The role of income diVerences in explaining social inequalities in self rated health in Sweden and Britain

Study objective—To analyse to what extent diVerences in income, using two distinct measures—as distribution across quintiles and poverty—explain social inequalities in self rated health, for men and women, in Sweden and Britain. Design—Series of cross sectional surveys, the Swedish Survey of Living Conditions (ULF) and the British General Household Survey (GHS), during the period 1992–95. Participants and setting—Swedish and British men and women aged 25—64 years. Approximately 4000 Swedes and 12 500 Britons are interviewed each year in the cross sectional studies used. The sample contains 15 766 people in the Swedish dataset and 49 604 people in the British dataset. Main results—The magnitude of social inequalities in less than good self rated health was similar in Sweden and in Britain, but adjusting for income diVerences explained a greater part of these in Britain than in Sweden. In Britain the distribution across income quintiles explained 47% of the social inequalities in self rated health among women and 31% among men, while in Sweden it explained, for women 13% and for men 20%. Poverty explained 22% for British women and 8% for British men of the social inequalities in self rated health, while in Sweden poverty explained much less (men 2.5% and women 0%). Conclusions—The magnitude of social inequalities in self rated health was similar in Sweden and in Britain. However, the distribution of income across occupational social classes explains a larger part of these inequalities in Britain than in Sweden. One reason for this may be the diVerential exposure to low income and poverty in the two countries. (J Epidemiol Community Health 2001;55:556–561) Previous studies have shown that there is a socioeconomic gradient in mortality and morbidity, regardless of whether socioeconomic status is measured by occupation, education or income. Depending on the measure, the size of the health diVerential between socioeconomic groups varies both within and between countries, but the socioeconomic gradient is always present. 2 Even though to a large extent diVerent measures of socioeconomic status are related to each other, they are not completely interchangeable. Education determines socioeconomic position in terms of occupational class and socioeconomic position determines income. The magnitude of diVerences in health between social positions are surprisingly similar in diVerent European countries, including the Scandinavian welfare states, 4 while the mechanisms generating these diVerences may be diVerent. During the past decade there has been a growing interest in the association between income/poverty and mortality/ morbidity, and the roles of income and poverty in contributing to socioeconomic inequalities in health. There has also been a growing interest in conducting comparative studies on social determinants of health. 11 12 The diVerences between welfare systems in western European countries allow us to compare the impact of income and poverty on socioeconomic inequalities in Sweden and Britain. In this study we have chosen to define socioeconomic position by occupational social class. The concept of social class, or socioeconomic position/group, is grounded in the function of society. In sociological theory about inequality a distinction is made between positions in social structure and the persons occupying these. Using the concept occupational social class is a way to try to see what constitutes these diVerent positions and the life chances for the people who occupy them. The concept occupational social class has been used in a previous study. The aim of the study is to analyse the role of diVerences in income, using two distinct measures—as distribution across quintiles and poverty—in explaining social inequalities in self rated health among men and women in Sweden and Britain. In relation to previous studies, our interest is to study income as a mediating factor in the association between occupational social class and health—not to use income as a measure of socioeconomic position. We would argue that our comparative perspective may also contribute to the ongoing discussion on the relation between income distribution and health. Comparing the role of income in explaining socioeconomic inequalities in Sweden and Britain provides us with two diVerent contexts, with diVerent income distributions, within which the relation between income and health on an individual level is analysed.