This longitudinal study utilizes a data set from the Survey of Living Conditions conducted by Statistics Sweden (SCB) during the years 1980-1981 and 1988-1989. It comprises a representative sample of the employed Swedish population (2,861 individuals) between the ages of 20 and 65. The objective of the study is to analyse the interaction between socio-economic and personal circumstances in explaining inequalities in health. It is based on a theoretical framework which presupposes that inequalities in health are likely to be explained by a complicated process involving a multitude of factors. At the same time, differential exposures and differential responses to risk factors between socio-economic classes for certain health outcomes are determined. The joint effect on general health status, seven years later, of being a manual worker and having reported psychosomatic symptoms is 113% greater than would have been expected on the assumption of additivity of the singular effects of these variables. It is suggested that it is necessary to highlight in further research the complex interactions and pathways between factors associated with health outcomes to improve our understanding of the causal processes involved and determine appropriate preventive measures.