Work Content and Serious Mental Illness among Middle-Aged Men: Results from a 6-Year Longitudinal Study in Japan

Low Zinc, Copper, and Manganese Intake is Associated with Depression and Anxiety Symptoms in the Japanese Working Population: Findings from the Eating Habit and Well-Being Study

Epidemiological studies have suggested that there is an association between diet and mental health. The aim of this study was to investigate the association between the intake of six minerals and mental disorders in a cross-sectional study. We used data from the Eating Habit and Well-being study in Japanese workers. Kessler’s six-item psychological distress scale was used to detect mental disorders, with a cut-off score of 12/13, and a validated food frequency questionnaire was used to estimate dietary mineral intake. A total of 2089 participants with no history of depression were included. The prevalence of mental disorders was 6.9%. The lowest quartiles of zinc, copper, and manganese intakes were associated with mental disorders, whereas the lowest quartiles of calcium, magnesium, and iron intake were not associated with mental disorders. Combination analysis of high (≥median) or low (<median) intake of zinc, copper, and manganese showed that low zinc and low copper intake, even with low or high manganese intake (odds ratio (OR), 2.71, 95% confidence interval (CI), 1.29–5.73, and OR, 3.06, 95% CI, 1.41–6.61, respectively) showed a higher OR than that of high zinc, high copper, and high manganese intake. Further studies are required to investigate the impact of dietary mineral intake on mental health.

Differences in stroke and ischemic heart disease mortality by occupation and industry among Japanese working-aged men

Occupation- and industry-based risks for stroke and ischemic heart disease may vary among Japanese working-aged men. We examined the differences in mortality rates between stroke and ischemic heart disease by occupation and industry among employed Japanese men aged 25–59 years. In 2010, we obtained occupation- and industry-specific vital statistics data from the Japanese Ministry of Health, Labour, and Welfare dataset. We analyzed data for Japanese men who were aged 25–59 years in 2010, grouped in 5-year age intervals. We estimated the mortality rates of stroke and ischemic heart disease in each age group for occupation and industry categories as defined in the national census. We did not have detailed individual-level variables. We used the number of employees in 2010 as the denominator and the number of events as the numerator, assuming a Poisson distribution. We conducted separate regression models to estimate the incident relative risk for stroke and ischemic heart disease for each category compared with the reference categories “sales” (occupation) and “wholesale and retail” (industry). When compared with the reference groups, we found that occupations and industries with a relatively higher risk of stroke and ischemic heart disease were: service, administrative and managerial, agriculture and fisheries, construction and mining, electricity and gas, transport, and professional and engineering. This suggests there are occupation- and industry-based mortality risk differences of stroke and ischemic heart disease for Japanese working-aged men. These differences in risk might be explained to factors associated with specific occupations or industries, such as lifestyles or work styles, which should be explored in further research. The mortality risk differences of stroke and ischemic heart disease shown in the present study may reflect an excessive risk of Karoshi (death from overwork).

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There are mortality risk differences of stroke and ischemic heart disease in Japan.

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These risk differences may reflect a risk of Karoshi (death from overwork).

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Occupation and industry correlated with stroke and ischemic heart mortality risk.

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Service and mining are high-risk for stroke and ischemic heart disease.

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Further research is necessary to clarify mechanisms of occupation- and industry-related disparity in mortality risk.

Inequality in mortality by occupation related to economic crisis from 1980 to 2010 among working-age Japanese males

The mortality rate for Japanese males aged 30–59 years in managerial and professional spiked in 2000 and remains worse than that of other occupations possibly associated with the economic downturn of the 1990s and the global economic stagnation after 2008. The present study aimed to assess temporal occupation-specific mortality trends from 1980 to 2010 for Japanese males aged 30–59 years for major causes of death. We obtained data from the Occupation-specific Vital Statistics. We calculated age-standardized mortality rates for the four leading causes of death (all cancers, suicide, ischaemic heart disease, and cerebrovascular disease). We used a generalized estimating equation model to determine specific effects of the economic downturn after 2000. The age-standardized mortality rate for the total working-age population steadily declined up to 2010 in all major causes of death except suicide. Managers had a higher risk of mortality in all leading causes of death compared with before 1995. Mortality rates among unemployed people steadily decreased for all cancers and ischaemic heart disease. Economic downturn may have caused the prolonged increase in suicide mortality. Unemployed people did not experience any change in mortality due to suicide and cerebrovascular disease and saw a decline in cancer and ischemic heart disease mortality, perhaps because the basic properties of Japan’s social welfare system were maintained even during economic recession.

Occupational differences in suicide mortality among Japanese men of working age

BACKGROUND

Although suicide rates among Japanese men of working-age have steadily increased over the past two decades, the distribution by occupation and industry is not uniform. Little is known regarding occupation and industry differences in relation to suicide risk. This study examined differences in suicide risk among Japanese men of working age (25-59 years) during 2010.

METHODS

We analysed the Japanese government's 2010 national survey data regarding occupation and industry-specific death rates. Poisson regression models were formulated for each occupation and industry to estimate the relative risk of death by suicide. Potential interactions between age and occupation/industry were also examined.

RESULTS

Suicide incidence was highest among workers in the fields of agriculture and mining. When compared with referent groups (sales for occupation and wholesale and retail for industry), the age-adjusted relative risk of suicide was highest for administrative and managerial workers (Incident Relative Risk [IRR]: 3.91, 95% Confidence Interval [95%CI]: 3.16-4.85), service industries (IRR: 3.63, 95%CI: 2.93-4.51) and agriculture (IRR: 3.53, 95%CI: 2.84-4.38) occupations, and for mining (IRR: 23.9, 95%CI: 19.4-29.4), fisheries (IRR: 6.26, 95%CI: 5.03-7.80), electricity and gas (IRR: 5.86, 95%CI: 4.71-7.30) and agricultural industries (IRR: 4.73, 95%CI: 3.78-5.91).

LIMITATIONS

Bias resulting from misclassification of deceased individuals' occupation or industry was a potential limitation of this study. Furthermore, detailed information regarding occupation-related factors, such as employment status, had not been recorded in the initial survey.

CONCLUSIONS

These findings help elucidate Japanese occupations and industries with a higher suicide risk, most likely due to economic changes or workplace factors relating to stress and depression.