Medical Humanities Lexicon: The McKeown Thesis

Today's entry in the Medical Humanities Lexicon is "the McKeown Thesis."  The McKeown Thesis is an important and contentious theme in epidemiology, public health, demography, and the history of public health.  Thomas McKeown, physician and demographic historian, put forth a fairly startling argument in several articles published during the 1950s and the 1960s: the so-called epidemiologic (or health) transition from approximately 1700-present had little to do with public health and medical interventions, but was prompted by social and economic changes.

The epidemiologic transition remains a crucial subject of inquiry for all manner of scholars and stakeholders: why exactly did mortality rates decline so precipitously during this period? The answer to this question is actually crucial, for it promises to shed some important light on why populations grow healthier -- or less healthy -- over time.  This is in turn would obviously have significant impact on thinking about our current public health policies and priorities.

There are some controversial and some relatively uncontroversial aspects of the McKeown thesis.  Relatively uncontroversial is the notion that medical care and the misleadingly named "therapeutic revolution" of the 19th century had little substantive effect on mortality rates.  In the first place, mortality rates were already in decline by the mid-19th century, and, more importantly, there were no "effective"* chemotherapeutics until the advent of the sulfa drugs during the 1930s.  Accordingly, it is extremely unlikely that improvements in medical care had a substantial effect in reducing mortality and morbidity during the period under examination, or at least did not do so until the very tail of the period.

I am continually surprised by how the impact of this aspect of the McKeown thesis seems to be dramatically understated.  The conclusion, generally conceded by most stakeholders, is that there is significant reason for doubting that improvements in medical care and technical innovation has a substantial effect on population health over time.  Thus, even as sharp a commentator as Jon Cohn feels the need to (correctly, IMO) explain why a proposal for universal health care will not unduly depress innovation, without even mentioning that the evidence for a robust link between increased innovation and population health is weak.

Indeed, given that such innovation is a substantial driver of (1) hyperinflationary health costs (estimates go as high as 40% of the increase can be attributed to new techniques); (2) socioeconomic disparities; and (3) health disparities, there is a plausible argument that acute care, research, and technical innovations may actually worsen health outcomes in the long run.  Note, this is not to suggest that innovation, research, or acute care is undesirable or should be abandoned; this is a particularly egregious false choice fallacy.  Nevertheless, the health policy scholar or medical humanist familiar with the McKeown thesis has a sound basis for questioning the relative priority of expenditures on acute care and technical innovation.

The controversial aspect of the McKeown thesis is the idea that public health interventions are also not responsible for the epidemiologic transition.  McKeown contended that the improvements in population health from 1700-1950 was due to "improvements in overall standards of living, especially diet and nutritional status, resulting from better economic conditions. His historical analysis called into question the effectiveness of some of the most basic and widely applied techniques in the public health armamentarium, including sanitary reforms, vaccination, and quarantine" (Colgrove 2002).

Interestingly, the furor over the McKeown thesis did not truly ignite until 1976, when McKeown published two books on his theory: The Modern Rise of Population, and The Role of Medicine: Dream, Mirage, or Nemesis.  This prompted a number of responses.  Two of the most critical were a 1981 book entitled The Population History of England 1541-1871, and a 1988 article by Simon Szreter in the journal Social History of Medicine.  The book, published by a distinguished group of scholars named the Cambridge Group was utterly dismissive of the McKeown thesis, charging that his argument was riddled with inaccuracies and errors.

Szreter, who remains a vocal critic of the McKeown thesis, attacked McKeown's arguments on a number of levels, arguing that the thesis suffered from a serious conceptual inaccuracy by relying on a notion of "rising standards of living" that masked a number of social conditions affected by public health reform (Colgrove 2002).  Szreter also argued that McKeown's interpretation of the data relied on a number of technical errors, and, most important, "that McKeown had allowed his a priori assumptions about the limited value of medical intervention and the need for social reform to predetermine his analytic categories, thus biasing his interpretation of evidence" (ibid).

In any case, the debate over the McKeown thesis continues to rage across public health, epidemiology, demographics, history, and health policy.  And, I submit, the discourse is crucial to examining a question that ought to be fundamental for any medical humanist: what is it that causes (good or bad) health? Why do mortality and morbidity rates rise or fall over time?   How we answer these questions ought to have a profound impact on what public health policies and priorities we set, IMO.  Finally, the discourse over the McKeown thesis also implicates work on social epidemiology and the social determinants of health, especially inasmuch as this work is primarily concerned with articulating how social conditions produce health or its lack.

_________________________________________________ 

Bibliography

James Colgrove, "The McKeown Thesis: A Historical Controversy and Its Enduring Influence," American Journal of Public Health 92, no. 5 (2002): 725-729.

Simon Szreter, "Rethinking McKeown: The Relationship Between Public Health and Social Change," American Journal of Public Health 92, no. 5 (2002): 722-725.

Simon Szreter, "The Importance of Social Intervention in Britain's Mortality Decline c. 1850-1914: A Reinterpretation of the Role of Public Health," Social History of Medicine 1 (1988): 1-38.

T. McKeown and R.G. Brown, "Medical Evidence Related to English Population Changes During the Eighteenth Century," Population Studies 9 (1955): 119-141.

T. McKeown and R.G. Record, "Reasons for the Decline in Mortality in England and Wales During the Nineteenth Century," Population Studies 16 (1962): 94-122.

Thomas McKeown, The Modern Rise of Population (New York: Academic Press, 1976).

Thomas McKeown, The Role of Medicine: Dream, Mirage, or Nemesis? (London: Nuffield Provincial Hospitals Trust, 1976).

E.A. Wrigley and R. Schofield, The Population History of England 1541-1871: A Reconstruction (Cambridge, UK: Cambridge University Press, 1981).

See also the Bibliography appended to the Lexicon entry on the Social Determinants of Health.

Comments

[Patrick S. O'Donnell]

Yet another very helpful and articulate introduction to an important concept, argument or theory in the "medical humanities lexicon." I know very little about McKeown's thesis, so the bibliography should also prove useful. Thank you.

[Jaipreet Virdi]

The American Journal of Public Health 92, 2002, in fact held a special issue on the "McKeown Thesis," and presented a few papers, including one by Szreter, that tackled the core of the debates. Its a worthwhile read, and provides different viewpoints on the issues at hand.

[david Egilman]

Ed Kass one of the most prolific student of antibiotics of the last century concluded the same with 20th century data in a paper called social change & infectious disease in 1971.

He got so much flack he never returned o the subject.