Socioeconomic gradients in health in international and historical context

BackgroundA large literature has developed researching the origins of socioeconomic gradients in child health in developed countries. Particularly, this research examines the age at which these gradient effects emerge and how they change across different stages of childhood. However, similar research on developing countries is limited.MethodsThis paper examines the socioeconomic gradients in early childhood health in two developing countries, Bangladesh and Nepal using the 2011 Demographic and Health Surveys. The paper separately studies two measures of household socioeconomic status: household wealth and maternal educational attainment. Two anthropometric measures of early childhood health, height-for-age and weight-for-age Z scores for 0–59 months of children, are used for our empirical exercise. The paper uses both non-parametric and multivariate ordinary least squares approaches to examine at what age socioeconomic disparities in health emerge, and investigates if these disparities increase with age in early childhood.ResultsThe paper provides significant evidence of age-specific socioeconomic gradients in early childhood health in both countries. Health disparities in household wealth exist in both countries. This disparity emerges in the first 11 months of life, and is particularly severe for children from the poorest quintile. On the other hand, while the emergence of maternal education gradients during the first 11 months is sensitive to the choice of childhood health measure, the study finds the children of mothers with higher education to enjoy significantly higher health outcomes in comparison to those with lower education. However, controlling for father’s education weakens the effects of maternal education on child health in both countries. Further, the paper does not find statistically significant evidence where socioeconomic gradients in health increase with age in early childhood.ConclusionsOur study concludes that socioeconomic disparities in health outcomes exist even in very early childhood in Bangladesh and Nepal. This has important implications for targeted policy interventions in the form of food security and nutrition supplement programs, free provision of health care, and maternal education in both countries.Electronic supplementary materialThe online version of this article (doi:10.1186/s12939-016-0364-2) contains supplementary material, which is available to authorized users.

Research and policy related to reducing health inequalities has progressed separately within Ireland and Northern Ireland. This paper describes the first exploration of the socio-economic influences on health on the island of Ireland since 1922. Postal survey. The response rate was 52%; 11,870 respondents. Men reported more long-standing illness (LLTI) or poor general health (PGH); depression was more common amongst women. Socio-economic gradients in health were evident in both jurisdictions, with the effects of household income being particularly marked. Overall, morbidity levels were significantly better in Ireland than in Northern Ireland: adjusted odds ratio of 0.79 (95% CI 0.71 - 0.88) for LLTI; 0.64 (0.57 - 0.72) for PGH; 0.90 (0.82 - 0.99) for depression. There is evidence of strong and similar socio-economic gradients in health throughout the island of Ireland. This would suggest joint policy approaches or at least further comparative evaluation of the initiatives in each jurisdiction.

Socioeconomic gradient in health in Canada: Is the gap widening or narrowing?

We investigated whether the processes underlying the association between income inequality and population health are related to those responsible for the socioeconomic gradient in health and whether health disparities are smaller when income differences are narrower. We used multilevel models in a regression analysis of 10 age- and cause-specific US county mortality rates on county median household incomes and on state income inequality. We assessed whether mortality rates more closely related to county income were also more closely related to state income inequality. We also compared mortality gradients in more- and less-equal states. Mortality rates more strongly associated with county income were more strongly associated with state income inequality: across all mortality rates, r= -0.81; P=.004. The effect of state income inequality on the socioeconomic gradient in health varied by cause of death, but greater equality usually benefited both wealthier and poorer counties. Although mortality rates with steep socioeconomic gradients were more sensitive to income distribution than were rates with flatter gradients, narrower income differences benefit people in both wealthy and poor areas and may, paradoxically, do little to reduce health disparities.

The socio-economic gradient in health does not seem to apply to overweight among Canadians adults. In the present study, we sought to determine the socio-economic gradient in overweight among Canadian children in distinct economic settings. We further examined socio-economic gradients in underlying behaviours, healthy eating and active living, as well as parental support for these behaviours. We surveyed 6430 grade five students and their parents in Alberta and Nova Scotia. Students completed dietary and activity questionnaires and had their height and weight measured. Parents completed questions on socio-economic background and their support for their child's health behaviours. We applied multi-level regression methods to characterize the socio-economic gradients. In both Alberta and Nova Scotia, we observed socio-economic gradients whereby children with parents who were more highly educated and had higher earnings were more physically active and less likely overweight. In contrast, we did not observe a socio-economic gradient with respect to healthy eating. Relative to socio-economically disadvantaged parents, those with better education and higher income were more likely to report encouraging their children's healthy eating and physical activity. Socio-economically disadvantaged parents, though, reported more engagement in physical activities with their children. Whereas the socio-economic gradient in overweight among Canadian adults is fading, we did not observe such a phenomenon among children. The mechanism preserving the socio-economic gradient among children may be related to more encouragement given to healthy eating and physical activity in the more socio-economically advanced families.

A University of Chicago Nobel Laureate in economics, RW Fogel, and a Dutch economist, JW Drukker, found that as the wealth of Western countries improved following the Industrial Revolution, life expectancy increased and the mean height of their populations improved (1,2). Since height is a product of genes and nutrition, they concluded that improved health was related to improved socioenvironments and better nutrition of children, not improvements in health care. Today, the health of populations in developed countries is a socioeconomic gradient. These health gradients (3) are linear, which means that whatever the socioeconomic factors influencing health today are, they affect everyone in society, including the wealthiest. The effect, however, is greatest on the poorest members of society. The Canadian Institute for Advanced Research’s (CIAR) population health program led by Robert Evans (University of British Columbia [Vancouver, British Columbia]) examined the factors contributing to the health gradients in Canada and other countries. They concluded that in the United Kingdom, Canada and the United States (US), the major factor contributing to inequities in health was more than poverty and a lack of health care (3). Hertzman et al (4) – members of the CIAR’s population health program – proposed that the socioeconomic conditions in early life affected adult health (physical and mental) throughout life. They and others suggested that the development of the brain and related biological pathways in early life were important factors. This led to the hypothesis that if the socioeconomic gradient in health was influenced by brain and biological pathway development in the early years, it was possible that there were similar socioeconomic gradients in education and behaviour (5). The CIAR established a program in human development to explore the concept. The scientists in this program found that the socioeconomic gradients in literacy, numeracy and behaviour were similar to the health gradients (6). They suggested that the effect of experience in early life on the development of the architecture and function of the brain was important in contributing to inequities in health and education. In 2002, the CIAR established a new program, ‘Experience-based Brain and Biological Development’ to study how genes and experience shape brain development that influences health, learning and behaviour trajectories throughout life.

In the second half of 2008, two events occurred that are, individually and together, highly significant for the future of global health. First, in August 2008 the World Health Organization (WHO)’s Commission on Social Determinants of Health (CSDH) released its final report (Commission on Social Determinants of Health, 2008; for a brief summary, see Marmot and Friel, 2008; Marmot et al., 2008). The 19-member Commission, established in 2005, began its extraordinary report with the observation that: ‘Social injustice is killing people on a grand scale’. The concepts of health equity and socioeconomic gradients in health were central to the Commission’s unequivocally normative analysis. Health equity was defined with reference to the absence of systematic differences in health that are avoidable by reasonable action … and the Commission considered most such differences to be avoidable and therefore inequitable (Commission on Social Determinants of Health, 2007, p. 1). Socioeconomic gradients in health are disparities in health outcomes related to various indicators of social (dis)advantage; such gradients are ubiquitous, not only between countries but also within them. The Commission’s perspective on such gradients is worth quoting at length:KeywordsGross Domestic ProductInternational Monetary FundSocial DeterminantHealth EquityGlobal Public GoodThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Accumulating Knowledge on the Social Determinants of Health and Infectious Disease

Equality in health does not require the elimination of all differences, but rather the reduction of unfair and preventable inequalities that arise from socio-determined conditions. Social determinants of health play a central role in understanding health equity as factors that contribute positively or negatively to health, as well as in the social processes that shape inequalities in the distribution of resources among groups with different levels of power and social influence. The investigation of health inequalities resulted in the development of specific theories. The relevant literature was searched in the PubMed, Scopus, and Google Scholar databases using search terms such as: ‘health inequalities’, ‘health disparities’, ‘health equity’, ‘social determinants of health’, ‘socioeconomic gradient in health’, and ‘access to healthcare services’. The literature search was conducted in English for the period 2015 to 2025. The issue of inequality is linked to complex social and economic processes, which means we need to adopt targeted policies to promote social justice and universal health coverage.

Mechanisms for the social gradient in health: Results from a 14-year follow-up of the Northern Swedish Cohort

A comparison of health and socioeconomic gradients in health between the United States and Canada

The presence of a socioeconomic gradient in health has been documented extensively in humans. 1 2 Social hierarchy has also been found to be associated with the health of non-human...

Although Latino immigrants come from countries with high levels of inequality, their socioeconomic gradients in health are generally weaker than those among their US-born co-ethnics and much weaker than those of US-born non-Hispanic (NH) whites. We review this literature among Latin American immigrants looking at the role of: factors related to conditions in the country of origin, or “gradient importation”; migration-related factors, such as Socioeconomic Status (SES)-graded health selectivity in emigration and return; destination-based factors, including SES-graded protection and selection; and data artifacts, which might be more likely to occur at lower levels of SES. Despite the relative scarcity of studies on the social gradients in health among immigrants, recent research has provided interesting insights on the potential mechanisms driving the Hispanic Health Paradox and on the potential role of socioeconomic status on “acculturation” in health. We discuss which of the reviewed mechanisms may be more relevant in late life, point out potential avenues for future research, and reflect upon the steepness of white gradients in the United States.

The relationship between maternal education and reported childhood conditions

Although relationships between social conditions and health have been documented for centuries, the past few decades have witnessed the emergence of socioeconomic gradients in health and mortality in most developed countries. These gradients indicate that health improves, although decreasingly so, at higher levels of socioeconomic status. To minimize problems with reverse causality, I tested competing hypotheses for observed socioeconomic gradients for infant mortality outcomes. I found no support for the income-inequality hypothesis and negligible support for the occupational-grade hypothesis. The results indicate that absolute material conditions are the most important determinants of socioeconomic effects on the risk of infant mortality and that while poverty has the most pronounced effect on risk, income is decreasingly salutary across the majority of the mortality gradient.