By Mark Green (sceincefromaway.com)
Hoosick Falls is a lovely town in upstate New York near the Vermont border and famous as the home of a remarkable painter: Grandma Moses. Recently, it became famous again, for the discovery that a chemical associated with the production of non-stick cookware, perfluorooctanoic acid (PFOA), is at a dangerously high level in drinking water found in town wells. PFOA is more than suspected of causing maladies as serious as cancer. Evidence of the danger of PFOA is that the corporate source of the water contamination is handing out free bottled drinking water in a local market. In an article in The New York Times, we learn that the suspicion of one town resident about the death of his father led him to test his drinking water. http://www.nytimes.com/2016/02/29/nyregion/fears-about-water-supply-grip-village-that-made-teflon-products.html?_r=0
This discovery led to frustrating and conflicting announcements (!!) from both the federal Environmental Protection Agency and the New York State Department of Health about the danger of PFOA and related chemicals in the town’s drinking water. Both agencies depend on laboratory results, but too often problems of this kind are not first detected or evaluated by analytical chemistry, but rather by the observations of people living in affected areas. Such observations belong to the category of epidemiology. It reflects the methods coal miners developed to protect themselves. Many years ago, coal miners, fearing noxious gases in the mine, including deadly carbon monoxide, would carry canaries with them. The bird with its rapid respiration and small size would keel over long before the miners were affected, allowing time for escape. Unfortunately, the residents of Hoosick Falls were the “canaries in the coal mine” for the presence of PFOA in the supposedly potable water in their town. All too often, laboratory tests involving minute amounts of chemicals that are dangerous to health do not reveal the danger. It takes the effect on our bodies to reveal the problem.
Epidemiology is constructed from the Greek language: epi–upon; demos–people; logos–study. There are some very inter-esting historical examples of the value of epidemiological studies, which are the foundation of the field of public health. They take us from supernatural sources of disease to a rational scientific basis for illness and death. Hippocrates (460–377 BC), the source of the advice to doctors to “do no harm,” is given credit for being the first epidemiologist. He pointed to the fact that yellow fever and malaria occurred most often in swampy areas. This led to a rational rather than a supernatural basis for disease and ways to protect people from contagion.
It was thousands of years later that Walter Reed, an army physician, made the connection between malaria and mosquitoes. But Hippocrates’ observation was the essential clue. Hippocrates focused much attention on the source of the water that people drink. This idea may have influenced John Snow (1813–1858), who tried to track down the source of recurrent cholera epidemics in London in the 1800s. Taking an epidemiological approach, Dr. Snow found a connection between those parts of the city affected by cholera and distinct sources of water. He proved his point by removing the handle from one water pump causing a sudden drop in cholera cases by people using that pump. This was before the bacterial source of disease was accepted; it demonstrated that something was in the water and that the source of cholera was not some mysterious miasma in the air.
Then there is the example of Ignaz Semmelweis (1818–1865), a medical doctor in Vienna who observed the difference between two clinics in a maternity hospital. In one, women were dying in large numbers from what was called childbed fever. In the other, far fewer met this fate. He found that in the deadly clinic, doctors were coming directly from autopsies without washing their hands. After hand washing was strictly required, deaths from childbed fever dropped precipitously. In this time before an understanding of the germ theory of disease, the connection with washing the hands was not clearly understood. In another convincing example, before the sources of disease were understood, it was observed in many places all around the world that servants who milked cows would often get cowpox but would be immune to smallpox leading to one of the foundations of the discovery of the value of vaccination first proposed for this problem by Edward Jenner (1749–1823).
There is so much more demonstrating the continuing value of epidemiology. For one example, did we understand the reason why people who smoked got lung cancer or other maladies? We were the canaries that demonstrated the danger of smoking long before medical research could find the reason for this danger. Are the people of parts of Louisiana the canary suffering from flooding caused by unprecedented rainfall arising from our behavior leading to global warming, which is misunderstood and denied by many?
For a detailed source on the historical basis of epidemiology in public health, visit: http://samples.jbpub.com/9780763766221/66221_CH02_5398.pdf