What is it about the South? (Hint: It’s not just the fried food.)

When it comes to public health, it’s not just how you live, it’s where you live

Germ theory is a wonderful and simple concept about disease causation. You have a germ, it infects you, you get sick. Kill the germ through heat, hand washing, or chemically — or get a vaccine — and you don’t get sick. If you find some new disease, like physicians did back in the late 1970s, and do a test for a new virus or bacteria. If you find something new, learn to kill or prevent it, and you’re good to go.

Simple enough, right?

Well, it’s not that simple. As John Snow learned back in 1854 with the London Cholera Outbreak, there was much more to what made some people sick while others stayed healthy.

Using what we call “shoe leather” epidemiology, Dr. Snow mapped out all the cases of cholera in London during the outbreak. From that map, he learned to make some informed guesses as to what was going on. While he didn’t know what was causing the cholera, he became convinced — and convinced others — that it was where people lived and worked that was more of an influence on whether or not they got cholera than most any other factor.

Even after germ theory was developed, epidemiologists continued to see that there were other factors that affected the risk of people getting a disease. There were those who were exposed to germs but didn’t get sick. Why? The answer would be not just what the particular exposure was but also where those people lived, and who lived around them.

There are those in public health who say that we are living in the chronic disease age of public health. It used to be that things like influenza and cholera would kill most of us, and do so early in our lives. Now we get to live long enough to get heart disease, high blood pressure, diabetes, strokes, lung disease, a variety of cancers, and other things that can kill us just as well as cholera.

For a long time, many in policy (not in public health) made the mistake of thinking that these chronic diseases were affecting people because those people did things which placed them at higher risk of contracting those chronic diseases. They would look at obesity and diabetes and say, “Well, maybe you shouldn’t have eaten so much,” or, “Maybe you should have gone for a walk more often.”

As you well know, life isn’t that simple.

We are seeing an obesity epidemic in the United States for a variety of reasons. It’s not just that we enjoy our cheeseburgers and love our television shows. There are social and geographic components as well. If you live in a city like Boston, which got over 108 inches of snow this winter, you might not be too physically active.

“But there’s gyms!” you say. Yes, there are gyms but they are not available or affordable to everyone. Believe it or not, there are people who sit in front of their televisions for hours and eat crappy food because that is the only thing they can do in their neighborhood and under the social and economic circumstances in their lives. If you live in a neighborhood plagued by violence, you’re probably not very prone to going for walks or having a garden where you can grow fresh vegetables. Also, the neighborhood supermarket may have closed because it was held up one too many times.

You dig?

When people who have access to healthy food and healthcare services — who stand on the upper echelons of political power — point to an overweight or obese person and use them as an example of lack of self-control, they are making an enormous assumption. They are assuming that the person lives in a place that allows them to be physically active. They are assuming that they live in a place where fresh and healthy food is readily available. And they are assuming that the person has the resources (monetary and otherwise) to know how to prevent themselves from becoming obese.

The same can be said of smoking and other habits that are not conducive to a healthy lifestyle. It is all much more complicated than our individual decisions.

That said, individual responsibilities do matter. You can still choose to fight back against your circumstances and improve them. But it is hard to do when people in power and the institutions they create are not exactly “comfortable” with the idea of an activist you.

I warned you that it was all very complicated.

There seems to be a disconnect between people who recommend public health policy and the people who implement it. Politics plays a role in this but so does misunderstanding. When a policymaker doesn’t understand the nature of the problem that needs to be addressed, they may not make the right decision or reach the wrong conclusions on how to address the problem. In the time of John Snow, there was no germ theory, yet his epidemiological conclusions helped understand cholera better. In our time, there are a myriad of problems which we have not fully deciphered, but it helps if we keep in mind everything that goes into disease, not just the what or the who or the how, but a lot of the where and the why.