Moving toward the reduction of publication/reporting biases in clinical trials using a new international standard.

Evidence-based medicine (EBM) is fundamental to ensuring high-quality medical care. It requires systematic reviews and meta-analyses to synthesize diverse information available from individual clinical studies. However, the literature reviewed may represent an incomplete and selective set of research findings, which could lead to publication/reporting biases and distort the true picture of research as a whole. Prospective registry of all clinical trials in the world is mandatory to reduce the biases, which have been disclosed on the International Clinical Trials Registry Platform (ICTRP) of the World Health Organization (WHO) since 2007. The Japan Primary Registries Network (JPRN) is included in the ICTRP. ClinicalTrials.gov, the U.S. clinical trial registry, reports the standardized data of registered trials and offers access to submitted outcomes online. However, the JPRN does not systematically include the outcomes. On April 14, 2015, the WHO published a new statement online on the public disclosure of clinical trial results, which requires researchers to define the timeframes of reporting main findings and key outcomes, to call for results-reporting older, but still unpublished trials, and to outline steps to improve linkages between clinical trial registry entries and their published results. The WHO's new position will facilitate global efforts to reduce publication/reporting biases in clinical trials. Japan will have to actively participate in these efforts as well.

[A literature review on epidemiologic research on sleep disturbances in the elderly].

One of the issues facing our super-aging society of Japan is to secure the elderly's safety and health. According to the latest 10-year statistics of the National Police Agency, the number of elderly driving deaths 75 years of age and over has risen 1.3 times from 2003 to 2013, whereas driving deaths decreased by less than half among the people under age 75 during the same period of time. This paper reviews the current literature on epidemiologic studies investigating the associations of sleep disturbances with adverse driving events and driving practice among elderly drivers. The results suggest a cognitive behavioral therapy for insomnia as a promising method for improving their driving capacity. Key words: elderly driving, epidemiology, sleep disturbances

Reliability of the strengths and difficulties questionnaire in Japanese preschool children aged 4-6 years.

BACKGROUND: The Strengths and Difficulties Questionnaire (SDQ) has been widely used as a brief behavioral screening. The aim of this study was to examine the internal consistency and test-retest reliability of the 3- to 4-year-old version of the SDQ (SDQ 3-4) in Japanese preschool children. METHODS: The SDQ 3-4 was administered to 754 parents who had 4- to 6-year-old children attending kindergartens or childcare centers in Wako City, Japan, at 2 different times (Time 1 and Time 2) over a 2-week interval between June and July 2012. Cronbach's α and correlation coefficients were used to examine internal consistency and test-retest reliability, respectively. RESULTS: Of 393 parents who returned their responses at Time 1 (response rate 52.1%), 383 were used for analysis after excluding 10 responses with missing data. Their children's mean age was 4.7 (standard deviation 0.7) years. The internal consistency (Cronbach's α) was good for the total difficulties score (0.74) and the prosocial behavior scale (0.70). However, it was slightly worse for the emotional symptoms, conduct problems, and hyperactivity scales (0.61-0.66) and poor for the peer problems scale (0.45). Of the 383 included respondents at Time 1, 211 parents returned their responses at Time 2 (response rate: 55.1%). Test-retest reliability (correlation coefficients) was good (0.73-0.82), except for the peer problems scale (0.58). CONCLUSIONS: The results support the reliability of the SDQ 3-4 being satisfactory for the total difficulties score and prosocial behavior scale and being acceptable for the emotional symptoms, conduct problems, and hyperactivity scales in Japanese preschool children aged 4-6 years.

Reliability of the Strengths and Difficulties Questionnaire in Japanese Preschool Children Aged 4-6 Years.

Background: The Strengths and Difficulties Questionnaire (SDQ) has been widely used as a brief behavioral screening. The aim of this study was to examine the internal consistency and test-retest reliability of the 3- to 4-year-old version of the SDQ (SDQ 3-4) in Japanese preschool children.Methods: The SDQ 3-4 was administered to 754 parents who had 4- to 6-year-old children attending kindergartens or childcare centers in Wako City, Japan, at 2 different times (Time 1 and Time 2) over a 2-week interval between June and July 2012. Cronbach's α and correlation coefficients were used to examine internal consistency and test-retest reliability, respectively.Results: Of 393 parents who returned their responses at Time 1 (response rate 52.1%), 383 were used for analysis after excluding 10 responses with missing data. Their children's mean age was 4.7 (standard deviation 0.7) years. The internal consistency (Cronbach's α) was good for the total difficulties score (0.74) and the prosocial behavior scale (0.70). However, it was slightly worse for the emotional symptoms, conduct problems, and hyperactivity scales (0.61-0.66) and poor for the peer problems scale (0.45). Of the 383 included respondents at Time 1, 211 parents returned their responses at Time 2 (response rate: 55.1%). Test-retest reliability (correlation coefficients) was good (0.73-0.82), except for the peer problems scale (0.58).Conclusions: The results support the reliability of the SDQ 3-4 being satisfactory for the total difficulties score and prosocial behavior scale and being acceptable for the emotional symptoms, conduct problems, and hyperactivity scales in Japanese preschool children aged 4-6 years.

Prevalence and incidence of amyotrophic lateral sclerosis in Japan.

BACKGROUND: Previous studies have reported a high incidence of amyotrophic lateral sclerosis (ALS) in endemic foci in the Kii Peninsula, Japan. However, little is known about the ALS frequency in the whole country. Furthermore, the presence of ethnic variation in the incidence of ALS remains unknown. METHODS: We conducted a nationwide survey of ALS frequency in 2013 to estimate its annual prevalence and incidence. ALS was diagnosed based on the El Escorial Criteria. The study period was the 2009 fiscal year, from April 2009 to March 2010. To compare the incidence of ALS among prefectures, standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated under the assumption of Poisson distribution. RESULTS: The annual crude prevalence and incidence rates per 100 000 people per year were 9.9 (95% CI 9.7-10.1) and 2.2 (95% CI 2.1-2.3), respectively. The age group with the highest prevalence as well as incidence was 70-79 years, and the male-female ratio was approximately 1.5. The annual incidence rate adjusted for age and sex using the 2000 U.S. standard population was 2.3 (95% CI 2.2-2.4) per 100 000 people. Some prefectures had significantly high SIRs: Okinawa, Nara and Wakayama in the Kii Peninsula, and Niigata for males; Kumamoto for females. CONCLUSIONS: This is the first report on the annual prevalence and incidence of ALS in the representative population of Japan. We identified some prefectures with a high incidence of ALS. However, the incidence of ALS in the Japanese population was much lower than in the Caucasian populations of Europe and North America.

Prevalence and Incidence of Amyotrophic Lateral Sclerosis in Japan.

Background: Previous studies have reported a high incidence of amyotrophic lateral sclerosis (ALS) in endemic foci in the Kii Peninsula, Japan. However, little is known about the ALS frequency in the whole country. Furthermore, the presence of ethnic variation in the incidence of ALS remains unknown.Methods: We conducted a nationwide survey of ALS frequency in 2013 to estimate its annual prevalence and incidence. ALS was diagnosed based on the El Escorial Criteria. The study period was the 2009 fiscal year, from April 2009 to March 2010. To compare the incidence of ALS among prefectures, standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated under the assumption of Poisson distribution.Results: The annual crude prevalence and incidence rates per 100 000 people per year were 9.9 (95% CI 9.7-10.1) and 2.2 (95% CI 2.1-2.3), respectively. The age group with the highest prevalence as well as incidence was 70-79 years, and the male-female ratio was approximately 1.5. The annual incidence rate adjusted for age and sex using the 2000 U.S. standard population was 2.3 (95% CI 2.2-2.4) per 100 000 people. Some prefectures had significantly high SIRs: Okinawa, Nara and Wakayama in the Kii Peninsula, and Niigata for males; Kumamoto for females.Conclusions: This is the first report on the annual prevalence and incidence of ALS in the representative population of Japan. We identified some prefectures with a high incidence of ALS. However, the incidence of ALS in the Japanese population was much lower than in the Caucasian populations of Europe and North America.

A Salmonella enterica Serovar Oranienburg Clone Caused a Cluster of Bacteremia Cases in Persons With No Recognizable Underlying Diseases in Japan.

Background: Salmonella enterica subspecies enterica serovar Oranienburg (SO) is a foodborne pathogen but rarely causes systemic infections such as bacteremia. Between July and September 2018, bacteremia cases caused by SO were identified in 12 persons without any underlying medical conditions in the southern Kyushu area of Japan. Methods: Randomly amplified polymorphic DNA (RAPD) analysis was performed to investigate the genetic similarity of the 12 bacteremia-related strains and other Japanese isolates. Furthermore, a series of whole-genome sequence (WGS)-based phylogenetic analyses was performed with a global SO strain set (n = 1648). Results: The resolution power of RAPD was insufficient to investigate the genetic similarity between the bacteremia-related strains and other strains. WGS-based phylogenetic analyses revealed that the bacteremia-related strains formed a tight cluster along with 2 strains isolated from asymptomatic carriers in 2018 in the same area, with a maximum within-cluster single-nucleotide polymorphism (SNP) distance of 11. While several strains isolated in the United States and the United Kingdom were found to be closely related to the bacteremia-related strains, 2 strains isolated in 2016 in the southern Kyushu area were most closely related, with SNP distances of 4-11 and 5-10, and had the same plasmids as the bacteremia-related strains. Conclusions: The 12 bacteremia cases identified were caused by a single SO clone. As none of the bacteremia patients had any underlying diseases, this clone may be prone to cause bacteremia. Although further analyses are required to understand its virulence, particular attention should be given to this clone and its close relatives in the surveillance of nontyphoidal salmonellae.

How can the national burden of Parkinson's disease comorbidity and mortality be estimated for the Japanese population?

BACKGROUND: Good medical care results in long survival for patients with Parkinson's disease (PD). However, little is known about the burden of PD comorbidity and mortality in Japan. This is the first study to examine comorbid diseases of PD decedents and extrapolate PD death rates from multiple-cause coding mortality data for the total population of Japan. METHODS: Data for 4589 certified deaths due to PD as the underlying cause of death (ICD-10 code: G20) were obtained from the 2008 Japanese vital statistics. Of those, comorbidities listed in the death certificates of 477 randomly selected decedents were analyzed. All diseases or conditions mentioned on death certificates were counted and ranked in descending order of frequency. The death rates (per 100,000 population) from PD were calculated using Japanese National Vital Statistics. The estimated rate of deaths with PD was extrapolated using US death data from a multiple-cause coding system, as no such system is available in Japan, with adjustment for the difference in disease structure between countries. RESULTS: Average age at death was 80.9 years. The top 5 comorbid diseases ranked as contributory causes of death were cerebrovascular diseases (4.0%), dementia (3.8%), diabetes mellitus (3.6%), malignant neoplasm (2.5%), and heart diseases (2.3%). Overall, the death rates from and with PD were 3.6 and 5.8, respectively. CONCLUSIONS: Analysis restricted to data from the underlying-cause coding system underestimated the national burden of PD comorbidity and mortality. Use of death certificates and multiple-cause mortality data complement the existing system.

ALS is a multistep process in South Korean, Japanese, and Australian patients.

OBJECTIVE: To establish whether amyotrophic lateral sclerosis (ALS) is a multistep process in South Korean and Japanese populations when compared to Australian cohorts. METHODS: We generated incident data by age and sex for Japanese (collected between April 2009 and March 2010) and South Korean patients with ALS (collected between January 2011 and December 2015). Mortality rates were provided for Australian patients with ALS (collected between 2007 and 2016). We regressed the log of age-specific incidence against the log of age with least squares regression for each ALS population. RESULTS: We identified 11,834 cases of ALS from the 3 populations, including 6,524 Australian, 2,264 Japanese, and 3,049 South Korean ALS cases. We established a linear relation between the log incidence and log age in the 3 populations: Australia r 2 = 0.99, Japan r 2 = 0.99, South Korea r 2 = 0.99. The estimate slopes were similar across the 3 populations, being 5.4 (95% confidence interval [CI], 4.8-5.5) in Japanese, 5.4 (95% CI, 5.2-5.7) in Australian, and 4.4 (95% CI, 4.2-4.8) in South Korean patients. CONCLUSIONS: The linear relationship between log age and log incidence is consistent with a multistage model of disease, with slope estimated suggesting that 6 steps were required in Japanese and Australian patients with ALS while 5 steps were needed in South Korean patients. Identification of these steps could identify novel therapeutic strategies.

[Epidemiologic research on insomnia in the general Japanese populations].

This paper reviews epidemiologic research on insomnia of the general Japanese populations in the last 10 years. Nationwide studies, 3 for adults and 2 for adolescents, were conducted in communities to estimate prevalence of insomnia and examine associated factors with insomnia. For adults, prevalence of insomnia was estimated of 17.3 to 22.3% for men and 20.5 to 21.5% for women. The associated factors were identified: increasing age, gender, being unemployed, poor health status, being psychological stressed, less physical activities, and use of hypnotic medications and nightcap. For adolescents, they were 23.3% for boys and 23.7% for girls. Gender, poor mental health, smoking, drinking, college-bound, and lifestyle (e.g., not eating breakfast, late bedtime, not involved in extramural activities) were suggested as the associated factors. These findings have contributed to enhance the social recognition about the importance of insomnia for the general population in Japan.

[Trends in mortality from intractable diseases in Japan, 1972-2004].

PURPOSE: In 1972, the Ministry of Health, Labour and Welfare of Japan defined intractable diseases as those with unknown etiology, no established treatment regimens, and severe sequelae of physical, mental and social difficulties. Since then, the Ministry has promoted scientific research on these diseases and offered financial support to those suffering from their effects. The purpose of the present study was to analyze trends in deaths from the diseases in Japan over the period from 1972-2004. METHODS: For the selected intractable diseases with 100 deaths or more per year, crude (CDR) and direct age-standardized death rates (ADR) were computed using the national underlying-cause-of-death mortality database of Japan based on International Classification of Diseases. Joinpoint regression analysis was applied to identify significant changes in the trends. RESULTS: The CDRs in the latest observed year per 1 million persons/year) for males and females were 25.55 and 25.93, respectively, for Parkinson's disease, 5.41 and 6.92 for aplastic anemia, 0.87 and 3.50 for systemic lupus erythematosus, 2.93 and 2.36 for amyloidosis, 1.40 and 1.54 for polyarteritis nodosa, 1.34 and 1.61 for idiopathic thrombocytopenic purpura, and 1.02 and 0.74 for ulcerative colitis. The respective annual percentage changes (APCs) for males and females during the overall period decreased for ulcerative colitis (-5.2% and -7.5%), aplastic anemia (-3.6% and -3.7%), idiopathic thrombocytopenic purpura (-2.1% and -3.0%), and systemic lupus erythematosus (-0.9% and -2.6%), while the APCs increased for amyloidosis (+3.3% and +3.5%), polyarteritis nodosa (+3.2% and +4.0%), and Parkinson's disease (+0.7% in males alone). With the APCs in the latest trend phase, polyarteritis nodosa and Parkinson's disease in females showed appreciable declines; on the other hand, amyloidosis in males demonstrated the significant increase, and ulcerative colitis in males exhibited an apparent leveling off of the decline. CONCLUSION: The ADRs for most of the intractable diseases have declined significantly in Japan over the last 3 decades. The decline might be attributed in large part to improved diagnosis and treatment because of the lack of effective primary prevention measures. Support for the affected patients and further research on etiology and radical cure of the diseases must be considered necessary.

Epidemiological study on chronotype among preschool children in Japan: Prevalence, sleep-wake patterns, and associated factors.

Our current 24-h society and the weekday-weekend switch of our social clocks may affect young children's sleep and circadian rhythms. However, such evidence is scarce. We conducted a nationwide epidemiological study of sleep and health in preschool children aged 3-5 years attending kindergarten or childcare centers in Japan, using stratified one-stage cluster sampling. The target population was 2 969 627 individuals (as of 1 April 2013). The Children's ChronoType Questionnaire was used to measure chronotypes (morning (M)-type, neither (N)-type and evening (E)-type), and weekday and weekend sleep-wake parameters. Randomly sampled population estimates were obtained via respondents with a person-level weight, which accounted for survey responses and poststratification. Standard errors and 95% confidence intervals were adjusted for the complex survey design using jackknife estimation. A linear regression model of the correlation between chronotype and sleep-wake parameters and a multivariate logistic regression model for the links between chronotype and putative associated factors were used for statistical analyses. The estimated prevalence of M-, N- and E-types were 31.6%, 55.9% and 10.0%, respectively. The corresponding numbers of children were 937 910, 1 659 574 and 296 083. The remaining 2.5% was not specified. The proportions of children who woke up by themselves during the weekdays were 55.1%, 43.0% and 1.9% for M-, N- and E-types, respectively. Overall, bedtime, sleep onset time, wake-up time and get-up time during the weekdays were 21:04, 21:26, 6:55 and 6:59, respectively. Nocturnal sleep period, time in bed (TIB) and 24 h TIB (TIB and nap) during the weekdays were 9.49, 9.93 and 10.55 h, respectively. Sleep-wake timings were significantly and linearly delayed from M-, N-, to E-types (p < 0.001). The weekday 24 h TIB (10.47-10.66 h) and weekend nocturnal sleep period (9.58-9.76 h) did not differ significantly among chronotypes. For E-types, socially advanced weekdays rising times (approximately 1 h) caused nocturnal sleep deficit (0.57 h). Children's socially scheduled times (e.g. start and finish times, mealtimes and daytime nap) and their parents' diurnal preferences had significant adjusted odds ratios among E-types, while the significant unadjusted odds ratios for morning sunlight and multimedia exposure disappeared. These results suggest the importance of chronobiologically planned sleep discipline at home as well as assessment of socially scheduled times in children.

An epidemiologic review on occupational sleep research among Japanese workers.

Epidemiologic sleep research on Japanese workers has been increasing in recent years. It is timely to give an overview of the sleep issues facing the Japanese working population by reviewing the accumulated epidemiological evidence, which will contribute to the promotion of a sound occupational health policy and the development of occupational sleep research in epidemiology. This paper reviews 24 studies, 13 for non-shift and 11 for shift Japanese workers, identified by using MEDLINE and Japan Cetra Revuo Medicina. The results reviewed are as follows: 1) the prevalence of insomnia and other sleep problems is substantially varied, 5 to 45% for non-shift and 29 to 38% for shift workers, 2) poor sleep quality is related to health, occupational activities and personal relations, 3) the risk or associated factors are identified in pathophysiology (e.g., hypertension), lifestyle behaviors (e.g., diet, alcohol, tobacco), job-related conditions (e.g., job stress, social support, job dissatisfaction, workload, shift schedules) and psychopathology (e.g., depressed mood). The methodological limitations found in the studies and the strategies of future epidemiologic sleep research in workers are discussed.

Associations of chronotype with social jetlag and behavioral problems in preschool children.

The timing, duration, and intensity of sleep are determined by the interaction between a sleep-wake-dependent homeostatic process and a sleep-wake-independent, intrinsic, clock-like circadian process. Chronotype represents individual differences in diurnal preferences, which are not only genetically determined but also influenced by social and environmental factors. Thus, the discrepancy between biological and social clocks, so-called "social jetlag", occurs. Chronotype, social jetlag, and the links between chronotype and behavioral problems are well documented in adults and adolescents. However, such studies on young children are limited. We conducted a survey of sleep and health for preschool children attending kindergarten or childcare centers in Wako, Okayama and Kurashiki cities, Japan, between May and July 2012. A total of 654 children aged 4-6 years (342 boys and 312 girls, with an average age of 4.7 years) were assessed using the Children's ChronoType Questionnaire and the Strength and Difficulties Questionnaire. Morning (M)-type, neither (N)-type and evening (E)-type accounted for 36.2%, 54.0% and 9.8% of the participants, respectively. The weekday-to-weekend differences in midsleep time--originally proposed as the concept of social jetlag--were 11, 25 and 35 min for M-, N- and E-types, respectively. There was a negative correlation between chronotype and sleep period during weekdays (p < 0.001) and a positive correlation on weekends (p < 0.001). The weekday-to-weekend difference in sleep period was 0.5 h for E-types, whereas there was no difference for M-types. Binomial logistic regression analyses were used to examine the links between chronotype and behavioral problems, adjusted for participants' sex, age, childcare programs and locations. Chronotype was significantly associated with hyperactivity/inattention: N-type (adjusted OR = 1.74, 95% CI = 1.03-2.95, p < 0.05) and E-type (adjusted OR = 2.47, 95% CI = 1.18-5.20, p < 0.05). E-type was significantly associated with conduct problems (adjusted OR = 2.11, 95% CI = 1.03-4.31, p < 0.05) and peer problems (adjusted OR = 2.75, 95% CI = 1.18-6.44, p < 0.05). The results suggest that E-type children are vulnerable to higher social jetlag and more behavioral problems. The immature adjustment function of their endogenous circadian pacemakers may not be able to correct a small but significant social jetlag to synchronize with their social clocks. Furthermore, guidance based on chronobiological evidence is required for parents, teachers and health professionals to help children achieve optimal sleep and reduce behavioral problems.

Impact and correlates of poor sleep quality in Japanese white-collar employees.

STUDY OBJECTIVES: This study estimated the prevalence, examined associated impacts, and identified correlated factors of poor sleep quality among Japanese white-collar employees who were working in a labor market that included extensive downsizing and restructuring. DESIGN: A cross-sectional self-administered questionnaire survey was conducted as part of 2 consecutive studies on sleep. Sleep quality was measured with the Pittsburgh Sleep Quality Index. SETTING: A telecommunications company in the Tokyo metropolitan area. PARTICIPANTS: Of 5,924 workers, 5,090 responded (85.9%). Results from 4,868 daytime employees were analyzed. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: The 1-month point prevalence of poor sleep quality was approximately 30% to 45% across age and gender and was significantly higher than in the general population of Japanese adults. The overall prevalence of absenteeism, poor physical and psychological health, problems in work performance and personal relationships, and accidents were 16.5%, 18.3%, 17.3%, 2.5%, 2.1%, and 1.8%, respectively. Poor sleepers were more likely to take sick leave, suffer from poor physical and psychological health, and have problems in occupational activities and personal relationships. The most strongly associated factor underlying poor sleep quality was perceived stress, followed by job dissatisfaction, being unmarried, poor bedroom environment, lower academic attainment, younger age, and hypertension. CONCLUSIONS: This study suggests that the cost related to poor sleep quality is extremely high. Comprehensive countermeasures against poor sleep quality at not only the individual, but also the organizational and societal levels, need to be considered for both employees and employers in order that health, safety, and productivity are ensured.

An epidemiologic study of self-reported sleep problems among Japanese adolescents.

STUDY OBJECTIVE: To examine the prevalence and correlates of sleep problems in Japanese adolescents. DESIGN AND SETTING: The survey was designed as a cross-sectional sampling. The targets of the survey were junior and senior high schools throughout Japan. Sample schools were selected by stratified cluster sampling. Self-reported anonymous questionnaires were sent to sample schools for all students to fill out. PARTICIPANTS: A total of 107,907 adolescents responded, and 106,297 questionnaires were subjected to analysis. MEASUREMENTS AND RESULTS: The overall prevalences of sleep problems in the month preceding the questionnaire were difficulty initiating sleep (boys: 15.3%, girls: 16.0%); nocturnal sleep duration less than 6 hours (boys: 28.7%, girls: 32.6%); excessive daytime sleepiness (boys: 33.3%, girls: 39.2%), and subjectively insufficient sleep (boys: 38.1%, girls: 39.0%). Multiple logistic regression analysis showed that female sex, being a senior high-school student, and having an unhealthy lifestyle (psychological stress, smoking, and drinking alcohol) were risk factors for sleep problems. CONCLUSION: Self-reported sleep problems in Japanese adolescents were common and were associated with multiple factors. There is a need for health education directed at solving sleep problems in Japanese adolescents.

Gender differences in excessive daytime sleepiness among Japanese workers.

Excessive daytime sleepiness (EDS) is serious concern in the workplace with respect to errors, accidents, absenteeism, reduced productivity and impaired personal or professional life. Previous community studies found a female preponderance of EDS, however, there is little research on EDS and gender in occupational settings. We examined the gender differences in prevalence and risk factors of EDS among employees working at a telecommunications company in the Tokyo metropolitan area. Our outcome measure of EDS was the Epworth Sleepiness Scale (ESS). A self-administered questionnaire on health and sleep including ESS was distributed to 5,571 workers between December 1999 and January 2000, and 5,072 responses were returned (91.0%). A total of 4,722 full-time, non-manual and non-shift employees aged 20-59 were used for analysis (3,909 men and 813 women). Chi-squared tests and multiple logistic regression analyses were applied for examining the gender differences in the prevalence and risk factors of EDS. The prevalence rates of EDS were 13.3% for women and 7.2% for men (P<0.001). We identified that deprived nocturnal sleep, an irregular sleep-wake schedule and depression were the risk factors of EDS for both genders, and being married worked as a protective factor against EDS for men alone. It is obvious that a ban on overtime work and a provision of mental health hygiene are the general strategies for reducing EDS at worksites. In the case of women, we suggest the formation of effective strategies for improving women's status at home and in the workplace must also be a solution for the prevention of EDS (e.g. promoting gender equality in the division of labor at home and strengthening family care policies for working women).

[Job stress among Japan Overseas Cooperation volunteers--using the Brief Job Stress Questionnaire].

Mental health problems have recently increased among Japan Overseas Cooperation volunteers since 1965, when the Ministry of Foreign Affairs (Japan International Cooperation Agency) launched this volunteer work project for improving hygiene and socioeconomic conditions in developing countries. There was little research on job stress among them dispatched despite previous surveys indicating job as an important stressor. To investigate stress and job-related stressors among them, we conducted a cross-sectional epidemiological study from October to December in 2003. The subjects were all 1,084 Japan Overseas Cooperation volunteers aged 20-40, who worked in 67 countries worldwide at the time of this study (485 and 599 males and females, 316, 332 and 436 for those staying overseas for 11, 7 and 4 months, respectively). Approximately 80% were involved in their dispatching occupational organizations as professionals in information technology, health & welfare, education, and research. Our main outcome measure used was the Brief Job Stress Questionnaire, which was developed to assess stress and job-related stressors or buffers for Japanese workers. Demographic and personality (Egogram) characteristics as well as other health information were obtained. The response rate was 86.9%. For psychological stress, prevalence was 5.5% (n = 49). Means (+/- SD) were 4.22 (+/- 3.98), and 4.89 (+/- 4.40) for males and females (p < 0.05), and 5.15 (+/- 4.17), 5.05 (+/- 4.45), 3.93 (+/- 4.40) for those staying overseas for 11, 7 and 4 months (p < 0.01), respectively. For physical stress, prevalence was 2.9% (n = 26). Means (+/- SD) were 1.10 (+/- 1.68), and 1.41 (+/- 1.74) for males and females (p < 0.01), and 1.47 (+/- 1.77), 1.35 (+/- 1.89), 1.11 (+/- 1.55) for those staying overseas for 11, 7 and 4 months (p < 0.05), respectively. The factors significantly associated with psychological stress were high job demand, poor human relationships at work, low job suitability, low social support from supervisors and colleagues, and being dissatisfied with their life, according to multiple logistic regression analysis. The present study suggested that psychological stress was more prevalent than physical. It also implied a significant relationship between psychological stress and job-related stressors among the subjects of this study as in employees in Japan. Mental health check-ups and counseling in the early stage of psychological stress is important from the viewpoint of prevention of developing stress-related mental health disorders. Education on stress-coping skills should be considered in a training program before they are sent overseas.

[Japanese national survey of adolescent drinking behavior: comparison between 1996 and 2000 surveys].

This report shows Japanese adolescent drinking behavior from the national surveys conducted in 1996 and 2000. We randomly selected 120 junior high schools and 100 senior high schools nationwide. We requested the cooperation of the principals of these schools and sent questionnaires to each school. Students answered anonymously the questionnaires during school time, and sealed in envelopes by themselves; then teachers collected the envelopes. The questionnaire focused on adolescent drinking behavior. Valid responses numbered 42,798 (1996) and 47,246 (2000) from the junior high schools and 73,016 (1996) and 59,051 (2000) from the senior high schools. The number of students surveyed represented about 1% of all Japanese junior high school students, and about 2% of all senior high school students. This report covers only students who gave answers on both drinking frequency and drinking quantity. It compares adolescent drinking behavior between the 1996 and 2000 surveys, such as drinking frequency, drinking quantities, drinking occasions, methods of obtaining alcohol, kinds of alcohol drunk, alcohol-related problems, opinions on the law that prohibits minors under 20 years of age from drinking alcohol, and distribution of drinking status of the subjects by the Quantity-Frequency Scale (QF scale). In a comparison of adolescent drinking behavior between the 1996 survey and 2000 survey, non-drinkers among junior high school students increased from 45% to 55%, and those among senior high school students increased from 27% to 33%. On the other hand, ratios of female students in both junior and senior high schools who drank 1 or more times per week were higher in the 2000 survey than in the 1996 survey. Comparison of the 1996 survey and 2000 survey did not indicate that Japanese adolescent drinking has increased or decreased.

Sleep/wake patterns and circadian typology in preschool children based on standardized parental self-reports.

We studied the sleep/wake patterns and circadian typology of Japanese preschool children living in the Tokyo metropolitan area (193 boys and 190 girls, 4-6 years of age) from June to July 2012 based on a standardized parental self-reporting questionnaire. Our major findings are as follows: (1) sleep/wake timing was delayed, and the duration of nocturnal sleep (sleep period as well as time in bed) increased from that on scheduled days (weekdays) to that on free days (weekends) for all ages. (2) The duration of daily sleep (24 h), including daytime nap, was longer for 4-year-old children compared with that in 5- to 6-year-old children, but not significantly different between scheduled and free days within each age group. (3) The distribution of chronotypes was 36.3% for morning (M)-type, 48.8% for neither (N)-type and 11.2% for evening (E)-type, and this distribution was independent of sex or age. (4) Sleep/wake timing delays were observed from M-type and N-type to E-type during scheduled and free days. (5) The duration of nocturnal sleep decreased but increased for 24-h sleep time from M-type and N-type to E-type on scheduled days. (6) Sleep durations did not differ among chronotypes on free days. (7) Chronotypes were associated with parents' diurnal preferences, mealtimes and attendance at kindergartens or childcare centers but not with sex, age, season of birth, exposure to multimedia or exposure to morning sunlight in their bedrooms. When these results were compared with those for older children and adolescents, similar sleep/wake patterns and circadian typology were observed, although to a lesser degree, in children as young as 4-6 years of age. Napping may compensate, in part, for an accumulated weekday sleep deficit. The distribution of chronotypes was associated with differences in sleep/wake timing and duration and was influenced by the parents' diurnal preferences and lifestyles. Further research on preschool children is required to investigate whether circadian typology affects their behavioral, emotional and cognitive development.