Several recent studies have shown that the psychosocial work environment is of significance to risk of developing CVD. Of particular importance in the recent development of this field is that theoretical models, such as the demand-control-support model and the social reward model, have been developed. They provide the basis for studies of the interaction between different environmental factors (e.g., between psychological demands and control, and between support and control). Such interactions have been studied in relation to physiological mechanisms of relevance to heart disease, and they have also been used in intervention studies that have focused on work organization factors underlying the perceived work environment.
Many epidemiological studies have explored the association between work environment and risk of heart disease. These studies have supported the hypothesis that the combination of high psychological demands and low decision latitude (small possibility for the individual to control conditions at work) is associated with increased risk of CVD. Direct effects of psychosocial work environment factors on neuroendocrine factors of relevance to CVD risk have been shown, such as high catecholamine output in job strain situations, as well as progressively increasing sympathoadrenal arousal, increasing sleep disturbance, and decreasing anabolism with increasing job strain. Significant relationships between the psychosocial work environment and the accepted cardiovascular risk factors-in particular, smoking habits-have aiso been shown in some studies. The relationship between job strain and blood pressure is difficult to study, and conflicting results have been found. Some of the inconsistencies in this field seem to have methodological explanations. The relationships between the demand-control model and social class, as well as between the model and gender, are presently being discussed in the literature.
Other disease categories have also been studied using the demand-control- support model. Some relationships between the model and symptoms in the locomotor system have also been found. In this case, the relationships may be different in different strata of the population and different for different outcomes (e.g., low back vs. neck and shoulder symptoms).
Intervention research has shown that the demand-control-support model is educationally useful. It could be used effectively in discussions about improved work conditions. Conversely, explorations regarding the basic dimensions have to become specific for different strata of the workforce, and our measurement instruments have to be improved to make further progress possible.