A brief journey on the London Underground from Oxford Circus station in central London to Star Lane station in the east equates to a loss of 2.6 years per mile in longevity—reflecting the 20-year gap in the average life expectancy at birth between people living around these two stations. Similarly striking gaps have been observed elsewhere—in Glasgow and New York City, for example—highlighting the startling health disparities that can exist between particular areas of the same city. The link between socioeconomic status (SES) and health outcomes is, of course, well documented: SES is inversely associated with the major indicators of health status, including cardiovascular disease (CVD) morbidity and mortality.
SES is usually measured by indicators such as educational attainment, income, or occupational class. Inequalities in life expectancy by education level exist across Europe, and the gap between men is wider—on average, 30-year-old men with less than upper secondary education live 8 years less than those with a tertiary education and, among women, this gap is 4 years. This disparity in life expectancy is due to higher mortality rates in low-educated people, mainly driven by CVD and cancer. A higher prevalence of risk factors such as smoking and excessive alcohol consumption among people with lower levels of education contribute to these higher mortality rates. A similar relationship is observed between level of income and health—in terms of the link between the distribution of income at both the country level and rate of mortality, and at the individual level where lower incomes and deprivation are associated with poorer health, even in countries with universal health coverage.
In this issue of the European Heart Journal, Agerström et al. use income and education as indicators of SES in Sweden to assess disparities in in-hospital cardiac arrest (IHCA) treatment and survival. There has been a trend of increasing gaps in life expectancy between groups with different education levels in Sweden: the average life expectancy at 30 years for men and women with post-secondary education was 6 years higher in 2017 than that of those who had only compulsory education, compared with a gap of 5 years for men and 5.2 years for women in 2012. In fact, education level has been found to be the strongest predictor of healthcare use in Sweden among older adults. In terms of income inequality, while Sweden fares better than other OECD countries (a Gini coefficient of 0.28 in 2018), there is a consistent trend of increasing inequality over the last two decades. Using Swedish registry data on 24 217 IHCA episodes between 2005 and 2018, Agerström and colleagues found that higher SES patients were less likely to receive delayed cardiopulmonary resuscitation (CPR) relative to low SES patients, after controlling for several clinical, demographic and contextual factors [highly educated, odds ratio (OR) 0.89, P = 0.012; high income, OR 0.98, P = 0.038]. They also found a higher likelihood of immediate survival after CPR, 30-day survival, and survival to discharge with good neurological outcome for high SES patients.
Importantly, the authors were able to assess variation in a clinical process measure—heart rhythm monitoring prior to the onset of the cardiac arrest—which is associated with shorter CPR delay and duration, and higher likelihood of survival. They found that higher SES patients were more likely to have their heart rhythm monitored prior to the onset of the cardiac arrest than low SES patients (highly educated, OR 1.16, P < 0.001; high income, OR 1.02, P = 0.001), and this partially explained the association between SES and CPR delay. This is an important insight since the limited number of previous studies that addressed the association between SES and outcomes after IHCA did not assess variations in clinical process measures. The authors acknowledge that the associations they found were small and that a large proportion of low SES patients were not subject to poor care quality relative to high SES patients. Nonetheless, their findings indicate the possibility of treatment bias or discrimination based on SES at the healthcare setting, and this warrants careful consideration.
It is notable that in the present study, the associations between SES and outcomes after IHCA differed based on the chosen SES indicator (education or income), highlighting the complex underlying pathways through which SES influences health. Additionally, the group of patients studied were relatively old (mean age of 73.6) and health inequalities are generally more pronounced among the elderly, suggesting that the influence of SES indicators on health is pervasive and can change over the life course. Therefore, it is important to recognize that a material conceptualization of SES, where it is assumed that education, income, or occupation provide a material advantage to improve health through better access to resources and knowledge, does not fully capture the means by which SES generates health disparities. The findings from the present study are better contextualized within a social psychology framework that emphasizes the relevance of the non-material components of SES as mediators of the SES–health association (Figure 1).
Schematic diagram summarizing a social psychology-based conceptualization of socioeconomic status (SES). SES influences health through many complex pathways. A material conceptualization of SES focuses on the resource-based advantages that improve health in high SES people. However, the SES–health association is additionally mediated by the non-material components of SES—personal and social identity, and also as an ascriptive characteristic that shapes interpersonal encounters.
The non-material conceptualization of SES recognizes that, in addition to being a determinant of resources, SES affects health through its influence on identity and social affiliation, and by being an ascriptive characteristic that shapes interpersonal encounters. Identities are multidimensional, with a combination of personal and social identities that act as reference points for social comparison and influence how people respond to life course events. For example, subjective social status is associated with health behaviour, mental health, physical health, and self-rated health, independent of objective status. The influence of these social identities on health would, of course, be conditional on the cultural and historical contexts within each country. Sweden may be widely recognized for its egalitarianism, but class tensions are at the centre of its current international-hit period drama The Restaurant co-created by Ulf Kvensler, in which the day-to-day running of a restaurant serves as a microcosm of post-war Swedish society and a reminder of the social class differences that defined this period. There is still evidence of significant intergenerational transmission of wealth at the very top of the income distribution.
SES as an ascriptive characteristic can shape interpersonal encounters in society including clinical episodes, and this is one possible explanation for the findings by Agerström and colleagues. Discrimination, prejudice, or bias in the healthcare setting based on ascriptive characteristics are associated with poorer physical and mental health. Variations in treatment can be driven by doctors' perception of these characteristics—for example, low SES patients have been given less demanding (as a result less effective) treatment regimens for diabetes. Importantly, perceived discrimination is associated with people refraining from seeking medical treatment. Therefore, the findings from the present study based on in-hospital episodes could be an indication of wider health disparities generated due to discrimination based on SES. However, all these studies come with significant limitations as any such discrimination by an agent in the healthcare setting is unobserved, and indirect inference of discrimination could be confounded by other unobserved factors. While careful consideration should be given to the limitations of these studies, they nevertheless provide important insights into the complex social processes that could be influencing health disparities.
However, while SES-based differences in treatment at the healthcare system level require our attention, health disparities are ultimately embedded in a broader social, political, and economic context with determinants that the healthcare system alone cannot resolve. Contextualizing the relationship between SES and health within a social psychology framework helps to take account of the complex social processes that generate health disparities. The British historian E. P. Thompson in an article entitled 'Moral Economy of the English Crowd in the Eighteenth Century' posited the concept of a moral economy based on the analysis of the food riots that took place in 18th century Britain. He argued that people during this time believed in an economy comprised of a set of attitudes and norms of social justice, with obligations and duties to the community—a moral economy that aligned economic concerns with moral concerns. Closing the gaps in life expectancy—not just in that journey across London but between different social groups Europe- and world-wide—will require us once more to align our economic and moral concerns, and address the societal conditions that generate health disparities in the first place.
Eur Heart J. 2021;42(8):870-872. © 2021 Oxford University Press
Copyright 2007 European Society of Cardiology. Published by Oxford University Press. All rights reserved.