Workplace social capital and CVD risk factors: baseline results from a large scale panel study of Japanese workers

Methods: We are going to establish five waves of data from a panel study of Japanese workers to investigate whether there are health inequalities across socioeconomic strata. Totally 9700 workers have been recruited by the end of May 2011. We analyzed 1136 workers in a railway company who completed the relevant questions and physical check-up at baseline.  A 6-item scale was developed for the measurement of WSC. The scale taps whether there are attitude/mood of collaboration and helping each other, mutual understanding and trust, and sharing information across the coworkers. Items were rated on a 4-point scale with higher scores representing higher WSC. Internal consistency was high, with coefficient alpha of 0.89. Ratings for all items were summed to provide a single index and the median in the distribution of the sum score was used as a cut-off point for high and low WSC.  We measured the following cardiovascular risk factors: age, sex, educational attainment, occupations, cigarette smoking, alcohol consumption, physical activity, body mass index, hypertension (physician-diagnosed hypertension or systolic/diastolic blood pressure >=130/85mmHg), diabetes mellitus (physician-diagnosed diabetes or HbA1c >= 6.5%), and dyslipidemia (physician-diagnosed dyslipidemia or low-density lipoprotein cholesterol/triglyceride >= 140/150mg/dl or high-density lipoprotein cholesterol <40mg/dl). Logistic regression analysis was conducted to examine the association between WSC and cardiovascular risk factors.  

Results: WSC was not associated with any behavioral risk factors (cigarette smoking, alcohol drinking, low physical activity or obesity), nor hypertension (OR; 1.03, 95%CI; 0.77-1.36) or dyslipidemia (OR; 0.92, 95%CI; 0.68-1.25). However, low WSC was significantly associated with diabetes mellitus (OR; 1.58, 95%CI; 1.02-2.43).  

Discussion: The individual-level ‘cognitive’ WSC was associated with diabetes mellitus. WSC could be a target work environment to improve worker’s cardiovascular health.