Misa Takegami

Development of a Japanese version of the Epworth Sleepiness Scale (JESS) based on Item Response Theory

BACKGROUNDnVarious Japanese versions of the Epworth Sleepiness Scale (ESS) have been used, but none was developed via standard procedures. Here we report on the construction and testing of the developer-authorized Japanese version of the ESS (JESS).nnnMETHODSnDeveloping the JESS involved translations, back translations, a pilot study, and psychometric testing. We identified questions in the ESS that were difficult to answer or were inappropriate in Japan, proposed possible replacements for those questions, and tested them with analyses based on item response theory (IRT) and classical test theory. The subjects were healthy people and patients with narcolepsy, idiopathic hypersomnia, or obstructive sleep apnea syndrome.nnnRESULTSnWe identified two of our proposed questions as appropriate replacements for two problematic questions in the ESS. The JESS had very few missing data. Internal consistency reliability and test-retest reliability were high. The patients had significantly higher JESS scores than did the healthy people, and higher JESS scores were associated with worse daytime function, as measured with the Pittsburgh Sleep Quality Index.nnnCONCLUSIONSnIn Japan, the JESS provides reliable and valid information on daytime sleepiness. Researchers who use the ESS with other populations should combine their knowledge of local conditions with the results of psychometric tests.

Association between number of comorbid conditions, depression, and sleep quality using the Pittsburgh Sleep Quality Index: results from a population-based survey.

OBJECTIVESnAlthough sleep problems are a serious public concern, it is not clear if the presence of depression or multiple comorbid conditions has an additive or multiplicative effect on sleep quality.nnnMETHODSnWe conducted a population-based, cross-sectional survey in a rural town in Japan. Multivariable-adjusted linear regression models were used to explore the association between the number of comorbid conditions and the Pittsburgh Sleep Quality Index (PSQI) global score. The association between the number of comorbid conditions and presence of depression, as defined by the five-item Mental Health Inventory (scores60), in those with poor quality sleep (PSQI global score>5) was determined using a non-parametric trend test.nnnRESULTSnOf 5107 respondents, 3403 (mean age: 51.0years, women: 52.6%) were used for the analysis after exclusion of missing PSQI data. The PSQI global score (mean: 4.9) increased as the number of comorbid conditions increased in a linear and statistically significant manner (p<0.0001). The PSQI global score increased by 0.374 for each additional comorbid condition (p<0.0001). Among those with poor sleep quality, the proportion with depression increased significantly and linearly (p<0.0001) as the number of comorbid conditions increased (37.5% for 0 vs. 59.9% for 4 comorbid conditions).nnnCONCLUSIONnThe number of comorbid conditions correlated positively with poor sleep quality, and as the number of comorbid conditions increased, the proportion of those also suffering from depression increased. Recognizing the signs of depression in patients with multiple comorbid conditions is important because of its exacerbation of poor sleep quality.

Locomotor dysfunction and risk of cardiovascular disease, quality of life, and medical costs: design of the Locomotive Syndrome and Health Outcome in Aizu Cohort Study (LOHAS) and baseline characteristics of the study population

BackgroundThere is little evidence regarding long-term outcomes of locomotor dysfunction such as cardiovascular events, quality of life, and death. We are conducting a prospective cohort study to evaluate risk of cardiovascular disease, quality of life, medical costs, and mortality attributable to locomotor dysfunction. The present study determined baseline characteristics of participants in the Locomotive Syndrome and Health Outcome in Aizu Cohort Study (LOHAS).MethodsCohort participants were recruited from residents between 40 and 80xa0years old who received regular health check-ups conducted by local government each year between 2008 and 2010 in Minami-Aizu Town and Tadami Town in Fukushima Prefecture, Japan. Musculoskeletal examination included assessment of physical examination of the cervical and lumbar spine, and upper and lower extremities and of physical function, such as grasping power, one-leg standing time, and time for the 3-m timed up-and-go test. Cardiovascular risk factors, including blood pressure and biological parameters, were measured at annual health check-ups. We also conducted a self-administered questionnaire survey.ResultsLOHAS participants comprised 1,289 men (mean age 65.7xa0years) and 1,954 women (mean age 66.2xa0years) at the first year. The proportion of obese individuals (body mass index 25.0xa0kg/m2) was 31.9% in men and 34.3% in women, and 41.0% of participants reported being followed up for hypertension, 7.0% for diabetes, and 43.6% for hypercholesterolemia. Prevalence of lumbar spinal stenosis was 10.7% in men and 12.9% in women, while prevalence of low back pain was 15.8% in men and 17.6% in women.ConclusionThe LOHAS is a novel population-based prospective cohort study that will provide an opportunity to estimate the risk of cardiovascular disease, quality of life, medical costs, and mortality attributable to locomotor dysfunction, and to provide the epidemiological information required to develop policies for detection of locomotor dysfunction.

Prevalence of pterygium in a population in Northern Japan: the Locomotive Syndrome and Health Outcome in Aizu Cohort Study

Purpose:u2002 The aim of the study was to determine the prevalence and risk factors for pterygium in a population aged 40–74u2003years in Fukushima Prefecture, Japan.

Prevalence of lumbar spinal stenosis, using the diagnostic support tool, and correlated factors in Japan: a population-based study

BackgroundFew studies have examined the prevalence of lumbar spinal stenosis (LSS) in the general population. The purposes of this study were to estimate the prevalence of LSS and to investigate correlated factors for LSS in Japan.MethodsA questionnaire survey was performed on 4,400 subjects selected from residents aged 40–79xa0years in Japan by stratified two-stage random sampling in 2010. The question items consisted of lower-limb symptoms suggestive of LSS, the diagnostic support tool for LSS (LSS-DST), demographic and lifestyle characteristics, comorbidities, the Japanese Perceived Stress Scale (JPSS), and the Mental Health Index 5 (MHI-5). Using the LSS-DST, the presence of LSS was predicted to estimate the prevalence of LSS. Logistic regression analysis was performed to examine the relationship between LSS and correlated factors.ResultsQuestionnaires were obtained from 2,666 subjects (60.6xa0%), consisting of 1,264 males (47.4xa0%). The mean (standard deviation) age was 60.0 (10.9) years. According to the LSS-DST, 153 subjects were regarded as having LSS. The prevalence was estimated to be 5.7xa0%. When standardizing this value with the age distribution of the Japanese population, it was estimated that 3,650,000 Japanese subjects aged 40–79xa0years might have LSS using the LSS-DST. Prevalence increased with age and was particularly high in subjects aged 70–79xa0years, irrespective of gender. As correlated factors, an advanced age (60xa0years or older), diabetes mellitus, urological disorders, and osteoarthritis/fracture as comorbidities, and depressive symptoms, were associated with LSS.ConclusionsThis study elucidated the prevalence of LSS and factors associated with LSS in Japan. This is the first report describing the estimated prevalence of LSS and associated factors using a strictly sampled representative population.

Differences in relationships among sleep apnoea, glucose level, sleep duration and sleepiness between persons with and without type 2 diabetes

Obstructive sleep apnoea is common in patients with diabetes. Recently, it was reported that short sleep duration and sleepiness had deleterious effects on glucose metabolism. Thereafter, several reports showed relationships between glucose metabolism and obstructive sleep apnoea, sleep duration or sleepiness. But the interrelationships among those factors based on recent epidemiological data have not been examined. We analysed data on 275 male employees (age, 44u2003±u20038u2003years; body mass index, 23.9u2003±u20033.1u2003kgu2003m−2) who underwent a cross‐sectional health examination in Japan. We measured fasting plasma glucose, sleep duration using a sleep diary and an actigraph for 7u2003days, and respiratory disturbance index with a type 3 portable monitor for two nights. Fifty‐four subjects (19.6%) had impaired glucose metabolism, with 21 having diabetes. Of those 21 (body mass index, 25.9u2003±u20033.8u2003kgu2003m−2), 17 (81.0%) had obstructive sleep apnoea (respiratory disturbance indexu2003≥u20035). Regarding the severity of obstructive sleep apnoea, 10, four and three had mild, moderate and severe obstructive sleep apnoea, respectively. The prevalence of obstructive sleep apnoea was greater in those with than without diabetes (Pu2003=u20030.037). Multiple regression analyses showed that the respiratory disturbance index independently related to fasting plasma glucose only in the diabetic subjects. In patients with diabetes, after adjustment for age, waist circumference, etc. sleep fragmentation had a greater correlation with fasting plasma glucose than sleep duration, but without significance (Pu2003=u20030.10). Because the prevalence of obstructive sleep apnoea is extremely high in patients with diabetes, sufficient sleep duration with treatment for obstructive sleep apnoea, which ameliorates sleep fragmentation, might improve fasting plasma glucose.

Association Between Sleep Apnea, Sleep Duration, and Serum Lipid Profile in an Urban, Male, Working Population in Japan

BACKGROUNDnDyslipidemia is often comorbid with obstructive sleep apnea (OSA), but few population-based studies have investigated their relationship. Short sleep duration is associated with hypertension and diabetes; however, its association with dyslipidemia is not well known. We investigated relationships among OSA, sleep duration, and the lipid profile in a community-based study.nnnMETHODSnWe measured the respiratory disturbance index (RDI) and sleep duration by a type 3 portable device and actigraph in 275 men in a Japanese company. Fasting blood parameters were obtained from periodic inspection data.nnnRESULTSnAccording to Japanese criteria, 143 subjects had dyslipidemia. Percent sleep time of oxygen saturation as measured by pulse oximetry (SpO2) < 90% and prevalence of severe OSA were greater and sleep duration and mean SpO2 during sleep were lower in subjects with dyslipidemia than in those without. Univariate analysis showed that the RDI was positively correlated with serum triglyceride (TG) levels (ρ = 0.20, P < .01), and sleep duration was negatively correlated with serum total cholesterol (TC) levels (γ = -0.13, P = .03) and serum low-density lipoprotein cholesterol levels (γ = -0.12, P = .04). Stepwise multiple regression analysis revealed that TG was correlated with RDI (β = 0.14, P = .02), BMI (β = 0.20, P < .01), and alcohol intake (β = 0.20, P < .01), and that TC was correlated with sleep duration (β = -0.13, P = .03), age (β = 0.15, P = .02), and waist/hip ratio (β = 0.15, P = .02).nnnCONCLUSIONSnShort sleep duration was associated with TC levels and RDI was positively associated with TG levels among working-aged men in an urban Japanese company. Correcting the status of OSA and/or short sleep duration might improve the lipid profile and cardiovascular consequences.

Racial Differences in Sexuality Profiles among American, Japanese, and Japanese American Men with Localized Prostate Cancer

INTRODUCTIONnAlthough there were marked racial differences in the clinical outcomes among Japanese men (JP), Caucasian men (CA), and Japanese American (JA) men with localized prostate cancer, the effect of race/ethnicity on sexual profiles remains unclear.nnnAIMnTo determine differences of sexual profiles in JP, CA, and JA with localized prostate cancer.nnnMETHODSnA total of 412 JP, 352 CA, and 54 JA with clinically localized prostate cancer were enrolled in separate studies of health-related quality of life outcomes. We developed a collaborative study in each database.nnnMAIN OUTCOME MEASUREnSexual function and bother were estimated before treatment with validated English and Japanese versions of the University of California in Los Angeles Prostate Cancer Index (UCLA PCI).nnnRESULTSnThe CA reported the highest sexual function score of all. Even after controlling for age, prostate specific antigen, clinical T stage, Gleason score and comorbidity, the JP were more likely than the CA to report poor sexual desire, poor erection ability, poor overall ability to function sexually, and poor ability to attain orgasm. With regard to sexual bother, however, no differences were reported between CA and JP. The JA reported sexual function closely approximate that of the JP, and they were less likely than the CA to report erection ability and intercourse. The JA were more likely to feel distress from their sexual function than the CA. When the JA were divided into two groups according to the ethnicity of their partners, UCLA PCI sexual function scores were equivalent between JA-partnered men and men partnered with other races. On the other hand, JA-partnered men were significantly less likely to report sexual bother scores than men partnered with other races.nnnCONCLUSIONnWe found significant interethnic variations among CA, JP, and JA with prostate cancer in terms of their sexual profiles. Ethnicity and/or country appear to modify some of these variables.

Health-related quality of life in Japanese men with localized prostate cancer: Assessment with the SF-8

Objectives:u2003 To evaluate health related quality of life (HRQOL) using the Medical Outcomes Study 8‐items Short Form Health Survey (SF‐8) questionnaire in Japanese patients with early prostate cancer.

Effects of the presence of hypertension on the relationship between obstructive sleep apnoea and sleepiness

Obstructive sleep apnoea (OSA) plays a significant role in increasing blood pressure. Significant decreases were reported in blood pressure of hypertensive OSA patients with sleepiness who underwent continuous positive airway pressure (CPAP) treatment, but not in non‐sleepy hypertensive OSA patients. More recently, however, significant decreases in blood pressure in non‐sleepy hypertensive OSA patients following CPAP were shown. Effects of sleepiness on hypertension in OSA patients have been investigated, but not the effects of hypertension on sleepiness in OSA patients. We investigated the relationships between hypertension and sleepiness in patients with OSA. We analysed data on 275 middle‐aged male subjects from a cross‐sectional epidemiological health survey. We measured blood pressure and sleep duration objectively using an actigraph for 7u2003days and the respiratory disturbance index (RDI) with a type 3 portable device for 2u2003nights, and assessed sleepiness using the Epworth Sleepiness Scale (ESS). The RDI correlated significantly with ESS scores in the 88 hypertensive subjects (ru2003=u20030.33, Pu2003=u20030.0024), but not in the 187 non‐hypertensive subjects (ru2003=u2003−0.01, Pu2003=u20030.91). Short sleep duration correlated significantly with ESS scores in both groups. Both the RDI and short sleep duration were related independently to sleepiness in only hypertensive subjects. Furthermore, the RDI was related negatively significantly to sleep duration in hypertensive subjects. Although short sleep duration was related significantly to sleepiness in both groups, hypertension may be important for the sleepiness in OSA patients. Detailed mechanisms of the difference in the relationship between sleepiness and the severity of OSA with or without hypertension should be studied further.