© Oxford University Press on behalf of the New York Academy of Medicine 2005
Metropolitan income inequality and working-age mortality: A cross-sectional analysis using comparable data from five countries
1Department of Geography, McGill University, Associate Health Analysis and Measurement Group, Statistics Canada, 805 Sherbrooke Street West, H3A 2K6 Montreal, Québec Canada
2School of Geography, University of Leeds, Leeds, UK
3Inner City Health Research Unit of St. Michael’s Hospital, Department of Geography, University of Toronto, Toronto, Ontario Canada
4Department of Social Medicine, Göteborg University, Göteborg, Sweden
5Public Health Information Development Unit, University of Adelaide, Adelaide, South Australia Australia
6Department of Epidemiology and Centre for Social Epidemiology and Population Health, Center for Human Growth and Development, Survey Research Centre, University of Michigan School of Public Health, Ann Arbor, Michigan
7Centre for Epidemiology, National Board of Health and Welfare, Stockholm, Sweden
Accepted February 28, 2005.
The relationship between income inequality and mortality has come into question as of late from many within-country studies. This article examines the relationship between income inequality and working-age mortality for metropolitan areas (MAs) in Australia, Canada, Great Britain, Sweden, and the United States to provide a fuller understanding of national contexts that produce associations between inequality and mortality. An ecological cross-sectional analysis of income inequality (as measured by median share of income) and working-age (25–64) mortality by using census and vital statistics data for 528 MAs (population >50,000) from five countries in 1990–1991 was used. When data from all countries were pooled, there was a significant relationship between income inequality and mortality in the 528 MAs studied. A hypothetical increase in the share of income to the poorest half of households of 1% was associated with a decline in working-age mortality of over 21 deaths per 100,000. Within each country, however, a significant relationship between inequality and mortality was evident only for MAs in the United States and Great Britain. These two countries had the highest average levels of income inequality and the largest populations of the five countries studied. Although a strong ecological association was found between income inequality and mortality across the 528 MAs, an association between income inequality and mortality was evident only in within-country analyses for the two most unequal countries: the United States and Great Britain. The absence of an effect of metropolitan-scale income inequality on mortality in the more egalitarian countries of Canada. Australia, and Sweden is suggestive of national-scale policies in these countries that buffer hypothetical effects of income inequality as a determinant of population health in industrialized economies.
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