Social Inequalities in Health: New Evidence and Policy ImplicationsBMJ 2006; 333 doi: https://doi.org/10.1136/bmj.39049.564502.59 (Published 30 November 2006) Cite this as: BMJ 2006;333:1177
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The relationship between the prevalence of an outcome and the size of relative differences in experiencing it
In his review of Social Inequalities in Health: New Evidence and Policy Implications,1 Kristensen notes as a negative aspect of the situation described in the book that Nordic welfare states do not have the comparatively small health inequalities that one would expect and that it is unclear why that should be the case. In the same vein, Kristensen also notes that experience has shown that implementation of general preventive measures may increase health inequalities.
The two observations are related in a way that involves a misunderstanding that calls into question much health inequalities research and commentary. In general, the rarer an outcome, the greater the relative difference between the rates at which more and less advantaged groups experience it (though the smaller the relative difference between rates of avoiding it).2-7. A 1997 study found that, despite being egalitarian societies, Norway and Sweden had among the largest relative inequalities in mortality rates in western Europe.8 But an obvious reason for such countries to show large relative inequalities in mortality rates is that they have low overall mortality rates.2,7.
Similarly, the observation that general improvements in health may increase inequalities is correct in the sense, for example, that overall declines in mortality will tend to increase relative differences in mortality rates. The reasons for this are simple enough. The more a society reduces mortality and other adverse outcomes, the more they will tend to be concentrated in the most susceptible segments of the population, and disadvantaged groups comprise increasing proportions of each progressively more susceptible segment of the overall population. Correspondingly, relative differences between rates of experiencing the outcomes increase.
But whether increases in relative differences in experiencing adverse health outcomes that flow solely from declines in the outcomes should be deemed increasing inequality in any meaningful sense is another matter, particularly when one recognizes that the relative difference in rates of avoiding the outcome has declined. A research priority ought to be the development of means of distinguishing changes in the respective situations of more and less advantaged groups that flow solely from changes in prevalence of an outcome from those that reflect something more meaningful. But whether such means exist is not altogether clear.2,6.
1 Kristensen P. Review of Social Inequalities in Health: New Evidence and Policy Implications. BMJ 2006;333:1167.
2. Scanlan JP. Can we actually measure health disparities? Chance 2006:19(2):47-51: http://www.jpscanlan.com/images/Can_We_Actually_Measure_Health_Disparities.pdf.
3. Scanlan JP. Measuring health disparities. J Public Health Manag Pract 2006;12(3):294 [Lttr]: http://www.nursingcenter.com/library/JournalArticle.asp?Article_ID=641470.
4. Scanlan JP. Race and Mortality. Society. 2000;37(2):19-35: http://www.jpscanlan.com/images/Race_and_Mortality.pdf.
5. Scanlan JP. Divining difference. Chance. 1994;7(4):38-9,48: http://jpscanlan.com/images/Divining_Difference.pdf.
6. Scanlan JP. The misinterpretation of health inequalities in the United Kingdom: Paper presented at: British Society for Population Studies Annual Conference 2006, Southampton, England, Sept. 18-20, 2006: http://www.jpscanlan.com/images/BSPS_2006_Complete_Paper.pdf (accessed Nov. 10, 2006).
7. Scanlan JP. The misinterpretation of health inequalities in Nordic countries: Paper presented at: 5th Nordic Health Promotion Research Conference, Esbjerg, Denmark, June 15-17, 2006, Esjberg, Denmark: http://www.jpscanlan.com/images/Esbjerg_Oral.pdf .
8. Mackenbach, J.P., Kunst, A.E., Cavelaars, et al. Socioeconomic inequalities in morbidity and mortality in western Europe, Lancet 1997; 349: 1655-59.
Competing interests: None declared
Competing interests: No competing interests