Phenomena: Exploring the "natural history" of disease

Table of Contents

Phenomena: Exploring the "natural history" of disease
Initial notes
Annotations on common readings
Annotated additions by students
Idea: Detailed observation (like a naturalist) or detective work--albeit informed by theoretical ideas--may be needed before we can characterize what the phenomenon is we are studying, what questions we need to ask, and what categories we need for subsequent data collection and analysis.

Initial notes

1. The initial motivation for this class was to highlight that epidemiology does not necessarily begin with data sets to analyze. There may be exploratory, investigative, detective, anthropological, and naturalist inquiries before phenomena are even noticed, categories are defined, questions are framed. Good examples of this seemed to be provided by John Snow's work on cholera, Barker's (1971) research in Uganda, and on "clues from geography" of infant mortality and heart disease (1998), and the three Lancashire towns, and Oxford's account of the conditions that provided a source for a global pandemic of the 1918 flu. (40 million died from flu, while 8.5m died from war.) Even Barker's (1999) speculation about anomalous French cardiovascular disease rates looks like someone who is able to connect dots of diverse kinds and that are spread out in time.

2. Brody's paper, in addition to drawing attention to the role of maps in this exploratory research, makes the Snow story more complicated and interesting. Snow had clear hypotheses that guided his mapping and his advocacy of stopping the water supply from the Broad St pump -- he was certainly not simply noticing patterns in the data and hypothesizing about the causes. This account opens up broader questions in philosophy of science. E.g., where do hypotheses that get assessed by research come from in the first place?

(Barker is a recently retired but still active epidemiologist whose reputation is linked to the "Barker hypothesis" that chronic diseases of later life are associated with fetal or early-life conditions. We'll address this hypothesis within the frame of "life course epidemiology" in week 10.)

Mini-lecture
Notes and annotations from 2007 course, 2009, 2011, 2013-
Common reading and cases: Oxford 2005 (1918 flu pandemic), Barker 1971 (buruli disease)
Supplementary Reading: Barker 1998,pp.1-12, 167-172, Barker 1999, Brody 2000, Cohen 2014, Friedman 2013, PBS "Killer flu" Video



Annotations on common readings


Annotated additions by students

(In alphabetical order by author's name with contributor's initials and date at the end.)

Brody, H., M. R. Rip, et al. (2000). “Map-making and myth-making in Broad Street: the London cholera epidemic, 1854.” The Lancet 356: 64-68.

This article juxtaposes the historical account of John Snow’s methodology in unearthing the transmission pathway of cholera, a water-borne route, against the pervasive spurious account of his role in abating the London cholera epidemic of 1854. Brody et al. posits that, the frequently disseminated apocryphal story dangerously maligns the rigorous nature of Snow’s scientific investigation. The authors purport the insufficiency of map-making and inductive reasoning as a means for elucidating cholera’s mode of transmission, the preeminent step for informing appropriate intervention. Although arguably, map-making and inductive reasoning is implicated in identifying the infamously contaminated Broad Street pump. The article charts a course of dispelling the notion of Snow’s use of his spot map (an illustrative device) as his primary analytical tool. Foundational evidence laid by the authors include details of Snow’s prior clinical exposure to cholera, his development of a theory for its pathobiology and his involvement in observational studies predating the 1854 cholera epidemic. Brody et al. proposes that the failure of other contemporary investigators, in possession of more accurate cholera-death spot maps, to yield any definitive conclusion demonstrates the reality that Snow’s grounded theory facilitated his discovery of the cholera outbreak source.
(Samorga)

Marks, H. M. (2003). "Epidemiologists Explain Pellagra: Gender, Race, and Political Economy in the Work of Edgar Sydenstricker." Journal of the History of Medicine and Allied Sciences 58(1): 34-55.

Goldberger, a US Public Health Service doctor who showed the connection between diet and pellagra through observation and experiments with a prison population, also worked with Sydenstricker in the mid-1910s to show the association in data derived from 7 mill towns in S. Carolina. The association was clear against income per adult male equivalent (with nutritional needs of wives and children set lower). They did not go beyond this statistic to examine distribution within households and shed no light the higher incidence of pellagra among women. In subsequent work on sharecroppers and tenant farmers in Mississippi, Sydenstricker examined the annual and debt-related restriction on food supply but made no distinction between whites and blacks and shed no light on the disproportionate incidence of pellagra among blacks. Marks concludes that, by distracting attention from gender and racial inequalities, "research methods and traditions, no less than overt ideologies, played a role in maintaining the subordinate social position of women and African-Americans in the southern United States" (p.34). There is more to Marks' account, including the more pluralistic idea of race in the areas of high immigration in the industrial Northern USA.
(Taylor)