Nighttime Sleep Duration Research Articles

Characteristics and Transition of Sleep–Wake Rhythm in Nursery School Children: The Importance of Nocturnal Sleep

In this study, we investigated the sleep–wake rhythm of nursery school children with the aim of supporting their health and mental/physical development. We analyzed 4881 children from infancy to 6 years of age, using 2 week sleep tables recorded by their guardians. The tables contained night bedtimes, wake times, nighttime/daytime sleep duration, and the differences in these between weekdays and weekends. The total sleep decrement of children with increasing age is attributed to a decrease in daytime sleep, while nighttime sleep duration remains almost unchanged at about 10 h, which is, therefore, referred to as the nighttime basic sleep duration (NBSD). Although bedtime stabilizes at around 9:30 p.m. by the age of 2, wake-up times tend to be before 7 a.m., which results in sleep insufficiency during weekdays. This lack of sleep is compensated for by long naps on weekdays and by catching up on sleep on weekend mornings, which may contribute to future social jet lag. Guardians are encouraged to know their children’s exact NBSD and set an appropriate bedtime to be maintained on weekdays. This helps to prevent sleep debt and fosters a consistent daily rhythm of waking up at the same time both on weekdays and weekends. These conditions are believed to support mental/physical development and school and social adaptation.

Association between screen time, homework and reading duration, sleep duration, social jetlag and mental health among Chinese children and adolescents

ObjectivesTo examine the associations of screen time, homework and reading duration, sleep duration, social jetlag with mental health in children and adolescents, as well as its gender differences.MethodsFrom December 2023 to April 2024, a total of 62 395 children and adolescents were selected from 51 schools in 17 cities of China by stratified cluster sampling. Screen time, homework and reading duration, sleep duration, and social jetlag were calculated by answering the questions about watching TV time, playing smartphones time, doing homework time, reading extracurricular books time, bedtime, wake-up time, and nap time during weekdays and weekends. Mental health was assessed by the Revised Mental Health Inventory-5 (MHI-5). The generalized linear model was used to determine the association between screen time, homework and reading duration, sleep duration, social jetlag, and mental health in children and adolescents.ResultsThe generalized linear model results showed that longer watching TV time, longer playing smartphones time, longer homework time, and greater social jetlag were correlated with poorer mental health in children and adolescents, while longer nighttime sleep duration, and longer daytime nap duration were correlated with better mental health. Moreover, in primary school and junior high school, we found that this association was stronger during the weekdays. However, in senior high school, this association was stronger during the weekends. After according to gender stratified, we found that the strength of this association was different in boys and girls at different study phases. Furthermore, our findings also revealed a significant quadratic relationship, indicating the association of better mental health with an optimal amount of sleep duration.ConclusionsThere was a significant association between screen time, homework and reading duration, sleep duration, social jetlag, and mental health in children and adolescents. This study has the potential to offer useful insights for the prevention and control of mental health issues in children and adolescents.

Validation of intrinsic capacity and healthy sleep pattern in middle-aged and older adults: a longitudinal Chinese study assessing healthy ageing

ObjectivesIntrinsic capacity (IC), a multidimensional construct encompassing mental and physical capacities, has been established in the aging framework by the World Health Organization. However, the detailed relationship between IC and Chinese sleep patterns (nighttime sleep and post-lunch naps) remains inadequately elucidated. MethodsParticipants in this study were individuals aged ≥45 years residing in China, included in the China Health and Retirement Longitudinal Study (CHARLS). We analyzed 4 years of CHARLS data from the first wave (May 2011–March 2012) to the second wave (July 2015–January 2016). Data from these waves were utilized for longitudinal analysis. Self-reported data included nighttime sleep and nap duration, along with other baseline characteristics. The IC evaluation involved physical examinations and blood tests. Initially, linear regression was used to assess the relationship between total sleep duration, nighttime sleep duration, nap duration, and IC change between the two waves that were determined by marginal effects (ME) and their corresponding 95% confidence intervals (CIs). Regression splines were employed to explore potential nonlinear associations. Subgroup and sensitivity analyses were conducted to investigate the heterogeneity of IC change under specific conditions and the robustness of our results. Mediation analysis was performed to identify potential factors mediating the relationship between sleep patterns and IC change. ResultsBoth excessive (>10 h) (total, ME: −1.12; 95% CI: −1.61, −0.64; nighttime, ME: −1.44; 95% CI: −2.29, −0.59) and insufficient (<6 h) sleep duration (total, ME: −0.43; 95% CI: −0.68, −0.18; nighttime, ME: −0.50; 95% CI: −0.73, −0.27) negatively impacted IC change. Moderate naps (≤60 min) mitigated the decline in IC change (ME: 0.28; 95% CI: 0.07, 0.49). IC values decreased at the slowest rate when nap time constituted one-seventh of total sleep time. The onset of dyslipidemia partially mediated the association between naps (≤60 min) and IC change (P = 0.02). ConclusionsThese findings suggest that maintaining a healthy sleep pattern of 6−8 h of nighttime or total sleep, along with a post-lunch nap of ≤60 min, helps preserve optimal IC or delay its decline. This is particularly beneficial for cognitive, psychological, and locomotion performance among middle-aged and older adults.

Sleep and risk of hip fracture and falls among middle-aged and older Chinese.

The study aimed to assess the prospective associations between sleep duration, sleep restfulness, midday napping and hip fracture (HF) and falls in a nationally representative Chinese population. Data were from the China Health and Retirement Longitudinal Study which was conducted from 2013 to 2018. In total, 10,508 individuals without a history of HF in 2013 were included. Nighttime sleep duration, sleep restfulness and midday napping were self-reported. Logistic regression analyses were performed to examine the relationships between sleep problems and HF as well as falls, adjusting for covariates. A total of 313 (3.0%) participants reported HF, and 3899 (37.1%) experienced at least one fall event over the following 5-year period. Participants who had a short sleep duration (≤ 6) were more likely to report HF (OR = 1.27, 95% CI = 1.00-1.62) and falls (OR = 1.18, 95% CI = 1.07-1.30) than those who had a normal sleep duration (6-9h) in the fully adjusted model. Participants having unrestful sleep were also more likely to report falls (OR = 1.23, 95% CI = 1.11-1.36) than those who had restful sleep. However, there was no significant association between midday napping and HF and falls. In conclusion, short sleep duration and sleep restfulness were independently associated with an increased risk of HF and falls, which may have important clinical and public health implications. Interventions to improve sleep quality may reduce the risk of HF and fall accidents among middle-aged and older people.

Association between nighttime sleep duration and quality with low back pain in middle-aged and older Chinese adults

BackgroundThis study aims to investigate the association between sleep duration, sleep quality, and the risk of low back pain (LBP) among middle-aged and elderly individuals in China. MethodsUtilizing data from the China Health and Retirement Longitudinal Study spanning 2011 to 2020, we categorized sleep duration into long, medium, and short categories, and sleep quality into good, fair, and poor levels. LBP status was determined based on self-reported information by participants. Multivariable logistic regression analysis was employed to assess the relationship between sleep duration, sleep quality, with the risk of LBP. ResultsA total of 6750 individuals were included in the longitudinal study. After 9 years of follow-up, the prevalence of LBP was 25.69 %. In the fully adjusted model, compared to individuals with medium sleep duration, those with short sleep duration had a 28 % increased risk of developing LBP (OR = 1.28, 95%CI: 1.12, 1.46). Additionally, when compared to individuals with good sleep quality, those with fair and poor sleep quality had a 35 % (OR = 1.35, 95%CI: 1.19, 1.54) and 33 % (OR = 1.33, 95%CI: 1.12, 1.58) increased risk of LBP, respectively. Joint analysis of both factors revealed that individuals with poor sleep quality and short sleep duration had the highest risk of LBP. ConclusionAmong middle-aged and elderly individuals in China, short sleep duration and poor sleep quality were associated with an increased risk of LBP. Future studies should further explore the mechanisms underlying this association and validate the findings through randomized controlled trials.

Regular sleep habits in toddlers are associated with social development and brain coherence

ObjectiveAlthough sleep habits are associated with the development of toddlers, factors affecting social development and brain function remain unclear. We aimed to elucidate the relationship between sleep habits and social development as well as brain coherence in toddlers. MethodsWe used the data set at 1.5-2 years old, in the longitudinal study until 6 years old. We evaluated sleep parameters, such as average wake-up time, bedtime, nighttime sleep duration, total sleep duration, and the standard deviation (SD) of sleep habits. We also examined the development, including the social stimuli fixation percentage using Gazefinder® and electroencephalography (EEG) coherence between brain regions. ResultsSeventy-two children (37 boys and 35 girls) were included. The fixation percentage for the human face was negatively correlated with the SD of the total sleep duration, nighttime sleep duration, nap duration, and bedtime (r=-0.516, p=0.000; r=-0.331, p=0.005; r=-0.330, p=0.005; and r=-0.324, p=0.005, respectively). The EEG analysis indicated that α-band coherence in the right centro-parietal area was negatively correlated with the total sleep duration (r=-0.283, p=0.016). The path diagram demonstrated a direct significant effect of sleep duration irregularity on development including social communication and fixation percentage for human faces. Additionally, total sleep duration exhibited a direct effect on α cortical coherence in the right centro-parietal area. ConclusionsIn this study, we found an association between sleep irregularity and the development of social communication, preference for humans, and brain coherence in toddlers. We suggest that regular sleep plays an important role in promoting the development of social communication.

Mediating role of inflammatory indicators in the association between sleep status and blood pressure in centenarians: evidence from China Hainan Centenarian Cohort Study.

To conduct a comprehensive analysis in Hainan centenarians on the link between sleep status and their blood pressure status. Furthermore, the study also aims to explore how inflammatory indicators may mediate the relationship. The China Hainan Centenarians Cohort Study (CHCCS) collected baseline data on sleep status, inflammatory indicators, and blood pressure data. The study used a mediation model to investigate how inflammatory indicators mediate the relationship between sleep status and blood pressure status. In this study, a total of 967 centenarians were included. The prevalence of hypertension among the centenarians was 71.4%. The analysis showed that centenarians with poor sleep quality had a 43% higher risk of hypertension compared to those with normal sleep quality (OR = 1.43, 95% CI: 1.03-1.97). Additionally, centenarians with nighttime sleep durations of ≤ 6 h or > 9 h had higher proportions of high pulse pressure (PP), with OR values of 1.76 (95% CI: 1.18-2.63) and 2.07 (95% CI: 1.34-3.19), respectively. Mediation analysis illustrated that complement C3 played a mediating role in the relationship between sleep quality and hypertension, with an effect ratio of 2.4%. Similarly, lymphocyte count, the neutrophil-to-lymphocyte ratio (NLR), and the systemic immune-inflammation index (SII) were identified as mediating factors in the association between nighttime sleep duration and high PP, with effect ratios of 91.22%, 36.93%, and 0.20%, respectively. In centenarians, poor sleep quality raises the risk of hypertension, with complement C3 as a mediator. Additionally, nighttime sleep durations of ≤ 6 h or > 9 h increases the risk of high PP, mediated by lymphocyte count, NLR, and SII.

Sleep status of centenarians and its association with death in the China Hainan Centenarian Cohort Study

ObjectiveThis study investigated the associations of sleep status (duration and quality) with all-cause death among centenarians, using data from the China Hainan Centenarians Cohort Study. MethodThe epidemiological distribution of sleep duration and sleep quality (estimated using the Pittsburgh Sleep Quality Index) was described based on the data from the China Hainan Centenarians Cohort Study. Cox regression was used to analyze the association between sleep status and all-cause mortality. ResultsA total of 994 centenarians, with an average age of 102.77 ± 2.75years, were included. The median (Q1, Q3) daytime sleep duration was 1.00 (0.50, 1.50) hour, while nighttime sleep duration and total sleep duration were 8.00 (7.00, 9.00) hours and 9.00 (8.00, 10.50) hours, respectively. By the end of the follow-up period, 517 centenarians had died, with a median follow-up time of 4.2 (1.3-5.0) years. A noteworthy finding emerged: male centenarians with a daytime sleep duration of at least 2 hours had a 97% greater risk of all-cause mortality (HR=1.97, 95%CI: 1.07-3.62, P = .039) than those who got less daytime sleep, after adjusting for potential confounders. ConclusionThe sleep duration patterns of centenarians in Hainan were comparable to those in other provinces of China. Centenarians who sleep longer had a higher risk of all-cause mortality. This risk plateaued after more than 9 hours of sleep, with no gender differences observed. Furthermore, the duration of daytime sleep was significantly associated with all-cause mortality among male centenarians.

Association of nighttime sleep duration at 1.5 years with height at 3 years: The Japan Environment and Children's Study.

Adequate nighttime sleep duration has been considered beneficial for linear growth in children; however, there is limited and conflicting evidence regarding the association between sleep duration and subsequent linear growth. To investigate the association between sleep duration at 1.5 years and height at 3 years of age. The Japan Environment and Children's Study is a nationwide prospective birth cohort study. Data from 52,140 term singleton births born at an appropriate-for-gestational age without background disorders that could potentially affect linear growth in the analyses were included. Nighttime and total sleep durations were calculated based on a self-administered questionnaire completed by caregivers. Tall stature was defined as height at or above the 75th percentile among participants. After adjustment for height at 1.5 years, sex, monthly age, mother's height, presence of siblings at 1.5 years, environmental tobacco smoke at 1.5 years, daily TV/DVD screen time at 2 years, attendance at nursery at 2 years, household annual income at birth, and parents' educational status, multivariate odds ratio (95% confidence interval) for tall stature at 3 years were 1.09 (1.01-1.17), 1.09 (1.01-1.17), and 1.25 (1.14-1.37) for 9.5 or 10, 10.5 or 11, and ≥ 11.5 h of nighttime sleep duration at 1.5 years, respectively, compared with those with ≤ 9 h sleep (p for trend <0.0001). Total sleep duration was not associated with tall stature. This study underscores the importance of nighttime sleep duration, not total sleep duration, in the linear growth of very young children.

The Associations between Sleeping Quality during nighttime and Personal Emotions among High School students

High school students prioritize academic and work-related responsibilities, they often overlook the critical role of sleeping quality in promoting physical recovery and students emotions. Notably, both insufficient and excessive sleep can adversely affect emotional states. Consequently, we conducted a study to investigate the relationship between nighttime sleep duration and student’s emotions in daytime. This study utilized sleep duration questionnaires and emotional state assessments administered over a one-week period.

Are Sleep Parameters and Chronotype Associated with Eating Disorder Risk? A Cross-Sectional Study of University Students in Spain.

Objectives: Eating disorders (EDs) have emerged as a growing public health concern. However, the role of sleep in this context remains underexplored. The aim of this cross-sectional study was to determine the associations between sleep parameters and chronotype with ED risk in a sample of university students in Spain. Methods: ED risk was assessed via the Sick, Control, One stone, Fat, Food Questionnaire, and sleep quality was assessed via the Pittsburgh Sleep Quality Index. Other sleep parameters and chronotypes were self-reported. Sociodemographic, body composition, lifestyle, and depressive symptom data were collected. Logistic and linear regression models adjusted for the main confounders were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) of the study associations. Results: A total of 403 students (70.2% female) aged 18 to 30 years participated in the study. Those reporting poor sleep quality (OR = 1.85, 95% CI 1.08-3.17, p = 0.025) and ≤6 h of night-time sleep duration (OR = 4.14, 95% CI 2.00-8.57, p < 0.01) were more likely to be at risk of EDs in the adjusted analyses. The association between night-time sleep duration and the risk of ED did not remain significant when we adjusted for sleep quality. In addition, an evening chronotype was associated with an increased risk of EDs (OR = 1.68, 95% CI 1.07-2.66, p = 0.039) only before adjustment for confounders. Conclusions: Among university students, poorer sleep quality was cross-sectionally associated with EDs. Future prospective studies are needed to examine whether promoting sleep quality may serve as an effective strategy for preventing the risk of EDs.

Identifying the subgroups of depression trajectories among the middle-aged and older Chinese individuals with chronic diseases: an 8-year follow-up study based on CHARLS.

Prior studies have demonstrated a prevalent occurrence of depression among the middle-aged and older Chinese individuals with chronic diseases. Nevertheless, there is limited research on the specific subgroups of depression trajectories within this population and the factors influencing these subgroups. To explore the changing trajectory and influencing factors of depression in the middle-aged and older individuals with chronic disease in China, and provide the data reference for the health management of the older adult population in China. A longitudinal cohort study was conducted using the data from the China Health and Retirement Longitudinal Study (CHARLS) in 2011, 2013, 2015, 2018, and 2020. A total of 2,178 participants with complete data were included. The level of depression was evaluated using the Center for Epidemiologic Studies Depression Scale (CESD-10). The Latent Class Mixed Models (LCMM) were employed to estimate trajectories of depressive symptoms. The Kruskal-Wallis H test and the Pearson χ 2 test were used to determine the significant factors affecting trajectory grouping. Subsequently, the multinomial logistic regression model was utilized to perform a multifactorial analysis of the variables impacting the trajectory subgroup of change in depressive symptoms. The LCMM-analysis revealed three distinct subgroups of depression trajectories: the "Low stable group" comprising 36.7% of the sample, the "Medium growth group" comprising 34.4% of the sample, and the "High growth group" comprising 28.9% of the sample. Among the baseline characteristics of different depression trajectory subgroups, there were significant differences in gender, residence, education, marital status, social activity participation, number of chronic diseases, smoking status, BMI, midday napping (minutes) and nighttime sleep duration (hours). Through multiple logistic regression analysis, our findings demonstrate that among the middle-aged and older Chinese individuals with chronic diseases, the following individuals should be the key groups for the prevention and treatment of depressive symptoms: Those who are young, female, residing in rural areas, having primary school education and below, being single, not participating in social activities, suffering from multiple chronic diseases, and having shorter naps and sleeping at night. There is heterogeneity in the subgroups of depression trajectories among the Chinese middle-aged and older individuals with chronic diseases. The focus should be on the distinct characteristics of various trajectories of depression within the realm of health management.

The Interplay between nighttime/midday sleep duration and the number of new-onset chronic diseases: A decade-long prospective study in China

ObjectiveTo investigate the interplay between individual nighttime and midday sleep duration and the number of new-onset chronic diseases and determine the optimal sleep duration associated with lowest number of new-onset chronic diseases. MethodsWe used data from the China Health and Retirement Longitudinal Study (CHARLS) covering a decade and involving 10,828 participants. A random intercept cross-lagged model was used to explore the interplay between nighttime/midday sleep durations and new-onset chronic diseases at both the within-individual and between-individual levels, followed by a dose–response analysis at the between-individual level to determine the optimal sleep duration. New-onset chronic diseases include 14 types of self-reported diseases diagnosed by doctors. ResultsWithin-individual analysis revealed that increased nighttime/midday sleep duration led to a higher number of new-onset chronic diseases, and an increased number of new-onset chronic diseases resulted in decreased nighttime sleep duration. Between nighttime and midday sleep, one type of sleep duration increase was likely to lead to an increase in another type. Between-individual analysis found a nonlinear relationship between the number of new-onset chronic diseases and nighttime sleep duration, identifying the optimal nighttime sleep duration as 7.46 h. ConclusionsThese findings elucidate the interplay between sleep duration and number of new-onset chronic diseases and underscore the need for public awareness and comprehensive interventions. Future studies should focus on refining sleep monitoring and exploring the sleep–chronic diseases nexus in greater depth.

Sleep characteristics during the first year postpartum in a cohort of Black and White women

Study objectivesThe postpartum period is a unique time when sleep deficiency often occurs. Black and White adults are reported to have differences in sleep characteristics, but little is known if these differences exist in the postpartum period. Therefore, the purpose of this study was to examine sleep characteristics in a cohort of Black and White women from 6-8 weeks to 12 months postpartum. MethodsParticipants were 49 Black and 85 White women who gave birth to an infant at ≥37 weeks gestation. Participants were instructed to wear an Actiwatch for 7 days at 6-8 weeks, 4, 6, 9, and 12 months postpartum. Mixed-effects linear models with a race by time interaction were used to examine if characteristics differed between races over time. ResultsOnly bedtime varied by race. White women had a later bedtime at 6-8 weeks compared to 6 months, but no significant change occurred for Black women. For the entire sample, average nighttime sleep duration increased from 385 min at 6-8 weeks to 404 min at 4 months postpartum. Percent sleep during the sleep interval and wake after sleep onset (WASO) improved by 6 and 9 months, respectively. However, average WASO remained >45 min and sleep efficiency <85 % at all timepoints for both Black and White women. Compared to White women, Black women had significantly shorter sleep duration (range: 40.6-59.9 min shorter across all timepoints, p < 0.0001) and time in bed (range: 17.5-67.6 minutes shorter, p = 0.0046), and lower percent sleep (range: 0.7-1.2 % lower, p = 0.0407) and sleep efficiency (range: 2.6-5.7 % lower, p = 0.0005). Sociodemographic factors were associated with sleep outcomes in Black and White women while behavioral factors were associated with sleep outcomes in White women only. ConclusionWhile there were improvements in nighttime sleep duration and quality, sleep duration remained suboptimal, and quality remained poor throughout the first year postpartum. In this sample, differences existed in factors associated with sleep outcomes between Black and White women.

Association between nighttime sleep duration, nap time, and mild cognitive impairment in Chinese older adults: a cross-sectional study

ObjectiveThis study aims to investigate the relationship between midday nap time, nighttime sleep duration, and mild cognitive impairment (MCI) in Chinese older adults and determine the recommended sleep duration to provide a scientific basis for preventing and managing MCI in this population.MethodsUtilizing the 2020 China Health and Retirement Longitudinal Study database, the demographic data, health status, and lifestyle information of the study participants were collected. A total of 5,314 valid samples were included in the analysis. Logistic regression and restricted cubic spline plots were employed to explore the relationship between sleep patterns and MCI.ResultsIn the cross-sectional analysis, a linear relationship was observed between midday nap duration and MCI among Chinese elderly. The probability of MCI was lowest among those who napped for less than 30 min at noon. Compared with individuals who napped for30-90 min, those who did not nap were more likely to have MCI (OR = 1.30, 95% CI: 1.05–1.60). Older adults with napping duration < 30 min (OR = 0.73, 95% CI:0.56–0.95) also exhibited lower probability of MCI when compared those without napping habit, Nighttime sleep duration exhibited a U-shaped relationship with MCI. Individuals with less than approximately 6 h of nighttime sleep showed a gradual decrease in the probability of MCI with increasing sleep duration, whereas those with more than 7.5 h demonstrated an increase in the probability of MCI with longer sleep duration. Older adults who slept less than 6 h at night (OR = 1.22, 95% CI: 1.01 ~ 1.46) or more than 8 h (OR = 1.78, 95% CI: 1.35–2.33) were more likely to develop MCI compared with those who slept 6 to 8 h.ConclusionAfter controlling for potential confounding variables, both nighttime sleep duration and midday nap duration exhibited a nonlinear “U”-shaped relationship with MCI among the elderly. The probability of depression was lower with a nap duration of approximately 60 min, and the optimal nighttime sleep duration was 6–8 h, with around 7 h providing the greatest cognitive benefits.

Factors Related to the Sleep Duration of 3-Month-Old Infants.

Objective To identify the factors related to sleep duration in 3-month-old infants. Materials and Methods From 2021 to 2023, we conducted a cross-sectional study in the city of Araraquara, Brazil, involving 140 mothers and their respective 3-month-old infants. Maternal socioeconomic, demographic, obstetric, and nutritional characteristics, as well as nutritional and morbidity characteristics of the respective infants, were evaluated. Sleep duration was determined by the Brief Infant Sleep Questionnaire (BISQ). Multivariate linear regression analysis was used to assess the associations of maternal, newborn, and infant factors with sleep duration at three months. Results The nighttime sleep duration of the infants was of 9 hours. There were negative associations between nighttime sleep duration and prone sleep position ( p = 0.011), falling asleep between 8:30 pm and 11:00 pm ( p = 0.032), falling asleep after 11:00 pm ( p < 0.001), respiratory infection ( p = 0.011), dermatitis ( p = 0.002), and the presence of children under 9 years of age in the household ( p = 0.013). Discussion In the present study, factors such as infant morbidity, the presence of other children in the household, and sleeping habits were associated with a decrease in sleep duration in 3-month-old infants. Therefore, we emphasize the importance of early diagnosis of morbidity in the first months of life and of promoting healthy habits such as regulating the time to go to sleep, providing an adequate sleep environment, and other practices that help improve the quality and duration of sleep.

Combined effects of sleep timing and nighttime sleep duration on non-alcoholic fatty liver disease

BackgroundWhile short sleep duration is linked to higher risk of non-alcoholic fatty liver disease (NAFLD), the combined effects of sleep timing and sleep duration on NAFLD are less explored. MethodsIn this cross-sectional study of 39,471 participants from Beijing-Tianjin-Hebei region of China, self-reported sleep information and ultrasonography-diagnosed NAFLD were obtained from Jan 2018 to Jan 2020. Sleep timing was categorized based on sleep midpoint: early-type (before 2:00 AM), intermediate-type (2:00–2:30 AM), and late-type (after 2:30 AM). We used multivariable logistic regression to explore the relationship between sleep timing, duration, and NAFLD. We analyzed sleep midpoint and duration categorically and continuously, and conducted stratification analyses by age, sex, body mass index, hypertension, diabetes, and dyslipidemia. ResultsIntermediate-type (OR: 1.15, 95% confidence interval: 1.05–1.26) and late-type sleep timing (OR: 1.08, 1.00–1.16) were associated with higher NAFLD risk compared to early-type. Additionally, longer sleep duration was linked to lower risk (OR: 0.92, 0.90–0.95 per hour increase). Notably, intermediate to late-type sleepers with normal sleep duration (7 to <8 h) exhibited a 20% higher NAFLD risk compared to early-type sleepers with the same duration (OR: 1.20, 1.04–1.39). The increased NAFLD risk associated with intermediate to late sleep timing was particularly evident in men, hypertension, and prediabetes or diabetes participants. ConclusionsIntermediate to late sleep timing, even with normal sleep duration, is associated with increased NAFLD risk. These findings underscore the importance of considering both sleep timing and sleep duration for NAFLD prevention, especially in men and individuals with cardiometabolic conditions.

Objectively Measured Sleep Duration and Health-Related Quality of Life in Older Adults with Metabolic Syndrome: A One-Year Longitudinal Analysis of the PREDIMED-Plus Cohort.

The aim of our cross-sectional and longitudinal study is to assess the relationship between daytime and night-time sleep duration and health-related quality of life (HRQoL) in adults with metabolic syndrome after a 1-year healthy lifestyle intervention. Analysis of the data from 2119 Spanish adults aged 55-75 years from the PREDIMED-Plus study was performed. Sleep duration was assessed using a wrist-worn accelerometer. HRQoL was measured using the SF-36 questionnaire. Linear regression models adjusted for socioeconomic and lifestyle factors and morbidity were developed. In cross-sectional analyses, participants with extreme night-time sleep duration categories showed lower physical component summary scores in Models 1 and 2 [β-coefficient (95% confidence interval) <6 h vs. 7-9 h: -2, 3 (-3.8 to -0.8); p = 0.002. >9 h vs. 7-9 h: -1.1 (-2.0 to -0.3); p = 0.01]. Participants who sleep less than 7 h a night and take a nap are associated with higher mental component summary scores [β-coefficient (95% confidence interval) 6.3 (1.3 to 11.3); p = 0.01]. No differences between night-time sleep categories and 12-month changes in HRQoL were observed. In conclusion, in cross-sectional analyses, extremes in nocturnal sleep duration are related to lower physical component summary scores and napping is associated with higher mental component summary scores in older adults who sleep less than 7 h a night.

Association between Sleep and Language Development in Children with Congenital Zika Syndrome.

Congenital Zika Virus Syndrome (CZS) presents notable hurdles to neurodevelopment, with language development emerging as a crucial aspect. This study investigates sleep patterns and language skills in children with CZS, aiming to explore the potential synchronization of sleep development with their neurodevelopment. We studied cross-sectionally 135 children with CZS aged 0 to 48 months, investigating sleep using the BISQ Questionnaire. Language development was assessed using the Early Language Milestone Scale, while motor development and cognitive and social ability were assessed using the Bayley Scales of Infant and Young Child Development 3rd edition. We also studied longitudinally a cohort of 16 children (initially aged 0 to 12 months) whom we followed for four years, assessing at one-year intervals. Sleep disturbances and language deficits were highly frequent in this population. In the 0-12 months group, a late bedtime and frequent nighttime awakenings were associated with poorer auditory expressive skills. At 13-24 months, nighttime awakenings were associated with poorer auditory expressive skills, while among 25-36-month-olds decreased auditory receptive skills were associated with longer sleep onset latency and reduced nighttime sleep duration. The brain alterations caused by Zika virus infection affect both sleep disturbances and delays in language development. It is possible that sleep disturbance may be a mediating factor in the pathway between CZS and delayed language development, as the three analyzed language skills showed a correlation with sleep parameters.

Association of night-time sleep and daytime napping with painful temporomandibular disorder.

Painful temporomandibular disorder (TMD) is the common cause of chronic oro-facial pain, which may interfere with sleep. Previous studies have documented an association between sleep and TMD. This study aimed to further explore the association of night-time sleep and daytime napping with painful TMD. A total of 419 patients (aged 31.88 ± 11.54 years with women forming 85.4%) from a TMD/Orofacial Pain center were enrolled. Patients' sleep conditions were evaluated with the Pittsburgh Sleep Quality Index (PSQI) questionnaire, and information on night-time sleep duration, napping duration and napping frequency was interviewed. TMD was diagnosed according to the Diagnostic Criteria for TMD protocol and stratified into myalgia (muscle pain), arthralgia (joint pain) and combined (muscle and joint pain) subgroups. The severity of TMD was measured with the Fonseca Anamnestic Index (FAI) questionnaire. Restricted cubic spline (RCS) regression models were established to explore relationships between sleep and painful TMD subgroups. Patients with poor sleep quality (PSQI≥6) had higher FAI scores (median 60, p < .001) and higher proportions of painful TMDs. The myalgia subgroup had higher PSQI scores (median 8, p < .001) than the arthralgia subgroup. The RCS models indicated a non-linear relationship between night-time sleep duration and myalgia (p < .001), which was not observed in arthralgia. However, there were no significant findings concerning napping and painful TMD subgroups. This study found that the association between sleep and TMD is mainly related to painful TMD conditions, which are associated with night-time sleep duration.