Decomposition of sources of income-related health inequality applied on SF-36 summary scores: a Danish health survey

Background: If the SF-36 summary scores are used as health status measures for the purpose of measuring health inequality it is relevant to be informed about the sources of the inequality in order to be able to target the specific aspects of health with the largest impact. Methods: Data were from a Danish health survey on health status, health behaviour and socioeconomic background. Decompositions of concentration indices were carried out to examine the sources of income-related inequality in physical and mental health, using the physical and mental health summary scores from SF-36. Results: The analyses show how the different subscales from SF-36 and various explanatory variables contribute to overall inequality in physical and mental health. The decompositions contribute with information about the importance of the different aspects of health and off-setting effects that would otherwise be missed in the aggregate summary scores. However, the complicated scoring mechanism of the summary scores with negative coefficients makes it difficult to interpret the contributions and to draw policy implications. Conclusion: Decomposition techniques provide insights to how subscales contribute to income-related inequality when SF-36 summary scores are used.