Depressive mood and suicide among middle-aged workers: findings from a prospective cohort study in Nagoya, Japan

Associations Between Consumption of Different Vegetable Types and Depressive Symptoms in Japanese Workers: A Cross-Sectional Study

Purpose

Vegetable intake is an important part of our everyday diet and is associated with many positive health outcomes. Although previous studies have investigated the association between vegetable consumption and depressive symptoms among various populations, no study has examined this association in the adult working population. The present study investigated whether the frequency of consumption of a specific type of vegetable is associated with the prevalence of depressive symptoms in Japanese adult workers.

Participants and Methods

The final participants consisted of 1724 Japanese adults, and a cross-sectional study was conducted to analyze the results. The frequency of vegetable consumption and depressive symptoms was evaluated using a brief-type self-administered diet history questionnaire and the Zung Self-Rating Depression Scale (SDS), respectively. The association between the variables was examined using Poisson regression analysis. Age-stratified analysis was performed, and SDS cut-off values of 45 and 50 were used to perform a sensitivity analysis.

Results

After adjustment for covariates, including age, body mass index, sociodemographic and lifestyle-related variables, health condition, C-reactive protein, and other dietary variables, an inverse association was found between tomato product consumption and the prevalence of depressive symptoms among men (P for trend <0.01); however, no significant association was found for other vegetable types. For women, there was no association between the frequency of consumption of any of the vegetable types and the prevalence of depressive symptoms. The results were confirmed by the age-stratified analysis for both genders.

Conclusion

Consumption of tomato products may help alleviate depressive symptoms, regardless of differences in dietary culture among men.

Depressive Symptoms on the Geriatric Depression Scale and Suicide Deaths in Older Middle-aged Men: A Prospective Cohort Study

Objectives:

Prospective evaluations of the associations between depressive symptoms and suicide deaths have been mainly performed in high-risk populations, such as individuals with psychiatric disorders or histories of self-harm. The purpose of this study was to prospectively examine whether more severe depressive symptoms assessed using the Geriatric Depression Scale (GDS) were associated with a greater risk of death from suicide in a general-risk population.

Methods:

A total of 113 478 men from the Korean Veterans Health Study (mean age, 58.9 years) who participated in a postal survey in 2004 were followed up for suicide mortality until 2010.

Results:

Over 6.4 years of follow-up, 400 men died by suicide (56.7 deaths per 100 000 person-years). More severe depressive symptoms were associated with greater risk of suicide death (p for trend <0.001). The unadjusted hazard ratios (HRs) in comparison to the absence of depression were 2.18 for mild depression, 2.13 for moderate depression, 3.33 for severe depression, and 3.67 for extreme depression. After adjusting for potential confounders, men with a potential depressive disorder had an approximate 90% higher mortality from suicide (adjusted HR, 1.92; 95% confidence interval [CI], 1.38 to 2.68; p<0.001) than men without depression. Each five-point increase in the GDS score was associated with a higher risk of death by suicide (adjusted HR, 1.22; p<0.001). The value of the area under the receiver operating characteristics curve of GDS scores for suicide deaths was 0.61 (95% CI, 0.58 to 0.64).

Conclusions:

Depressive symptoms assessed using the GDS were found to be a strong independent predictor of future suicide. However, the estimate of relative risk was weaker than would be expected based on retrospective psychological autopsy studies.

Analysis of structural relationship among the occupational dysfunction on the psychological problem in healthcare workers: a study using structural equation modeling

Purpose. The purpose of this study is to demonstrate the hypothetical model based on structural relationship with the occupational dysfunction on psychological problems (stress response, burnout syndrome, and depression) in healthcare workers.

Method. Three cross sectional studies were conducted to assess the following relations: (1) occupational dysfunction on stress response (n = 468), (2) occupational dysfunction on burnout syndrome (n = 1,142), and (3) occupational dysfunction on depression (n = 687). Personal characteristics were collected through a questionnaire (such as age, gender, and job category, opportunities for refreshment, time spent on leisure activities, and work relationships) as well as the Classification and Assessment of Occupational Dysfunction (CAOD). Furthermore, study 1 included the Stress Response Scale-18 (SRS-18), study 2 used the Japanese Burnout Scale (JBS), and study 3 employed the Center for Epidemiological Studies Depression Scale (CES-D). The Kolmogorov–Smirnov test, confirmatory factor analysis (CFA), exploratory factor analysis (EFA), and path analysis of structural equation modeling (SEM) analysis were used in all of the studies. EFA and CFA were used to measure structural validity of four assessments; CAOD, SRS-18, JBS, and CES-D. For examination of a potential covariate, we assessed the correlation of the total and factor score of CAOD and personal factors in all studies. Moreover, direct and indirect effects of occupational dysfunction on stress response (Study 1), burnout syndrome (Study 2), and depression (Study 3) were also analyzed.

Results. In study 1, CAOD had 16 items and 4 factors. In Study 2 and 3, CAOD had 16 items and 5 factors. SRS-18 had 18 items and 3 factors, JBS had 17 items and 3 factors, and CES-D had 20 items and 4 factors. All studies found that there were significant correlations between the CAOD total score and the personal factor that included opportunities for refreshment, time spent on leisure activities, and work relationships (p < 0.01). The hypothesis model results suggest that the classification of occupational dysfunction had good fit on the stress response (RMSEA = 0.061, CFI = 0.947, and TLI = 0.943), burnout syndrome (RMSEA = 0.076, CFI = 0.919, and TLI = 0.913), and depression (RMSEA = 0.060, CFI = 0.922, TLI = 0.917). Moreover, the detected covariates include opportunities for refreshment, time spent on leisure activities, and work relationships on occupational dysfunction.

Conclusion. Our findings indicate that psychological problems are associated with occupational dysfunction in healthcare workers. Reduction of occupational dysfunction might be a strategy of better preventive occupational therapies for healthcare workers with psychological problems. However, longitudinal studies will be needed to determine a causal relationship.

Prevalence of depression and its relationship with work characteristics in a sample of public workers

Occupation is a fundamental right, enabling social interaction and financial support for the individual. However, it is an undeniable source of stress, with consequences for physical and mental health. The prevalence of depression and somatic complaints were assessed in 1,013 public workers using the Beck Depression Inventory and a questionnaire investigating for the presence of somatic problems designed by the research team. The results were related to demographic characteristics, history of previous depressive episodes, work schedule (day work, night and day rotating shift work, day rotating shift work), and duration of current work schedule. There were more cases of moderate depression in the day rotating shift workers (84%) than in those working at night (83%). More women had mild or moderate depression than men (22% and 4% versus 10% and 3%, respectively). Severe depression was found only in men. Nearly 10% of depressed individuals reported previous depressive episodes. A link between depression and somatic complaints was also found. In particular, 59% of depressed subjects reported gastrointestinal complaints and 41% did not (P<0.001). In conclusion, the occurrence of depressive symptoms could be facilitated by occupation. A history of depressive symptoms should not be neglected, given the risk of recurrence. Somatic complaints could represent a "wake-up call" regarding depression. Global assessment and effective support are fundamental for promotion of a better quality of life in the at-risk category of workers.

Personality disorders and health problems distinguish suicide attempters from completers in a direct comparison

BACKGROUND

Whether suicide attempters and completers represent the same population evaluated at different points along a progression towards suicide death, overlapping populations, or completely different populations is a problem still unresolved.

METHODS

446 Adult suicide attempters and knowledgeable collateral informants for 190 adult suicide probands were interviewed. Sociodemographic and clinical data was collected for both groups using semi-structured interviews and structured assessments. Univariate analyses and logistic regression models were conducted to explore the similarities and differences between suicide attempters and completers.

RESULTS

Univariate analyses yielded significant differences in sociodemographics, recent life events, impulsivity, suicide intent, and distribution of Axis I and II disorders. A logistic regression model aimed at distinguishing suicide completers from attempters properly classified 90% of subjects. The most significant variables that distinguished suicide from attempted suicide were the presence of narcissistic personality disorder (OR=21.4; 95% CI=6.8-67.7), health problems (OR=20.6; 95% CI=5.6-75.9), male sex (OR=9.6; 95% CI=4.42-20.9), and alcohol abuse (OR=5.5; 95% CI=2.3-14.2).

LIMITATIONS

Our study shares the limitations of studies comparing suicide attempters and completers, namely that information from attempters can be obtained from the subject himself, whereas the assessment of completers depends on information from close family or friends. Furthermore, different semi-structured instruments assessed Axis I and Axis II disorders in suicide attempters and completers. Finally, we have no data on inter-rater reliability data.

CONCLUSIONS

Suicide completers are more likely to be male and suffer from alcohol abuse, health problems (e.g. somatic illness), and narcissistic personality disorder. The findings emphasize the importance of implementing suicide prevention programs tailored to suicide attempters and completers.

Mental disorders and suicide in Japan: a nation-wide psychological autopsy case-control study

BACKGROUND

The purpose of the present nationwide psychological autopsy case-control study is to identify the association between mental disorders and suicide in Japan, adjusting for physical conditions.

METHODS

A semi-structured interview was conducted of the closest family members of 49 suicide completers and 145 gender-, age-, and municipality-matched living controls. The interview included sections of socio-demographic characteristics, physical conditions, and a psychiatric interview producing DSM-IV diagnoses of mental disorders prior to suicide (or at survey). We compared prevalences of mental disorders between the two groups, using conditional logistic regression.

RESULTS

A significantly higher proportion with any mental disorder was found in the suicide group (65.3%) compared to the control group (4.8%) (p=0.003, odds ratio [OR]=7.5). The population attributable risk proportion associated with mental disorder was 0.24. Mood disorder, particularly major depressive disorder, was the most strongly associated with suicide (p<0.001). Anxiety disorder, alcohol-related disorder, and brief psychotic disorder were also significantly associated with suicide (p<0.05). These patterns were unchanged after adjusting for serious chronic physical conditions.

LIMITATIONS

The present study had some limitations, such as small sample size, sampling bias and information bias.

CONCLUSIONS

Most mental disorders, particularly mood disorder, were significantly associated with a greater risk of suicide in Japan, independent of physical conditions. Mental disorders are a major target of suicide prevention programs in Japan.

A proposed approach to suicide prevention in Japan: the use of self-perceived symptoms as indicators of depression and suicidal ideation

The incidence of suicide in Japan has increased markedly in recent years, making suicide a major social problem. Between 1997 and 2006, the annual number of suicides increased from 24,000 to 32,000; the most dramatic increase occurred in middle-aged men, the group showing the greatest increase in depression. Recent studies have shown that prevention campaigns are effective in reducing the total number of suicides in various areas of Japan, such as Akita Prefecture. Such interventions have been targeted at relatively urban populations, and national data from public health and clinical studies are still needed. The Japanese government has established the goal of reducing the annual number of suicides to 22,000 by 2010; toward this end, several programs have been proposed, including the Mental Barrier-Free Declaration, and the Guidelines for the Management of Depression by Health Care Professionals and Public Servants. However, the number of suicides has not declined over the past 10 years. Achieving the national goal during the remaining years will require extensive and consistent campaigns dealing with the issues and problems underlying suicide, as well as simple screening methods for detecting depression. These campaigns must reach those individuals whose high-risk status goes unrecognized. In this review paper, we propose a strategy for the early detection of suicide risk by screening for depression according to self-perceived symptoms. This approach was based on the symposium Approach to the Prevention of Suicide in Clinical and Occupational Medicine held at the 78th Conference of the Japanese Society of Hygiene, 2008.

Low control at work and the risk of suicide in Japanese men: a prospective cohort study

BACKGROUND

Although adverse psychosocial job characteristics are suspected predictors of suicide death, prospective studies based on established stress instruments are limited.

METHODS

In a multicenter community-based Japanese cohort study, we prospectively investigated the association between psychosocial job characteristics and the risk of death from suicide among male workers. Baseline examination was conducted from 1992 to 1995 to determine the socioeconomic, behavioural and biological variables in addition to the psychosocial job characteristics of 3,125 male workers aged 65 and under and free from major illness. Low job control and high job demands were measured as adverse psychosocial job characteristics according to a job demand-control model questionnaire. Suicide deaths were identified using the Cause-of-Death Register.

RESULTS

During the 9-year follow-up, 14 suicides were identified. The suicide death rate was 48.1 per 100,000 person years. Multivariate analysis revealed a more than fourfold increase in the risk of suicide among men with low control at work (relative risk: 4.10; 95% confidence interval: 1.31-12.83) compared with counterpart men after adjustment for age, marital status, educational attainment, occupation, smoking status, alcohol consumption, total cholesterol level, and study area. Job demands were not associated with risk of death from suicide.

CONCLUSIONS

By using a job demand-control model questionnaire, low control at work was revealed as a predictor of suicide death among Japanese male workers. The finding implies that job redesign aimed at increased worker control could be a worthwhile strategy in preventing, or at least reducing, the risk of suicide death.

Usefulness of five-item and three-item Mental Health Inventories to screen for depressive symptoms in the general population of Japan

Background

The five-question Mental Health Inventory (MHI-5) is a brief questionnaire that can be used to screen for depressive symptoms. Removing the 2 anxiety-related items from the MHI-5 yields the MHI-3. We assessed the performance of the Japanese versions of the MHI-5 and MHI-3 in detecting depressive symptoms in the general population of Japan.

Methods

From the population of Japan, 4500 people 16 years old or older were selected by stratified-random sampling. The Medical Outcomes Study 36-Item Short Form Health Survey (SF-36, which includes the MHI-5) and the Zung Self-rating Depression Scale (ZSDS) were included in a self-administered questionnaire. ZSDS scores of 48 and above were taken to indicate the presence of moderate or severe depressive symptoms, and scores of 56 and above were taken to indicate the presence of severe depressive symptoms. We computed the correlation coefficient between the ZSDS score and the scores on the MHI-5 and MHI-3. We also computed the sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve.

Results

Of the 3107 subjects (69% of the 4500 initially selected), 14.0% had moderate or severe depressive symptoms, and 2.0% had severe depressive symptoms as measured with the ZSDS. The correlations of ZSDS scores with MHI-5 scores and with MHI-3 scores were similar: -0.63 and -0.61, respectively. These correlation coefficients were almost the same whether or not the data were stratified by age and sex. For detecting severe depressive symptoms with the MHI-5, the area under the ROC curve was 0.942 (95%CI: 0.919 – 0.965); for the MHI-3, it was 0.933 (95%CI: 0.904 – 0.962).

Conclusion

The MHI-5 and MHI-3 scores were correlated with the ZSDS score, and can be used to identify people with depressive symptoms in the general population of Japan.

Knowledge of and attitudes toward suicide and depression among Japanese in municipalities with high suicide rates

BACKGROUND

Knowledge of and attitudes toward suicide and depression have not been fully investigated in Japan.

METHODS

Study areas comprised municipalities in northern Japan where standardized mortality ratios (SMRs) from suicide compared with a Japanese standard ranged from 1.62 to 3.72 in men and from 1.43 to 3.49 in women. We conducted a questionnaire survey on a random sample of 7,136 participants aged 20 to 79 years, and analyzed data of 5,547 (77.7%) subjects. We categorized seven municipalities, from which the subjects were drawn, into three groups according to the SMR from suicide. Self-Rating Depression Scale (SDS) score was used for evaluation of depressive states.

RESULTS

The SDS score was significantly higher in the high SMR group in women, but no significant difference among the three SMR groups was observed in men. The percentage of subjects with nine years or less of education was significantly higher in the high SMR group both in men and in women. The percentage of men who drank alcohol once a week or more was significantly higher in the high SMR group. The percentages of subjects unaware that depressive states are treatable by medication were not significantly different among the three SMR groups both in men and in women, while the percentage of men unwilling to see a psychiatrist when depressed was the lowest in the high SMR group.

CONCLUSION

Although a significant difference in SDS score was observed in women, most of the psychosocial factors or knowledge of and attitudes toward suicide and depression were not adversely associated with SMR group.

Temperament and job stress in Japanese company employees

BACKGROUND

This study aims to demonstrate the relevance of temperament to job stress.

METHOD

The subjects were 848 male and 366 female Japanese company employees. Temperament Evaluation of Memphis, Pisa, Paris and San Diego-Autoquestionnaire version (TEMPS-A) and Munich Personality Test (MPT) were administered to assess temperaments, and the NIOSH Generic Job Stress Questionnaire (GJSQ) to assess job stress. We used hierarchical multiple linear regression analysis in order to demonstrate whether temperament variables added any unique variance after controlling the effects of other predictors such as gender, age and job rank.

RESULTS

In all subscales of the GJSQ, temperament predicted a large share of the variance in job stress. Remarkably, for interpersonal relationship stressors, the temperament variables added greater variance than that predicted by gender, age and job rank. Summary of the hierarchical linear regression analysis showed that the irritable temperament was associated with the most prominent vulnerability, followed by cyclothymic and anxious temperaments. The schizoid temperament had difficulty in the area of social support. On the other hand, the hyperthymic temperament displayed significant robustness in facing most job stressors; the melancholic type showed a similar pattern to a lesser degree.

LIMITATION

The findings may be different in a clinical Japanese sample, or a cohort of healthy employees from a different cultural background.

CONCLUSIONS

Temperament influences job stress significantly-indeed, it impacts on such stress with greater magnitude than age, gender and job rank in most areas examined. Temperament influences interpersonal relationship stressors more than workload-related stressors. Interestingly, in line with previous clinical and theoretical formulations, the hyperthymic and melancholic types actually appear to be "hyper-adapted" to the workplace.

Psychiatric diagnoses in 3275 suicides: a meta-analysis

BACKGROUND

It is well known that most suicide cases meet criteria for a psychiatric disorder. However, rates of specific disorders vary considerably between studies and little information is known about gender and geographic differences. This study provides overall rates of total and specific psychiatric disorders in suicide completers and presents evidence supporting gender and geographic differences in their relative proportion.

METHODS

We carried out a review of studies in which psychological autopsy studies of suicide completers were performed. Studies were identified by means of MEDLINE database searches and by scanning the reference list of relevant publications. Twenty-three variables were defined, 16 of which evaluating psychiatric disorders. Mantel-Haenszel Weighted Odds Ratios were estimated for these 16 outcome variables.

RESULTS

Twenty-seven studies comprising 3275 suicides were included, of which, 87.3% (SD 10.0%) had been diagnosed with a mental disorder prior to their death. There were major gender differences. Diagnoses of substance-related problems (OR = 3.58; 95% CI: 2.78-4.61), personality disorders (OR = 2.01; 95% CI: 1.38-2.95) and childhood disorders (OR = 4.95; 95% CI: 2.69-9.31) were more common among male suicides, whereas affective disorders (OR = 0.66; 95% CI: 0.53-0.83), including depressive disorders (OR = 0.53; 95% CI: 0.42-0.68) were less common among males. Geographical differences are also likely to be present in the relative proportion of psychiatric diagnoses among suicides.

CONCLUSIONS

Although psychopathology clearly mediates suicide risk, gender and geographical differences seem to exist in the relative proportion of the specific psychiatric disorders found among suicide completers.

Economic slump and suicide method: preliminary study in Kobe

During the recent half decade, Japan's suicide rate at approximately 25 deaths per 100 000 people has been one of the highest rates in the world. From the perspective of suicide prevention by restricting access to suicidal means, the aim of the present study was to examine what kind of suicidal method increased during prolonged economic slump. During 21 years (1981-2001), for all suicide victims (5161 cases) the gender, age, and suicide methods were investigated. The yearly full unemployment rate was also used as a representative socioeconomic factor during the same periods in Japan using government statistics, and the relationship between methods of suicide and full unemployment rate was investigated. Pearson's correlation suggested that there was a significant correlation only for hanging rate (r = 0.736, P < 0.001), but not for the percentages of other methods of suicide. This finding that unemployed persons may have a susceptibility towards certain suicide methods could help in the prevention of suicides. Mental health in Japan should be given more attention, especially for the working population, and social programs offering help should be considered widely.