[Show abstract][Hide abstract] ABSTRACT: 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.
Journal of Epidemiology 08/2014; · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: 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.
Journal of Epidemiology 08/2014; · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We aimed to examine the reliability and validity of the Japanese version of the Children's ChronoType Questionnaire (CCTQ) in preschool children. The CCTQ consists of 16 items on sleep-wake parameters for scheduled and free days, a 10-item of the Morningness/Eveningness Scale (CCTQ-M/E), and a single item on chronotype. Out of 502 children aged 3-6 years living in Okayama Prefecture, we evaluated 346 (188 boys and 158 girls) between May and June 2012. Their parents filled out the questionnaires two times at an interval of two weeks. Cronbach's α of the CCTQ-M/E was 0.77. For test-retest reliability, Pearson's correlation coefficient of the CCTQ-M/E between the two observations was 0.898 (p < 0.001). Kruskal-Wallis test with post-hoc tests was used to compare sleep-wake parameters measured with the CCTQ among the three groups of children, morning (M)-type, neither (N)-type and evening (E)-type, who were classified according to the CCTQ-M/E score. Sleep-wake parameters in timing were significantly different among the children with M-type, N-type and E-type (p < 0.001). Post-hoc pairwise comparisons revealed that sleep-wake parameters in timing were significantly delayed from the M-type to the N-type children (p < 0.001), from the M-type to the E-type children (p < 0.001), and from the N-type to the E-type children (p < 0.001), except that wake-up time and get-up time were not significantly different between the children with N-type and E-type on scheduled days when their start time was regularly fixed. Out of these 346 children, we evaluated 72 (35 boys and 37 girls) to see the correlations between subjectively and objectively measured sleep-wake parameters from June to October 2012. Spearman's correlation coefficients between sleep-wake parameters measured with the CCTQ and an actigraph were 0.512-0.836 on scheduled days (p < 0.001) and 0.380-0.786 on free days (p < 0.001). Based on these findings we conclude that the Japanese version of the CCTQ is a reliable and valid measure for assessing chronotypes in preschool children.
[Show abstract][Hide abstract] ABSTRACT: 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.
Chronobiology International 11/2013; · 4.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: 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.
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.
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.
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.
Journal of Epidemiology 03/2011; 21(3):211-6. · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The present study examined temporal trends and geographic clustering of amyotrophic lateral sclerosis (ALS) mortality in Japan, during 1995-2004, using vital statistics based on death certificates. ALS was usually diagnosed by neurologists according to clinical guidelines that complied with the El Escorial Criteria. The underlying cause of death for ALS was coded as G12.2A. Regression analysis was used to examine temporal trends. Spatial scan statistic was used to detect any area of elevated risk as a cluster. A total of 12,173 (6864 male and 5309 female) ALS deaths were reported. Annual crude mortality rate per 100,000 population was 1.07 (1.26 for males and 0.89 for females) in 2004. Although the overall temporal trend was stable, the trend increased in the 70+ years age group (p for trend, <0.001 in males and <0.05 in females), while it declined in the under 70 years age group (p for trend, <0.01 for both sexes). Male preponderance and M/F ratio remained nearly constant over time. Three clusters were detected: two (p<0.005 in males and p<0.05 in females) in northeast and one (p<0.05 in males) in west-central Japan. Further research is needed to clarify contributing factors for the observed trends and clusters in ALS mortality.
Journal of the neurological sciences 11/2010; 298(1-2):78-84. · 2.32 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study examined the long-term effects of a brief behavioral intervention for sleep improvement. The program was designed as a complete self-help approach by correspondence, and consisted of self-assessments of sleep-related behavior, target-setting for behavior change, an educational booklet, self-monitoring of the behaviors for one month and reinforcement. The participants of the program at a Japanese worksite replied for a one-year followed up survey. Forty-seven poor sleepers whose sleep onset latency was 30 min or more and/or sleep efficiency was less than 85% were analyzed. Eight sleep parameters and nine sleep-related behaviors were evaluated using questionnaires at baseline, post-intervention and follow-up. At one year, total sleep time increased by 27 min, sleep onset latency shortened by 17.5 min and sleep efficiency improved by 6.9 points. Desirable changes were obtained in 4 sleep-related behavior including not being active before bedtime, not working or watching TV in the bedroom, not oversleeping on holidays and having a relaxed bath time. These results suggest that this brief behavioral intervention could improve sleep quality through the modification of sleep-related behavior.
[Show abstract][Hide abstract] ABSTRACT: There is suggested to be a geographical difference in Creutzfeldt-Jakob disease (CJD) mortality in Japan. We performed a study to detect localized clusters and hot-spot areas of deaths from CJD in Japan during the 10-year period from 1995 to 2004.
The diagnosis of CJD was taken from the death certificate (coded as A81.0 in the ICD-10). A total number of 1,168 CJD deaths (500 males and 668 females) were used for analysis using empirical Bayes estimates of standardized mortality ratios and the flexible spatial scan statistic to detect clusters. To detect the most likely cluster, p values were obtained using Monte Carlo hypothesis testing (with p < 0.05 as statistical significance).
The most likely cluster of CJD mortality was located in the northwest region from the base of Mt. Fuji, stretching over the two neighboring prefectures of Yamanashi and Shizuoka (relative risk = 2.28, p = 0.021). Some other clusters were detected but were not significant.
The present study supports the evidence of geographical clustering of deaths from CJD at a specific location in Japan.
[Show abstract][Hide abstract] ABSTRACT: 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.
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.
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.
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.
[Nippon kōshū eisei zasshi] Japanese journal of public health 11/2007; 54(10):684-94.
[Show abstract][Hide abstract] ABSTRACT: Trend of the mortality rate of Creutzfeldt-Jakob disease (CJD) in Japan is still unclear. This study aimed to estimate annual crude mortality rates due to CJD and examine the CJD mortality trend in Japan during the period of 1979-2004.
National death certificate data on CJD were used (CJD coded as 046.1 for ICD-9 and A81.0 for ICD-10). Trends in age-standardized mortality rates for CJD were examined by using time series analyses including the joinpoint regression analysis.
A total of 1,966 deaths (862 males and 1,104 females) were identified with CJD coded as the underlying-cause-of-death. The annual number of deaths and crude mortality rates peaked in 2004 at 163 (66 for males and 97 for females) deaths and 1.28 (1.06 for males and 1.48 for females) deaths per million population per year, respectively. The age-specific mortality rates rapidly increased with age between 50 and 74 years, especially among females, and sharply declined at 80+ years. Throughout the observed period, there were no significant change points, and the annual percentage changes (95% confidence intervals) were +3.09 (2.18 - 4.02) % for males and +3.90 (2.98-4.83) % and females. The total number of CJD deaths under 50 years of age was 131, and there was found no increase in the annual number of deaths for the past few years in this age group.
CJD mortality in trend data based on death certificates has significantly increased in Japan during the period of 1979-2004.
Journal of Epidemiology 08/2007; 17(4):133-9. · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The commercial availability of psychotropic drugs has an important effect on the consumption of medications for the symptomatic treatment of insomnia. Traditional benzodiazepines have been the most frequently prescribed psychotropic medications for promoting sleep in clinical practice in Japan. In recent years, non-diazepine drugs, antidepressant selective serotonin-reuptake inhibitors and over-the-counter sleep aids have been introduced into the Japanese pharmaceutical market. This study aimed therefore to make a poplulation-based assessment of sleep-medication use using the baseline data of a nationally representative sample of 2800 Japanese adults collected in 1997 before such changes. The Pittsburgh Sleep Quality Index was used to measue the symptoms of insomnia and the use of sleep medicine. A total of 1871 subjects participated in our analyses. The overall age-adjusted prevalence of sleep-medication use was 7.4% : 1.3%, 2.0% and 4.1% for <1 time, 1–2 times, and 3+ times per week during the past month, 6.5% and 0.9% for medically prescribed medicine and self-medicated sleeping pills, respectively. Of those with frequent insomniac symptoms, 75% remaied untreated. However, 3% of the users suggests the possibiliy of hypnotic-dependency. Over one-half of the users had multiple illnesses and consulted two or more different medical specialists. Physicians accounted for a disproportionately high percentage of all prescriptions of sleep medicine. Neuropsychiatrists replaced physicians after sociodemographic adjustments. Diabetes mellitus, heart disease, hypertension, and gastroduodenal ulcer represented the most common medical illnesses relating to sleep medication. This study drives the need to further investigate how to manage and treat individuals with insomnia.
[Show abstract][Hide abstract] ABSTRACT: To examine the prevalence and correlates of sleep problems in Japanese adolescents.
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.
A total of 107,907 adolescents responded, and 106,297 questionnaires were subjected to analysis.
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.
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.
[Show abstract][Hide abstract] ABSTRACT: Great public concern about health effects of dioxins emitted from municipal solid waste incinerators has increased in Japan. This paper investigates the association of adverse reproductive outcomes with maternal residential proximity to municipal solid waste incinerators.
The association of adverse reproductive outcomes with mothers living within 10 km from 63 municipal solid waste incinerators with high dioxin emission levels (above 80 ng international toxic equivalents TEQ/m3) in Japan was examined. The numbers of observed cases were compared with the expected numbers calculated from national rates adjusted regionally. Observed/expected ratios were tested for decline in risk or peak-decline in risk with distance up to 10 km.
In the study area within 10 km from the 63 municipal solid waste incinerators in 1997-1998, 225,215 live births, 3,387 fetal deaths, and 835 infant deaths were confirmed. None of the reproductive outcomes studied here showed statistically significant excess within 2 km from the incinerators. However, a statistically significant peak-decline in risk with distance from the incinerators up to 10 km was found for infant deaths (p=0.023) and infant deaths with all congenital malformations combined (p=0.047), where a "peak" is detected around 1-2 km.
Our study shows a peak-decline in risk with distance from the municipal solid waste incinerators for infant deaths and infant deaths with all congenital malformations combined. However, due to the lack of detailed exposure information to dioxins around the incinerators, the observed trend in risk should be interpreted cautiously and there is a need for further investigation to accumulate good evidence regarding the reproductive health effects of waste incinerator exposure.
Journal of Epidemiology 06/2004; 14(3):83-93. · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: While completing their degree courses, graduate students often complain about poor sleep and mental health, which is mainly caused by the academic environment and the uncertainty of their success in obtaining their degree. To estimate the prevalence of sleep disturbances among them and the related adverse consequences, we conducted a cross-sectional epidemiological survey at 12 university graduate schools in Kyoto, Japan. A total of 241 responses were returned (44%) and the data of 219 graduate students, representing 0.1% of the total number of Japanese graduate students in Japan (158 males and 61 females, aged 22–39 years), were analyzed. Participants completed the self-reported Pittsburgh Sleep Quality Index questionnaire, together with specific questions designed for the purpose of the study. Among graduate students, 29.8% reported fatigue, 9.6% health problems, 5% university absenteeism, and 3.2% accidents at their university as adverse consequences of their sleep problems. The prevalence rate of excessive daytime sleepiness was 4.1% in this study, lower than the reported rate in the general young adult population. The prevalence rates of other sleep disturbances were similar to the reported rates for the general young adult population; we consequently suggest that the prevalence rates of the adverse consequences of sleep problems are higher for the general young adult population than for the less sleepier graduate students. Graduate students also reported a low consultation rate for sleep problems despite high prevalence rates of adverse consequences, indicating the need to increase awareness of sleep problems and their prevention among them.
[Show abstract][Hide abstract] ABSTRACT: 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.
Nihon Arukōru Yakubutsu Igakkai zasshi = Japanese journal of alcohol studies & drug dependence 11/2003; 38(5):425-33.
[Show abstract][Hide abstract] ABSTRACT: There is little known about epidemiologic evidence on periodic leg movements during sleep (PLMS) for the Japanese. The present study was a cross-sectional epidemiologic study to estimate the prevalence of PLMS and examine the associated factors of PLMS in Japanese community-dwelling adults.
The subjects were 884 with bed partners or bedroom mates of 1,889 Japanese adults aged 20 years and over randomly selected from the general population. The case ascertainment of PLMS was based on the assessments of their bed partners or bedroom mates using the Pittsburgh Sleep Quality Index. Multiple logistic regression analyses were used for investigating the associated factors.
The age-adjusted prevalences (95% confidence interval) were 5.8% (4.7-6.8%) and 1.3% (0.8-1.9%) for 1 to 2-times, and 3-times or greater of PLMS per week during the preceding month, respectively. Those with PLMS were more likely to experience difficulty in initiating sleep, snore during sleep, be depressed, and suffer from peptic ulcer. Sex, age, difficulty in maintaining sleep, excessive daytime sleepiness, medication use to aid sleep, and any psychoactive substances (tobacco, alcohol, and caffeine) were not identified as significant associated factors of PLMS.
The results suggest that the prevalence of PLMS in Japanese community-dwelling adults is not so high as those reported from Western countries, and that PLMS is correlated with some sleep and health disturbances.
Journal of Epidemiology 10/2003; 13(5):259-65. · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The 12-item General Health Questionnaire (GHQ-12) has been extensively used in a variety of settings across countries. The main aim of the present study was to assess the factor structure of the GHQ-12 for the Japanese general adult population. Data came from a sample of 1808 Japanese aged 20 years or older who were randomly selected based on the 1995 census (897 men and 911 women). Cronbach's alpha coefficients were 0.83 for men and 0.85 for women. Overall, the corrected item-total correlation coefficients were >0.20 for both genders. The GHQ-12 yielded a two-factor solution of psychological distress (items 2, 5, 6, 9, 10 and 11) and social dysfunction (items 1, 3, 4, 7 and 8), which jointly accounted for 49.1% of the total variance, for women. Item 12 on happiness was not discernable. For men, item 12 was separated from a social dysfunction factor and yielded the third factor with item 3 on social role, and the three factors jointly accounted for 57.6%. The results of the present study suggest that the GHQ-12 can be used as an internally reliable and homogeneous scale that produces mainly the factors of psychological distress and social dysfunction. Item 12 may be structurally different in the case of Japanese adults.
Psychiatry and Clinical Neurosciences 08/2003; 57(4):379-83. · 2.04 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: 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.
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.
A telecommunications company in the Tokyo metropolitan area.
Of 5,924 workers, 5,090 responded (85.9%). Results from 4,868 daytime employees were analyzed.
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.
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.
[Show abstract][Hide abstract] ABSTRACT: The effects of mediated minimal behavioral intervention on poor sleepers were examined. A behavioral sleep education trial was applied to 114 Japanese workers. The program was designed as a complete self-help approach by means of mediated intervention. The self-checking of sleeping habits, goal setting, self-monitoring, and reinforcement were used as behavior modification techniques. A manual was also referred to. After the intervention, six kinds of sleep-related behaviors were significantly improved. As for sleep, total sleep time was significantly increased, sleep latency, time in bed after sleep offset shortened, and sleep efficiency was also increased. These results suggest that a simple behavioral approach is effective in the improvement of sleep quality.
[Show abstract][Hide abstract] ABSTRACT: 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).
Social Science [?] Medicine 02/2003; 56(4):883-94. · 2.73 Impact Factor