preference and physical and cognitive performance in adolescence: A scoping review

Adolescence is a crucial period of development which coincides with changes in circadian rhythmicity. This may augment the impact of circadian preference on performance in this group. We aimed to scope the literature available on chronotypes and their effect on physical and mental aspects of performance in adolescents. Studies were identified by systematically searching bibliographical databases and grey literature. The Morningness-Eveningness Questionnaire was the most frequently reported tool for circadian preference assessment. Academic achievement was the most prevailing outcome, with evidence suggesting that morning type adolescents tend to outperform evening types, yet the results vary depending on multiple factors. Performance in tests of intelligence and executive functions was generally better at optimal times of the day (synchrony effect). Physical performance was examined in 8 studies, with very heterogeneous outcomes. Although the associations between circadian preference and performance in adolescents are evident in some areas, there are many factors that may be involved in the relationship and require further investigation. This review highlights the assessment of physical performance in relation to chronotypes, the multidimensional assessment of circadian preference, and the need for longitudinal studies as priorities for further research.Protocol: OSF Registration - Public registration, DOI: 10.17605/OSF.IO/UCA3Z.

Adolescent sleep health in Africa: a scoping review protocol

INTRODUCTION

Problematic sleep is a major threat to health and quality of life among adolescents. Hence, to provide directions for research and interventions, there is a need to examine the literature on adolescent sleep health in Africa. However, available studies on adolescent sleep health in Africa have not been properly mapped. Thus, this scoping review aims to investigate the extent and type of available evidence concerning sleep health among adolescents in Africa and to highlight the relationship of adolescent sleep health with adverse mental health outcomes and cardiometabolic risk factors. The review will further highlight areas of agreement and controversies on adolescent sleep health, and identify evidence gaps that require research attention across the continent.

METHODS AND ANALYSIS

This scoping review will be conducted using Arksey and O'Malley's six-step procedure. Thus, we have prepared this protocol according to the framework for scoping reviews developed by the Joanna Briggs Institute. To identify eligible studies, we will search MEDLINE, Scopus, PsycINFO, AJOL, JSTOR, HINARI and Google Scholar. The review will include all published articles in English, French, Spanish, Portuguese and Italian languages on adolescent sleep health in Africa from the inception of the databases, while relevant information will be extracted from included studies using an adapted data extraction tool. The results will be presented using tables and charts as appropriate.

ETHICS AND DISSEMINATION

The scoping review does not require ethical approval because the publications to be used for the review are publicly available and the study does not involve contact with humans or other animals as research participants. Furthermore, clinical records will not be used for the study. Upon completion, findings from the study will be disseminated through presentations at scientific meetings and publication in a relevant peer-reviewed journal.

SCOPING REVIEW REGISTRATION

Open Science Framework (https://osf.io/5sjwq/).

The effect of solution-focussed education and counselling on problematic internet usage, sleep quality and school achievement: A randomized controlled trial

AIM

The aim of this study was to determine the effects of solution-focussed education and counselling on problematic internet usage, sleep quality and school achievement.

METHODS

This randomized controlled trial was conducted between January - December 2016 with 44 adolescents who participated in a solution-focussed intervention to address their problematic internet usage and poor sleep quality. After the intervention, the teens were followed up for 6 months to measure problematic Internet usage, sleep quality and school achievement using the Internet Addiction Test, Pittsburg Sleep Quality Index, Parent-Child Internet Addiction Scale and the students' end-of-term school grades. Data were analysed in Statistical Package for the Social Sciences programme using Chi-square test, Independent t test, Man-Whitney U test, Friedman test and Spearman correlation analysis.

RESULTS

The median Internet Addiction Test and Pittsburg Sleep Quality Index scores of the adolescents in the intervention group were significantly lower than those of the controls (P < 0.05), and there was a positive and moderate association between problematic Internet usage and sleep quality in both groups after the follow-up (r = 0.537, P = 0.010; r = 0.576 P = 0.005).

CONCLUSION

The education and counselling intervention decreased problematic Internet usage and increased sleep quality. There was also an improvement in school achievement, but the difference was not significant.

The Impact of Sleep and Mental Health on Working Memory and Academic Performance: A Longitudinal Study

Sleep and mental health can affect cognition and academic performance. The present study aimed to investigate the relationships between sleep, mental health, working memory, and academic performance. We collected demographic data from university students during the non-academic summer period and the academic term. We also measured academic performance (GPA), sleep (PSQI), depression (PHQ-9), anxiety (GAD-7), and disordered social media use (SMDS). Working memory was assessed by the Cambridge Neuropsychological Test Automated Battery (CANTAB). We assessed 83 students (42.2% male) with a mean age of 21 years. Compared to the non-academic summer period, students had significantly worse sleep and distress scores in the academic term. Anxiety, depression, and distress scores were significantly correlated with worse sleep quality. Despite worse mental health and sleep in the academic term, working memory improved compared to the non-academic summer period and was also correlated with a higher GPA. However, a higher GPA was significantly associated with longer sleep latency, increased sleep disturbances, and increased use of sleep medication. Students experiencing poor sleep suffered from poor mental health, although they maintained high GPA and working memory scores. Cognitive resilience, including higher working memory, may mask poor sleep quality and mental health among university students.

"Leave your smartphone out of bed": quantitative analysis of smartphone use effect on sleep quality

Smartphones have become an integral part of people's everyday lives. Smartphones are used across all household locations, including in the bed at night. Smartphone screens and other displays emit blue light, and exposure to blue light can affect one's sleep quality. Thus, smartphone use prior to bedtime could disrupt the quality of one's sleep, but research lacks quantitative studies on how smartphone use can influence sleep. This study combines smartphone application use data from 75 participants with sleep data collected by a wearable ring. On average, the participants used their smartphones in bed for 322.8 s (5 min and 22.8 s), with an IQR of 43.7-456. Participants spent an average of 42% of their time in bed using their smartphones (IQR of 5.87-55.5%). Our findings indicate that smartphone use in bed has significant adverse effects on sleep latency, awake time, average heart rate, and HR variability. We also find that smartphone use does not decrease sleep quality when used outside of bed. Our results indicate that intense smartphone use alone does not negatively affect well-being. Since all smartphone users do not use their phones in the same way, extending the investigation to different smartphone use types might yield more information than general smartphone use. In conclusion, this paper presents the first investigation of the association between smartphone application use logs and detailed sleep metrics. Our work also validates previous research results and highlights emerging future work.

Association between sleep habits and behavioral problems in early adolescence: a descriptive study

Background

Sleep habits are related to children's behavior, emotions, and cognitive functioning. A strong relationship exists between sleep habits and behavioral problems. However, precisely which sleep habits are associated with behavioral problems remains unclear. Therefore, the purpose of this study is to clarify the relationship between sleep habits and behavioral problems in early adolescence.

Methods

This study used data from a larger longitudinal research, specifically, data from the year 2021. First-year junior high school students (12–14 years) in Japan were surveyed; their parents (N = 1288) completed a parent-report questionnaire. The main survey items were subject attributes, the Pittsburgh Sleep Quality Index (PSQI), and the Strength and Difficulties Questionnaire (SDQ).

Results

Of the 652 valid responses received, 604 individuals who met the eligibility criteria (no developmental disability in the child and completion of all survey items) were included in the analysis. To examine the relationship between sleep habits and behavioral problems, logistic regression analysis using the inverse weighted method with propensity score was conducted with sleep habits (sleep quality, time to fall asleep, sleep duration, sleep efficiency, sleep difficulty, use of sleeping pills, difficulty waking during the day, and sleep disturbances) as explanatory variables and behavioral problems (overall difficulty in SDQ) as objective variables. The propensity score was calculated by employing the logistic regression using the inverse weighted method based on propensity scores. Propensity scores were calculated based on gender, family structure, household income, and parental educational background. The results showed that behavioral problems tended to be significantly higher in the group at risk for sleep quality, sleep difficulties, daytime arousal difficulties, and sleep disturbances than in the group with no risk.

Conclusion

The results suggest that deterioration in sleep quality, sleep difficulties, daytime arousal difficulties, and sleep disturbances may increase the risk of behavioral problems in adolescents.

Psychosocial factors related to sleep in adolescents and their willingness to participate in the development of a healthy sleep intervention: a focus group study

BACKGROUND

Over the last decades, adolescents' sleep has deteriorated, suggesting the need for effective healthy sleep interventions. To develop such interventions, it is important to first gather insight into the possible factors related to sleep. Moreover, previous research has indicated that chances of intervention effectivity could be increased by actively involving adolescents when developing such interventions. This study examined psychosocial factors related to sleep in adolescents and investigated adolescents' willingness to participate in the development of a healthy sleep intervention.

METHODS

Nine focus group interviews were conducted with seventy-two adolescents (63.9% girls, 14.8 (± 1.0) years) using a standardized interview guide. Interviews were audio-recorded and thematic content analysis was performed using Nvivo 11.

RESULTS

Adolescents showed limited knowledge concerning sleep guidelines, sleep hygiene and the long-term consequences of sleep deficiency, but they demonstrated adequate knowledge of the short-term consequences. Positive attitudes towards sleep were outweighed by positive attitudes towards other behaviors such as screen time. In addition, adolescents reported leisure activities, the use of smartphones and television, high amounts of schoolwork, early school start time and excessive worrying as barriers for healthy sleep. Perceived behavioral control towards changing sleep was reported to be low and norms about sufficient sleep among peers were perceived as negative. Although some adolescents indicated that parental rules provoke feelings of frustration, others indicated these have a positive influence on their sleep. Finally, adolescents emphasized that it would be important to allow students to participate in the development process of healthy sleep interventions at school, although adult supervision would be necessary.

CONCLUSION

Future interventions promoting healthy sleep in adolescents could focus on enhancing knowledge of sleep guidelines, sleep hygiene and the consequences of sleep deficiency, and on enhancing perceived behavioral control towards changing sleep. Interventions could also focus on prioritizing positive sleep attitudes over positive attitudes towards screen time, finding solutions for barriers towards healthy sleep and creating a positive perceived norm regarding healthy sleep. Involving adolescents in intervention development could lead to intervention components that match their specific needs and are more attractive for them.

Characteristics of Sleep Patterns in Adolescents: Comparisons between Saudi Arabia and the UK

There are concerns regarding sleep deprivation among adolescents, especially with mounting evidence for the importance of sleep during puberty, and its effects on health and families. The present study aimed to characterise sleep in typical development (TD) adolescents in Saudi Arabia, and compare their sleep profiles to TD adolescents in the UK, to evaluate sleep patterns in adolescents in Saudi Arabia, and to examine the relationship between sleep patterns and the use of social media in both groups. Findings from the current study reported a shorter sleep duration for the Saudi Arabia group than in previous studies and the UK group, which may be attributed to the lack of sleep hygiene practised in Saudi Arabia. Multiple analysis of variance results found significant differences in daytime sleepiness (p < 0.001) and a preference for morningness/eveningness (p < 0.001) between Saudia Arabia and UK adolescents. Statistically significant negative correlations (p > 0.05) between the duration of social media usage and sleep duration were found in both the Saudi Arabia and UK adolescents, where a lower number of sleep hours was observed with a higher duration of social media use. This study fills a gap in the research of sleep in Saudi Arabia in adolescents, and offers important insights on the comparison in sleep habits between Saudi Arabia and UK adolescents.

An Exploratory Analysis of the Effect of Demographic Features on Sleeping Patterns and Academic Stress in Adolescents in China

Adolescents typically engage in unhealthy lifestyle habits including short sleep and high academic stress. These in turn may have serious impacts on their development. The present study examines the effect of demographic characteristics on sleep patterns and academic stress in adolescents. A sample of 244 (119 females) junior high school adolescents aged between 11 and 16 were recruited from China. The Student Life Stress Questionnaire and the School Sleep Habits Survey were used to assess participants' sleep habits and academic stress. Multipair and corrected pairwise Kruskal-Wallis tests were conducted to assess the effect of school grade, gender, academic performance level, living situation, single child status, and parental education on adolescents' sleeping patterns and academic stress. Significant changes in facets of sleeping patterns emerged when examining groups of students in terms of school grade, living situation, and single-child status. Furthermore, caffeine consumption was found to be significantly higher in males, in students with poorer academic performances, and in single-child adolescents. Ultimately, academic stress was modulated by adolescents' school grade, academic performances, living situation, and single-child status. Developmental trajectories in sleep patterns together with differential exposure to stressors and adopted coping mechanisms are discussed in the manuscript.

Do Children of Patients with Bipolar Disorder have a Worse Perception of Sleep Quality?

INTRODUCTION

The offspring of bipolar parents (BO) is a high-risk population for inheriting the bipolar disorder (BD) and other early clinical manifestations, such as sleep disturbances.

OBJECTIVE

To compare the presence of psychiatric disorders and sleep disturbances of BO versus offspring of control parents (OCP).

METHODS

A cross-sectional analytical study was conducted that compared BO versus OCP. The participants were assessed using valid tools to determine the presence of psychiatric symptoms or disorders. The "Sleep Evaluation Questionnaire" and "School Sleep Habits Survey" were used to determine sleep characteristics and associated factors. Sleep records (7-21 days) were also obtained by using an actigraphy watch.

RESULTS

A sample of 42 participants (18 BO and 24 OCP) was recruited. Differences were found in the presentation of the psychiatric disorder. The BO group showed a higher frequency of major depression disorder (MDD; P = .04) and Disruptive Mood Dysregulation Disorder (DMDD; P = .04). The OCP group showed a higher frequency of Attention Deficit and Hyperactivity Disorder (ADHD; P = .65), and Separation Anxiety Disorder (SAD; P = .46). Differences were also found in sleep by using subjective measurements. Compared to the OCP group, BO had a worse perception of quality of sleep (P = .02), a higher frequency of nightmares (P = .01), a shorter total sleep time, and a higher sleep latency. Nevertheless, no differences were found between groups in the actigraphy measurements.

CONCLUSIONS

The BO group had a higher frequency of Mood Disorders, and at the same time a higher number of sleep disturbances in the subjective measurements. It is possible that there is an association between mood symptoms, sleep disturbances, and coffee intake. No differences were found in the sleep profile by using actigraphy.

Too Jittery to Sleep? Temporal Associations of Actigraphic Sleep and Caffeine in Adolescents

Caffeine consumption has been linked to poor sleep health in adolescents, but it is unknown whether poor sleep predicts caffeine consumption, and/or whether caffeine consumption predicts poor sleep, particularly when sleep is measured objectively. Data were collected from a micro-longitudinal sub-study of the age 15 wave of the Fragile Families and Child Wellbeing Study (n = 589). Adolescents wore an actigraphy device and completed daily surveys for ~1 week. Daily surveys assessed subjective sleep quality and caffeinated beverage consumption (0 = no caffeine, 1 = any caffeine). Separate mixed models assessed whether actigraphy-measured sleep duration, timing, maintenance efficiency, and subjective quality predicted next-day caffeinated beverage consumption within and between adolescents. Variability (standard deviation) of sleep duration and timing, sleep regularity index, and social jetlag were tested as additional between-person predictors. Lagged models tested whether daily caffeinated beverage consumption predicted sleep that night (n = 458). Adolescents with more variable sleep duration and midpoint had higher average odds of consuming caffeinated beverages compared to others. After adolescents consumed ≥1 caffeinated beverage, they had later sleep onset that night and wake time the next morning than usual versus when they did not consume caffeine. Curbing caffeinated beverage consumption may aid in the maintenance of regular sleep schedules and advance sleep timing in adolescents.

Use of Technology and Its Association With Academic Performance and Life Satisfaction Among Children and Adolescents

Introduction: In the last years, there has been a rise in the use of technology among children and adolescents, which has led to a greater concern about its impact on their socioemotional and cognitive development. Aims: To explore the time spent using technology, the risk perception of its use by students, and the association between frequency of technology use and life satisfaction and academic performance among children and adolescents in Chile. Additionally, we explored the mediating effect of sleep deprivation on these outcomes. Methods: This is a cross-sectional study, where 2,440 students (9-12 years old) from 13 schools participated. Data was collected using an online survey answered by students during school hours. The association analyses were performed using multivariable regression models considering life satisfaction and academic performance as dependent variables. Additionally, mediating analyses were conducted using structural equation modeling. Results: Time watching television and using cellphones were similar on weekdays, and playing video games was the most frequent activity during weekends. A 42.1% of students reported playing online video games with strangers, and 12.7% had sleep deprivation. Lower self-reported academic performance was associated with cyberbullying victimization, sleep deprivation, being hacked, exposure to violent content, time spent using cell phones during weekdays and weekends, and playing video games during weekdays. Students who perceived that playing video games after 9 pm affected their sleep had a higher academic performance. There was a clear mediating effect of sleep deprivation in the relationship between time spent using a cellphone during weekdays and weekends and playing video games during weekdays and GPA. Conclusions: Time spent using technological devices was not associated with life satisfaction; however, the time spent using cell phones and playing video games was related to lower self-reported academic performance, mediated by sleep deprivation. Future research may focus on a better understanding of the mechanisms involved in the effect of technology use on sleep routines among adolescents and potential interventions to reduce its impact on academic performance.

Adolescent Energy Drink Consumption and Academic Risk: Results From the Monitoring the Future Study, 2010-2016

AIMS

The current study aims to examine the role of energy drink and energy shot consumption in school disengagement, low academic performance, and academic expectations, and investigates the robustness of these associations across sex, grade, race, and substance use history.

METHOD

This study employs a pooled cross-sectional design and uses a nationally representative sample of 8th (ages 13-14 years) and 10th (ages 15-16 years) grade adolescents from seven recent cohorts (2010-2016) of the Monitoring the Future study. Logistic regression and negative binomial regression were employed to examine the association between energy drink and energy shot consumption and academic risk factors, controlling for sociodemographic factors and other health and social behaviors. Ancillary robustness checks across key subgroups in the data were also performed.

RESULTS

The results indicate that energy drink and energy shot consumers are significantly more likely to report all academic risk outcomes. Specifically, youth who heavily use energy drinks and shots have significantly higher odds of each of the academic risk outcomes relative to both less habitual users and nonusers. These patterns hold across subgroups, despite associations being somewhat stronger among females, younger participants, Whites, and youth with no substance use history.

CONCLUSIONS

The current study suggests that energy drink consumption (particularly heavy consumption) may be an early warning sign of academic risk. It may be beneficial to limit adolescent energy drink consumption, provide early intervention for heavy adolescent consumers, and raise awareness of the dangers associated with their use.

Circadian preference and intelligence - an updated meta-analysis

A large number of previous studies reported a link between circadian preference and psychometric intelligence with mixed results and various hypotheses about the source of this correlation. In this study, we aimed to update a previous meta-analysis about the correlation between circadian preference and intelligence. Our literature search identified a large number of new studies, resulting in an increase of over 100% in the number of studies and over 400% in the number of involved participants (total k = 30, total N = 11160) over the previous meta-analysis, sampling a much wider age range from children to adults in late middle age. Our meta-analysis revealed no significant link between morningness and intelligence (r = -0.008) when the entire sample was studied, and no evidence for publication bias. This overall effect, however, obscured the moderating effect of age. The morningness-intelligence correlation decreased with mean sample age (R² = 54%), ranging from a non-significant positive trend in children and adolescents to a significant negative correlation after young adulthood. Eveningness was positively correlated with intelligence (r = 0.056), but this finding is based on a more age-restricted sample and only reached significance with some model specifications. We hypothesize that the age-moderated correlation between circadian preference and intelligence reflects social effects, where more intelligent individuals are more able to adjust their daily schedules to their natural circadian rhythm.

Circadian preference and academic achievement in school-aged students: a systematic review and a longitudinal investigation of reciprocal relations

We provide a systematic review of findings on the relation between circadian preference and school achievement published after the last comprehensive review in 2015. We further test this relation in a longitudinal study. Our review of 26 studies revealed a positive relation between morningness and students' school achievement, and a negative relation between eveningness and school achievement. In most studies, these relations were not affected by students' age, sex, or intelligence, but were significantly mediated by students' conscientiousness, motivation, and sleep behavior. Furthermore, circadian preference and school achievement showed no significant relation when school started in the afternoon. All studies were cross-sectional. Therefore, the direction of the relations between circadian preference, school achievement, and potential mediating variables like conscientiousness and motivation could not be investigated. In our longitudinal study, we tested the direction of the relations between circadian preference, academic achievement, conscientiousness, self-efficacy, and attitude toward school over time in a sample of 764 German high school students who were tested in the first (T1) and third (T2) year of high school. Findings from confirmatory cross-lagged models indicated reciprocal relations between circadian preference and school achievement: T1 morningness positively predicted change in grade point average over time while T1 grade point average positively predicted change in morningness and negatively predicted change in eveningness. Furthermore, T1 conscientiousness and T1 attitude toward school both positively predicted change in morningness, whereas T1 morningness and T1 eveningness did not significantly predict change in these variables.

Test Anxiety and Poor Sleep: A Vicious Cycle

BACKGROUND

Test anxiety may be better thought of as a biopsychosocial process affecting academic performance during the days leading up to an exam, rather than a static appraisal of attitudes related to test taking. This was a passive observational study following students 2 days before a midterm exam and was designed to test the Sleep Anxiety Performance Process (SAPP) model in the context of a psychology statistics exam.

METHODS

Undergraduates (N = 167) enrolled in a statistics class, January-November 2015. Participants completed an electronic battery of measures and Sleep Mood Study Diaries (SMS) during the mornings, 2 days before a statistics exam. Instructors confirmed exam scores.

RESULTS

A path model showed a reciprocal bi-directional relationship between Sleep Quality and restfulness (Q&R) and test anxiety 2 days before a scheduled exam, with test anxiety measured in the morning, before the exam predicting exam performance. Prior exam performance, being a non-native English speaker (ESL), and class performance motivation also predicted exam performance.

CONCLUSIONS

These data support the SAPP model's premise that that sleep and anxiety feed one another, as a reciprocal process, that collectively impairs academic performance, with direct effects on academic performance, but with implications for overall student health.

The impact of reduced sleep on school related outcomes for typically developing children aged 11–19: A systematic review

This systematic literature review examines the relationship between restricted and reduced sleep and school performance, learning and cognitive functioning in typically developing adolescents. Correlational and experimental data were evaluated from 17 studies which included participants ranging from 11 to 19 years in studies from seven countries around the world. The review found that there is evidence that restricted and reduced sleep is negatively associated with school performance and cognitive outcomes, although the findings were mixed. Implications for psychologists working with schools are discussed. More research and evaluation is needed to establish how these factors relate to each other conclusively.

Do Children of Patients with Bipolar Disorder have a Worse Perception of Sleep Quality?

INTRODUCTION

The offspring of bipolar parents (BO) is a high-risk population for inheriting the bipolar disorder (BD) and other early clinical manifestations, such as sleep disturbances.

OBJECTIVE

To compare the presence of psychiatric disorders and sleep disturbances of BO versus offspring of control parents (OCP).

METHODS

A cross-sectional analytical study was conducted that compared BO versus OCP. The participants were assessed using valid tools to determine the presence of psychiatric symptoms or disorders. The "Sleep Evaluation Questionnaire" and "School Sleep Habits Survey" were used to determine sleep characteristics and associated factors. Sleep records (7-21 days) were also obtained by using an actigraphy watch.

RESULTS

A sample of 42 participants (18 BO and 24 OCP) was recruited. Differences were found in the presentation of the psychiatric disorder. The BO group showed a higher frequency of major depression disorder (MDD; P=.04) and Disruptive Mood Dysregulation Disorder (DMDD; P=.04). The OCP group showed a higher frequency of Attention Deficit and Hyperactivity Disorder (ADHD; P=.65), and Separation Anxiety Disorder (SAD; P=.46). Differences were also found in sleep by using subjective measurements. Compared to the OCP group, BO had a worse perception of quality of sleep (P=.02), a higher frequency of nightmares (P=.01), a shorter total sleep time, and a higher sleep latency. Nevertheless, no differences were found between groups in the actigraphy measurements.

CONCLUSIONS

The BO group had a higher frequency of Mood Disorders, and at the same time a higher number of sleep disturbances in the subjective measurements. It is possible that there is an association between mood symptoms, sleep disturbances, and coffee intake. No differences were found in the sleep profile by using actigraphy.

Which sleep hygiene factors are important? comprehensive assessment of lifestyle habits and job environment on sleep among office workers

BACKGROUND

Although several lifestyle habits are associated with sleep, it is unclear which factors are important. Among office workers, the effect of job environment should also be considered. The multivariate analyses on the effects of lifestyle habits and job environment on sleep among office workers was conducted.

METHODS

A cross-sectional survey of 6,342 employees from 29 companies was conducted in 2017-2019. Complete responses and informed consent were provided by 5,640 participants. The survey examined demographic variables, sleep schedules, Pittsburgh Sleep Quality Index (PSQI), Brief Job Stress Questionnaire (BJSQ), and lifestyle habits.

RESULTS

Mean values were as follows: age, 36.9 years (±10.2); PSQI, 6.52 (±2.83); and total sleep time, 6h06m (±1h40m) on work days and 7h39m (±1h58m) on free days. After adjusting for job environment and demographic variables, irregular meal time (1.45-2.86), not eating vegetables every day (1.35), nightcap (2.74-3.55), weight gain (1.20-1.42), lack of sunlight in the morning in the bedroom (1.48-1.60), waking up before dawn (2.18), electronic display use in bed (1.50), and daily caffeine intake (1.27) were significantly associated with sleep disturbance. Irregular meal time (1.51-2.37), lack of morning breakfast (1.74-2.95), having dinner within 2 hours before bed time (0.49-0.64), not eating vegetables every day (1.52), lack of sunlight exposure in the morning (1.43-2.01), and caffeine use every day (1.42) were also associated with eveningness (p<.01).

CONCLUSION

Each sleep hygiene factor had a different effect size. Sleep hygiene interventions to promote worker sleep health should prioritize factors in accordance with effect size.

Association between sleep-wake habits and use of health care services of middle-aged and elderly adults in China

OBJECTIVE

To examine the relationship between sleep-wake habits and the use of health care services.

RESULTS

The proportions of the participants who were "early to bed" and "late to bed" were 48.7% and 51.3%, respectively. In the full sample, compared with those who were early to bed and early to rise, participants who went to bed late were more likely to report physician visits (late to bed and early to rise: OR = 1.13, 95% CI: 1.08-1.19, late to bed and late to rise: OR = 1.27, 95% CI: 1.18-1.38, respectively). We found no significant association between sleep-wake habits and the number of hospitalization.

CONCLUSIONS

Those middle-aged and elderly people who stayed up late and got up late are more likely to visit the doctors than those who went to bed early and got up early.

METHODS

We obtained data from a cohort study of retired employees in China, and 36,601 (95.59%) involved in the present study. The participants were allocated into 4 sleep-wake habits groups: Early-bed/Early-rise, Early-bed/Late-rise, Late-bed/Early-rise, and Late-bed/Late-rise. We explored the association between sleep-wake habits with the number of physician visits and hospitalizations.

Effects of Mobile Use on Subjective Sleep Quality

PURPOSE

The objective of this study was to find out the association between mobile use and physiological parameters of poor sleep quality. It also aimed to find out the prevalence of mobile-related sleep risk factors (MRSRF) and their effects on sleep in mobile users.

MATERIALS AND METHODS

This cross-sectional study was conducted on 1925 students (aged 17-23yrs) from multiple Colleges of Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia. The study tools used were Pittsburgh sleep quality index (PSQI) and MRSRF online questionnaires.

RESULTS

The mean age (±SD) of participants was 19.91 ± 2.55 years. Average mobile screen usage time was 8.57±4.59/24 hours, whereas average mobile screen usage time in the bed after the lights have been turned off was 38.17±11.7 minutes. Only 19.7% of subjects used airplane mode, while 70% kept the mobile near the pillow while sleeping. The blue light filter feature was used by only 4.2% of the participants. "Screen usage time of ≥8 hours" was positively correlated with sleep disturbances and decrease in the length of actual sleeping time (p =0.023 and 0.022). "Using the mobile for at least 30 minutes (without blue light filter) after the lights have been turned off" showed positive correlation with poor sleep quality, daytime sleepiness, sleep disturbances and increased sleep latency (p= 0.003, 0.004 and 0.001). "Keeping the mobile near the pillow while sleeping" was also positively correlated with daytime sleepiness, sleep disturbances and increased sleep latency (p =0.003, 0.004 and 0.001).

CONCLUSION

This study concludes that using mobile screen ≥8 hours/24 hours, using the mobile for at least 30 minutes before sleeping after the lights have been turned off and keeping the mobile near the pillow are positively associated with poor sleep quality. Moreover, we observed that MRSRF were highly prevalent amongst the mobile users.

The association among demographic factors, health behaviors and sleep quality in youth with Autism Spectrum Disorder

BACKGROUND

A majority of youth with Autism Spectrum Disorder (ASD) have disrupted sleep patterns, but there has been limited research examining factors associated with sleep in this population.

OBJECTIVE

The objective of this study was to compare demographic and lifestyle behaviors with sleep quality in youth with ASD.

METHODS

A total of 49 children (12.44 years; 78% male) with ASD wore the Actigraph GT9X accelerometer over seven days and nights to assess moderate to vigorous physical activity (MVPA), sedentary behavior (SB), total sleep duration, and sleep efficiency. Parents reported their child's weekly amount of screen time and demographic information. Participants were classified according to whether they met sleep criteria for duration and efficiency (8-9 h of sleep duration and ≥85% sleep efficiency). T-tests and ANOVA were used to compare demographic and lifestyle factors between the groups.

RESULTS

Participants who meet both sleep duration and efficiency criteria had greater minutes of MVPA per day (113.65 min/day) than participants who only met sleep efficiency criteria (40.27 min/day) and participants who did not meet either sleep criteria (67.5 min/day; p < 0.0001). Additionally, participants who met both sleep criteria had fewer minutes of SB compared to those who only met sleep efficiency criteria (384.79 vs 526.05 min/day; p = 0.02).

CONCLUSIONS

Youth who had indicators of good sleep quality had greater amounts of MVPA and lower amounts of SB. Studies should further examine the relationship between sleep and health behaviors in youth with ASD to determine causal mechanisms, leading to more effective sleep interventions.

Predictor of sleep difficulty among community dwelling older populations in 2 African settings

Sleep deprivation is a common phenomenon among older population and is commonly linked to behavioral, physiological, and psychosocial factors. Not much is known about sleep deprivation among older population in Africa. Therefore, in this study we aimed to investigate the basic sociodemographic and psychosocial predictors of self-reported sleep deprivation among older population.In this study we analyzed cross-sectional data on 1495 community dwelling men and women aged 50 years and above. Data were collected from the SAGE Well-Being of Older People Study conducted in South Africa and Uganda. Outcome variable was self-reported sleep difficulty last 30 days. Multivariable logistic regression models were used to identify the variables significantly associated with sleep difficulty.The prevalence of mild-moderate sleep difficulty was 32.6% (27.9, 37.6) and severe/extreme 23.0% (20.3, 26.0) respectively. Multivariable analysis revealed that sleep difficulty was associated with several behavioral, environment, and illness conditions. In South Africa, those who reported dissatisfaction with living condition had 1.592 [1.087, 2.787] times higher odds of reporting mild/moderate sleep difficulty. Poor subjective quality of life (QoL) was associated with higher odds of severe/extreme sleep difficulties (odds ratios [OR] = 4.590, 95% confidence interval [CI] = 2.641, 7.977 for South Africa, and OR = 4.461, 95% CI = 2.048 and 9.716 for Uganda). In Uganda, perceived depression was associated with higher odds of severe/extreme (OR = 2.452, 95% CI = 1.073, 5.602) sleep difficulties among men, and both mild/moderate (OR = 1.717; 95% CI = 1.011, 2.914) and severe/extreme sleep difficulties among women (OR = 2.504, 95% CI = 1.408, 4.453).More than half of the participants had sleep difficulty of certain degrees, emphasising an urgent need for intervention for sleep deprivation in the population. Interventions targeting to promote subjective health, quality of life, and living environment may prove beneficial for improving sleep health in this regard.

Do sleeping habits mediate the association between time spent on digital devices and school problems in adolescence?

Background

This study examined the associations of Internet and computer screen time with school difficulties and the role of sleep quality and soft and energy drinks consumption.

Methods

We used data from the cross-sectional Health Behaviour in School-aged Children study collected in 2014 among Slovak adolescents (aged 11.0-15.9 years, N = 7595, 48.1% boys). We examined the inter-relations between time spent with on digital devices (time spent playing digital games or Internet use), sleeping quality (sleeping shortage, sleeping difficulties), soft/energy drinks consumption and school problems (low academic achievement, disliking school, being pressured by schoolwork and truancy), using structural equation modeling.

Results

Results showed that the more time adolescents spent on digital devices during leisure time, the more school problems they had. This association was mediated by a higher consumption of soft or energy drinks and a lower quality of sleeping. The direct effect of time spent on digital devices on school problems and its indirect effect via sleeping quality were relatively small (-0.26 and -0.30, respectively, standardized solution), compared with the indirect effect of time spent on digital devices via soft/energy drinks consumption as well as sleeping quality (0.65, standardized solution).

Conclusions

Time spent on digital devices is associated with school problems, with sleeping and soft/energy drinks consumption playing a substantial role in this association.

Children Sleep and Antisocial Behavior: Differential Association of Sleep with Aggression and Rule-Breaking

There is a strong relationship between sleep and behavioral problems. These findings are often interpreted via environmental explanations, such that poor sleep directly exacerbates or causes symptoms of aggression and behavior problems. However, there are other possible explanations, such that the genes predicting poor sleep also predict aggression or rule-breaking. The current study sought to elucidate the origin of this relationship. The sample was composed of 1030 twin pairs (426 monozygotic and 604 dizygotic). The sample was 51.3% male with a mean age of 8.06 years (range 6-11.96; SD = 1.45). Aggression, rule-breaking and sleep were assessed through the Child Behavior Checklist (CBCL). We fitted bivariate Cholesky genetic models to the data, decomposing the variance within, and the covariance among, aggression, rule-breaking, and sleep functioning into their genetic and environmental components. Genetic correlations between all sleep variables and aggression were significant and moderate to large in magnitude, but mostly small and non-significant between sleep and rule-breaking. We did not find evidence of a causal or environmental relationship between the majority of sleep variables and aggression, but rather clear evidence of genetic pleiotropy. However, the pattern of associations between rule-breaking and sleep measures was less consistent. Aggression and rule-breaking appear to be differentially associated with sleep.

Sleep disorders in adolescents and young adults: Insights into types, relationship to obesity and high altitude and possible lines of management

A sleep disorder is a medical disorder of the sleep pattern of a person that may be serious enough to interfere with normal physical, mental and emotional functioning. Disruptions in sleep can be caused by a variety of causes, from teeth grinding to night terrors. Sleep disorders are usually prevalent among adolescents and young adults, possibly due to factors related to life style, dietary habits, hormonal and emotional disturbances. Other factors that may precipitate sleep disorders include environmental, psychological and genetic factors. Sleep disorders may lead to serious psychological and mood disorders and may even affect the immune system. Management of sleep disorders depends on amelioration of the precipitating factors and the use of certain drugs that may help to restore the normal sleep-wake cycle. This review sheds light on sleep disorders in adolescents and young adults regarding their types, etiology, dangers and possible lines of management.

Sleep disorders in a sample of students in Taif University, Saudi Arabia: The role of obesity, insulin resistance, anemia and high altitude

AIM

The aim of this study was to assess the incidence of sleep disorders and excessive daytime sleepiness (EDS) among Taif University students and to explore the precipitating factors of these disorders.

METHODS

This study was carried out on 1066 students in Taif University of both sexes aging from 18 to 25 years. All included individuals were subjected to full history taking and thorough clinical examination, with special concern on anthropometric measurements (weight, height, waist-to-hip ratio and body mass index). Also, fasting blood glucose, fasting serum insulin, homeostatic model assessment (HOMA) index and blood hemoglobin levels were measured. Sleep disorders were assessed using sleep disturbances scale and the Epworth sleepiness scale.

RESULTS

The overall incidence of sleep disorders and EDS was 31.33% and 15.29% respectively with statistically significant prevalence in females than males. There was significant positive correlation between sleep disturbances scale and Epworth sleepiness scale on one hand and body weight, body mass index, waist-to-hip ratio, the height of the residence place above the sea level, fasting and post-prandial blood glucose, fasting serum insulin and HOMA index on the other hand. Also, there was significant negative correlation between sleep disturbances scale and Epworth sleepiness scale on one hand and blood hemoglobin levels on the other hand.

CONCLUSION

Sleep disorders and EDS in Taif University students were precipitated by high altitude, anemia, obesity and glucose intolerance. Control of these factors may have a positive impact on the incidence of sleep disorders and EDS in this age group.

Cross-sectional and longitudinal associations of screen time and physical activity with school performance at different types of secondary school

Background

Previous studies have already reported associations of media consumption and/or physical activity with school achievement. However, longitudinal studies investigating independent effects of physical activity and media consumption on school performance are sparse. The present study fills this research gap and, furthermore, assesses relationships of the type of secondary school with media consumption and physical activity.

Methods

The consumption of screen-based media (TV/video, game console, PC/internet, and mobile phone) and leisure physical activity (organized and non-organized) of 10 – to 17-year old adolescents participating in the LIFE Child study in Germany were related to their school grades in two major school subjects (Mathematics and German) and in Physical Education. In addition to a cross-sectional analysis at baseline (N = 850), a longitudinal analysis (N = 512) investigated the independent effects of these activities on the school grades achieved 12 months later. All associations were adjusted for age, gender, socio-economic status, year of data assessment, body-mass-index, and school grades at baseline. A further analysis investigated differences in the consumption of screen-based media and physical activity as a function of the type of secondary school (highest vs. lower secondary school).

Results

Adolescents of lower secondary schools reported a significantly higher consumption of TV/video and game consoles than adolescents attending the highest secondary school. Independently of the type of school, a better school performance in Mathematics was predicted by a lower consumption of computers/internet, and a better performance in Physical Education was predicted by a lower consumption of TV/video and a higher frequency of non-organized physical activity. However, the association between non-organized physical activity and subsequent grades in Physical Education was significant in girls only.

Conclusion

The present results suggest that media consumption has a negative effect on school achievement, whereas physical activity has a positive effect, which, however, is restricted to the subject Physical Education. Future studies might explore the relationship between media consumption and school career, for example, the choice or change of the secondary school type, in more detail.

Trial registration

LIFE Child study: ClinicalTrials.gov, clinical trial number NCT02550236

Neighborhood social capital and sleep duration: a population based cross-sectional study in a rural Japanese town

Background

Studies on social capital and health outcomes have become common, but the relationship between neighborhood social capital and sleep duration by gender is still unclear. We examined the relationship between neighborhood social capital and sleep duration by gender in adults living in a rural community in Japan.

Method

We conducted a cross-sectional survey of 12,321 residents aged ≥20 years in a town in Mie Prefecture in January–March 2013. Self-completed questionnaires were collected from the residents (n = 7782; valid participation rate, 63.2%). We used five items to assess the neighborhood social capital (Cronbach’s α = 0.86). We summed up the scores of each item, and then divided the participants into four groups by quartile of total scores of neighborhood social capital (lowest, low, high, and highest). Sleep duration of < 7 h/day was defined as insufficient sleep duration according to previous studies. To adjust for potential confounders, we performed a multiple log-binominal regression analysis and estimated the prevalence ratios (PRs) and 95% confidence intervals (CIs) for insufficient sleep.

Results

Overall 42% of the men and 45% of the women had insufficient sleep. In the men, the lowest group of neighborhood social capital presented a 22% higher prevalence of insufficient sleep (PR 1.22; 95% CIs 1.08–1.38) compared to the highest group of neighborhood social capital. Similarly the low group of neighborhood social capital and the high group of neighborhood social capital had 20 and 19% higher prevalence of insufficient sleep (PR 1.20; 95% CIs 1.06–1.36; PR 1.19; 95% CIs 1.06–1.34, respectively) compared to the highest group of neighborhood social capital. For women there was no significant association between neighborhood social capital and insufficient sleep after controlling for all potential confounders.

Conclusion

Having lower neighborhood social capital was associated with insufficient sleep among Japanese adults, particularly in the men. This suggests that the context of neighborhood social capital by gender should be considered to promote healthier behaviors with regard to getting enough sleep.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-5204-4) contains supplementary material, which is available to authorized users.

Sleep quality and its association with psychological distress and sleep hygiene: a cross-sectional study among pre-clinical medical students

Objective:

This study aimed to investigate subjective sleep quality and its association with demographics, psychological health, and sleep hygiene related behaviors in pre-clinical medical students.

Methods:

In this cross-sectional study, a self-administered questionnaire consisting of demographics, sleep hygiene behaviors, Pittsburgh Sleep Quality Index (PSQI), and Depression, Anxiety and Stress Scale-21 (DASS21) was handed out to all medical students of Tehran University of Medical Sciences at pre-clinical stage.

Results:

The questionnaire was filled out by 553 (89.7%) of 616 students approached. About 60% of our sample had a global PSQI score of more than 5 (cut off of poor sleep quality) with mean global PSQI score of 6.32 (SD=2.72). The prevalence of moderate to extremely severe depression, anxiety and stress scores were 26.1%, 29.61%, and 14.5% respectively. Poor sleep quality was associated with later year in the school, psychological distress and several lifestyle behaviors. Constructing a multivariate logistic model, depression, anxiety and some sleep hygiene behaviors were significantly associated with higher PSQI score.

Discussion:

Our findings suggest that poor sleep quality is a common problem among pre-clinical medical students and is associated with some psychological symptoms and sleep hygiene behaviors. This issue demonstrates necessity of interventions to improve the sleep quality in this population group.

Comprehensive assessment of the impact of life habits on sleep disturbance, chronotype, and daytime sleepiness among high-school students

OBJECTIVE

Sleep affects adolescents in various ways. However, the effects of multiple factors on sleep hygiene remain unclear. A comprehensive assessment of the effects of life habits on sleep in high-school students was conducted.

METHODS

A cross-sectional survey of 344 high school students (age range 15-17; 171 boys, 173 girls) in Tokyo, Japan was conducted in 2015. Complete responses were provided by 294 students. Demographic variables, Pittsburgh Sleep Quality Index (PSQI), diurnal type scale, Pediatric Daytime Sleepiness Scale (PDSS), and life habits such as dinnertime, viewing electronic displays, caffeine intake, sunlight in the morning, and the brightness of the room in the night were asked.

RESULTS

The mean scores were PSQI: 5.9 (±2.3), PDSS: 19.0 (±5.8), and the diurnal type scale: 16.7 (±3.4). Using an electronic display in bed (OR = 3.01; (95%CI) 1.24-7.30), caffeine intake at night always (OR = 2.22; 1.01-4.90), and waking up before dawn (OR = 3.25; 1.34-7.88) were significantly associated with sleep disturbance. Irregular timing of the evening meal (OR = 2.06; 1.10-3.84) and display viewing within 2 h before bedtime (OR = 2.50; 1.01-6.18) or in bed (OR = 3.60; 1.41-9.21) were significantly associated with excessive daytime sleepiness. Using an electronic display within 2 h before bedtime (OR = 2.64; 1.10-6.38) or in bed (OR = 3.50; 1.40-8.76) and a living room which is bright at night (OR = 1.89; 1.06-3.36) were significantly associated with eveningness.

CONCLUSION

Each type of sleep-related problem had its own associated life habit factors.