The Occupy movement and the insurgent campaigns of Bernie Sanders and Jeremy Corbyn have brought inequality to a central stage in the political conversation on both sides of the Atlantic. For the most part this conversation has focused on the social and economic impacts of inequality. However, research over the last four decades has shown that some of the most persistent and destructive impacts of inequality are on health. A new book The Health Gap by the Australia-trained physician Dr. Michael Marmot seeks to describe these impacts and lay out ways by which they may be mitigated.
With this large goal in mind, The Health Gap should really be called The Health Gaps. In laying out how inequalities lead to different health outcomes for different populations, three significant gaps become clear. The first, and probably most famous gap, is that between low and high income countries. Low income countries lag behind higher income countries in almost all health measures. The lack of money and resources necessary to have a strong health infrastructure has a lot to do with this, but as countries become wealthier, this link between money and health outcomes begins to disappear. As Marmot notes, “Even more money does not guarantee good health. Above a national income of about $10,000 there is very little relationship between national income and life expectancy.”
This central point is illustrated by a graph shaped like the top half of a ‘C’ showing that as a nation’s GDP on the x-axis increases, life expectancy on y-axis also increases, but this relationship rapidly flattens as the GDP becomes higher with essentially no relationship between GDP and life expectancy even in the wealthiest countries. So yes money does matter in poor countries, but not so much in wealthy countries.
This leads to the second health gap—that between different ‘developed’ countries. Those countries located further down that GDP curve. Despite there being no
difference in health outcomes based on income in these countries, there are indeed differences. The U.S., for instance, has a life expectancy of 84 while Japan has a life expectancy of 76, despite the U.S’s much greater GDP.
While it may be easy to explain what accounts for the differences in health between developed and less developed countries, it is more difficult to explain differences between developed countries. It is clear that one explanation we might think of—health care spending—does not account for all of it. As was stated ad nausea during the debate around Obamacare, the U.S. spends more than almost any industrialized nation on health care, bus as we have already seen, this does not lead to better health outcomes.
So what does account for these differences? Marmot states his answer: “The pollutant is poverty, or more generally lower rank in the social hierarchy (111).” As he makes clear throughout the book in chapters about role of childhood, working life, and old age, societies that provide for more equality during these periods also tend to have better health outcomes.
Of course this does not account for all the differences in health. It is not as though inequality alone is a magic wand creating poor health. It is instead the case that economic and social inequalities have a tendency to create health gradients within societies. Therefore, if a society is more unequal there will be more individuals who fall at lower ends of these gradients. This gap within society, the health gradient as one moves from the top of the socioeconomic ladder to the bottom, is the third gap described in Marmot’s book.
These conclusions are not speculative. They are backed up by years of research. For Marmot, they began with his research into the Whitehall cohort of British Civil Servants where he identified a clear gradient in cardiovascular mortality by occupational grade, with those of lower grade in employment having more cardiovascular disease mortality than those in higher grades. Since then evidence has been amassed by Marmot and other health researchers around the world about how social factors, ranging from income to racisms impact our health.
With these huge volumes of evidence in mind then the question remains—why do most of us when we discuss health focus on factors like lack of exercise and unhealthy diet. These factors certainly affect health, but they tended to be found disproportionately among poor individuals—why is this?
Marmot refers to socioeconomic factor as “the cause of causes” saying “My argument is that tackling disempowerment is crucial for improving health and improving health equity. “To Marmot if we want to do anything about health behaviors, we must alter the socioeconomic factors that cause them in the first place. Otherwise it’s just like trying to stop a leak in a roof while it’s still raining. You might plug a few holes, but more are just going to open back up. In the same way, structural factors like our occupations, our neighborhoods, and how much control we have over our lives, what are usually termed the social determinants of health, must be confronted if we want to do anything about these wider problems.
Marmot’s early research into these important issues was conducted in the United Kingdom and that is important. The U.K. has always had a well-defined class system making it easier to talk about how these class differences can cause health differences. In the United States where we often imagine that there is no hierarchical class structure, this conversation is more difficult. But this seems to be changing. Hopefully as inequality becomes an ever more persistent topic, so will health inequities.
Devan Hawkins is an epidemiologist at the Massachusetts Department of Public Health and freelance writer.