Yoshiharu Aizawa

Job strain, social support in the workplace, and haemoglobin A1c in Japanese men

OBJECTIVES To examine the association between job strain (defined in the model of job demands and job control) and social support at the workplace with levels of glycosylated haemoglobin A1c (HbA1c) METHODS All male employees aged 40–60 in a manufacturing firm, Japan, were invited to take part in the study. A blood sample was taken from the participants and HbA1c (%) was measured. Job strain and social support at the workplace were assessed with the job content questionnaire (JCQ). After excluding those who had a history of diabetes mellitus or other chronic diseases, data from 268 male day workers were analyzed. RESULTS Age adjusted average concentrations of HbA1c were significantly higher in the highest quartile group of job strain or the lowest quartile group of social support at the workplace (p<0.05). Multiple linear regression analysis indicated that job strain was significantly and positively related to HbA1c (p<0.05), whereas social support at the workplace was significantly and negatively related to HbA1c (p<0.05), both after controlling for other covariates. CONCLUSIONS Greater job strain and lower social support at the workplace may be associated with increased concentrations of HbA1c. Increased blood glucose may be a physiological mediator between job strain or social support at the workplace and coronary heart disease.

Association between Intention to Stay on the Job and Job Satisfaction among Japanese Nurses in Small and Medium-sized Private Hospitals

Association between Intention to Stay on the Job and Job Satisfaction among Japanese Nurses in Small and Medium‐sized Private Hospitals: Yasushi Kudo, et al. Department of Preventive Medicine and Public Health, Kitasato University School of Medicine—In order to examine the relationship between the intention to stay on the job and job satisfaction among Japanese nurses, and to obtain clues for preventing turnover, we conducted a questionnaire survey. The subjects involved in the survey included 625 female nurses (registered nurses, licensed practical nurses and assistant nurses) working in 4 small and medium‐sized private hospitals, excluding directors of nursing. Of the 625 questionnaires distributed, 556 (89.0%) were returned. After excluding the questionnaires with missing values, 480 questionnaires were analyzed (effective response rate, 76.8%). The average age of the respondents was 32.8 yr (range: 20–65). The content of the questionnaire was nurse attributes, job satisfaction (30 items) and intention to stay on the job. For job satisfaction, factor analysis (principal factor method and promax rotation) was performed, and factors with an eigenvalue of ≥1 were extracted. Six factors were extracted by factor analysis. These factors were interpreted as “Work as specialists” (1st factor), “Relationship with superiors” (2nd factor), “Comfortable life” (3rd factor), “Relationship among nurses” (4th factor), “Communication with physicians” (5th factor) and “Working conditions” (6th factor). The factor scores were calculated and used as a scale for the evaluation of job satisfaction. To investigate the factors associated with intention to stay on the job among nurses, the standard partial regression coefficient was computed by multiple linear regression analysis, with intention to stay on the job as the dependent variable, and nurse attributes and job satisfaction (factor scores) as independent variables. Various factors including the organizational culture of each hospital may affect the relationship between job satisfaction and the intention to stay on the job. In order to adjust for these factors, differences among hospitals were included in the statistical model as independent variables. The result of the multiple regression analysis suggests that the intention to stay on the job was higher among nurses who were older and more satisfied with work as specialists (1st factor) and working conditions (6th factor).

An Epidemiological Study of Work-related Violence Experienced by Physicians who Graduated from a Medical School in Japan

An Epidemiological Study of Work‐related Violence Experienced by Physicians who Graduated from a Medical School in Japan: Mayuri Arimatsu, et al. Department of Work Systems and Health, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Japan—Healthcare workers are at high risk of being victim of verbal and physical violence perpetrated by patients. There are only a few studies on work related violence among physicians. The aim of this study was to determine how prevalent work‐related violence against physicians is and whether gender, age, specializations and workplaces are associated with verbal and physical violence against physicians in Japan. A questionnaire was mailed to all the 1,705 physicians who had graduated from one medical school in Japan and had practiced for a minimum of 3 yr by the time of this study. The verbal and physical violence experienced by physicians at the hands of their patients and/or clients in the last 6 months preceding this study were collected. We defined ‘verbal violence’ as ‘any threatening statement or complaint’ while ‘physical violence’ referred to ‘the attempted or actual exercise by persons of any physical force so as to cause injury to a physician’. Multiple logistic regression analysis was used to determine the independent contribution of each factor with violence. A total of 540 men and 158 women responded. The adjusted response rate was 41.8%. Among the participants, 168 (24.1%) physicians had experienced verbal violence and 15 (2.1%) physicians had experienced physical violence in the prior 6 months. Verbal violence was positively associated with physicians who were under 30 yr old (odds ratio [OR] = 2.1; 95% confidence interval [CI], 1.0–4.1 for 27–29 yr old) and, psychiatry (OR, 2.4; 95% CI, 1.1–5.4). Physical violence was significantly associated with women (OR, 3.8; 95% CI, 1.1–13.5), specializations such as emergency and anesthesiology (OR, 18.9; 95% CI, 2.8–126.1), and psychiatry (OR, 7.6; 95% CI, 1.6–35.4). There was a considerable number of physicians exposed to violence. Younger physicians and psychiatrists are likely to be exposed to verbal violence. Female physicians, psychiatrists, and emergency physicians are likely to be exposed to physical violence. Education on avoiding from violence should be provided for physicians early in their career.

Physician Job Satisfaction and Working Conditions in Japan

Physician Job Satisfaction and Working Conditions in Japan: Koji Wada, et al. Department of Preventive Medicine and Public Health, Kitasato University School of Medicine

Development of Japanese version of the checklist individual strength questionnaire in a working population.

Development of Japanese Version of the Checklist Individual Strength Questionnaire in a Working Population: Yutaka Aratake, et al. Department of Occupational Mental Healthl, Graduate School of Medical Sciences, Kitasato University—The aims of the present study were to develop and validate the Japanese version of the checklist individual strength questionnaire (CIS) which is used to measure prolonged fatigue not only in the general population but also in the working population. We obtained permission to use CIS from its author and translated the questionnaire into Japanese. Then, the Japanese version of the questionnaire was translated back into English by a bilingual person. The author of the original version agreed that the back‐translated version was conceptually and linguistically equivalent to the original CIS. To validate CIS, 399 workers (66.7% were men) from different companies answered the Japanese version of the CIS (CIS‐J), Maslach burnout inventory‐general survey (MBI‐GS), Beck Depression Inventory‐II (BDI‐II), visual analogue scale (VAS) questionnaires for subjective fatigue, number of overtime hours and number of hours of sleep. Cronbachs α for the total CIS‐J score was 0.91. The test‐retest reliability assessed with an intra‐class correlation coefficient was 0.82. Although confirmatory factor analysis did not show an ideal model fit, the correlation coefficients between the total CIS score and the MBI‐GS exhaustion score, the BDI‐II score and the VAS score were 0.58 (p<0.01), 0.66 (p<0.01) and 0.63 (p<0.01), respectively. The less workers slept and the longer they worked, the higher their total CIS score became. CIS‐J showed good reliability and acceptable validity in the working population. Thus, it could be useful for studying fatigue among Japanese working populations.

Job stressors and long-term sick leave due to depressive disorders among Japanese male employees: findings from the Japan Work Stress and Health Cohort Study

Background Research on the association between job strain or other job stressors and depressive disorders is still limited. The purpose of the present study was to investigate the prospective association of job strain, role stressors and job insecurity with long-term sick leave due to depressive disorders. Methods A prospective study was conducted of a total of 15 256 men aged 18–67 years with no previous history of mental disorders employed in six manufacturing factories located in several regions of Japan. At baseline, they were surveyed using a self-administered questionnaire, including self-reported measures of job strain, as well as its components (job overload and job control), role stressors (role ambiguity and role conflict), social support at work, job insecurity and other demographic and psychological covariates. During the follow-up, a long-term sick leave of 30 days or more due to depressive disorders was recorded. Results During 5.14 years of follow-up on average, 47 incident cases of sick leave of 30 days or more due to depressive disorders were observed. High job control at baseline was associated with a lower risk of long-term sick leave due to depressive disorders, after adjusting for demographic variables, depressive symptoms and neuroticism at baseline (hazard ratio 0.28, 95% CI 0.11 to 0.71); high role ambiguity was associated with the higher risk (hazard ratio 3.49, 95% CI 1.43 to 8.49). Conclusion Job control and role ambiguity may be important predictors of long-term sick leave due to depressive disorders among male employees, independent of depressive symptoms and neuroticism.

Change in obstructive pulmonary function as a result of cumulative exposure to welding fumes as determined by magnetopneumography in Japanese arc welders.

OBJECTIVES: To examine the effect of chronic exposure to welding fumes on pulmonary function by a direct estimate of fumes accumulated in the lungs. METHODS: The strength of the residual magnetic field of externally magnetised lungs (LMF) was used as an estimate of fumes accumulated in the lungs. The results of forced spirometry manoeuvres obtained in 143 of 153 male welders in the original sample were cross sectionally evaluated according to LMF. Seven conventional forced spirogram indices and two time domain spirogram indices were used as pulmonary function indices, and height squared proportional correction was performed when necessary. RESULTS: The distribution of LMF values was considerably skewed towards positive. There was a weak but significant positive relation between age and log transformed LMF. Obstructive pulmonary function indices correlated well with LMF. After adjustment for age and smoking, however, a significant association with LMF was only found with percentage rate of forced expiratory volume in one second (FEV1%) divided by forced vital capacity (FVC) and mu, and average component of assumed time constant distribution of lung peripheral units. Neither FVC nor vital capacity (VC), as indices of restrictive disorders, showed a significant association with LMF. Based on the results of multiple regression analyses, a 0.6% decrease in FEV1% and 0.039 unit increase in mu were expected for each doubling of LMF. CONCLUSION: Obstructive changes in pulmonary function were found to be related to level of cumulative exposure to welding fume in male Japanese arc welders after controlling for age and smoking, assuming that LMF adequately reflects accumulation of welding fumes in the lungs.

Association between asymptomatic hyperuricemia and new-onset chronic kidney disease in Japanese male workers: a long-term retrospective cohort study

BackgroundHyperuricemia is prevalent in patients with chronic kidney disease (CKD). We explored the hypothesis that asymptmatic hyperuricemia may be associated with new-onset CKD.MethodsThe participants were all male factory workers in Kanagawa, Japan (n = 1,285). All were over 40 years of age and had undergone annual health examinations from 1990 to 2007. Individuals with a history of gouty attacks were excluded from the study. A retrospective cohort study was conducted by following the estimated glomerular filtration rate (eGFR) for each participant over a maximum period of 18 years. The endpoint was new-onset CKD defined as eGFR < 60 mL/min/1.73 m2. The associations between new-onset CKD and the presence of hyperuricemia, low serum high-density lipoprotein cholesterol, hypertension, diabetes, and obesity were analyzed.ResultsThe mean (± standard deviation) follow-up period was 95.2 (± 66.7) months, and new-onset CKD was observed in 100 participants (7.8%) during this follow-up. Cox proportional hazards model revealed that the hazard ratio of new-onset CKD due to hyperuricemia, low serum high-density lipoprotein cholesterol, hypertension and obesity were 3.99 (95% confidence interval: 2.59-6.15), 1.69 (1.00-2.86), 2.00 (1.29-3.11) and 1.35 (0.87-2.10), respectively. Concerning hyperuricemia, low serum high-density lipoprotein cholesterol, hypertension and obesity, the log-rank tests showed P values of < 0.01, 0.01, < 0.01 and < 0.01, respectively.ConclusionThe results of this study suggest that asymptomatic hyperuricemia is a predictive factor for new-onset CKD for Japanese male workers.

Morbidity rates of complications in persons with spinal cord injury according to the site of injury and with special reference to hypertension

It has been reported that since 1982 the incidence in persons with spinal cord injury (SCI) of hypertension is commoner than it is in the general population of the same age groups in Japan. In the current study, we examined outpatient morbidity rates and standardised outpatient morbidity ratios (SOMR) according to the site of injury, as well as blood pressure levels and history of disease, and compared the incidences with those for the general population. The subjects consisted of 195 men with SCI. All were engaged in light work at special centres while living with other persons at the centres. The mean age was 49.5 years old, and the average post-injury period was 17.9 years. With respect to the site of injury, 19 patients had had injuries at the level of C-T5, 24 at T6-T10, 139 at T11-L1, and 13 at L2 or lower. The SOMR (general population = 100) for hypertension was closely related to the site of injury, i.e. 0 at C-T5, 250 at T6-T10, 221 at T11-L1 and 308 at L2 or below. Among the patients treated with antihypertensive agents (41 persons), 17.1% were under treatment for renal diseases, 4.9% for diabetes, and 4.9% for hepatic disorders. In 68% of the SCI persons examined, however no disease (such as renal disease, diabetes mellitus, hepatic disease or endocrine abnormality) could be regarded as a cause of secondary hypertension. In addition, the survey revealed that the body weight of SCI persons was lower than that of the general populations.

Problems in the health management of persons with spinal cord injury

This study was conducted to clarify the features of complications attending spinal cord injury (SCI). A comparison was made of the prevalence of disease among patients with SCI (SCIP) with that in the general population in Japan (National Livelihood Basic Survey). For this purpose, a survey was conducted on 244 males at 8 Rosai Rehabilitation Centers (Workmans Accident Compensation Rehabilitation Workshops). The average age was 49.6 years. To eliminate age effects on this parameter, the prevalence rates were expressed as standardized outpatient morbidity ratios (SOMRs), with the value for the general population set at 100. The SOMR data for cystitis were particularly high (16,278, p < 0.01). The SOMRs for other diseases were also high: renal diseases, 2,642; disorders of the skin, 361; gastritis, 339; and hepatic disorders, 381 (p < 0.01). These disorders may be regarded as primary or secondary lesions associated with SCI. SCIP with diseases associated with aging, such as hypertension and diabetes mellitus, are on the increase in Japan. The SOMR for hypertension was 250 (p < 0.01), and for diabetes mellitus it was 323 (p < 0.01).