Miscellaneous amused views on topics in the domains of neuropsychiatric epidemiology, defined broadly to encompass the entire envirome and genome, including infective agents; alcohol, tobacco, and other drugs; traumatic events; you name it. Comments welcome. Will be moderated by a volunteer among one of our MSU program's chief fellows or alum.
Thursday, April 27, 2017
Old Age Psychiatry: The Baby Boom Generation and What to Expect: Performance-Enhancing Drugs
Re-Thinking Epidemiology for the Mid-21st Century
Anyone who knows me appreciates that I was destined to be no more than a limited 'futurist' as compared to the best futurists. I lay the blame on the Catholic Church, becoming an altar boy, studying Latin for more years than I wish to count (including a year of self-study), and gaining too much respect for early origins and roots. Think about me as a conservative radical, conserving the roots. I might be too 'conservative' to be a good futurist.
At the same time, I also am known as an iconoclast, because I do not hesitate to challenge bogus concepts when they creep into our field of epidemiology, among which I can specify 'risk factor' and 'reverse causality' as special within-field jargon terms that have almost no communication value when we, as epidemiologists, try to describe our evidence to audiences beyond the local 'tribe'. (Worse yet, there are non-tribe members who actually think they know what we mean when we use these jargon-terms, as has occurred when my non-baseball friends have thought I'm talking about mental health when I use the term 'screwball' when describing a baseball pitcher.)
With that background in mind, you can imagine my response when I was giving an end-of-semester talk to my research trainees and students about some challenges that epidemiologists are going to face during the next few decades. I thought back to two issues raised when I was early in my studies of epidemiology back in the late 1970s: (1) an idea that David Mechanic and Bill Eaton mentioned about epidemiology having run out of ideas and theories, and (2) an idea that Bruce Dohrenwend offered about epidemiology being little more than a toolkit or collection of methodological approaches.
For my students, I framed my response to a hypothetical question about the challenges they might face in relation to these two ideas, and I offered this statement: "The most serious challenge you will face in your career is running out of substantive ideas and theories that deserve testing."
For the past day, I have been thinking about what I told them, and I realized that there might be an empirical indication of the degree to which epidemiology, as a discipline, has started to run out of ideas and theories, and has entered a terminal (?) stage of being a methods-oriented field of study as might be distinguished from a science, akin to the way we'd differentiate 'operations research' as a field of study without thinking about it as a 'science' in the generally accepted sense of the term.
My realization of an empirical approach required a reflection on (a) an early expression of Wade Hampton Frost's idea that epidemiology has to do with infective agents and infectious diseases, and he was uncertain about whether it made sense to think about epidemiology as applied to other conditions that did not originate with an exposure to an infective agent, (b) Mort Levin's assertion in a Milbank Memorial Fund session that Ernie Gruenberg had organized, which amounted to this statement: "There can be an epidemiology, and there can be a set of psychiatric disorders, but I'm not sure there needs to be an epidemiology of psychiatric disorders," and (c) a general principle I first learned from my PhD advisor Len Schuman at University of Minnesota, which also later was stressed by my local colleague and friend Nigel Paneth, along the lines of the advantages gained by restricting the prefix adjective for epidemiology to the domain of individual disease entities or disease classification names, as in 'cholera epidemiology' and 'infectious disease epidemiology,' as opposed to alternatives based on prefix adjectives that shifted attention from the epidemiological response under study in the direction of the causal explanations under study (e.g., 'genetic epidemiology').
When I first appreciated this point as it was being made by Len Schuman in my early years after starting graduate studies in epidemiology, I had not read Wade Hampton Frost nor had I met Mort Levin. I was out in Minnesota, ignorant of Mechanic's medical sociology program at University of Wisconsin, and completely ignorant about Bruce and Barbara Dohrenwend's social psychological research program at Columbia. Nonetheless, it was not long until I was reading the Lilienfeld-Gifford 'Chronic Diseases and Public Health' book assigned by Schuman, and I recognized a clear distinction being made between 'Infectious Disease Epidemiology' and 'Chronic Disease Epidemiology' (hereinafter abbreviated as ID and CD).
[At this point, I stopped for refreshment and I pick up the thread down below.]
Now that I have drawn attention to this separation of 'ID epidemiology' from 'chronic disease' epidemiology, I can offer a thought experiment that some enterprising young epidemiologist might try to pursue. (The most valuable thought experiments are those that can be investigated empirically once the experiment has been specified.)
The empirical work involves the study of time trends in appearance of adjectives used to modify the term 'epidemiology' as can be seen in traces such as Web of Science or Google Search or JSTOR or other bibliographic search tools that have emerged as a consequence of internet advances.
An initial interesting time trend will depict the relative frequency of 'infectious disease epidemiology' and 'chronic disease epidemiology' as these terms appeared in the published literature, year by year, over time. Here, the expectation would be an increasing frequency of both terms, but in addition, even with de-trending, the ID/CD ratio might be expected to decline, at least until the mid-1980s, given (1) increasing prominence of work in CD epidemiology until (2) emergence of HIV/AIDS research as priorities for NIH before 1990. (I have not studied these trends so these expectations are based solely on my 'seat of the pants' reckoning, and I might well be wrong.)
A savvy approach will put into play de-trending research approaches that compensate for generally increasing frequencies of 'epidemiology' as a search term, based on knowledge that NIH and other funding sources increased their investments in epidemiology across these years. A more savvy approach will take other interesting issues into account, such as might be illuminated by studying citation counts as opposed to what can be learned via 'topic' or 'title' restricted searches over these years.
But I leave these issues up to others in order to focus on the possibility that epidemiology's de-celerating rate of innovative ideas might be reflected by studying (1) the relative frequency of 'disease entity' adjectives positioned as prefix terms before 'epidemiology' appears as a noun, and (2) the corresponding relative frequency of 'non-disease-entity' adjectives positioned as prefix terms. Here, by 'disease entity' adjectives, I'll use as examples 'cancer epidemiology' and 'dementia epidemiology.' For 'non-disease-entity' examples, I'll use examples 'social epidemiology' and 'genetic epidemiology' or 'nutrtional epidemiology' or 'life-course epidemiology.'
It is fair to ask why the relative frequency of these prefix adjectives might convey something important about the content of epidemiological research and the inherent generativity of epidemiology as a source of new ideas and theories. I have little more than a simple answer of the following form, expressed in relation to 'Types' of epidemiology:
(Type 1) When the prefix adjective is focused on the response variable, such as a cancer or a dementia, then the domain of potential explanations is expanded almost infinitely to cover whatever might be accounting for variation in the incidence rates and prevalence proportions for that response. The epidemiologist is faced with the challenge of drawing from multiple disciplines in an effort to understand what might account for the population-level variations in the epidemiological parameters. Let's think of the specification of the response variable as one dimension of epidemiology.
(Type 2) When the prefix adjective is focused on a domain of explanation (e.g., 'social' or 'nutritional' or 'genetic'), there is a greater constraint on the range of sources of variation. The epidemiologist is faced with a more circumscribed challenge, which is to ask whether and under what circumstances that domain of explanation might be more or less important in attempts to account for population-level variations in the epidemiological parameters. Let's think of the specification of the explanatory domain as a second dimension of epidemiology, when 'second' denotes a time sequence rather than my own pre-judgement (prejudice) about the ordinal ranking of importance or public health significance.
(Type 3) When the prefix adjective is focused on a domain of process (e.g., life-course'), there is a third dimension that can be considered quite separately from the first two dimensions, and the third dimension has a correlation with time. This dimension might reflect age (considered subgroup by subgroup, as in a cohort-sequential study), or aging (considered as a progression from one birthday to the next), or as developmental (as in the relatively fuzzy sets that we use to distinguish developmental stages along the lines of (a) pre-term, full-term, etc., with respect to measured gestational age of a newborn, or (b) 'pre-pubertal,' 'pubertal,' etc., along the lines of the Tanner stages, or (c) pre-senile versus senile, as in the differentiation of age of onset of dementia syndromes based on when the syndrome was detected, earlier for those with trisomy-21, at mid-life for those with certain familial histories of early-onset, or later for those formerly known as 'sporadic' due to the absence of the family history of mid-life onset of the dementia syndrome. This is a third dimension, separable from the first two dimensions.
It is my speculation that an increasing frequency of prefix adjectives of type (2) and (3), relative to type (1), over time, can serve as an indication of the degree to which epidemiology, per se, has stopped generating its new ideas and theories, and instead is turning in the direction of other disciplines to fill a gap of imagination or generativity that otherwise would not require turning toward these other disciplines.
I have no idea whether this speculation has merit. I offer it as a suggestion for epidemiologists and historians of science who might wish to seek quantitive evidence about the degree to which a discipline has 'run out of its own ideas and theories' versus the alternative of borrowing from other disciplines.
I look forward to comments and to any empirical evidence on these matters.
Some dance to remember; some dance to forget... or drink in this case?
Saturday, April 22, 2017
Opioids epidemic: points to ponder
Please, each of you, sign up, and monitor situation.
Tuesday, April 18, 2017
On risk factor, and its essential meaninglessness
Monday, April 10, 2017
The Prevescalation Concept and its origin
Saturday, April 8, 2017
Friday, April 7, 2017
Xanax human interest story
Incremental Validity - some thoughts
This problem might not occur to those of you who don't devise new measurements, but it is an interesting topic anyway, and the article introduced me to a new validity concept: "incremental validity"
It's what you get when you can make an established screening test into a better predictor by adding new information. Or, as they cast the problem, when you want to evaluate prediction from one already accepted test and you think your test will perform better.
I'm not entirely convinced that p-values and significance testing are the right tools to solve this problem in the first place. I think more in terms of AUC parameter estimation.
Nevertheless, read it and see if you can convince me that the significance testing approach is the correct one.
Thursday, April 6, 2017
Race, skin color, ethnic self-identification, or...
Interesting arguments about how to objectively measure 'race'
skin color, not race
Tuesday, April 4, 2017
Monday, April 3, 2017
Opium, labor, capitalism, and Peru
Saturday, April 1, 2017
Aaron Joshua Rosanoff (26JUN1878 - 07JAN43)
https://en.m.wikipedia.org/wiki/Kings_Park_Psychiatric_Center