A cross-sectional study of workplace social capital and blood pressure: a multilevel analysis at Japanese manufacturing companies

Objectives: We examined the contextual effect of workplace social capital on systolic blood pressure (SBP). Design: Cross-sectional. Setting: A conglomerate from 58 workplaces in Japan. Participants: Of the 5844 workers at a Japanese conglomerate from 58 workplaces, 5368 were recruited. Individuals who received drugs for hypertension (n=531) and who lacked information on any variable (n=167) were excluded from the analyses, leaving 4735 individuals (3281 men and 1454 women) for inclusion. Primary and secondary outcome measures: Systolic blood pressure. Results: The contextual effect of workplace social capital on SBP was examined using a multilevel regression analysis with a random intercept. Coworker support had a contextual effect at the workplace level (coefficient=-1.97, p=0.043), while a lack of trust for coworkers (coefficient=0.27, p=0.039) and lack of helpfulness from coworkers were associated with SBP (coefficient=0.28, p=0.002). Conclusions: The present study suggested that social capital at the workplace level has beneficial effects on SBP.