Relationship between morningness-eveningness typology and cumulative fatigue or depression among Japanese male workers.

This study clarified relationships between morningness-eveningness typology and cumulative fatigue or depressive state in Japanese male workers. 959 male chemical factory workers answered a questionnaire that included the MEQ, SDS, CFSI, age, marital status, sleep indexes, life habits, and labor load. Logistic regression analysis was performed with SDS and CFSI as objective variables.

The antioxidant and non-antioxidant contributions of vitamin E in vitamin E blended ultra-high molecular weight polyethylene for total knee replacement.

Vitamin E (VE) blended ultra-high molecular weight polyethylene (UHMWPE) has been developed in Japan as a material for use in total knee replacement (TKR). Various results have demonstrated that VE blended UHMWPE reduces the incidence of delamination failure and lowers the amount of wear produced during knee simulator testing. It was also found that wear particles from VE blended UHMWPE elicited a reduced biological response compared to conventional UHMWPE.

[Qualitative research of contexts of occupational physician's advice].

Objectives: No consistent procedure has been established for advice given by occupational physicians concerning scope of disease, criteria of diagnosis and laboratory data, and basis of judgment. The aim of this study was to identify practice-based contexts of occupational physician's advice.

Methods: We interviewed 6 occupational physicians, and held focus group discussions (FGD) involving 19 occupational physicians, academic researchers, and clinical doctors.

Strain-induced crystallization and orientation of vitamin E-blended ultrahigh molecular weight polyethylene.

The effects of vitamin E addition on the strain-induced crystallization and molecular chain orientation of ultrahigh molecular weight polyethylene (UHMWPE) were examined in order to clarify the wear mechanism of vitamin E-blended UHMWPE in knee prostheses. The structure changes of vitamin E-blended UHMWPE before and after tensile strain were analyzed by X-ray diffraction, Raman spectroscopy and image correlation method. The vitamin E-blended UHMWPE exhibited lower strain-induced crystallization than virgin UHMWPE but a higher Ic value in Raman spectroscopic analysis.

Benchmark duration of work hours for development of fatigue symptoms in Japanese workers with adjustment for job-related stress.

The objective of this study was to calculate benchmark durations and lower 95% confidence limits for benchmark durations of working hours associated with subjective fatigue symptoms by applying the benchmark dose approach while adjusting for job-related stress using multiple logistic regression analyses. A self-administered questionnaire was completed by 3,069 male and 412 female daytime workers (age 18-67 years) in a Japanese steel company. The eight dependent variables in the Cumulative Fatigue Symptoms Index were decreased vitality, general fatigue, physical disorders, irritability, decreased willingness to work, anxiety, depressive feelings, and chronic tiredness.

Shift work is a risk factor for increased blood pressure in Japanese men: a 14-year historical cohort study.

To clarify the effect of shift work on blood pressure in Japanese men, a 14-year historical cohort study was conducted in day workers (n=3963) and alternating shift workers (n=2748) who received annual health checkups between 1991 and 2005 in a Japanese steel company. The end points were a >or=10%, >or=15%, >or=20%, >or=25%, or >or=30% increase in systolic blood pressure or diastolic blood pressure from baseline during the period of observation. The association between shift work and an increase in blood pressure was investigated adjusting for age, body mass index, hemoglobin A1c, total serum cholesterol, creatinine, aspartate aminotransferase, gamma-glutamyl transpeptidase, uric acid, drinking habit, smoking habit, and habitual exercise by multivariate pooled logistic regression analyses.

A longitudinal study on the effect of shift work on weight gain in male Japanese workers.

Objective: This study compared the effect of alternating shift work and day work on weight gain in Japanese male workers.

Methods And Procedures: A longitudinal cohort study was conducted in day workers (n = 4,328) and alternating shift workers (n = 2,926) of a steel company who received annual health checkups over a 14-year period between 1991 and 2005. The association between the type of job schedule and weight gain was investigated using multivariate pooled logistic regression analyses.

Estimation of benchmark dose as the threshold amount of alcohol consumption for blood pressure in Japanese workers.

In order to determine the threshold amount of alcohol consumption for blood pressure, we calculated the benchmark dose (BMD) of alcohol consumption and its 95% lower confidence interval (BMDL) in Japanese workers. The subjects consisted of 4,383 males and 387 females in a Japanese steel company. The target variables were systolic, diastolic, and mean arterial pressures.

Working hours and mental and physical fatigue in Japanese workers.

Background: Establishing a threshold number of working hours is very important when making recommendations to protect people from the potentially harmful health effects caused by long working hours.

Aim: To clarify the influence of working hours on both mental and physical symptoms of fatigue and use the data obtained to determine permissible working hours.

Methods: Cross-sectional survey of male day-shift workers using the Self-Rating Depression Scale (SDS) and the Cumulative Fatigue Symptoms Index (CFSI).

Investigation of renal damage among residents in the cadmium-polluted Jinzu River basin, based on health examinations in 1967 and 1968.

The purpose of this study was to investigate the prevalence of renal disorders in the Jinzu River basin in Toyama Prefecture, Japan where Itai-itai disease was endemic, based on the results of epidemiological studies performed in 1967 and 1968. Furthermore, was there a regional accumulation of the prevalence of abnormal urinary findings in that area? Early morning urine samples were collected from 13 183 subjects (6155 men, 7028 women) who then responded to questionnaires about lifestyle and health. The subject participation rate was 90%.

Estimation of the number of working hours critical for the development of mental and physical fatigue symptoms in Japanese male workers - application of benchmark dose method.

Background: To clarify the influence of working hours on subjective fatigue symptoms and obtain the critical dose (number of hours) to determine the number of permissible working hours, we calculated the benchmark dose (BMD) and the 95% lower confidence limit on BMD (BMDL) of working hours for subjective mental and fatigue symptoms using multivariate logistic regression.

Methods: Self-administered questionnaires were distributed to all 843 male daytime workers aged < or = 60 years in a single chemical factory, and 715 provided complete replies. The odds ratios of daily working hours were determined using positive findings of the Self-rating Depression Scale and 8 subscales of the Cumulative Fatigue Symptom Index as dependent variables, and other potential covariates as independent variables.

Health status of workers in small and medium-sized companies as compared to large companies in Japan.

The health status of workers in small companies has been noted to be relatively poor, but no actual comparisons of groups of variously sized companies within the same region based on the same methodology have ever been conducted. We undertook this study to clarify differences in health status according to company size. The subjects comprised workers of a Japanese steel company and various subcontractors who received health checkups in 2003.

Long-term longitudinal study on the relationship between alternating shift work and the onset of diabetes mellitus in male Japanese workers.

Objective: This study investigated the effect of alternating shift work (ASW) on the onset of diabetes mellitus in Japanese workers compared with onset in day-shift work (DSW).

Methods: A longitudinal study was carried out on a DSW group (n = 3203) and ASW group (n = 2426) of a steel company who received their annual health checkups over a 10-year period between 1991 and 2001. The association between job schedule type and onset of diabetes mellitus (glycated hemoglobin A1c > or =6.

Benchmark dose of working hours in relation to subjective fatigue symptoms in Japanese male workers.

Purpose: We used a multiple logistic regression model to calculate benchmark doses (BMDs) and their 95% lower confidence bound (BMDL) of working hours for subjective fatigue symptoms.

Methods: A self-administered questionnaire survey was conducted in 3069 male daytime workers between the ages of 18 and 60 years who worked in a Japanese steel company. Dependent variables were positive findings for eight properties by using the Cumulative Fatigue Symptoms Index (CFSI): decreased vitality, general fatigue, physical disorders, irritability, decreased willingness to work, anxiety, depressive feelings, and chronic tiredness.

A longitudinal study on the relationship between shift work and the progression of hypertension in male Japanese workers.

Objective: In this 1991-2001 cohort study of 6495 male workers in a Japanese steel company, we investigated whether shift work affects progression from mild hypertension to severe hypertension.

Design: A prospective cohort study.

Participants: Participants had mild hypertension at entry into the study with systolic blood pressure of 140-159 mmHg or diastolic blood pressure of 90-99 mmHg or both before treatment.

Three-shift system increases job-related stress in Japanese workers.

We assessed the relationship between shift work and job stress. The target subjects were 4,962 male workers (3,078 day workers and 1,884 shift workers) aged 18 to 60 yr who work in a Japanese steel company. We used the "Brief Job Stress Questionnaire", which was developed by a research group organized by the Japanese Ministry of Labour.

Health effects of cadmium exposure in the general environment in Japan with special reference to the lower limit of the benchmark dose as the threshold level of urinary cadmium.

Objectives: This study investigates renal dysfunction in areas without known environmental cadmium pollution and calculates the threshold level of urinary cadmium.

Methods: Urinary total protein, beta2-microglobulin (beta2-MG), and N-acetyl-beta-D-glucosaminidase (NAG), used as indicators of renal dysfunction, and urinary cadmium concentration, used as an indicator of cadmium exposure, were measured in two sets of 24-hour urine samples from each of 828 participants (410 men, 418 women), aged 40-59 years and living in three areas without any known environmental cadmium pollution. In multiple regression and logistic regression analyses the association between indicators of cadmium exposure and indicators of renal dysfunction were studied.

Association of working conditions and lifestyle with increased serum gamma-glutamyltransferase: a follow-up study.

Background: This study investigated the association of working conditions and lifestyle with the development of increased serum gamma-glutamyltransferase (GGT) in Japanese workers.

Methods: A follow-up study was carried out on workers of a telecommunication enterprise who received their first annual health check-up between 1992 and 1996, when they were between 40 and 54 years of age. Workers who had high serum GGT (> or =60 IU/L in males, > or =30 IU/L in females), a past history of disease, or current illness at their first check-up were excluded from the analysis.

Environmental cadmium exposure, adverse effects and preventive measures in Japan.

In Japan the most heavily cadmium (Cd)-polluted region is the Jinzu river basin, where Itai-itai disease is endemic and the Kakehashi river basin is the second most polluted region.. The village average Cd concentrations in rice were distributed in the range between 0.

Relationship among prevalence of patients with Itai-itai disease, prevalence of abnormal urinary findings, and cadmium concentrations in rice of individual hamlets in the Jinzu River basin, Toyama prefecture of Japan.

This study investigated the associations among prevalence of patients with Itai-itai disease, and prevalence of abnormal urinary findings and cadmium (Cd) concentrations in rice in individual hamlets of the Jinzu River basin. From the 13,183 participants of the 1967 and 1968 health examinations, we selected 3,094 subjects as the target population who had resided in the current hamlet for a total of 30 years or longer and aged >/=50 years, and in the hamlet both the Cd concentration in rice and prevalence of patients with Itai-itai disease were known. When the inhabitants were divided into four groups according to the Cd concentration in rice or prevalence of abnormal urinary findings, significant relationships among three factors (Cd concentration in rice, prevalence of abnormal urinary findings and prevalence of patients with Itai-itai disease) were demonstrated clearly using the Cochran-Armitage test.

Lack of association of human G-protein beta 3 subunit variant with hypertension in Japanese workers.

Objective: To examine the association between hypertension and the C825T polymorphism in the G-protein beta 3 subunit gene in Japanese workers.

Methods: This study used logistic regression analysis and multiple regression analyses to investigate whether the C825T polymorphism was associated independently with hypertension or blood pressure when factors such as age, body mass index, blood chemistry and lifestyle were taken into consideration. The target subjects were 1452 male and 1169 female workers selected from 3834 male and 2591 female workers in a single company.

Lack of association between human G-protein beta3 subunit variant and overweight in Japanese workers.

We examined the association of the G-protein beta3 subunit gene (GNB3) C825T polymorphism with overweight in Japanese workers. This cross-sectional study used multivariate analysis to investigate whether a polymorphism in the C825T polymorphism was associated independently with overweight when factors such as age and lifestyle were taken into account. The study in 1453 men and 1172 women involved identifying subjects with the C825T genotype using the polymerase chain reaction, followed by restriction fragment-length polymorphism analysis.

An association between smoking habits and blood pressure in normotensive Japanese men: a 5-year follow-up study.

Background: There are few studies on the effects of smoking on blood pressure (BP) that consider confounding factors such as age, obesity, lifestyle and blood chemistry. As such, we conducted a 5-year follow-up study to clarify the effects of smoking habits on blood pressure in normotensive Japanese men.

Methods: The subjects were 2107 normotensive male steelworkers aged 40-54 years.

Allowable level of lifetime cadmium intake calculated from the individuals in the Jinzu River basin of Japan.

We investigated a dose-response relationship between renal dysfunction and lifetime cadmium intake in individual subjects using logistic regression analysis and calculated the allowable level of lifetime cadmium intake among the inhabitants of the Jinzu River basin. From the participants of 1967 and 1968 health examinations, target subjects in whose hamlet the cadmium concentration in rice was known and whose history of residence was also known were selected. Cadmium concentrations in rice from data analyzed by the Toyama Prefecture from 1971 to 1976 were used.

Total cadmium intake and mortality among residents in the Jinzu River Basin, Japan.

This study investigated the relationship between total cadmium intake and mortality among rural inhabitants of the Jinzu River Basin, Japan. A follow-up survey was conducted for 6,128 days on 3,236 inhabitants. The rural communities were divided into 2 groups, one with a total cadmium intake of < 2.