Association between job characteristics and plasma fibrinogen in a normal working population: a cross sectional analysis in referents of the SHEEP study

Study objective-To explore the association between job characteristics and plasma fibrinogen concentrations. Design-Cross sectional design. Setting-The Greater Stockholm area. Subjects-A total of 1018 men and 490 women aged 45-70 who were randomly sel ected from the general population during 1992-1994. They were all employed and had no history of myocardial infarction. Main results-The self reported job characteristics were measured by a Swedi sh version of the Karasek demand-control questionnaire. For inferred scorin g of job characteristics, psychosocial exposure categories (job control and psychological demands) were assigned by linking each subject's occupationa l history with a work organisation exposure matrix. Job strain was defined as the ratio between demands and control. In univariate analyses, expected linear trends were found in three of four tests of association between high plasma fibrinogen and low control (the self reported score for women and t he inferred score for both sexes), in one of four tests of association betw een high plasma fibrinogen and high demands (the inferred score for women) and in two of four tests of association between high plasma fibrinogen and job strain (the inferred score for both sexes). Multiple logistic regressio n analyses showed that men in the inferred job strain group have an increas ed risk of falling into the increased plasma fibrinogen concentration group (above median level of the distribution) (odds ratio (OR) 1.2; 95% CI 1.0, 1.5) after adjustment for the variables that were associated with plasma f ibrinogen in the univariate analyses. In women, low self reported control, high inferred demand, and inferred job strain were significantly associated with increased plasma fibrinogen concentration (OR 1.3; 95% CI 1.0, 1.8, O R 1.5; 95% CI 1.0, 2.2, OR 1.5; 95% CI 1.1, 2.2, respectively). Conclusions-These results indicate that adverse job characteristics may be related to plasma fibrinogen concentrations and this relation is more relev ant in female workers. The dearest evidence for psychosocial effects on pla sma fibrinogen seems to be with job control and the associations are cleare r for the objective than for the self report variables.