Mr Epidemiology: Today, I’m welcoming Lindsay Kobayashi to the blog. You can find out more about Lindsay at the end of this post.

Health inequity is a global and a local problem.

As epidemiologists, we are concerned with uncovering the factors in populations that determine who gets sick, who stays healthy, who lives, and who dies. Human life is inherently social, and looking toward our societies and geography can help explain who is healthy or sick, and why. “Location, location, location” is a mantra that rings true with respect to life expectancy. In Canada and the United States, men can expect to live to 79 or 76 years, respectively, while women can expect to live over 80 years (1). The story is similar for most wealthy and developed countries. By contrast, take Afghanistan or any one of several sub-Saharan African countries, where a baby born today could expect to live only until his or her mid-40s or 50s(1).

Temporarily setting aside biologic limitations on health (a loaded issue for another blog post), human-made health limitations clearly exist in our world. A person’s life chances greatly depend on where he or she is born and lives and some people do not reach the same level of health achievable by others. Inequities in life expectancy exist within countries as well: Canada-wide, women residing the poorest neighbourhoods live two years less on average than women residing in the richest neighbourhoods, and this difference is four years for men(2). This striking inequity brings us back to the original question: What determines health?

Assuming human biology is roughly equal between rich and poor places, whether they are neighbourhood or country, we must turn to social factors to answer this question. How human society affects health is the focus of social epidemiologists, who grapple with this exceedingly complex issue every day. Two of these scholars, Dennis Raphael and Juka Mikkonen, have compiled a Canadian-specific list of the determinants of health that have social origins (the “social determinants of health”): Aboriginal status, gender, race, disability, housing, early life, education, income and income distribution, employment and working conditions, unemployment and job security, food insecurity, health services, social safety nets, and social exclusion(2). A comprehensive and straight-forward review of these factors in Canada can be found in their publication, “The Social Determinants of Health: The Canadian Facts.”

Income inequality has direct and relevant consequences for epidemiologists (via The Canadian Facts)

And the fact is that inequality within Canada is rising. Canada is one of the two OECD countries that saw increases in income inequality over the past two decades(2). Our middle class is “hollowing-out”, with more people being on the poorest and richest ends of the scale(2). Knock down the “Occupy” movement all you like, their point remains a valid concern for health and social well-being that we have not even begun to solve. Raphael and Mikkonen’s social determinants of health are all influenced at the structural level by governmental policy and society. Our solutions to health problems, however, are mostly relegated to the health sector, which can only attempt to bandage the wound. Any real solution to inequities in health and life expectancy must come from the sectors outside of health that can address the structural “root causes” of health inequities.

As epidemiologists, what can we do? Understanding of the social determinants of health will allow us to frame our work within the societal landscapes of the places in which we conduct our research. This understanding will allow us to indirectly address health inequities by ensuring our research, from recruitment and data collection to knowledge translation, is undertaken with equity in mind, and to answer big research questions such as, “How do our ever-changing social landscapes and governmental policies affect health and health inequities in society”? A role does exist for scientist-as-advocate, because our overall objective as epidemiologists is to improve health and reduce disease in populations. A critical understanding of our society’s role in the unequal distribution of health and disease is only our first step.

About the Author: Lindsay Kobayashi is a Community Health and Epidemiology MSc student at Queen’s University. Her thesis research is on lifetime physical activity and risk of molecular marker-defined breast cancer subtypes in women. She is planning to research social inequalities in cancer screening participation for her PhD beginning in September (location to be determined…) and is generally interested in the social epidemiology of cancer and cancer inequalities. When she’s not researching, she’s running triathlons and reading. You can follow her on Twitter at @1lindsayk

World Health Organization (2011). World Health Statistics 2011 Geneva: World Health Organization

Mikkonen J, & Raphael D (2010). Social Determinants of Health: The Canadian Facts Toronto: York University School of Health Policy and Management