Sumiko Kurioka

Socioeconomic Status is Significantly Associated with Dietary Salt Intakes and Blood Pressure in Japanese Workers (J-HOPE Study)

The association of socioeconomic status (SES) with nutrients intakes attracts public attention worldwide. In the current study, we examined the associations of SES with dietary salt intake and health outcomes in general Japanese workers (2,266) who participated in this Japanese occupational cohort. SES was assessed by a self-administered questionnaire. Dietary intakes were assessed with a validated, brief, self-administered diet history questionnaire (BDHQ). Multiple linear regression and stratified analysis were used to evaluate the associations of salt intake with the confounding factors. Education levels and household incomes were significantly associated with salt intake, as well as blood pressures (P < 0.05). After adjusting for age, sex and total energy intake, both years of education and household income significantly affect the salt intake (for education, β = −0.031, P = 0.040; for household income, β = −0.046, P = 0.003). SES factors also affect the risk of hypertension, those subjects with higher levels of education or income had lower risk to become hypertensive (ORs for education was 0.904, P < 0.001; ORs for income was 0.956, P = 0.032). Our results show that SES is an independent determinant of salt intake and blood pressure, in order to lower the risk of hypertension, the efforts to narrow the social status gaps should be considered by the health policy-makers.

Altered DNA methylation status of human brain derived neurotrophis factor gene could be useful as biomarker of depression

Brain‐derived neurotrophic factor (BDNF) is involved in the survival, development, and synaptic plasticity of neurons. BDNF is believed to be associated with the pathophysiology of psychiatric disorders. Several studies have suggested the relevance of DNA methylation in its promoter region with depression. Here, we report different methylation statuses in groups with different depressive scores or undergoing different levels of job‐stress. DNA samples were extracted from the saliva of 774 Japanese workers, and the methylation status was determined using the Illumina HumanMethylation 450 K Microarray. Depressive symptoms were measured using the Kesslers K6 questionnaire. Job‐stress scales were assessed via a self‐administered questionnaire. Independent DNA pools were formed based on K6 and job‐strain scores, and the methylation levels were compared among these pools. The average DNA methylation rate was significantly decreased in the highest K6 score group compared to the lowest group (methylated signals, 14.2% vs. 16.5%, P = 2 · 16 × 10−198). This difference remained for the CpG island in the promoter region (10.4% vs. 5.8%, P = 3 · 67 × 10−133). Regarding the job‐strain score, there was a slight increase in the methylation level of the whole gene in the group with the highest score compared to that with the lowest score; however, these groups showed no difference in the promoter region. Our results revealed significant changes in the DNA methylation status of the complete human BDNF gene in persons with depression compared to normal individuals, especially in the promoter region of exon 1. This indicates that DNA methylation in this gene is a promising biomarker for diagnosing depression.

Japanese dietary pattern consistently relates to low depressive symptoms and it is modified by job strain and worksite supports

BACKGROUND This study examined the association between traditional Japanese dietary pattern and depressive symptoms in Japanese workers, employing large-scale samples, considering socioeconomic status (SES) and job stress factors. METHODS A cross-sectional study of 2266 Japanese employees aged 21-65 years from all areas of Japan was conducted as part of the Japanese Study of Health, Occupation and Psychosocial factors related Equity (J-HOPE). Habitual diet was assessed by FFQ (BDHQ). The depression degree and job stress factors (job demand, job control, and worksite support) were measured by K6 and Job Content Questionnaire. RESULTS Participants with high scores for the balanced Japanese dietary pattern were significantly less likely to show probable mood/anxiety disorders (K6≥9) with multivariate adjustment including SES and job stress factors (odds ratio=0.66 [0.51-0.86], trend P=0.002). Other dietary patterns were not associated with depressive symptoms. Even after stratification by job stress factors, the Japanese dietary pattern was consistently protective against depressive symptoms. Furthermore, a highly significant difference between the first and third tertiles of the dietary pattern was observed in participants with active strain (high demand and high control) with low worksite supports (8.5 vs. 5.2, P=0.011). LIMITATIONS Female participant sample was relatively small. CONCLUSIONS Japanese dietary pattern consistently related to low depressive symptoms in this large-scale cohort of Japanese workers, even after adjusting for SES and job stress factors. The protective impact is especially strong for workers with active strain and low support. Making better use of traditional dietary patterns may facilitate reducing social disparities in mental health.

Folate intake and depressive symptoms in Japanese workers considering SES and job stress factors: J-HOPE study

BackgroundRecently socioeconomic status (SES) and job stress index received more attention to affect mental health. Folate intake has been implicated to have negative association with depression. However, few studies were published for the evidence association together with the consideration of SES and job stress factors. The current study is a part of the Japanese study of Health, Occupation and Psychosocial factors related Equity (J-HOPE study) that focused on the association of social stratification and health and our objective was to clarify the association between folate intake and depressive symptoms in Japanese general workers.MethodsSubjects were 2266 workers in a Japanese nationwide company. SES and job stress factors were assessed by self-administered questionnaire. Folate intake was estimated by a validated, brief, self-administered diet history questionnaire. Depressive symptoms were measured by Kessler’s K6 questionnaire. “Individuals with depressive symptoms” was defined as K6≧9 (in K6 score of 0–24 scoring system). Multiple logistic regression and linear regression model were used to evaluate the association between folate and depressive symptoms.ResultsSeveral SES factors (proportion of management positions, years of continuous employment, and annual household income) and folate intake were found to be significantly lower in the subjects with depressive symptom (SES factors: p < 0.001; folate intake: P = 0.001). There was an inverse, independent linear association between K6 score and folate intake after adjusting for age, sex, job stress scores (job strains, worksite supports), and SES factors (p = 0.010). The impact of folate intake on the prevalence of depressive symptom by a multiple logistic model was (ORs[95% CI]: 0.813 [0.664-0.994]; P =0.044).ConclusionsOur cross-sectional study suggested an inverse, independent relation of energy-adjusted folate intake with depression score and prevalence of depressive symptoms in Japanese workers, together with the consideration of SES and job stress factors.

Optimum cut-off point of the Japanese short version of the effort-reward imbalance questionnaire.

Optimum Cut‐off Point of the Japanese Short Version of the Effort‐Reward Imbalance Questionnaire: Sumiko KURIOKA, et al. Department of Health Policy and Management, Graduate School of Medical Science, University of Occupational and Environmental Health, Japan—

Relationship between sickness presenteeism (WHO-HPQ) with depression and sickness absence due to mental disease in a cohort of Japanese workers.

BACKGROUND Absence due to mental disease in the workplace has become a global public health problem. We aimed to evaluate the influence of presenteeism on depression and absence due to mental disease. METHODS A prospective study of 1831 Japanese employees from all areas of Japan was conducted. Presenteeism and depression were measured by the validated Japanese version of the World Health Organization Health and Work Performance Questionnaire (WHO-HPQ) and the K6 scale, respectively. Absence due to mental disease across a 2-year follow up was surveyed through medical certificates obtained for work absence. RESULTS After adjusting for age and gender, participants with higher rates of sickness absolute and relative presenteeism (the lowest tertile of the scores) were significantly more likely to be absent due to mental disease (OR=4.40, 95% CI: 1.65-11.73, and OR=3.31, 95% CI: 1.50-7.27). Subsequently, higher rates of sickness absolute or relative presenteeism were significantly associated with higher rates of depression (K6≥13) one year later (OR=3.79, 95% CI: 2.48-5.81, and OR=2.89, 95% CI: 1.98-4.22). LIMITATIONS The number of females in the sample was relatively small. However, the rates of absence for females with and without mental illness did not significantly differ from those of men. CONCLUSIONS More sickness presenteeism scores were found to be related to higher rates of depression and absence due to mental disease in this large-scale cohort of Japanese workers. Measurement of presenteeism could be used to evaluate the risk for depression and absenteeism. Furthermore, our findings suggest that intervention to improve presenteeism would be effective in preventing depression and absence due to mental illness.

Association of Job Demands with Work Engagement of Japanese Employees: Comparison of Challenges with Hindrances (J-HOPE)

Objectives Recent epidemiological research in Europe has reported that two groups of job demands, i.e., challenges and hindrances, are differently associated with work engagement. The purpose of the present study was to replicate the cross-sectional association of workload and time pressure (as a challenge) and role ambiguity (as a hindrance) with work engagement among Japanese employees. Methods Between October 2010 and December 2011, a total of 9,134 employees (7,101 men and 1,673 women) from 12 companies in Japan were surveyed using a self-administered questionnaire comprising the Job Content Questionnaire, National Institute for Occupational Safety and Health Generic Job Stress Questionnaire, short 10-item version of the Effort-Reward Imbalance Questionnaire, short nine-item version of the Utrecht Work Engagement Scale, and demographic characteristics. Multilevel regression analyses with a random intercept model were conducted. Results After adjusting for demographic characteristics, workload and time pressure showed a positive association with work engagement with a small effect size (standardized coefficient [β] = 0.102, Cohen’s d [d] = 0.240) while role ambiguity showed a negative association with a large effect size (β = −0.429, d = 1.011). After additionally adjusting for job resources (i.e., decision latitude, supervisor support, co-worker support, and extrinsic reward), the effect size of workload and time pressure was not attenuated (β = 0.093, d = 0.234) while that of role ambiguity was attenuated but still medium (β = −0.242, d = 0.609). Conclusions Among Japanese employees, challenges such as having higher levels of workload and time pressure may enhance work engagement but hindrances, such as role ambiguity, may reduce it.

Risk of progression to hypertension in nonhypertensive Japanese workers aged 20-64 years.

Objective: Prehypertension is a known risk factor for hypertension in individuals aged less than 20 or more than 35 years, but no large studies have investigated this risk in individuals aged 20–34 years. This study investigated progression to hypertension in nonhypertensive individuals aged 20–34 years and compared this group with individuals aged 35–64 years. Methods: A total of 12 639 nonhypertensive individuals aged 20–64 years were followed from 1999 to 2008. Hazard ratios for progression to hypertension were calculated for men and women according to three blood pressure (BP) categories (optimal BP: <120/80 mmHg; normal BP: 120–129/80–84 mmHg; high-normal BP: 130–139/85–89 mmHg) and three age groups (20–34, 35–49 and 50–64 years). Results: Progression to hypertension occurred in 4617 individuals (36.5%). The risk of progression to hypertension increased significantly with increasing baseline BP category in men and women in all age groups. The association between baseline BP and progression to hypertension was stronger in the group aged 20–34 years than in the older age groups, especially in men. Conclusion: The results of this study confirm that normal or high-normal BP increases the risk of progression to hypertension in individuals aged 20–34 years. In men, the association between baseline BP and progression to hypertension is stronger in this age group than in older age groups. Health providers should be aware that normal or high-normal BP is a risk factor for progression to hypertension even in individuals aged 20–34 years.

Occupational and socioeconomic differences in actigraphically measured sleep

Occupational conditions, together with socioeconomic status, may modulate sleep. This study examined the association of occupational conditions and socioeconomic status with actigraphic measures of sleep in workers. Fifty‐five employees (40 ± 12 years) wore a wrist actigraph during sleep for seven consecutive nights. Sleep variables addressed included total sleep time, sleep efficiency, mean activity during sleep, sleep‐onset latency, and wake after sleep onset. We also measured household income, occupational class, work schedule, weekly work hours, job demand, job control, worksite social support, effort–reward imbalance, organizational justice, and workplace social capital. Multiple linear regression models were used to determine the association of occupational indicators, socioeconomic status, as well as age and gender with each sleep variable. Higher workplace social capital was associated consistently with longer total sleep time (P < 0.001), higher sleep efficiency (P < 0.05) and lower mean activity during sleep (P < 0.07). Low occupational class (P < 0.01), higher job demand (P < 0.05) and lower job control (P < 0.05) were associated with longer total sleep time. No associations were significant for sleep‐onset latency or wake after sleep onset. These preliminary results suggest that enhanced workplace social capital is closely associated with better quality and quantity of sleep.

Socioeconomic Status Is Significantly Associated with the Dietary Intakes of Folate and Depression Scales in Japanese Workers (J-HOPE Study)

The association of socioeconomic status (SES) with nutrient intake attracts public attention worldwide. In the current study, we examined the associations of SES with dietary intake of folate and health outcomes in general Japanese workers. This Japanese occupational cohort consisted off 2266 workers. SES was assessed by a self-administered questionnaire. Intakes of all nutrients were assessed with a validated, brief and self-administered diet history questionnaire (BDHQ). The degree of depressive symptoms was measured by the validated Japanese version of the K6 scale. Multiple linear regression and stratified analysis were used to evaluate the associations of intake with the confounding factors. Path analysis was conducted to describe the impacts of intake on health outcomes. Education levels and household incomes were significantly associated with intake of folate and depression scales (p < 0.05). After adjusting for age, sex and total energy intake, years of education significantly affect the folate intake (β = 0.117, p < 0.001). The structural equation model (SEM) shows that the indirect effect of folate intake is statistically significant and strong (p < 0.05, 56% of direct effect) in the pathway of education level to depression scale. Our study shows both education and income are significantly associated with depression scales in Japanese workers, and the effort to increase the folate intake may alleviate the harms of social disparities on mental health.