Relationship between workplace social capital and suicidal ideation in the past year among employees in Japan: A cross-sectional study

Background: A growing body of evidence has demonstrated the associations between social capital and health. In residential or geographical areas, social capital has attracted attention for its protective effects against suicide. However, to this date, the relationship between social capital and suicidal ideation is not fully elaborated in the occupational setting. Therefore, the aim of the present study was to examine the association between workplace social capital and suicidal ideation in the past year among employees in Japan. Methods: A cross-sectional, web-based survey was conducted in February/March 2017 via an anonymous self-administered questionnaire distributed to workers in Tsukuba Science City, Japan. Binomial logistic regressions were used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for suicidal ideation in the past year, controlling for age group, marital status, educational attainment, and annual household income. The results were shown stratified by sex and occupation. Results: In total, 7255 of 19,481 workers responded, out of which we could analyze 6325 responses (4030 men, 2295 women). The prevalence of suicidal ideation in the past year was 5.9% for men and 7.8% for women. Low workplace social capital was statistically significantly associated with suicidal ideation both for men (OR = 2.57, 95% CI = 1.72-3.83) and for women (OR = 1.75, 95% CI = 1.15-2.66), compared with high workplace social capital after controlling for socioeconomic factors. Conclusion: Higher workplace social capital was associated with a reduced risk of suicidal ideation in the past year. Promoting workplace social capital could contribute to preventing suicide among employees in Japan.