Public Health, Defined...

What's a surefire way to instantly animate a seemingly quiet public health professional? Ask them what public health actually is. 

Like "hipster", "centrist" or "slow food", it's one of those nebulous things you think you know, but maybe not.  My public health professors here seem determined to make sure we accurately understand what we're getting into. In the Powerpoint-governed dictatorship of modern education, Slide #1 of about 10 lectures thus far consistently asksd "What is Public Health"? 

It's actually an interesting question to ponder - especially since most people apparently don't. In fact, a recent survey conducted by the Public Health Brand Identity Coalition found that 80% of Americans "did not think that public health had touched their lives in any way." 

But as Berkeley healthcare journalism lecturer David Tuller notes, that's the point of public health: to be invisible. 

Successful health interventions prevent bad health forces from happening - in fact, making them so rare that they're just historical curiosities, or plot elements of an action movie.


In the U.S., we don't habitually wake up each morning thinking of all the water-borne diseases or diarrheal outbreaks we're escaping as a result of sewage systems, or gleeful that our risk of contracting polio hovers below 0.001%.  But those vaccine campaigns which have rendered smallpox virtually extinct, and the late 19th-century movement in the United States to establish sanitation systems are silent successes of public health. 

We are often acutely aware when public health intervention is needed - when the system is "failing": We notice when eggs are pulled off the shelves, when there's a violent shooting in a public school, or when a hurricane devastates a city and its residents need help in the face of a chaotic, disorganized response. 

Likewise, doctors may not miss the cases of childhood mumps or hookworm outbreaks - diseases generally prevented by effective public health interventions.  But most practicing physicians sense that they seem to be treating a lot more patients with high cholesterol, obesity and diabetes, or that more of their patients can't pay for their healthcare. They diagnose pregnancy in a fifth-grader coming to clinic with abdominal pain and swelling in inner-city Detroit, life-threatening skin infections in a 500-pound patient who couldn't bend over to properly clean himself, tuberculosis in a homeless uninsured man who can't afford the drugs needed to treat him (and prevent its spread to others). 

 These health issues arise from population-level root causes:  they fall under the purvey of "health", and the mission of a public health professional is finding effective measures to prevent them from happening. 

Dr. George Benjamin, director of the American Public Health Association and emergency-room physician (quoted in Dr. Tuller's article), explains the distinction between individual treatment and population-wide prevention as follows. "I tell people that when someone would come into the room with a rat bite, I took care of the rat bite...if ten people came in with rat bites, the best public health intervention I could do would be taking out the rats - solving the problem versus providing clinical care." 

So how do we take out the rats?  

History describes champion "rat-killers" in the field of preventing diseases spread through water and food: think turn-of-the-century hookworm epidemic among farmers in the Deep South, virtually eliminated by installing outhouses; or London's 1854 deadly cholera epidemic, subsequently halted after a polluted water pump was removed.  

Such measures are still sorely needed around the world -  2.6 billion people have no access to sanitation systems, and a third of the world's population system lives in slums. 

But in addition, in both the developing countries experiencing fast economic growth and in wealthy countries, a rising modern epidemic features "lifestyle" or "chronic" diseases as the villains: heart disease, high blood pressure, diabetes, lung disease, cancer. These diseases are now the leading cause of death worldwide - 35 million people, or 60% of deaths around the world - and 80% of deaths from chronic disease occur in developing countries. A key point: in a number of cases, the massive disability and death caused by lifestyle diseases is preventable.

The public health-oriented, practical solution to this emerging global modern epidemic is complex. Take obesity, for example. Its status as well-traveled highway to the land of "lifestyle" disease - implicated in everything from lung disease to diabetes - makes it a modern, high-priority public health target. (In case you weren't convinced, here are some facts and figures detailing America's obesity epidemic. Notable fact: 2/3 of Americans are currently overweight.)  

But how, exactly, do you go about preventing obesity? Telling doctors to remind more patients to eat healthy? Taxing soda? Giant warning labels on Twinkies? 

 The "pyramid" of public health impact, as explained by the Centers for Disease Control and Prevention director Dr. Thomas Frieden, sheds some light on the practical design of a public health strategy.

In thinking of approaches to fix a population-level issue, fact #1: All the levels in the pyramid are essential to health. 

With that said, as public health strategies move up the pyramid, those near the tip require more effort and carry a smaller impact on a population scale. (Even though it could still be an important, dramatic impact for a small group of people.)  If doctors were to counsel every single patient they saw in clinic on eating  healthy and exercising, for example (top tier) or give overweight patients a weight-loss drug (tier 2 or "clinical intervention"), the impact on health would depend on 1) overweight patients actually coming to the clinic and 2) patients willing and able to follow the counseling advice and treatment. 

Unfortunately, losing weight is tough. Eating healthy is hard when you're hungry, have a five-dollar bill in your pocket, and are faced with a choice of a cheap, filling fast food fix versus a raw apple costing $1.50. Taking a weight loss drug is difficult when it causes "icky side effects", and costs $50 per pill.  

What if you began an approach which promoted healthy eating in people before they became overweight - ie. young children in elementary school, who seem naturally capable of burning 30,000 calories a day - with healthy eating campaigns and nutrition education? This would fall under the "long lasting preventive intervention" category (tier 3)- a one-time intervention which, if all goes well, might prevent habits that could lead to obesity and ill health. 

The potential impact, while broader in scale than the approach of individually counseling or treating already-overweight patients, still depends on 1) how many schools are able to implement the program 2) the quality of such a program and 3) the durability of the program's message in influencing a child's future eating habits. 

Now imagine if people naturally made the choice to eat healthy because it is easy to do so. That is, healthy food is readily available, cheap and tasty - becoming a more "default" option than junk food.   An approach leading to this outcome - such as removing junk-food or soft drinks from schools or taxing junk food - would "change the default environment", reduce the number of unhealthy calories consumed, prevent obesity and have a potentially far-reaching impact for community health.  

The problem is, the things needed to create this 'changed default environment' are precisely the most controversial. They require laws, rules, regulations and taxes - all words that often inspire distaste in the minds of the voting public. They make public health the bad guy. (Would you want to be the one who outlawas deep-fried chicken from the American diet? I'm thinking death threats.)  Exhibit A, B, C: the backlash on smoking bans; the public disapproval over a proposed junk food tax; or the huge battle over healthcare reform. (How does healthcare reform change the default context? By providing more people with insurance, universal access would remove a  contextual "barrier" which damages health, thereby provide a default entry into the healthcare system for sick patients.) 

What about the base-tier - addressing the socioeconomic factors?


As this is the level in which I'm most interested, you can expect several future posts about the scope for public health in this area. But for now, a quick preview:


Clearly, there is a powerful between socioeconomic status and health - in rich and poor countries alike. Things that improve living conditions will, logically, improve health on a profound scale. We're already familiar with the impact of a successful base-tier public health strategy: providing poverty-stricken areas access to clean water. (In the United States, sanitation improvements introduced in urban areas in the 1900s likely drove mortality down by nearly 50%.) 

But the relationship between socioeconomic status and health goes beyond the increased chance of contracting tuberculosis or becoming malnourished among poor residents. Inequality, as well as absolute poverty, causes disease. In the United States, a country characterized by large gaps separating the rich and poor, residents of poor communities are more likely to be shot, smoke, not know how to read, be overweight and die much earlier - a staggering 35 years earlier in some counties, as a Harvard study showed. (More - much more - to come on this in future posts.). 

Addressing the persistent, socioeconomic issues currently affecting health in the U.S. - inequality, the disturbing and complex relationship between class, race, violence in urban areas, educational gaps, crime and homicide - is daunting, to say the least. But it is a key priority for social justice and, as you now know, it is a key priority for public health.


The base tier of this pyramid also happens to be why I decided to come back to school and study public health. Other than good intentions, a remarkable ability to ramble, and some mad typing skills, I don't possess much in the way of a useful skillset, at present, to combat the specter of poverty and health.


But I'm a fast learner. And if there ever was a place for do-gooding, activism, and training practical idealists, the Bay Area has to be its capital.


I'll keep you posted. In the meantime, off to study some statistics....taking it one day at a time.