Notes on the History of Epidemiology

12/2/03

Epidemiology as a unique discipline began within the sanitary reform movement in Victorian England. In 1834, The Statistical Society of London was founded, and in 1850 the Epidemiological Society of London was chartered. 

In the 20th century, epidemiology matured into a mature science. In the first half of the 20th century, methods were develop to advance epidemic theory, outbreak investigation methods were "perfected," field survey methods were developed, the study noninfectious diseases through nonexperimental methods (e.g., case-control and cohort methods) were introduced, and randomized clinical trials were advanced as a "gold standard" way of learning. In addition, medical education was reformed in the 1910s and 1920s. The second half of 20th Century saw the control of infectious diseases, improved nutrition, greater life expectancy (and resultant increases in "diseases of aging") and lifestyle diseases. Improvements in disease surveillance were instituted. 

Additional notes (pp. 11 - 26)

• Early environmental understandings of health and disease can be traced back to the Hebrew bible (e.g., Book of Daniel). However, it wasn't until Hippocrates (~400 BCE) freed the study of health from superstition, religion, "reason without empirical evidence" until medicine was studied scientifically. Following the era of the Greeks, the medicine (as the rest of the world) receded to into the Dark Ages. The Age of Enlightenment (starting ~1500) restarted scientific observations of health. The text cites early medical reformers such as Sydenham in the 1600s (the English Hippocrates) and Potts (1700s) as exemplars of this renaissance. The text characterizes some element in the scientific observations of disease, such as classifying, grouping, confirming, observing, etc, (p. 12), but avoids rigid definitions for scientific observation. 
• John Graunt's (1600s) demographic approach to studying health and disease is address on p. 12. What a lovely demonstration we see in the middle of p. 13, in which Graunt describes the survival of 100 hypothetical newborns of his day: at the end of 6 years -- 64 surviving(!), at age 16 years 40 surviving, and so on. What lessons can modern epidemiologists learn from Graunt? Brevity, clear reason, repeated and varied testing, openness to criticism, openness to revision, avoidance of mechanical interpretations. Elegant.
• Germ theory - Epidemics were still explained in terms of "miasma atmospheres" well into the 1800s. It took some great minds (Pasteur, Henle, Snows) to convince the world otherwise
•  The Numerical Method Many of the leaders of medical and public health movements of the 19th century can be traced to the great French physician and teacher Pierre Charles-Alexandre Louis (1800s).  Louis's careful recordings of bloodletting and survival are shown on p. 17. What a inspiring sight this is! The finding that early 44% of early-treated patients died compared with 25% of late-treated patients was met with skepticism, but ultimately put the nail in the coffiin of this archaic form of treatment.. It is interesting to note that Louis never concluded that bloodletting was harmful--perhaps we can learn from his cautious inference. Nevertheless, Louis's greatest contribution was conveying his beliefs to his students -- men who would go on to establish scientific medicine and public health in Europe and the United States.
•  The London Epidemiological Society was chartered established in 1850, and what an incredible charter (p. 17)! Many men were involved in this organization, including William Farr. Farr was an innovator himself, but was also a friend of the recognized hero of the field, John Snow. Snow fought the idea that cholera was caused by foul smelling gases and miasma atmosphere, using clinical observation and epidemiologic studies to establish the waterborne transmission of the disease. We are inspired by Snow's three main studies For a pretty good multimedia presentation of Snow's efforts, click here.
• Epidemiology came into its own in the 20th century. From 1900 to 1950, there were innovations in field epidemiology and cohort studies. After WWII, epidemiology evolved to its current form with such landmark studies as the Framingham Heart Study, the British Doctors Cohort, and numerous case-control studies and human trials.