In 1842, the English social reformer Edwin Chadwick documented a 30-year discrepancy between the life expectancy of men in the poorest social classes and that of the gentry. Today, people in the most affluent areas of the United Kingdom, such as Kensington and Chelsea, can expect to live 14 years longer than those in the poorest cities, such as Glasgow.

 

Such inequalities exist, to varying degrees, in all developed countries. Poorer groups fare particularly badly in the neo-liberal system of the United States; gaps in life expectancy in some US cities, such as New Orleans, are as large as 25 years.

 

Understanding and reducing these health inequalities remains a major public-policy challenge worldwide. It is not only a moral issue; health inequalities carry significant economic costs. But the causes of such inequalities are complex and contested, and the solutions are elusive.

 

The prevailing explanation for health inequalities is rooted in the social determinants of health – that is, the environments in which people work and live. Affluent people have better access to health-promoting environments, such as well-maintained schools that offer a good education, high-quality housing, and stable jobs in secure, safe settings. The poorer you are, the more exposed you are likely to be to health-damaging environments.

 

Various theories draw on this basic framework – and each competing explanation suggests different strategies for reducing health inequalities. For example, the “cultural-behavioral” approach explains health inequalities in terms of differences in individual behaviors, asserting that poorer people have worse health outcomes, owing to a higher propensity to smoke, drink alcohol, and eat less healthy foods. This view naturally underpins interventions like targeted smoking-cessation services or health-education initiatives.

 

The “materialist” approach takes a broader view, arguing that people with more money can essentially purchase better health through superior education, health care, and social services. Accordingly, countries can reduce health inequalities by introducing higher minimum incomes for their poorest citizens and guaranteeing universal access to public services.

 

By contrast, “psychosocial” theories suggest that it is the psychological experience of inequality – the feelings of inferiority or superiority generated by social hierarchies – that matters. This view implies that the poorest individuals and communities need to feel productive, valued, and empowered to take control of their own lives, rather than feel trapped in a subordinate position.

 

The “life course” approach combines multiple theories to contend that the unequal accumulation of social, psychological, and biological advantages or disadvantages over time, beginning in utero, produces health inequalities. It demands early intervention to put children on a positive health path, together with an adequate social safety net throughout citizens’ lives.

 

The most encompassing view is that of the “political-economy” school, which argues that health inequalities are determined by capitalist economies’ hierarchical structure and the associated political choices about resource distribution. This analysis calls for the most radical action: to develop an economic and social system in which resources, particularly wealth and power, are more evenly distributed.

 

Given that all of these theories can, to some extent, be supported by scientific evidence, politics can matter more than science in determining which strategies policymakers pursue to reduce health inequalities. After all, some potential solutions are politically easier to implement within existing systems than others.

 

For example, interventions aimed at changing individual behavior are far less challenging to prevailing power structures than those that demand extensive social investment or revitalization of the entire system. Thus, governments interested in closing the health gap – such as the British Labour government in 1997-2010 – usually end up pursuing such relatively painless “downstream” interventions.

 

But this approach has proved to be only partly successful in reducing health inequalities, leaving little doubt that more comprehensive measures are needed. Indeed, most of the health gains over the nineteenth and twentieth centuries were brought about by far-reaching economic, political, and social reforms.

 

Ultimately, more equal societies have better health outcomes. While even the most egalitarian developed countries have health inequalities, all of their citizens are better off and live longer. The poorest and most vulnerable groups in social-democratic countries like Sweden and Norway are far healthier and live longer than their counterparts in neo-liberal countries such as the UK or the US. These more egalitarian countries have also achieved comparatively stable, inclusive economic growth and a high standard of living. So, if assessed from a neutral standpoint, social democracy is clearly the better choice for all.