For three decades, the United Kingdom has been a leader in health disparities research, and the Whitehall Studies have played a significant role in such research. In the main, such research has relied on relative differences in adverse outcomes and has interpreted increasing relative differences in mortality as reflecting increasing health inequality without regard to the extent to which increases in relative differences in mortality are a statistical function of declining mortality or whether relative differences in survival rates have declined. The Whitehall Studies are particularly noteworthy for their finding of a larger social gradient in mortality within the Whitehall cohort than within the UK at large. That relative differences in mortality have been found to be larger among this relatively homogenous group whose members suffer from little material deprivation than in the population at large has formed the basis for a number of theories. These include that health disparities in the population at large must in fact be greater than they seem, but the size of the disparities has been obscured by the absence of socioeconomic indicators as precise as the occupational grades in the Whitehall cohorts. The observed patterns have also been interpreted to suggest that psycho-social factors play as large a role in health inequalities as material circumstances. But such interpretations have been reached without consideration of the extent to which large relative inequalities in mortality (or small relative differences in survival) among British civil servants are a function of the low mortality in that population. These and related issues are addressed in references below.
Item 3 of the references also discusses theorizing to the effect that relative differences in mortality tend to be smaller among retired workers in the Whitehall cohort because they are no longer subjected to the working environment responsible for the mortality differences. Such reasoning, like much other reasoning about the comparative size of health disparities among the young compared with the old, overlooks the statistical reasons to expect that relative differences in adverse outcomes will be larger among the young (where such outcomes as less common) than among the old, while relative differences in favorable outcomes will be larger among the old than the young. See item 3.
2. Recognizing why dichotomous and continuous measures may yield contrary results. BMJJune 11, 2007 (responding to (Chandola T, Ferrie J, Sacker A, Marmot M. Social inequalities in self reported health in early old age: follow-up of prospective cohort study. BMJ 2007:334:990-996): http://www.BMJ.com/cgi/eletters/334/7601/990
3. Recognizing expected patterns of relative differences in the Whitehall cohort. Journal Review June 25, 2007 (responding to van Rossum CTM, Shipley MJ, van de Mheen H, et al. Employment grade differences in cause specific mortality. A 25-year follow up of civil servants from the first Whitehall study. J Epidemiol Community Health 2000;54:178-84): http://jpscanlan.com/images/Van_Rossum_JECH_2000.pdf
4. Problems with the measurement of changes in health inequalities over time using dichotomous variables and possibilities using continuous variables. Journal Review June 19, 2007 (responding to Ferrie JE, Shipley MJ, Davey Smith GD. Change in health inequalities among British civil servants: the Whitehall II study. J Epidemiol Community Health 2002:56:922-926): http://jpscanlan.com/images/Ferrie_JECH_2002.pdf