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Background Having no or few confidants is found to be associated with more severe mental health problems and a higher prevalence of depression in adults, but research examining this association in adolescents is scarce. Social relationships may be particularly critical during adolescence, as it is an important developmental period during which vulnerability to mental health problems increases. The present study examined the relationship between having no or few confidants and anxiety/depressive symptoms in adolescents. Methods Cross-sectional self-report data from 17,829 Japanese students (49.7% boys) in public junior and senior high schools were analyzed. Associations between anxiety/depressive symptoms (12-item General Health Questionnaire; score range: 0–12) and the number of confidants (None, 1–3, or ≥ 4) were examined using multilevel regression analyses. The analyses were stratified by gender and school level (junior/senior high), and adjusted for experiences of physical abuse and bullying. Results Having 1–3 or no confidants was associated with more anxiety/depressive symptoms, compared to having ≥ 4 confidants (p

This study aimed to investigate the associations between objectively measured sleep timing and habitual dietary intake among university students. We hypothesized that a later chronotype and larger social jetlag (SJL) are associated with an undesirable dietary intake. The 82 healthy university students included in this study were asked to undertake a seven-day wrist activity recording. All the participants also completed a self-administered questionnaire during the recording period, including questions on demographic characteristics and habitual dietary intakes. Dietary intake and the score for adherence to the Japanese Food Guide Spinning Top (food guide score) over the previous month were evaluated using a self-reported diet history questionnaire. Nocturnal sleep timing and total sleep time for each night were estimated using the recorded wrist activity. Chronotype was calculated as weekend (WE) mid-sleep time corrected for catch-up sleep on weekdays (WDs). SJL was calculated by subtracting WD mid-sleep time from WE mid-sleep time. Multivariable linear regression showed that a later chronotype was significantly (P < .05) associated with a lower consumption of eggs, greater consumption of grains, and lower food guide score. Multivariable linear regression also showed significant (P < .05) associations of a larger value in SJL with a lower total energy intake, lower consumption of grains, and greater consumption of sugar and confectioneries. The results suggest that chronotype and SJL may be differently associated with undesirable dietary intake in young adults. These findings have important implications for developing novel strategies, focusing on sleep timing, for improving dietary intakes and preventing lifestyle-related diseases.

STUDY OBJECTIVES: The aim of this research was to investigate the relationships between objectively measured sleep duration and physical function in older adults. METHODS: We recruited community-dwelling older adults aged ≥ 60 years old in Taipei City, Taiwan. Sleep duration was measured with accelerometers and recorded as the total hours of sleep per night for each participant. The following physical functions were assessed: 1) grip strength (measured by handgrip dynamometer), 2) balance (1-leg standing test), 3) lower body strength (5-timed chair stand), 4) basic mobility (timed up and go test), 5) gait speed (5-m walk test). The relationships between sleep duration and physical function outcomes were analyzed using generalized additive models, controlling for objectively measured sedentary behavior and moderate-to-vigorous physical activity, and other sociodemographic variables. RESULTS: A total of 121 older adults (men = 28.9%; mean age = 70.0 ± 5.0 years) was included in this study. A positive association of sleep duration with grip strength was found after adjusting for covariates (P = .005). No significant associations were observed between sleep duration and the other physical function outcomes. CONCLUSIONS: For older adults, lengthening their sleep duration may be helpful to enhance the grip strength. This result has implications for improving their health by targeting better performance in specific physical functions. Further studies of sleep duration and physical function among older adults should investigate the underlying mechanisms. CITATION: Huang W-C, Lin C-Y, Togo F, et al. Association between objectively measured sleep duration and physical function in community-dwelling older adults. J Clin Sleep Med. 2021;17(3):515–520.

School-based education is a potentially effective approach for improving mental health literacy (MHL) in adolescents. This study evaluated the effects of the "Short MHL Program (SMHLP)", a brief (50 min), school teacher-led program, on MHL in adolescents in a quasi-cluster randomized controlled trial.A total of 975 high school first graders (age 15-16) in Japan were allocated to classes such that gender and academic achievement ratios were almost equivalent at the time of admission to the high school. They were assigned at the class level to the SMHLP (n = 364 from 10 classes) or a control group (n = 611 from 17 classes). The program consisted of a 50-minute session and was delivered by a school teacher. The students completed a self-report questionnaire at 3 time points: pre-, (immediately) post- and 2-month follow-up. Outcomes included "Knowledge about mental health/illnesses", "Recognition of the necessity to seek help", "Intention to seek help", and "Intention of helping peers". Mixed effects modeling was employed for analyses.Scores of all outcomes were significantly improved in the intervention group compared to the control group post-intervention (p.001). These improvements were maintained at 2-months follow-up for all outcomes (p.001-.05). Questionnaire scores did not differ between groups at baseline.The effect of the SMHLP was confirmed in grade 10 students. Brief, yet effective programs can be a viable option to promote understanding of mental health problems and have the potential to be incorporated into regular school curriculum. ".

STUDY OBJECTIVES: Despite considering it as a common geriatric condition, sarcopenia is linked to various behavioral factors that may be changeable. As sleep is one of the important routines in physiological homeostasis, further investigating the underlying relationships of sleep behavior with sarcopenia is urgently needed. We examined the association between sleep parameters (ie, sleep duration, bedtime, wake time, or midsleep time) and sarcopenia risks in older adults, in the total sample and age group subsamples. METHODS: A total of 1,068 older adults in Taiwan were included. Data on bedtime, wake time, and sleep duration were collected through telephone interview. Midsleep time was calculated by the midpoint of bedtime and wake time. Sarcopenia was screened by the SARC-F questionnaire composed of 5 questions (the strength, assistance in walking, rising from a chair, climbing stairs, and falls) as well as higher scores was related to greater risks. Generalized additive models were conducted to examine the nonlinear relationships between sleep parameters and sarcopenia risks. RESULTS: The covariate-adjusted analysis showed that a reverse J-shaped relationship for sleep duration and sarcopenia risk (P < .001) and a significant association for wake time and the SARC-F score (P = .009) in total sample, with considering age-related interaction. No associations were found in the other sleep parameters (bedtime and midsleep time) and sarcopenia in older adults. Similar associations were observed between wake time and the SARC-F score across age groups, while diverse associations of sleep duration with the SARC-F score were found in different age groups. CONCLUSIONS: The sleep pattern is significantly associated with sarcopenia risks in aging adults. Improving inappropriate sleep behaviors in older adults is suggested to prevent a decline in muscle function and promote healthy aging. CITATION: Huang W-C, Lin C-Y, Togo F, et al. Nonlinear associations between sleep patterns and sarcopenia risks in older adults. J Clin Sleep Med. 2022;18(3):731–738.

Background School teachers are well-positioned to recognize mental health problems in their students and to help them seek appropriate help. Therefore, teachers need to have high levels of mental health literacy (MHL). In East Asia, however, few studies have examined MHL levels in teachers. In this study, MHL levels were investigated in Japanese teachers. Methods Teachers (n = 665) from 27 Japanese high schools answered a self-administered questionnaire which assessed (a) knowledge about mental health/illnesses, (b) correct recognition of specific illnesses (depression, schizophrenia and panic disorder), (c) confidence in helping students with depressive symptoms, and (d) confidence in teaching mental health knowledge to students. Results The average proportion of correct answers to the knowledge questions (n = 20) was 58.1%. The proportion of those who correctly answered about the presence of a sharp increase of mental illnesses in adolescence was 51.7%. Few teachers correctly answered about the life-time prevalences of major mental illness in general (21.9%), depression (37.8%) and schizophrenia (19.8%). Depression, schizophrenia and panic disorder in vignette were correctly recognized by 54.1, 35.3 and 78.0% of teachers, respectively. Correct recognition was significantly lower in male than in female teachers. Only a small proportion of teachers had confidence in helping depressed students (19.9%) and in teaching mental health knowledge to students (11.1%). Conclusions MHL in Japanese high school teachers appears to be low. Education programs should be developed and implemented to improve teacher MHL with the aim of helping them to support students suffering from mental health problems.

Aim The prevalence of mental disorders increases sharply during adolescence. Therefore, school teachers are in a good position to provide initial assistance to students with mental health problems. Although effects of a number of mental health literacy programs aimed at teachers have been reported, they have not yet been reviewed in a systematic manner. This study conducted a systematic review of the effectiveness of mental health literacy programs for teachers. Methods PubMed, PsycINFO, CINAHL, ERIC, Web of Science and reference lists of included studies were searched in September 2018. Studies that quantitatively measured at least one of the main components of mental health literacy, including (a) knowledge of mental illnesses, (b) stigma towards mental illnesses, (c) confidence in helping students, and (d) behaviour of helping students, were included regardless of study design. Risk of bias was rated for each included study according to the Cochrane tool for randomized studies and the Cochrane tool, for raondomized studies, and the Risk of Bias Assessment Tool for Nonrandomized Studies (RoBANS), for nonrandomized studies. Results Sixteen studies met the inclusion criteria, including 1 randomized controlled trial (RCT), 2 cluster RCTs, 1 controlled before-and-after study and 12 case series. Most of the studies claimed significant improvement of knowledge, attitudes, behaviour and/or confidence. However, the overall quality for all outcomes was relatively low; 15 studies had high/unclear risk of bias due to lack of allocation concealment, not controlling for confounders, and/or inadequate analysis for attrition. Conclusions More high quality evidence is required before the effectiveness of mental health literacy programs for teachers can be established.

Background Previous studies suggest that the forced changes in sleep timing and chronotype may be associated with dietary intake. However, no studies have examined associations between objectively measured sleep timing on weekdays and weekends and habitual dietary intake. This study aimed to investigate the associations among university students. Methods All the 35 healthy university students included in this study were asked to undertake a 7-day wrist activity recording, and to record the bedtimes and wake-up times. All the participants also completed a self-administered questionnaire during the recording period that included demographic characteristics, habitual dietary intakes, and morningness-eveningness. Dietary intakes over the previous 1 month were evaluated using a self-reported dietary history questionnaire (DHQ). The Japanese version of the Morningness-Eveningness Questionnaire (MEQ) was used to measure the self-rated morningness-eveningness. The score for adherence to the Japanese Food Guide Spinning Top (food guide score) was calculated from the results of the DHQ to assess the diet quality. Nocturnal sleep timing on each night was estimated from the recorded wrist activity. Results Multivariate linear regression showed that a later sleep timing on weekends was significantly (p < 0.05) associated with lower intakes of pulses (β = −0.416) and dairy products (β = −0.396) and a lower food guide score (β = −0.386), while the relative sleep timing on weekdays was not (p > 0.05). Multivariate linear regression also showed that an earlier relative sleep timing on weekdays was significantly (p < 0.05) associated with a lower intake of cereals (β = 0.548) and a higher intake of sugar and confectioneries (β = −0.461), while the sleep timing on weekends was not (p > 0.05). Conclusions The results suggest that later sleep timing on weekends and earlier relative sleep timing on weekdays may be independently associated with unfavorable food intake in young adults. These findings have important implications for the development of novel strategies for improving dietary intakes and for preventing lifestyle-related diseases.

This study aims to investigate independent associations of habitual sleep durations and sleep timings on weekdays and weekends with depressive symptoms in adolescents who have classes in the morning. We studied grade 7–9 students (942 males and 940 females, aged 12–15 years), who had classes in the morning, at public junior high schools in Japan in a cross-sectional design. The students answered a self-report questionnaire, which covers habitual sleep durations, bedtimes and wake-up times on weekdays and weekends, and depressive symptoms. The Short Mood and Feelings Questionnaire (SMFQ) was used to determine the level of depressive symptoms. The relationship between the variables on sleep habits and the SMFQ score were studied using multivariate linear regression and generalized additive models (GAM), controlling for sex, age and school. Multivariate linear regression analysis revealed that sleep duration on weekdays and relative mid-sleep time on weekdays (i.e. mid-sleep time on weekdays – mid-sleep time on weekends) were independently significantly (p p

Aim A concise teacher-led program for mental health literacy (MHL), suitable for schools with tight schedules was developed, and its effects were examined in pre-teens. Methods Participants comprised 662 grade 5 to 6 students from nine Japanese elementary schools. The program consisted of a 45-minute session, delivered by school teachers using a 10-minute animated film. Program focuses included: mental health problems are common, can be associated with lifestyle and that seeking help from reliable adults is a key to finding solutions. Participants filled out self-report questionnaires before, immediately after and 3 months post-intervention. Changes in MHL were analyzed using multilevel models. Results Knowledge about mental health/illnesses, recognition of mental health state and intention to help peers/seek help when suffering from mental health problems, were significantly improved immediately and 3 months post-intervention. Conclusions Concise teacher-led programs administered in schools can have positive and lasting effects on MHL in pre-teens.

Summary Objectives: This study aimed to describe a robust method with high time resolution for estimating the cortico-thalamo-cortical (CTC) loop strength and the delay when using a scalp electroencephalography (EEG) and to illustrate its applicability for analyzing the wake-sleep transition. Methods: The basic framework for the proposed method is the parallel use of a physiological model and a parametric phenomenological model: a neural field theory (NFT) of the corticothalamic system and an autoregressive (AR) model. The AR model is a “stochastic” model that shortens the time taken to extract spectral features and is also a “linear” model that is free from the local-minimum problem. From the relationship between the transfer function of the AR model and the transfer function of the NFT in the low frequency limit, we successfully derived a direct expression of CTC loop strength and the loop delay using AR coefficients. Results: Using this method to analyze sleep-EEG data, we were able to clearly track the wake-to-sleep transition, as the estimated CTC loop strength (c 2) decreased to almost zero. We also found that the c 2-distribution during nocturnal sleep is clearly bimodal in nature, which can be well approximated by the superposition of two Gaussian distributions that correspond to sleep and wake states, respectively. The estimated loop delay distributed ∼0.08 s, which agrees well with the previously reported value estimated by other methods, confirming the validity of our method. Conclusions: A robust method with high time resolution was developed for estimating the cortico-thalamo-cortical loop strength and the delay when using a scalp electroencephalography. This method can contribute not only to detecting the wake-sleep transition, but also to further understanding of the transition, where the cortico-thalamo-cortical loop is thought to play an important role.

Suicide is a leading cause of death in adolescents, but detection of its risk is often challenging. Many mental illnesses share the common symptom of appetite loss and it is also known that people who suffer from these illnesses are at greater risk of suicide. However, the relationship between appetite loss and suicide risk has yet to be examined. For adolescents in particular, questions about appetite loss may be easier to answer than sensitive questions regarding mental health. The present study aims to investigate the association of appetite loss with suicidal ideation and self-harm in adolescents. Rates of adolescents with suicidal ideation or self-harm associated with appetite-loss were examined in 18,250 Japanese junior and senior high school students (aged 12-18) using a self-report questionnaire. Insomnia, a physical symptom which has previously been associated with suicide risk, was also controlled for in the analysis. Results showed that rates of adolescents with suicidal ideation or self-harm significantly increased according to the degree of self-reported appetite loss. Similar results were observed for insomnia. Odds ratios (ORs) for suicidal ideation and self-harm were 5.5 and 4.1 for adolescents with appetite loss compared to those without it, and the ORs were 5.5 and 3.5 for those with insomnia compared to those without it, respectively, adjusting for sex and age (p 0.001). ORs remained statistically significant after adjusting for depression/anxiety (General Health Questionnaire-12 score). In conclusion, self-reported appetite loss was highly associated with suicidal ideation and self-harm in adolescents; adolescents reporting physical symptoms such as loss of appetite or insomnia should be given careful attention.

A method to extract latent semantic components from noisy categorical time-series data based on the Takens’ time-delay-embedding method and singular value decomposition is presented. A demonstration of this method to analyze a sleep stage time-series is demonstrated. The first component extracted by this method, i.e., the component with the largest singular value can be considered the circadian rhythm. The second component, which exhibits damping oscillation, can be interpreted as the ultradian rhythm, and matched with the moving-averaged $c_{2}$; which is an estimation of the cortico-thalamo-cortical loop strength calculated from the corresponding electroencephalogram data using the method previously reported. The sleep stage is treated as a nominal variable instead of an ordinal variable in this method; however, the quantitative variation of sleep state is extracted from the sleep stage time-series. We believe that this result suggests the validity and usefulness of both the methods, i.e., the method reported in the present study and the method reported in a previous study.

Patients with chronic fatigue syndrome (CFS) and fibromyalgia (FM) often have sleep-related problems. In this chapter, we will review studies on sleep in CFS and FM patients in order to better understand their sleep problems, effects of treatment of their sleep problems, and differences between these two conditions. Polysomnographic studies have shown sleep problems in CFS and FM, that is, increased Stage 1 sleep, reduced slow-wave sleep, more arousals, prolonged sleep onset, reduced sleep efficiency, and microarousals or subcortical arousals during sleep, while dynamic aspects of sleep show different patterns between CFS and FM patients. Studies on pharmacological and nonpharmacological interventions such as antidepressants, graded exercise, and cognitive behavior therapy have been shown to produce improvements in sleep problems. However, limited research has been conducted on the effects of nonpharmacological interventions on sleep problems in patients with CFS or FM for revealing the optimal strategy for exercise therapy and cognitive behavior therapy in patients with CFS and/or FM.

OBJECTIVES: This observational study aimed to determine how 1-year changes in work time control (WTC) have an impact upon objectively measured fatigue and sleep among employees. METHODS: Thirty-nine employees were divided into two groups according to whether or not their WTC increased from baseline to 1 year later. Psychomotor vigilance task (PVT) and wrist actigraphy were used to objectively measure fatigue and sleep, respectively. Self-reported outcomes were also measured. RESULTS: The increased WTC group showed gradual improvements in PVT performance and sleep quality over the course of the follow-up period compared with the not-increased WTC group. Between-group differences were statistically significant for PVT lapses and tended to be significant for PVT speed after 1 year. CONCLUSIONS: A progressive increase in WTC could play a crucial role in reducing fatigue and promoting sleep among employees. Language: en

To investigate the longitudinal relationship between sleep habits and mental health in adolescents.Multipoint observation data of up to five years were employed from a prospective cohort study of sleep habits and mental health status conducted from 2009 to 2013 in a unified junior and senior high school (grades 7-12) in Tokyo, Japan. A total of 1078 students answered a self-report questionnaire, including items on usual bed and wake-up times on school days, and the Japanese version of the 12-item General Health Questionnaire (GHQ-12).Latent growth model (LGM) analysis, which requires three or more time point data, showed that longitudinal changes in bedtime and GHQ-12 score (or score for depression/anxiety) were significantly and moderately correlated (correlation coefficient = 0.510, p 0.05). Another result of interest was that, using an autoregressive cross-lagged (ARCL) model, bedtime and the depression/anxiety score had reciprocal effects the following year: ie, bedtime significantly affects the following year's depression/anxiety, and vice versa. In addition, the analysis provided estimates of mutually predicted changes: one-hour bedtime delay may worsen the GHQ-12 score by 0.2 points, and one-point worsening of the score may delay bedtime by 2.2 minutes.By using up to five multiple time point data, the present study confirms the correlational and reciprocally longitudinal relationship between bedtime delay and mental health status in Japanese adolescents. The results indicate that preventing late bedtime may have a significant effect on improving mental health in adolescents.

There is growing interest in within-person associations of objectively measured physical and physiological variables with psychological states in daily life. Here we provide a practical guide with SAS code of multilevel modeling for analyzing physical activity data obtained by accelerometer and self-report data from intensive and repeated measures using ecological momentary assessments (EMA). We review previous applications of EMA in research and clinical settings and the analytical tools that are useful for EMA research. We exemplify the analyses of EMA data with cases on physical activity data and affect and discuss the future challenges in the field.

Although effects of sleep duration and physical activity (PA) have been demonstrated on mental health in adolescents, their interactive effect has not been studied. This cross-sectional study first examines this interactive effect on anxiety/depression in adolescents. A total of 983 Japanese students aged 12-17 were studied, using a self-report questionnaire. The interaction of sleep duration and amount of PA and their main effects on anxiety/depression, assessed using the 12-item General Health Questionnaire (GHQ-12), were investigated employing multiple regression, adjusting for grade and sex. Sleep duration and amount of PA were classified as being adequate or not, according to the duration and amount recommended by the National Sleep Foundation and World Health Organization, respectively. As a result, the interaction between sleep duration and amount of PA and their main effects were statistically significant. GHQ-12 score was significantly better in adolescents with either adequate sleep or adequate PA, not both, than those with neither adequate sleep nor adequate PA. The score, however, seemed no further improved in those with both adequate sleep and PA. The present study suggests that effects of sleep and PA on mental health need to be studied with consideration to their interaction.

Rotating shift workers are associated with imbalanced dietary intakes. Rotating shift workers and dietary intakes in adults who do not engage in night work have also been shown to be associated with chronotype. However, no studies have examined associations between morningness-eveningness (i.e., the degree to which people prefer to be active in the morning or the evening), rotating shift work and dietary intakes. Therefore, our first purpose was to elucidate the association between morningness-eveningness and habitual food group intakes in rotating shift workers. The second purpose was to elucidate the association of morningness-eveningness and rotating shift work with food group intakes, considering habitual sleep durations. Japanese nurses (1095 day workers and 1464 rotating shift workers) were studied using a self-administered questionnaire. The questionnaire covered habitual dietary intakes, morningness-eveningness and demographic characteristics of the participants. A Japanese version of the Morningness-Eveningness Questionnaire (MEQ) was used to measure self-rated morningness-eveningness. Dietary intakes over the previous 1 month were evaluated using a semi-quantitative food frequency questionnaire. Intakes of pulses, green/yellow vegetables, white vegetables, fruits, algae, eggs, confectioneries/savory snacks and sugar-sweetened beverages were significantly (p 0.05) associated with the MEQ score in rotating shift workers. Among these food groups, intakes of green/yellow vegetables, white vegetables, fruits and algae were significantly (p 0.05) lower in rotating shift workers than in day workers, and intakes of confectioneries/savory snacks and sugar-sweetened beverages were significantly (p 0.05) higher in rotating shift workers than in day workers. Intakes of these food groups were also significantly (p 0.05) associated with the MEQ score in day workers. In addition, the MEQ score was significantly (p 0.05) lower in rotating shift workers than in day workers, indicating greater eveningness among rotating shift workers. Multivariate linear regression revealed that the MEQ scores were significantly (p 0.05) associated with intakes of these food groups, while rotating shift work was associated only with confectioneries/savory snacks. These results suggest that morningness-eveningness is associated with unbalanced dietary intakes in rotating shift workers as well as day workers, which may partially explain associations between rotating shift work and unfavorable dietary intakes. These findings have important implications for the development of novel strategies for preventing poor health caused by imbalanced dietary intakes in rotating shift workers.

Background: Galvanic vestibular stimulation delivered as zero-mean current noise (noisy GVS) has been shown to improve static and dynamic postural stability probably by enhancing vestibular information. Objective: /Hypothesis: To examine the effect of an imperceptible level of noisy GVS on dynamic locomotion in normal subjects as well as in patients with bilateral vestibulopathy. Methods: Walking performance of 19 healthy subjects and 12 patients with bilateral vestibulopathy at their preferred speed was examined during application of noisy GVS with an amplitude ranging from 0 to 1000 μA. The gait velocity, stride length and stride time were analyzed. Results: Noisy GVS had significant effects on gait velocity, stride length and stride time in healthy subjects as well as in patients with bilateral vestibulopathy (p 0.4). Conclusion: Noisy GVS is effective in improving gait performance in healthy subjects as well as in patients with bilateral vestibulopathy.

Objective Galvanic vestibular stimulation (GVS) delivered as zero-mean current noise (noisy GVS) has been shown to improve static and dynamic postural stability probably by enhancing vestibular information. The purpose of this study was to examine the effect of an imperceptible level noisy GVS on ocular vestibular-evoked myogenic potentials (oVEMPs) in response to bone-conducted vibration (BCV). Materials and methods oVEMPs to BCV were measured during the application of white noise GVS with an amplitude ranging from 0 to 300 µA [in root mean square (RMS)] in 20 healthy subjects. Artifacts in the oVEMPs caused by GVS were reduced by inverting the waveforms of noisy GVS in the later half of the stimulus from the one in the early half. We examined the amplitudes of N1 and N1–P1 and their latencies. Results Noisy GVS significantly increased the N1 and N1–P1 amplitudes (p 0.05). Noisy GVS had facilitatory effects in 79% of ears. The amplitude of the optimal stimulus was 127 ± 14 µA, and it increased the N1 and N1–P1 amplitude by 75.9 ± 15% and 47.7 ± 9.1%, respectively, as compared with 0 µA session (p

Higher depressive symptoms have been reported in rotating shift workers compared with day workers. Depressive symptoms in adults who do not engage in night work have also been shown to be associated with chronotype and sleep duration. This study examines associations between depressive symptoms, morningness-eveningness (i.e. the degree to which people prefer to be active in the morning or the evening), sleep duration and rotating shift work. Japanese nurses (1252 day workers and 1780 rotating shift workers, aged 20–59) were studied using a self-administered questionnaire. The questionnaire covered depressive symptoms, morningness-eveningness, sleep habits and demographic characteristics of the participants. The Center for Epidemiologic Studies Depression Scale (CES-D) was used to determine the levels of depressive symptoms. A Japanese version of the Morningness-Eveningness Questionnaire (MEQ) was used to measure morningness-eveningness. The CES-D score of shift workers was significantly (p < 0.05) higher than that of day workers. The MEQ score was significantly (p < 0.05) lower (i.e. greater eveningness) in shift workers than in day workers. Sleep duration on the day shift was significantly (p < 0.05) shorter in shift workers than in day workers. Simple linear regression revealed that the MEQ score, sleep duration on the day shift and current work shift (i.e. rotating shift work) were significantly (p < 0.05) associated with the CES-D score. Multivariate linear regression indicated that greater eveningness and shorter sleep duration were independently associated with higher CES-D scores, while rotating shift work was not. These associations between the MEQ score, the sleep duration and the CES-D score were also confirmed in both day workers and shift workers when the groups were analyzed separately. These results suggest that greater eveningness and shorter sleep duration on the day shift were independently associated with higher levels of depressive symptoms, which may explain associations between rotating shift workers and depressive symptoms. These findings have important implications for the development of novel strategies for preventing poor mental health in day workers and rotating shift workers.

Objective Higher body mass index (BMI) values have been reported in rotating shift workers compared with regular daytime workers. This study examines the relationship between work schedule and BMI, and considers whether lifestyle habits could explain the relationship. Methods Japanese female nurses (1179 day workers and 1579 rotating shift workers, aged 20-59) were studied using self-administered questionnaires. The questionnaires assessed height, weight, and dietary intake, physical activity, and sleep (lifestyle) habits. Results The BMI of shift workers was significantly higher than that of day workers. Shift workers consumed significantly higher amounts of sugar-sweetened beverages and slept for significantly shorter durations on nights between days on the day shift compared with day workers—factors which were also independently associated with higher BMI. In addition, multivariable linear regression coefficients for BMI showed a significant correlation with rotating shift work (β = 0.051), after controlling for lifestyle habits. Conclusions Higher consumption of sugar-sweetened beverages and shorter sleep duration were associated with rotating shift work and higher BMI. This should be taken into consideration in preventing obesity in real-life shift work situations. Other shift work-related factors, such as abnormal timing of meals and/or sleep, should also be identified.

AIM The purpose of this study was to examine the effects of bright light exposure on behavioral and psychological symptoms of dementia (BPSD), including sleep disturbances and the burden on caregivers in institutionalized elderly with cognitive decline. METHODS The subjects included eight people with cognitive decline (mean [SD] age, 79.9 [9.1] years) living in geriatric healthcare facilities for the elderly. BPSD and the burden on caregivers were measured over three weeks using the CMAI (Cohen-Mansfield Agitation Inventory), NPI-NH (Neuropsychiatric Inventory-Nursing Home Version) and J-ZBI (Modified Japanese Version of the Zarit Caregiver Burden Interview) at the end of each week. During the second week, the subjects received either 12,000 K (white) or 2,400 K (orange) of light corresponding to approximately 2,000 lux from a light-emitting diode (LED) device, measured before the eyes in the gaze direction, from 9 : 00 to 9 : 30 during occupational tasks, such as origami and coloring. Differences in the variables obtained at the different weeks were assessed using ANOVA with multiple comparisons. RESULTS The scores for the severity of BPSD, including sleep disturbances and the burden on caregivers, on the NPI-NH significantly (P

Chronic fatigue syndrome (CFS) is a medically unexplained illness characterized by persistent or relapsing fatigue lasting at least 6 months and producing substantial interference with normal activities accompanied by rheumatologic, infectious and neuropsychiatric complaints of similar duration (Fukuda et al., 1994). Prominent among these are cognitive difficulties including problems with information processing, learning, memory, and problem solving (Deluca, Johnson, & Natelson, 1993; Short, McCabe, & Tooley, 2002; Tiersky, Johnson, Lange, Natelson, & Deluca, 1997; Wearden & Appleby, 1997). Although impairments have been found in a variety of cognitive domains, the most robust findings in individuals with CFS are inefficient, slowed information processing in the verbal (Deluca, Johnson, Ellis, & Natelson, 1997) as well as visual domains (Deluca et al., 2004). Information processing is a basic cognitive component providing the underpinning for many other higher order cognitive functions including learning, memory, and problem solving. As speed of information processing decreases, the amount of information held at any one time in working memory, which stores and manipulates information, decreases (Wilhelm & Oberauer, 2006). Reduced working memory capacity can in turn affect an individual's ability to set decision making priorities, resolve conflicts, inhibit irrelevant information and make decisions appropriately, smoothly, efficiently, and cumulatively. These functions are subsumed under the term executive function, useful and often necessary for multi-tasking. Many individuals with CFS are challenged by multiple and competing input – leading to difficulties with multi-tasking especially under conditions of increasing complexity when there is a need to screen out irrelevant information. The development of the Attention Network Task (ANT) (Fan, McCandliss, Sommer, Raz, & Posner, 2002) is based on a well-developed neural network model of the human attention system (Fan et al., 2002; Posner & Petersen, 1990). The ANT combines a cued reaction time task (Posner, 1980) and a flanker task (Eriksen & Eriksen, 1974) and was developed to assess the operation of the attention system across three kinds of attention processing: alerting, orienting, and executive control (Posner & Petersen, 1990). The alerting condition of the ANT reflects the extent to which there is a benefit of temporal cueing to maintain cognitive vigilance. To assess orienting, a spatial cue is used before onset of the primary stimulus which reveals the efficiency with which subsequent targets can be located in space. Executive function is assessed by using peripheral or flanking arrows incongruent with a central target arrow that requires quick decision making, response coordination, and execution. We hypothesized that individuals with CFS would have significantly more difficulties (i.e., perform significantly more slowly) on the executive function component of the ANT when controlling for generalized slowing (measured using a simple reaction time task) consistent with previous findings (Deluca et al., 2004), using a different set of cognitive performance measures. In an earlier anatomical neuroimaging study, Lange et al. (1999) found CFS patients to have the most abnormalities in the frontal lobes – the region of the brain which includes a part of the executive control network. A functional neuroimaging study showed that activations of the alerting, orienting, and executive control networks were associated with the thalamic activations, parietal activations, and anterior cingulate cortex activations, respectively (Fan, McCandliss, Fossella, Flombaum, & Posner, 2005). Therefore, we also hypothesized that individuals with CFS would not have difficulties on the alerting and orienting component of the ANT when controlling for generalized slowing.

The purpose of this study was to investigate whether scheduling meals earlier in the day affects the circadian phase of the cardiac autonomic nervous system as assessed by heart rate variability (HRV) and serum lipid levels. Healthy men aged 21.4 ± 0.5 years (n = 14) with a habit of regularly skipping breakfast participated in this parallel trial involving altered feeding schedules. Participants in the early mealtime group (EM group, n = 8) were asked to eat three meals at 8:00, 13:00, and 18:00, and the control group (n = 6) ate at 13:00, 18:00, and 23:00 for 2 weeks. On the measurement day before and after intervention, fasting blood samples and 24-h electrocardiograph recordings were collected. Spectral analysis was used for approximate 10-min HRV segments. Low frequency (LF) power, high frequency (HF) power, and the ratio of HF to total power (%HF) were calculated to assess sympathovagal balance. Acrophases of the circadian rhythm of HRV variables were obtained by nonlinear least squares regression. Triglyceride and total and LDL cholesterol levels were significantly decreased in the EM group when compared with the control group (p = 0.035, 0.008, and 0.004, respectively). Acrophases for HRV variables were advanced in the EM group and their difference between before and after the intervention in LF power (−3.2 ± 1.2 h) and %HF (−1.2 ± 0.5 h) reached significant level, respectively (p

We determined whether alterations in heart rate dynamics during sleep in patients with chronic fatigue syndrome (CFS) differed from controls and/or correlated with changes of sleepiness before and after a night in the sleep laboratory. We compared beat-to-beat RR intervals (RRI) during nocturnal sleep, sleep structure, and subjective scores on visual analog scale for sleepiness in 18 CFS patients with 19 healthy controls aged 25–55 after excluding subjects with sleep disorders. A short-term fractal scaling exponent (α1) of RRI dynamics, analyzed by the detrended fluctuation analysis (DFA) method, was assessed after stratifying patients into those who reported more or less sleepiness after the night’s sleep (a.m. sleepier or a.m. less sleepy, respectively). Patients in the a.m. sleepier group showed significantly (p < 0.05) higher fractal scaling index α1 during non-rapid eye movement (non-REM) sleep (Stages 1, 2, and 3 sleep) than healthy controls, although standard polysomnographic measures did not differ between the groups. The fractal scaling index α1 during non-REM sleep was significantly (p < 0.05) lower than that during awake periods after sleep onset for healthy controls and patients in the a.m. less sleepy group, but did not differ between sleep stages for patients in the a.m. sleepier group. For patients, changes in self-reported sleepiness before and after the night correlated positively with the fractal scaling index α1 during non-REM sleep (p < 0.05). These results suggest that RRI dynamics or autonomic nervous system activity during non-REM sleep might be associated with disrupted sleep in patients with CFS.

Background Misalignment of circadian systems is detrimental to human health. However, only a few studies have examined the influence of late meals on the human circadian system. The purpose of this study was to investigate whether delayed meals affect circadian rhythm as assessed by heart rate variability (HRV). Methods Seven healthy men (aged 22.4 ± 0.4 years) participated in this study, which involved delaying mealtimes by 5 h for two weeks. Prior to this study, the regular mealtimes of participants were at 08:00, 13:00, and 18:00 (Baseline). During the intervention, each meal was provided at 13:00, 18:00 and 23:00 (Late mealtimes). Circadian variation was assessed by HRV based on R–R intervals calculated from a pulse at the rising phase of each spike in the QRS complex in a 24-h electrocardiograph record. The ratio of low frequency (LF) to high frequency (HF) power (LF/HF) and the ratio of HF power to total power (%HF) were calculated using spectral analysis. The phase and amplitude of HRV variables in a 24-h period were mathematically obtained with double cosinor analysis. Results The acrophase and amplitude for LF power, HF power and %HF in a 24-h period were not significantly different between Baseline and Late mealtimes. On the other hand, the acrophase significantly differed between Baseline and Late mealtimes for heart rate (95%CI, 1.1–3.8 h), standard deviation of R–R intervals (95%CI, 2.5–4.4 h) and LF/HF (95%CI, 1.1–2.3 h). Conclusions Our findings suggest that delayed mealtimes shift the phase of circadian rhythm of the autonomic nervous system.

Objectives Our study examines differences in eating behaviour between day workers and rotating shift workers, and considers whether diurnal preference could explain the differences. Methods Japanese female nurses were studied (39 day workers and 123 rotating shift workers, aged 21–63 years) using self-administered questionnaires. The questionnaires assessed eating behaviours, diurnal preference and demographic characteristics. The questionnaire in the Guidelines for the management of obesity disease issued by the Japan Society for the Study of Obesity was used to obtain scores for the levels of obesity-related eating behaviours, including cognition of constitution, motivation for eating, eating as a diversion, feeling of satiety, eating style, meal contents and temporal eating patterns. The Japanese version of the Morningness–Eveningness (ME) questionnaire was used to measure self-rated preference for the degree to which people prefer to be active in the morning or the evening (ME). Results The scores for meal contents and temporal eating patterns in rotating shift workers were significantly higher than those in day workers. The ME score of rotating shift workers was significantly lower, indicating greater eveningness/less morningness among rotating shift workers. Multivariate linear regression revealed that the ME score was significantly negatively associated with temporal eating patterns and showed a negative association with the score for meal contents at a trend level, while current work shift was not significantly correlated with the scores. Conclusions These results suggest that eating behaviours for rotating shift workers are associated with a more unbalanced diet and abnormal temporal eating patterns and that the associations may be explained by diurnal preference rather than by rotating shift work.

Vestibular dysfunction causes postural instability, which is prevalent in the elderly. We previously showed that an imperceptible level of noisy galvanic vestibular stimulation (nGVS) can improve postural stability in patients with bilateral vestibulopathy during the stimulus, presumably by enhancing vestibular information processing. In this study, we investigated the after-effects of an imperceptible long-duration nGVS on body balance in elderly adults. Thirty elderly participants underwent two nGVS sessions in a randomised order. In Session 1, participants received nGVS for 30 min twice with a 4-h interval. In Session 2, participants received nGVS for 3 h. Two-legged stance tasks were performed with eyes closed while participants stood on a foam rubber surface, with and without nGVS, and parameters related to postural stability were measured using posturography. In both sessions, the postural stability was markedly improved for more than 2 h after the cessation of the stimulus and tended to decrease thereafter. The second stimulation in Session 1 caused a moderate additional improvement in body balance and promoted the sustainability of the improvement. These results suggest that nGVS can lead to a postural stability improvement in elderly adults that lasts for several hours after the cessation of the stimulus, probably via vestibular neuroplasticity.

STUDY OBJECTIVES To investigate sleep duration associated with the least depression/anxiety in adolescence. METHODS Grades 7-12 Japanese students (n = 18,250, aged 12-18 y) from public junior high/high schools were studied in a cross-sectional design. Due to missing/implausible data, 15,637 out of the 18,250 students were statistically analyzed. Relationship between sleep duration on school nights and depression/anxiety, measured using self-report questionnaires, including the General Health Questionnaire-12 (GHQ-12), were studied by sex and grade, controlling for bedtime regularity. RESULTS When sleep duration was classified by 1-h intervals, rate of adolescents with a GHQ-12 score ≥ 4 was the lowest in males and females who slept 8.5-9.5 h and 7.5-8.5 h, respectively, (designated "references") in both grades 7-9 and 10-12. The rate was significantly higher than the references in both males and females who slept < 7.5 h, regardless of grade (P < 0.05, logistic regression). GHQ-12 tended to be worse in adolescents (2.0%-13.5%) who slept longer than the references. Sleep duration for the minimum GHQ-12 score was estimated to be 8.8 and 8.5 h in males, and 8.0 and 7.5 h in females, in grades 7-9 and 10-12, respectively, using the General Additive Model. CONCLUSIONS Sleep duration of ≥ 8.5 h on school nights may be associated with the lowest risk of depression/anxiety on average in male adolescents. Although the duration was estimated to be shorter in females (≥ 7.5 h) than males, this should be interpreted carefully. Most adolescents may currently be sleeping less than the optimal duration. COMMENTARY A commentary on this article appears in this issue on page 1491.