Epidemiology is, strictly speaking, the study of epidemics. Polio. Malaria. Small pox. Tuberculosis. Flu. Nasty, infectious, buggy stuff. It's been a life saver, a brilliant investment, a true giant in the medical-scientific arena. In fact, it's been so successful, it damned near put itself out of government-funded business. But, as we all know, government funding has become the nearest thing we know to perpetual life. And epidemiology is no exception to the phenomena.
In the olden days, when science was science and meant what it said, epidemiological studies were concerned with identifying an agent, incubation period, mode of transmission, population at risk, and methods of disease control. But what's a kid (or a government agency) to do when he's won all the prizes and still has a closet full of sports equipment? One solution is to fold the tent and move on to more gainful employment. Another is to invent a new game that uses every ball on the shelf even if the new use is utterly inappropriate to the new game. Epidemiology empire builders have chosen the second course.
Dumbed down science?
Basically what happened with epidemiology is what has happened with too many things -- it got dumbed down by redefining the word "epidemic" to include lifestyle risk factors. Diet, obesity, inactivity, drinking, smoking, low socio-economic status, race, sex -- you name it. Rather than devoting attention to the etiology of actual communicable diseases, it has -- at least in the U.S -- morphed into a sort of Anti-Indulgence Industry. Like a 400-lb gorilla, epidemiology is now whatever it says it is.
Today just about anything you'd care to name is a potential "epidemic." Just ask the Centers for Disease Control and Prevention (they added "Prevention" to their name a few years ago while inventing their new game rules). According to CDC lifestyle choices (not communicable diseases) and humdrum conditions of aging are now potential epidemics.
CDC now doggedly pursues behavioral research studies on a bizarre range of topics totally unrelated to communicable disease, listing the following categories for "Behavioral Surveillance:" Alcohol, arthritis, asthma, cancer, cardiovascular disease, cholesterol, colorectal, dental, diabetes, environmental tobacco smoke, falling down, farming injuries, fetal alcohol syndrome, fires, firearms, flu/pneumonia (an actual disease!), folic acid, food preparation , fruits and vegetables (?), HIV/AIDS (aha! another communicable disease crept in), health insurance, health status, household recycling behavior, hypertension, illicit drug use, injuries, lead poisoning, osteoporosis, obesity, physical activity, preventive counseling, prostate screening, quality of life, routine check ups, safety belt use, sexual behavior, social context (whatever the hell that means), suicide, sun exposure, tobacco use, tuberculosis (bravo! -- disease number three), violence and crime, water, weight control, well testing (well people or water wells?) and women's health.
And, depending on how they read the chicken entrails this week, any one of these items can become next week's "epidemic."
Chronic diseases deserve attention
Chronic diseases deserve a special place in medical and epidemiological research. Rheumatoid arthritis, lupus, early-onset conditions of all sorts, have long been scientific puzzles. Our greatest successes may come years down the road as the Human Genome Project begins to bear fruit.
Chronic disease epidemiology, which emphasizes a more complex interaction of independent and dependent disease variables, doesn't fall into the same category as "lifestyle" epidemiology, but it has, unfortunately, spawned some highly questionable statistical methodology. One of the reasons is that studies of chronic disease focus more on analytical bumfoozle than on experimental, clinical trials. If chronic disease epidemiology were predicated on successful methods of infectious disease epidemiology -- modes of disease transmission, host susceptibility, incubation periods, and clinical trials -- we might make more progress. Instead, there has been a trend toward developing a seemingly endless multifactorial etiology of many chronic diseases that totally ignores biological plausibility.
And that's a problem. Because the analytical and statistical bumfoozle has kidnapped scientific terms and forced them into misuse under conditions they were never supposed to face. And it's resulted in proliferation of lawsuits and legislation (no, no, not a "Toxic Tort Epidemic," please!) based on sheer speculation and sophistry.
Cancer & heart disease aren't epidemics
The biggest risk factors for both cancer and heart disease aren't diet or smoking. Nope. The two biggest risk factors are age and socio-economic status. And there's damn-all science or medicine can do about either one of 'em. The U.S. has thrown nearly 30 billion dollars down the cancer rat hole. And rat hole may be exactly the right term. Just last week, on July 29, the New York Times ran a front page article about a technique developed to induce cancer in human cells. Was it important? You bet it was -- but the biggest piece of news was missing: it's taken 15 years after inducing malignant changes in rodent cells to pull off the same stunt with human ones. How come? Because humans are hugely different from rodents.
Faced with this enormous disparity between rodents and humans -- illustrated so beautifully by the difficulty in figuring out how to cause malignant transformation in human cells even when we knew how to do it with rodents for 15 years -- why the hell do we still take as "gospel" assessments of carcinogenicity based on massive doses required to cause cancer in rats and A/J mice? Can you say "funding?"
Lifestyle epidemiologists jumps on this rodent stuff like ducks on a June bug. Is benzo[a]pyrene a carcinogen? Well, yes it is if you're a mouse, rat or hamster reluctantly undergoing treatment with a Maximum Tolerated Dose. Is B[a]P present in secondhand or environmental tobacco smoke (ETS)? Yep. The EPA reports that 0.00009 mg or B[a]P are put out by an average burning cigarette. What would it take to reach a threshold limit value of B[a]P if you're worried about such stuff? Well, first you'd have to find a 10x10x10 meter room that was sealed and unventilated. Then you'd have to figure out a way to squeeze in 222,000 smokers. Good luck.
Tiny risks, tiny minds?
What is it about this lifestyle risk stuff that attracts such itty-bitty thinkers? And such huge amounts of money? I'm going to hearken back to the ETS stuff, because, to me, it's the Bell Cow of the epidemiology "epidemic." Since 1986, according to a report from the American Council on Science and Health, the number of cases examining acute and chronic diseases in humans exposed to ETS has more than doubled. Why? Reasonable and expected levels of exposure to ETS have been declining since the mid-80s. An open window and a box fan take care of any exposure problems a healthy person might (but probably wouldn't) encounter.
Even the American Council on Science and Health, as hysterically anti-smoking as any other group, concludes that ETS is, at best, "a weak risk factor for lung cancer among nonsmokers." The MONICA study, a long-term, multi-national study on coronary heart disease, failed to substantiate the expected links between active smoking and heart disease -- much less ETS and heart disease.
Electromagnetic flapdoodle
Nearly $3.5 million in federal funding just got flushed down the tubes when investigators found a UC Berkeley "scientist" had fudged his figures on risks associated with Electromagnetic Fields. If have doubts about releasing raw data from federally funded studies that are used to form public policy, this one ought to shake you out of your complacency. Can you imagine the cost involved in burying power lines in this country? Can you imagine that people who are a bit down the socio-economic scale might be more likely to live near power transmission lines than, say you average yuppie?
Hey, the UK Whitehall study had this one wrapped up in 20 years ago. Mortality rates vary continuously and precisely with people's socio-economic status. Mortality rates for the lowest civil service classification were three times those for those in the highest grade. And a 25-year follow-up of the 17,000+ study participants, published in 1996, showed that this disparity persisted well past retirement, even among men aged 80 and over. This sounds like an economic problem to me, not a medical or epidemiological one.
Can we learn to "Just Say No" to lifestyle risk assessment?
So why waste all this money and energy studying a "weak risk factor" when basic, clinical and applied research are the arenas in which a cause and a cure will ultimately arise? Why not shut down the Lifestyle Epidemiology Empire and throw the money where it matters? I dunno. Politics, maybe? Epidemiology Empire maintenance?
It really is time to call a halt to all this nonsense -- before it's too late to save epidemiology as the great scientific specialty it used to be and before we create an "epidemic" of either ambient anxiety or bored indifference among the U.S. public in response to the scaremongers who cry "wolf" weekly in so-called "professional" journal press releases.
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