Re: Wing: Descriptive Epidemiology by Any Other Name...

[Bernard L Cohen <blc+@pitt.edu>]

n Wed, 26 Feb 1997, Ron L. Kathren wrote:

> Vintage Dan Strom -- clearly thought out, well put (albeit lengthy).
>

	--If someone does not understand the difference between testing a
linear-no threshold theory and determining a dose-response relationship,
he is surely not thinking clearly. 
	If a person can't put his criticisms of a scientific work into a
scientific paper or letter-to-the-editor suitable for publication, he is
surely not thinking clearly.
 
Bernard L. Cohen
Physics Dept.
University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245
Fax: (412)624-9163
e-mail: blc+@pitt.edu

Bernard L. Cohen
Physics Dept.
University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245
Fax: (412)624-9163
e-mail: blc+@pitt.edu


On Wed, 26 Feb 1997, Ron L. Kathren wrote:

> Vintage Dan Strom -- clearly thought out, well put (albeit lengthy).
> 
> When, oh when, are we going to get together on the work for ALOO?
> 
> Ron
> 
> >In 1877 Henle and Koch first addresssed association and causation (Evans 
> >1976), and their work was revisited two decades ago (Rothman 1976).  Sir 
> >Austin Bradford Hill published an influential work on association and 
> >causation (Hill 1965).  Another perspective can be found in the work of 
> >Susser (1991).  Canadian and U.S. leaders addressed the quality of 
> >epidemiologic evidence under the title "Hierarchy of Evidence" (U.S. 
> >Preventive Services Task Force 1989).  Most recently, the Federal Focus 
> >expert panel explained why descriptive epidemiology studies don't get 
> >much respect among risk analysts when they try to come to quantitative 
> >conclusions (Graham et al. 1996).  
> >
> >I have always been critical of the application of descriptive 
> >epidemiology (e.g., ecologic studies) to quantitative problems (Strom 
> >1997, 1991a).  "Descriptive studies are generally viewed as useful for 
> >identifying or formulating causal hypotheses, but not a sufficient to 
> >test such hypotheses, because they lack data on individuals, such as 
> >individual exposures, potential confounding exposures, factors affecting 
> >individual susceptibility, and potential biases.  In contrast, studies 
> >generally termed 'analytic' aim to establish risk factors for 
> >populations and individuals by ascertaining individual exposures and 
> >controlling for other variables such as gender, age, race, or exposure 
> >to other agents that could affect risk estimates independently 
> >(potential 'confounders'), potential study biases, and variations in 
> >host susceptibility.  There are two main types of analytic epidemiology: 
> >case-control and cohort studies..."  This quote is from a new book 
> >written by an expert panel of risk assessors in 1995 entitled 
> >"Principles for Evaluating Epidemiologic Data in Regulatory Risk 
> >Assessment"  (Graham et al. 1996).  The panel was comprised of an 
> >international group (mostly from the USA, however) of well-respected, 
> >middle-of-the-road risk assessors from universities, governments, and 
> >industry groups.  
> >
> >Steve Wing and colleagues have published a reanalysis of TMI health 
> >effects data (Wing et al. 1997).  Both the new Wing study and the work 
> >of B.L. Cohen (Cohen 1995) are in a category of descriptive 
> >epidemiology, as opposed to analytical epidemiology.  
> >
> >Whether descriptive or analytic, virtually all occupational and 
> >environmental epidemiology studies are "observational" as opposed to 
> >"experimental" (a.k.a. clinical or interventional) studies.  Since human 
> >experimentation, outside of closely supervised clinical trials, is out 
> >of the question, we are left with observational study designs which, 
> >unfortunately, are not the most cogent designs because of uncontrolled 
> >factors.  Neither the Wing TMI study nor Cohen's study are 
> >"experiments," but rather compilations and analyses of whatever data are 
> >available.
> >
> >If you are upset by Wing yet celebrate Cohen, I ask that you examine why 
> >descriptive studies are compelling in one case and not in the other.  To 
> >me, the bottom line is that neither have data for individuals, neither 
> >has meaningful control for confounders and biases, and no amount of 
> >statistical analysis will change that.  Both fail to meet many of the 
> >criteria presented by leading risk analysts.
> >
> >I am reminded of the brouhaha about Steve Wing and co-workers' earlier 
> >study of ORNL workers (Wing et al. 1991), which at least was an analytic 
> >cohort study.  Lest I be branded as being on one side of the the issue 
> >of radiation risks, I note that my reply to Wing (Strom 1991b) included 
> >direct criticism of the methods as well as a reminder to consider the 
> >Bradford Hill criteria (Hill 1965) for interpreting an association as 
> >causal as reiterated by the Expert Panel (Graham et al. 1996).
> >
> >As an illustration of the Bradford Hill criteria, I offer a 
> >tongue-in-cheek quote from my colleague Dwight Underhill: "In the 
> >winter, I wear galoshes.  In the winter, I get colds.  Therefore, 
> >galoshes cause colds."  Association?  22 standard deviations, I'd guess. 
> >Causation?  Not by criteria I use.
> >
> >I must also confess that I do not form my opinions on the basis of books 
> >published by what National Public Radio calls "the Libertarian Cato 
> >Institute," which published Steve Milloy's "Junk Science" book.  At the 
> >associated web site, one finds ecologic studies celebrated if they 
> >support deregulation, no effects, or hormesis; and denounced if they 
> >support regulation, or harmful effects of some agent or other.  Again, 
> >these are not criteria I use to judge the weight of epidemiologic 
> >evidence.
> >
> >References
> >
> >Cohen, B.L.  Test of the Linear-No Threshold Theory of Radiation 
> >Carcinogenesis for Inhaled Radon Decay Products.  Health Physics 
> >68(2):157-174; 1995.
> >
> >Evans, A.S.  Causation and Disease: The Henle-Koch Postulates Revisited. 
> > Yale Journal of Biology and Medicine 49:175-195; 1976.
> >
> >Graham, J.D.; Koo, L.C.; Paustenbach, D.J.; Wynder, E.L.; Ashby, J.; 
> >Carlo, G.; Cohen, S.M.; Evans, J.S.; Holland, W.; Matanoski, G.M.; 
> >North, G.W.; Pershagen, G.; Schlesselman, J.J.; Starr, T.B.; Swenberg, 
> >J.A.; Teta, M.J.; Wichmann, E.; Williams, G.M.; Kelly Jr., W.J.; 
> >Auchter, T.G.; Landeck, S.; Ploger, W.D.  Principles for Evaluating 
> >Epidemiologic Data in Regulatory Risk Assessment. Washington, DC: 
> >Federal Focus, Inc. 1996.
> >
> >Hill, A.B.  The Environment and Disease: Association or Causation?  
> >Proceedings of the Royal Society of Medicine 58:295-300; 1965.
> >
> >Rothman, K.J.  Causes.  American Journal of Epidemiology 104(6):587-592; 
> >1976.
> >
> >Strom, D.J.  The Ecologic Fallacy.  Health Physics Society Newsletter 
> >19(3):13; 1991a.
> >
> >Strom, D.J.  A Critique of "Mortality Among Workers at Oak Ridge 
> >National Laboratory".  Nuclear News 34:67-74; 1991b.
> >
> >Strom, D.J.  Radon Study Shows Little Correlation.  Letter.  Health 
> >Physics 72(3):488-489; 1997.
> >
> >Susser, M.W.  What is a cause and how do we know one?  A grammar for 
> >pragmatic epidemiology.  American Journal of Epidemiology 133:635-648; 
> >1991.
> >
> >U.S.Preventive Services Task Force.  Guide to Clinical Preventive 
> >Services. Baltimore: Williams & Wilkins; 1989.
> >
> >Wing, S.; Shy, C.M.; Wood, J.L.; Wolf, S.; Cragle, D.L.; Frome, E.L.  
> >Mortality Among Workers at Oak Ridge National Laboratory: Evidence of 
> >Radiation Effects in Follow-Up Through 1984.  Journal of the American 
> >Medical Association 265(11):1397-1402; 1991.
> >
> >Wing, S.; Richardson, D.; Armstrong, D.; Crawford-Brown, D.J.  A 
> >Reevaluation of Cancer Incidence Near the Three Mile Island Nuclear 
> >Plant: The Collision of Evidence and Assumptions.  Environmental Health 
> >Perspectives 105(1):52-57; 1997.
> >
> >
> >The opinions expressed above are my own, and have not been reviewed or 
> >approved by Battelle, the Pacific Northwest National Laboratory, or the 
> >U.S. Department of Energy.
> >
> >Daniel J. Strom, Ph.D., CHP
> >Staff Scientist
> >Health Protection Department K3-56
> >Pacific Northwest National Laboratory
> >Battelle Boulevard, P.O. Box 999
> >Richland, WA 99352-0999 USA
> >(509) 375-2626
> >(509) 375-2019 fax
> >dj_strom@pnl.gov
> >
> >
>