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Last Updated

20 May 2003

Source: The Chronicle of Higher Education, May 23, 2003 (posted 5/20/03)


Epidemiologists Need to Shatter the Myth of a Risk-Free Life


When I went to graduate school to study epidemiology 25 years ago, almost nobody knew what it was; now it is popular enough that you can get a doctorate in it at any of 30 American universities. Unfortunately, AIDS has helped to bring epidemiology into the public's awareness. As has Laurie Garrett's book The Coming Plague, about emerging infectious diseases, and Richard Preston's The Hot Zone, about an outbreak of the Ebola virus in a lab near Washington. Then came hepatitis C, Lyme disease, the West Nile virus, anthrax, and, of course, severe acute respiratory syndrome (SARS). Not to mention the current threats of chemical and biological warfare. Suddenly, everyone wants an epidemiologist around.

But as the field has become better known and more widely respected, it also has contributed to a national delusion about health: that it is possible to lead a risk-free life. What epidemiologists broadcast as a statement about the probability of illness is heard as a personal prescription. A man reads that smokers, on average, die at a younger age than nonsmokers, so he quits smoking, believing he will live longer. Another hears that heart disease occurs more commonly among people who never exercise, so he takes up jogging. But those statements about average probability -- that is, about risk -- say nothing about what will happen to the individual: The guy who quit smoking is run over by a bus; the jogger drops dead of a heart attack anyway.

To put it starkly, epidemiologists can't predict your future. Epidemiology is a science, yes, but its subjects are humans, in all their confounding unpredictability. Epidemiologists can tell you what's likely to happen in general, but never what is going to happen to you in a specific situation. Epidemiologists can make statements only about probability, the likely rate with which a disease will occur in a particular population. The population is the demos that epidemiology gets its name from.

When people apply our disease-risk statements personally, though, it leads inevitably to the mirage of a risk-free life. But there is no such thing as "risk-free" where disease is concerned. The only exceptions are diseases of organs that you don't have: Women, for instance, cannot develop prostate cancer.

Yet Americans today are great consumers of the hoax of a risk-free life. Eat less fat, eat more broccoli, stop smoking, use condoms, wear a bicycle helmet, join a gym. Put enough time and money into adjusting your behavior, goes the deception, and you won't have to worry about disease. You'll have lowered your risk.

The illusion that immunity can be created by changing your behavior (or spending money) sets us up for terror. Whoever sent anthrax through the mail in 2001 managed to kill a total of five people -- sad, but frankly no worse than many car wrecks. The anthrax scare touched off hysteria (and a multimillion-dollar industry in anthrax prevention) because it exposed the bitter truth that the risk-free life is illusory. If we try to cling to the illusion, we'll continue to be susceptible to health terrorism, a term that is more to the point than bioterrorism -- that is, we'll continue to be terrorized that our health is in imminent jeopardy.

How did Americans come to have such faith in the risk-free life? We epidemiologists have to bear some of the burden. We made three mistakes: We bought into the focus on personal behavior rather than social reform, we provided too much information, and we colluded with the moralism of risk reduction.

Behavior instead of social reform. My epidemiologist hero is Joseph Goldberger. He was a physician with the U.S. Public Health Service in the early 20th century, and he dedicated his career to elucidating the link between poverty and the dietary-deficiency disease called pellagra, then responsible for a continuing epidemic of skin disease with diarrhea and, sometimes, dementia in the rural South.

Goldberger followed in a long tradition of epidemiologists whose aim was to expose how the structure of modern society created opportunities for disease to spread. In other words, they recognized that epidemiology must serve public health and understood both the demos in epidemiology and the public in public health. They were confident that good people, suitably enlightened, would make the needed public policies to allow everyone to enjoy good health. Even later, when epidemiologists started studying the relation of behavior to disease -- smoking and lung cancer, lack of exercise and heart disease -- they worried about how a person's social class and circumstances determined the relevant behavior.

But social-reform epidemiology was killed by AIDS. When it arrived, in Reagan-era America, epidemiologists -- particularly those at the federal Centers for Disease Control -- were unwilling to run the political risk of naming the social forces that drove people into the circles and venues where they were likely to contract the AIDS virus. Epidemiologists didn't speak out about racial discrimination, poverty, neglect of urban problems, unemployment, and sexual intolerance. Instead, they turned the discussion to what people do: Epidemiologists studied how people have sex and why some use drugs. Behavior, especially unpopular behavior, was the perfect focus of public pronouncements for a national administration thick with moralists, eager to do nothing to save the lives of gay men and poor nonwhites.

Epidemiologists, shamefully, bought into the moralist agenda, recoded the work of epidemic control in terms of behavioral proscription and prescription, and started talking about the individual instead of the society. Academic epidemiologists should have objected, but we didn't. Now individual behavior is the focus of almost all American epidemiology.

Too much information. Epidemiologists talk too much. Our second contribution to the personalization of risk is publicizing every finding, no matter how trivial, about how individual behavior might relate to a higher or lower probability of getting sick. Many of these risk assertions conflict with the ones issued the month or year before. Eating fiber used to be recommended as a way to prevent colon cancer; now it seems not to have much to do with colon cancer at all.

Smoking causes lung cancer, right? Then, out of a hundred 35-year-old men who smoke cigarettes, many will die of lung cancer by age 70, right? The answer is no: On average, only eight of them die of lung cancer. Fruit and vegetable consumption will lower your risk of lung cancer if you smoke cigarettes, according to a recent study published in the American Journal of Epidemiology. So, persuade smokers to eat fruits and vegetables and you would lower the rate of lung cancer, right? Perhaps, yes; but about 25,000 people would have to change their diet to eliminate as few as 25 cases a year. Most diseases, even dreaded ones like lung cancer, breast cancer, or AIDS, are extremely rare. You can do something that raises by quite a lot the chances of getting a disease and still be very unlikely to contract it.

Academic epidemiologists are especially culpable here. In the rush to publish, we have become accustomed to advertising the most inconsequential research findings as if they were earth shattering. And we fail to point out that most diseases remain rare, even when people do what their mothers cautioned them not to. We never tell the whole story: that most smokers do not die of lung cancer, most bicyclists who ride without helmets do not die of head injuries, most people who have sex without a condom do not get AIDS. No wonder people think that their individual behavior is paramount in deciding whether they will get sick or stay healthy.

The moralism of risk. Risk reduction is the new religion. Americans today make risk sound like sin, the way earlier generations did with communism, atheism, or, well, sin. We talk about "risky sex" and mean not that you might fall in love and get your heart broken, but that you didn't use a condom. We no longer label habits "bad" because they smell nasty, like smoking; make you unattractive, like eating a diet of fried foods; or startle your neighbors, like having sex in public bathrooms. The old language of bad habits invited the uncomfortable discussion about who really suffers and therefore about who gets to dictate mores and morals. Disguising revulsion as a concern about health lets you push your moral code on everyone; nobody can be against health.

This is the newest incarnation of an old trend in public health in this country. Some Americans with a moral agenda have always wanted other Americans to reform their behavior and have often used public health as one way to advance their case. Segregating black people, vilifying those who drink alcohol, and keeping girls at home and celibate until they were married were all, at one time, justified as ways of controlling epidemic disease. Now health officials push sexual temperance, sexual conformity, and abstention from "addictive substances." Worst of all, public-health practitioners have been so indoctrinated in the risk-reduction religion that most disease-control programs today emphasize stamping out "risky behavior" -- and in so doing, promote a moral agenda -- instead of changing society.

Academic epidemiologists think of ourselves as liberal-minded and, by and large, suspicious of moralism. Yet we fail to speak out against this inclusion of moral agendas in public-health messages. In fact, some of us make a living producing yet more trivia about how behavioral fine-tuning -- drinking more tea and less coffee, buying a bicycle -- will lower your risk of various diseases.

Academics in public health, it turns out, are not really opposed to moralist messages. Not long ago, I pointed out to a group of colleagues discussing AIDS that, as many surveys show, most people don't like condoms and won't use them. I suggested that public-health practitioners stop hawking condoms as emblems of virtue, stop making people feel stupid or sinful for having sex without them. I noted, using a simple calculation with available data, that in most parts of America you would have to offer a state-of-the-art condom-use-education campaign to about 100,000 people for at least a year to stop a single HIV infection from occurring. One of my colleagues responded by warning me never to say that in public. I think he meant, Don't put grant money in jeopardy.

What academic epidemiologists could do is restore a sense of proportion to the prevention of epidemic diseases. Of course, the epidemic of obesity is a consequence of Americans' taking in more calories than they expend, and a lot of those calories come from fast food. Good epidemiology would focus attention less on our lust for French fries and more on fast-food companies' increasing their profits by advertising their products to children and locating their restaurants in poor neighborhoods. We could acknowledge that many homeless people are addicted to drugs or alcohol, but also pay attention to the failure of national and local governments to provide safe and affordable housing. We should recognize that HIV can be spread through sexual contact but go on to look for underlying causes, like the way global capitalism forces many poor women into prostitution by offering them too few other jobs and too little education and child care.

Current concerns about terrorism, or even SARS, could be just the spur people need to revise their thinking about health and disease. If Americans are serious about preventing health terrorism, then the way to go is not to hunt down rogue germ labs or spend millions of dollars on high-tech surveillance systems. The first thing to do is recognize that the risk-free life is a mirage. If we stop thinking that we can avoid disease or escape death -- if we recognize that most infectious diseases have not been conquered, that epidemics still happen, that disease always take a human toll -- we can stay calmer when epidemic disease does strike, whether it comes naturally or is produced deliberately by human hands.

The world since 9/11 is not new, despite what many people say. All that has happened is that Americans have been forced to recognize what generations before us knew and accepted: Epidemics and other disasters are facts of life. Some people get sick. Sometimes, many people get sick all at once. Some die young. Some die doing things that seem innocuous, some live even though they do things that seem perilous, and some die doing nothing at all. You can take all the right steps to lower your risk, but if someone flies an airplane into your building, you die anyway. There is no such thing as a risk-free life.

Philip Alcabes is an associate professor of urban public health at the City University of New York's Hunter College.