The greatest risk factor

by Kevin Boehnke

Throughout recorded human history, millions of people have died from infectious diseases like tuberculosis, mumps, and measles. In many parts of the world,  they still do. Public health scientists aim to improve human health by identifying risk factors for disease and setting up systems to reduce those risks. To achieve this, they study everything from systemic problems like unclean air and water to individual factors like diet and exposure to single chemicals. These include:

Unclean air, and exposure to particulate matter that 2.5 microns or smaller (PM2.5). Unclean water and exposure to waterborne diseases. Lack of sewage treatment. Helicobacter pylori. Poor quality food: high fat, high salt, low fiber, nutrient-poor. Obesity, heart disease, non-alcohol fatty acid disease, diabetes. Heavy metals like lead, mercury, arsenic, and cadmium. Pesticides in the air, water, and food.  Endocrine disrupting chemicals like phthalates and BPA. Injuries. Reckless behavior. Lawlessness. Domestic violence. Risky sexual behavior. Lack of family cohesiveness and social structure. Poor education. Drug abuse. Smoking. Alcohol abuse.  Cancer. Diarrheal disease. Tuberculosis. Malaria. Multi-drug resistant Staphylococcus aureus. HIV/AIDS.  

However, there is one thing that puts people at risk for most or all of the items on this list: being poor. Industries are more likely to dump their waste and pollute more heavily in poor communities, and governments are less likely to enforce protective regulations to protect the poor. Poor people are more likely to be imprisoned. They are less able to access safe air, safe water, high quality food, and healthcare. They typically have far less political power: in the era of money being equated with speech and influence in our political system, poor people are much quieter than their wealthier counterparts. In short, poor people make up the vast underclass; less healthy, less influential, and more likely to be stuck in a cycle of poverty.

In the field of public health, it is challenging to get funding to study a large systemic problem like poverty. Scientists are expected to narrow down their interests and specialize. They are told, “Focus on one thing and really become an expert“. This is well and good; it is important to understand what is really happening before trying to enact policy changes.

Untitled phd knowledge

However, if one risk factor is so intrinsically related to all of these problems, does it fall on the institutions in our society to help address it? Concern over environmental pollution in the United States led to the formation of the Environmental Protection Agency, the Clean Water Act, and the Safe Drinking Water Act. As a result, the government successfully implemented extensive programs to provide clean drinking water and build publicly operated wastewater treatment systems all over the country. Malaria and polio were eliminated through cohesive government action.

But, things get sticky when it comes to helping the poor. President Johnson’s Great Society tried to address problems with poverty, and his programs led to a substantial decrease in the poverty rate. Social security, welfare, and food stamps all helped provide food, shelter, and other services to people with low incomes.  These programs contributed to a substantial decrease in poverty, as seen in the figure below.


Rates of absolute poverty from 1960 to 1991. Source: Wikimedia commons and here

However, these programs were slowed in following decades by ideological concerns about the welfare state, socialism, and the disproportionate amount of money being funneled to minorities. Starting with President Nixon, the War on Poverty Programs were decentralized, a process the accelerated under President Reagan. In 1996, President Clinton “ended welfare as we know it”, with the Personal Responsibility and Work Opportunity Act, an expression of the ideological change away from helping the poor that had occurred since the 1960s. While many of these programs remain intact, they are consistently attacked as “unsustainable entitlements“, even though welfare spending has decreased about 15% in real dollars since 1965.

Disclaimer: I wrote this post after reflecting on how it is really easy (and intellectually stimulating) to study one scientific problem in depth without looking at the bigger picture. I am writing from the viewpoint of a public health scientist, and as such am not concerned with ideological considerations such as creeping socialism or welfare dependency. Instead, I am deliberately focusing on how to holistically reduce negative health outcomes associated with being poor.

So what is to be done about this problem? More specifically, what can public health scientists do to address the roots of poverty, rather than on individual symptoms of poor health? I propose that it is possible to focus and specialize on individual issues, but still be able to step back, look at the bigger picture, and help handle this wider problem. Public health experts are particularly well-positioned to do this; they already facilitate interdisciplinary teams to understand how these problems tie into economics, sociology, education, agriculture, chemistry, biology, and myriad other fields. 

Click here for a bigger image. Source: Getting to

Integrating all of these fields is absolutely necessary to develop whole system approaches to health problems related to being poor. Any sort of sweeping policy changes are likely far into the future, so we must start by first having a conversation to get at the underlying foundation of poverty as well as attacking the many-headed hydra of symptoms.

File:Hercules and the Hydra of Lerna LACMA 65.37.9.jpg

Disclaimer 2: I am not suggesting that the poor cannot help themselves. Some of the greatest political changes have come from grassroot organizing and long struggles against the status quo, which was strongly enforced by the US government.


  • Laden, Francine, et al. “Association of fine particulate matter from different sources with daily mortality in six US cities.” Environmental health perspectives108.10 (2000): 941. link
  • Payment, Pierre, et al. “A randomized trial to evaluate the risk of gastrointestinal disease due to consumption of drinking water meeting current microbiological standards.” American journal of public health 81.6 (1991): 703-708. link
  • Eckel, Robert H., and Ronald M. Krauss. “American Heart Association call to action: obesity as a major risk factor for coronary heart disease.” Circulation97.21 (1998): 2099-2100. link
  • James, W. Philip, et al. “Socioeconomic determinants of health. The contribution of nutrition to inequalities in health.” BMJ: British Medical Journal314.7093 (1997): 1545. link
  • Panel, NHLBI Obesity Education Initiative Expert. “Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults.” (1998). link
  • Järup, Lars. “Hazards of heavy metal contamination.” British medical bulletin68.1 (2003): 167-182. DOI
  • Alavanja, Michael CR, Jane A. Hoppin, and Freya Kamel. “Health Effects of Chronic Pesticide Exposure: Cancer and Neurotoxicity* 3.” Annu. Rev. Public Health 25 (2004): 155-197. DOI
  • Casals-Casas, Cristina, and Béatrice Desvergne. “Endocrine disruptors: from endocrine to metabolic disruption.” Annual review of physiology 73 (2011): 135-162. DOI
  • Campbell, Tim, and Alana Campbell. “Emerging disease burdens and the poor in cities of the developing world.” Journal of Urban Health 84.1 (2007): 54-64. DOI
  • Frumkin, Howard, ed. Environmental health: from global to local. Vol. 11. John Wiley & Sons, 2005. link
  • Tacconelli, Evelina, et al. “Does antibiotic exposure increase the risk of methicillin-resistant Staphylococcus aureus (MRSA) isolation? A systematic review and meta-analysis.” Journal of Antimicrobial Chemotherapy 61.1 (2008): 26-38. DOI
  • Shiffman, Jeremy. “Donor funding priorities for communicable disease control in the developing world.” Health Policy and Planning 21.6 (2006): 411-420. DOI
  • Blakely, Tony, et al. “The global distribution of risk factors by poverty level.”Bulletin of the World Health Organization 83.2 (2005): 118-126. DOI
  • Kenworthy, Lane. “Do social-welfare policies reduce poverty? A cross-national assessment.” Social Forces 77.3 (1999): 1119-1139. link