Objective: One of the practical models for assessment of stressful working conditions due to job strain is "job demand and control" or Karasek's job strain model. This model explains how adverse physical and psychological effects including cardiovascular disease risk factors can be established due to high work demand. The aim was to investigate how certain cardiovascular risk factors including body mass index (BMI), heart rate, blood pressure, serum total cholesterol levels, and cigarette smoking are associated with job demand and control in workers.
Materials and methods: In this cohort study, 500 subjects completed "job demand and control" questionnaires. Factor analysis method was used in order to specify the most important "job demand and control" questions. Health check-up records of the workers were applied to extract data about cardiovascular disease risk factors. Ultimately, hypothesis testing, based on Eta, was used to assess the relationship between separated working groups and cardiovascular risk factors (hypertension and serum total cholesterol level).
Results: A significant relationship was found between the job demand-control model and cardiovascular risk factors. In terms of chi-squared test results, the highest value was assessed for heart rate (Chi(2) = 145.078). The corresponding results for smoking and BMI were Chi(2) = 85.652 and Chi(2) = 30.941, respectively. Subsequently, Eta result for total cholesterol was 0.469, followed by hypertension equaling 0.684. Moreover, there was a significant difference between cardiovascular risk factors and job demand-control profiles among different working groups including the operational group, repairing group and servicing group.
Conclusion: Job control and demand are significantly related to heart disease risk factors including hypertension, hyperlipidemia, and cigarette smoking.