Nationwide epidemiological study of insomnia in Japan.

BACKGROUND: This study was a nationwide epidemiological study of insomnia in Japan. It was conducted because very few studies on this topic have previously been performed for the general Japanese population. METHODS: An interview survey on symptoms of insomnia (difficulty initiating sleep, difficulty maintaining sleep with difficulty resuming sleep, and early morning awakening with difficulty resuming sleep) and daytime dysfunction was conducted on the general nationwide population in the winter (February) and summer (August) of 2008. Data from 2614 participants who provided valid responses (age range 20-95 years, valid response rate 54.2%) were analyzed. RESULTS: The prevalence of difficulty initiating sleep, difficulty maintaining sleep with difficulty resuming sleep, and early morning awakening with difficulty resuming sleep was 8.3%, 5.8%, and 5.8%, respectively, in men, and 11.0%, 8.1%, and 7.4%, respectively, in women. The prevalence of insomnia was 12.2% in men and 14.6% in women, and the prevalence of insomnia with daytime dysfunction was 3.2% in men and 4.2% in women. The results of logistic regression analyses indicated that the factors aggravating insomnia for men were unemployment and having mental health issues, and for women they were being aged ≥70 years, completing fewer years of schooling, and having mental health issues. Seasonality and regionality in association with insomnia were also examined, but no significant associations were found. CONCLUSION: In the present survey, insomnia was defined by using criteria that were closer to the clinical diagnostic criteria (eg, coexistence of both difficulty resuming sleep and daytime dysfunction was considered). Therefore, it is believed that the results of this study were representative of the clinical actuality of insomnia in Japan.

Anger and Impulsivity Among Japanese Adolescents: A Nationwide Representative Survey.

OBJECTIVE: This study aimed to clarify the prevalence of anger and impulsivity and its associated factors through a nationwide survey of junior and senior high school adolescent students in Japan. METHODS: A self-administered questionnaire covering (1) personal data, (2) lifestyle, (3) mental health status, and (4) feelings of anger and impulsivity was distributed to junior and senior high school students in Japan. Among the total of 10,955 junior high schools and 5,115 senior high schools nationwide, 130 and 110 were randomly selected, respectively. Of those, 92 junior and 80 senior high schools participated in the survey. The survey period was from December 2008 to the end of January 2009. A total of 95,680 questionnaires were collected. After excluding invalid responses, the remaining 94,777 responses (response rate: 62.3%) were analyzed. RESULTS: From the questions regarding anger and impulsivity, 8.7% (95% CI, 8.5%-8.9%) and 7.5% (95% CI, 7.3%-7.7%) of the participants were considered to have experienced intense anger and impulsivity, respectively. Logistic regression analysis indicated that the odds ratios for experiencing intense feelings of anger were significantly higher (all P values < .05) among students who smoked, consumed alcohol, skipped breakfast, did not wish to go to university, had short sleep duration, had decreased positive feelings, had increased depressive feelings, or used mobile phones for longer hours. The odds ratios for experiencing intense impulsivity were significantly higher among students who smoked, consumed alcohol, skipped breakfast, did not participate in club activities, had short sleep duration, had decreased positive feelings, had increased depressive feelings, or used mobile phones for longer hours. CONCLUSIONS: The results suggest that healthy lifestyle habits, good sleep habits, and improved mental health are important for preventing intense feelings of anger and impulsivity among adolescents.

Irritable bowel syndrome among Japanese adolescents: A nationally representative survey.

BACKGROUND AND AIM: No nationally representative survey of irritable bowel syndrome (IBS) among adolescents has ever been performed in Japan. In the present study, we aimed to clarify the prevalence of IBS among Japanese adolescents and the factors associated with it. METHODS: The items related to the diagnostic criteria for IBS based on the Rome III Diagnostic Criteria for Functional Gastrointestinal Disorders were included in a cross-sectional nationwide survey of "alcohol consumption and smoking habits among junior and senior high school students." The participating schools were sampled from among all junior and senior high schools in Japan using the cluster-sampling method, and self-administered questionnaires were sent to the selected schools by mail. Among 99 416 questionnaires that were collected, data from 98 411 valid responses were analyzed. RESULTS: The results showed that the prevalence of IBS was 18.6%. Although no sex difference was observed in the overall prevalence of IBS, the prevalence of diarrhea-predominant IBS was higher among boys than among girls, and the prevalence of constipation-predominant IBS was higher among girls than among boys. The prevalence of IBS increased with progression of the school grade, and there were the significant relationships between IBS and sleep-phase delay and insomnia symptoms. IBS was also significantly associated with poor mental health status. CONCLUSION: These results indicate that IBS is common among junior and senior high school students, and associated with lifestyle and mental health.

A cross-sectional study of the association between working hours and sleep duration among the Japanese working population.

OBJECTIVES: This study aimed to clarify the association between long working hours and short sleep duration among Japanese workers. METHODS: We selected 4,000 households from across Japan by stratified random sampling and conducted an interview survey of a total of 662 participants (372 men; 290 women) in November 2009. Logistic regression analyses were performed using "sleep duration <6 hours per day" as a dependent variable to examine the association between working hours/overtime hours and short sleep duration. RESULTS: When male participants who worked for ≥7 but <9 hours per day were used as a reference, the odds ratio (OR) for short sleep duration in those who worked for ≥ 11 hours was 8.62 (95% confidence interval [CI]: 3.94-18.86). With regard to overtime hours among men, when participants without overtime were used as a reference, the OR for those whose period of overtime was ≥ 3 hours but <4 hours was 3.59 (95% CI: 1.42-9.08). For both men and women, those with long weekday working hours tended to have a short sleep duration during weekdays and holidays. CONCLUSIONS: It is essential to avoid working long hours in order to prevent short sleep duration.

Preferable forms of relaxation for health promotion, and the association between recreational activities and self-perceived health.

Little research has been done on the association between relaxation and health. In the present study, by conducting a nationwide cross-sectional survey, we aimed to obtain scientific data on the preferable forms of relaxation for health promotion, and to clarify the associations between specific recreational activities and self-perceived mental and physical health. We selected 4,000 households by stratified random sampling from across Japan in November 2009 and used the interview method to collect data (number of subjects: 2,206). The questionnaire contained items on sleep, recreation status, recreational activities, and self-perceived mental and physical health status. We obtained responses from 1,224 adults (response rate: 55.5%). Insufficient rest from sleep, short sleep duration (<6 h/day), ineffective use of free time, and less free time used for activities other than rest showed independent positive associations with poor mental and physical health. The results of the logistic regression analyses showed significantly low adjusted odds ratios with regard to the status of poor mental and physical health for outings/walking among men (0.33 [95% confidence interval; 0.16-0.68] and 0.49 [0.26-0.90], respectively), and for community activities among women (0.19 [0.04-0.79] and 0.27 [0.09-0.77], respectively). Relaxation for the promotion of health should include both passive relaxation (rest) and active relaxation (recreation). In addition, ensuring sufficient sleep duration is important for passive relaxation, and engaging in outings/walking for men and community activities for women are important for active relaxation.

The association between use of mobile phones after lights out and sleep disturbances among Japanese adolescents: a nationwide cross-sectional survey.

STUDY OBJECTIVE: The objective of this study was to examine the association between the use of mobile phones after lights out and sleep disturbances among Japanese adolescents. DESIGN AND SETTING: This study was designed as a cross-sectional survey. The targets were students attending junior and senior high schools throughout Japan. Sample schools were selected by cluster sampling. Self-reported anonymous questionnaires were sent to schools for all students to fill out. PARTICIPANTS: A total of 95,680 adolescents responded. The overall response rate was 62.9%, and 94,777 questionnaires were subjected to analysis. INTERVENTION: N/A. MEASUREMENTS AND RESULTS: Daily mobile phone use, even if only for a brief moment every day, was reported by 84.4%. Moreover, as for use of mobile phones after lights out, 8.3% reported using their mobile phone for calling every day and 17.6% reported using it for sending text messages every day. Multiple logistic regression analysis showed that mobile phone use for calling and for sending text messages after lights out was associated with sleep disturbances (short sleep duration, subjective poor sleep quality, excessive daytime sleepiness, and insomnia symptoms) independent of covariates and independent of each other. CONCLUSION: This study showed that the use of mobile phones for calling and for sending text messages after lights out is associated with sleep disturbances among Japanese adolescents. However, there were some limitations, such as small effect sizes, in this study. More studies that examine the details of this association are necessary to establish strategies for sleep hygiene in the future.

Nightmare and sleep paralysis among Japanese adolescents: a nationwide representative survey.

OBJECTIVE: The objective of this study was to clarify the prevalence of nightmares and sleep paralysis and associated factors among Japanese adolescents. METHODS: This study was designed as a cross-sectional sampling survey. The targets were junior and senior high schools throughout Japan. Self-reported anonymous questionnaires were sent to schools for all students to complete. RESULTS: A total of 90,081 questionnaires were analyzed. The overall response rate was 62.6%, and the prevalence of nightmares and sleep paralysis was 35.2% and 8.3%, respectively. Multiple logistic analyses revealed that female sex, drinking alcohol, poor mental health, difficulty initiating sleep, low subjective sleep assessment, presence of excessive daytime sleepiness, and presence of sleep paralysis had higher odds ratios than others for nightmares. Male sex, poor mental health, drinking alcohol, taking a long daytime nap, early or late bedtime, difficulty initiating sleep, low subjective sleep assessment, presence of excessive daytime sleepiness, and presence of nightmares had higher odds ratios than other factors for sleep paralysis. CONCLUSIONS: This study has revealed the prevalence of nightmares and sleep paralysis among Japanese adolescents. Furthermore, the results of this study suggest that it is important to maintain regular sleep habits for preventing these symptoms. We propose that health education about regular sleep habits should be promoted among Japanese adolescents.

Age verification cards fail to fully prevent minors from accessing tobacco products.

BACKGROUND: Proper age verification can prevent minors from accessing tobacco products. For this reason, electronic locking devices based on a proof-of age system utilising cards were installed in almost every tobacco vending machine across Japan and Germany to restrict sales to minors. OBJECTIVE: We aimed to clarify the associations between amount smoked by high school students and the usage of age verification cards by conducting a nationwide cross-sectional survey of students in Japan. METHODS: This survey was conducted in 2008. We asked high school students, aged 13-18 years, in Japan about their smoking behaviour, where they purchase cigarettes, if or if not they have used age verification cards, and if yes, how they obtained this card. RESULTS: As the amount smoked increased, the prevalence of purchasing cigarettes from vending machines also rose for both males and females. The percentage of those with experience of using an age verification card was also higher among those who smoked more. Somebody outside of family was the top source of obtaining cards. Surprisingly, around 5% of males and females belonging to the group with highest smoking levels applied for cards themselves. CONCLUSIONS: Age verification cards cannot fully prevent minors from accessing tobacco products. These findings suggest that a total ban of tobacco vending machines, not an age verification system, is needed to prevent sales to minors.

Association between depression and insomnia subtypes: a longitudinal study on the elderly in Japan.

STUDY OBJECTIVE: To examine the association between depression and three subtypes of insomnia, namely, difficulty initiating sleep (DIS), early morning awakening (EMA), and difficulty maintaining sleep (DMS). DESIGN: Cross-sectional and longitudinal study. SETTING: Community dwellers in Japan. PARTICIPANTS: Nationally representative samples of adults aged 65 and over (total N=4,997) were selected by a multistage stratified random sampling method in 1999 and were interviewed face-to-face in 1999, 2001, 2003, and 2006. Those who responded to the 3rd survey conducted in 2003 and the 4th survey conducted in 2006 were used in this study. MEASUREMENT AND RESULTS: Depression was evaluated according to the 11-item short form of the CES-D scale at 2 points in time. Insomnia subtypes were assessed by self-reported measures. A logistic regression was employed to examine the association between insomnia subtypes and the presence of depression, controlling for relevant factors. A cross-sectional analysis based on the 2003 data demonstrated statistically significant odds ratios (ORs) for DIS and EMA. In the longitudinal study, DIS at the time of the 3rd survey was found to be significantly related to the presence of depression at the time of the 4th survey, with an odds ratio (95%CI) of 1.592 (1.012 to 2.504). EMA (OR 1.070; 95% CI, 0.664 to 1.723) and DMS (OR 1.215; 95% CI, 0.860 to 1.716), however, were not found to be significantly related to the presence of depression. CONCLUSION: The longitudinal study revealed a statistically significant relationship, controlling for other relevant factors, between DIS and the presence of depression three years later, but not between EMA or DMS and depression. Based on our findings, we recommend that the association between insomnia subtypes and depression be studied longitudinally in clinical settings.

[Cognitive behavior therapy].

Insomnia is one of the most frequently encountered disorders in general clinical practices. At present, the most commonly used therapy for insomnia is pharmacotherapy. There are some problems in pharmacotherapy such as side effects. Therefore nonpharmacological therapy for insomnia is needed. The cognitive behavior therapy for insomnia (CBT-I) is a nonpharmacological therapy attracting attention most. CBT-I not only alleviates insomnia symptoms in patients but also enables them to reduce/discontinue the use of hypnotics. I reviewed a study about the effectiveness of CBT-I and commented the future directions of CBT-I.

Associations between sleep disturbance and mental health status: a longitudinal study of Japanese junior high school students.

BACKGROUND: A limited number of longitudinal studies have addressed the association between sleep disturbance and mental health status among adolescents. To examine whether each of these is a risk factor for the onset of the other, we conducted a prospective longitudinal study of Japanese adolescents. METHODS: In 2004, we performed a baseline study of students attending three private junior high schools in Tokyo, and in 2006, a follow-up study was performed on the same population. The mean age of the subjects was 13 years. The Pittsburgh Sleep Quality Index was used to evaluate sleep disturbance, and the 12-item General Health Questionnaire was used to evaluate mental health status. RESULTS: The subjects were 698 students, of whom 516 were suitable for analysis. The incidence of newly developed poor mental health status during the 2 years leading to the follow-up study was 35.1%. New onset of poor mental health status was significantly associated with new onset of sleep disturbance and lasting sleep disturbance. The incidence of sleep disturbance during the 2 years leading to the follow-up study was 33.3%. New onset of sleep disturbance was significantly associated with new onset of poor mental health status and lasting poor mental health status. CONCLUSIONS: Sleep disturbance and poor mental health status increase each other's onset risk.