Workplace social capital and the onset of major depressive episode among workers in Japan: a 3-year prospective cohort study

Asuka Sakuraya, Kotaro Imamura, Akiomi Inoue, Akizumi Tsutsumi, Akihito Shimazu, Masaya Takahashi, Takafumi Totsuzaki, Norito Kawakami

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BACKGROUND: This study examined the prospective association of workplace social capital (WSC) with major depressive episode (MDE) among Japanese employees.

METHODS: A 3-year prospective cohort study was conducted among 1058 employees from a private think-tank company who participated in a baseline survey; after excluding those with MDE in the past 12 months, 929 were followed up. WSC at baseline was measured using a 3-item scale. MDE was assessed at baseline and at follow-up every year, by using a web-based, self-administered version of the WHO Composite International Diagnostic Interview (WHO-CIDI) 3.0 depression section, based on the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition: Text Revision (DSM-IV-TR)/DSM-5 criteria. Cox discrete-time hazards analyses were used to estimate HRs and 95% CIs, adjusting for covariates.

RESULTS: A group with middle-level WSC scores had the lowest risk of MDE after being fully adjusted (HR 0.34, 95% CI 0.14 to 0.84, p=0.02). The relationship between WSC and MDE was U-shaped, although a non-linear model fit better than a linear model, with only marginally statistical significance (p=0.06). Dichotomised and continuous variables of WSC scores were significantly and negatively associated with MDE (p=0.03 and p<0.01, respectively).

CONCLUSIONS: The current study replicated a previous finding from Finland that WSC was a protective factor of the onset of MDE in Japan. The slightly U-shaped relationship, that is, the group with high WSC having a small elevated risk of MDE, may reflect a dark side of WSC in a country with collectivity-oriented and hierarchy-oriented culture, such as Japan.

Original languageEnglish
Pages (from-to)606-612
Number of pages7
JournalJournal of Epidemiology and Community Health
Issue number6
Publication statusPublished - Jun 2017

Bibliographical note

Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to


FundersFunder number
Japan Society for the Promotion of Science26253042, 26860433


    • Adult
    • Cohort Studies
    • Depressive Disorder, Major/epidemiology
    • Female
    • Humans
    • Male
    • Prospective Studies
    • Social Capital
    • Stress, Psychological/epidemiology
    • Work Performance/statistics & numerical data
    • Workplace/psychology


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