Socioeconomic status and the course of quality of life in coronary heart disease and cancer: from description toward an explanation

The present thesis provides insights into the impact of socio-economic status (SES) on cancer and coronary heart disease (CHD) by exploring cross-sectional and longitudinal differences in patients’ quality of life (QoL) and by suggesting possible mechanisms which might regulate such disparities. Additionally this research considers potential explanations for the relation between SES and disparities in QoL by addressing the mediating role of psychological resources. The methodological strengths of all four studies presented in the thesis are the longitudinal and prospective designs and the multiple assessments of the patients. This research points to the conclusion that the influence of SES on the course of QoL is disease-specific and, in the long term, is relevant to CHD but not to cancer. Regarding CHD, most socioeconomic inequalities in the course of the disease are related to functional status, particularly physical functioning. However, due to the unique prospective design of the study it is possible to attribute disparities in physical functioning after diagnosis to pre-morbid conditions, rather than to the direct consequences of the disease. Regarding the role of psychological factors in the relation between SES and the course of QoL, two main findings emerged. 1) Heart failure patients with different SES respond differently to the same level of psychological distress: high SES patients experience less impairment in role functioning, possibly due to an uneven distribution of resources between socioeconomic groups. 2) Self-efficacy is the only aspect of perceived control which mediates the relationship between SES and changes in physical functioning in CHD patients.