The selection hypothesis of social inequalities in health: The Oslo Mortality Study

We wanted to use the possibilities of Norwegain statistics to test if health-related mobility explains some of the social inequalities in mortality, the so-called selection hypothesis. Premature death was regarded as an expression of health potentials at a group level. Social mobility was followed by the occupation of all employed Oslo inhabitants in the age group 20-39 years in 1960 to their occupation at the age of 40-59 years in 1980. Deaths were registered at the age of 50-74 in 1990-94. We found that those moving upwards in the social hierachy had lower mortality than their class of origin, supporting the selection hypothesis, but higher mortality than their class of destination, contradictory to the hypothesis. As expected, the oppostite pattern was found for downward mobility. The analysis is not finished. We will try to calculate the net effect of social mobility on the cross-sectional inequalities in mortality in Oslo. After the Black report in 1981 documented increasing differences in mortality between the social classes in post-war Western countries, the reasons for these dif-ferences have been vividly discussed (1). Most resear-chers today believe that social class differences i