A few updates

Hopkins: In May I finished final exams for my 4th quarter at Johns Hopkins. That means I'm done with the required four quarters (one year) of coursework towards the MSPH in International Health "Global Disease Epidemiology and Control" (GDEC) track. Looking back I realize that I've learned an incredible amount this year. At some point I hope to write a bit more about the Hopkins experience and major themes in our GDEC coursework, especially for the prospective students who I see end up here through Google searches. The quarter system has pros and cons: it moves fast, which can burn students out by the third or fourth term, but you're also able to shovel a huge dose of knowledge into your brain in a short period of time, leaving the second year of the Masters program more open-ended in comparison to other programs. One reason I chose the MSPH at Hopkins is that flexibility in the second year: you can return and take additional classes after your practicum, or you can spend the entire second year working abroad gaining additional field experience. That flexibility is nice, especially since I'm hoping to work abroad after completing my graduate education and most of my experience in the developing world has been for short periods of time.

In early June I took the comprehensive exams for the MSPH (and hopefully passed!). That means the only requirements I have remaining are a practicum -- 4+ months doing work in international health using the skills I've acquired -- and a Masters paper/thesis based on that practicum. My original plan was to move abroad for a year-long practicum in September, possibly in Nepal, and be done with the MSPH in May of 2012, but that's changed a bit.

New York: This summer I'm part of the New York City Department of Health's Epi Scholars program. Epi Scholars is a training program that pairs graduate students in epidemiology with researcher mentors in the Department of Health. It's been great so far and I plan to write more about the Department, the training experience, and my particular project -- an in-depth review and analysis of severe lead poisoning cases in New York City in the last 5-10 years. The Epi Scholars program is in its fifth year and has its largest class to date (11 participants this year) so it's been great getting to know the other students as well.

Princeton: This fall I'll be starting work on a Masters of Public Affairs (MPA) at Princeton's Woodrow Wilson School. I'll be doing the Field IV (Economics and Public Policy) concentration at WWS to get their most rigorous training in economics, but I imagine I'll take a number of courses from the Field III (Development Studies) concentration as well. While Hopkins and Princeton don't have an official joint degree program, I've been able to make arrangements to complete both Masters degrees in a total of three years. The right people at both schools have been incredibly supportive of this idea and have helped me work out the details. My timeline will be something like this:

  • August 2010 - May 2011 - coursework at Johns Hopkins in Baltimore, MD done!
  • June - August 2011 - summer internship (NYC Dept of Health Epi Scholars Program) in New York, NY (in progress)
  • August 2011 - May 2012 - coursework at the Woodrow Wilson School in Princeton, NJ
  • June - December 2012 - practicum work abroad (including writing my Masters thesis for Hopkins), location TBA
  • January - May 2013 - back at Princeton for a final semester

The Woodrow Wilson School also gives students the option of taking a "middle year out" if their summer internship is going well or leads naturally to a full-time job. If I went that route I might not finish the MPA until May 2014, but I'd have significantly more work experience when I finally get back on the job market.

I decided to pursue the dual degree as I realized more and more that my interests -- and the work I want to be prepared to do -- lie at the intersection of global health and economics. I'm interested in the traditional 'applied epidemiology' of studying public health interventions, as well as how those methods are increasingly being used to evaluate development interventions outside of health programs. (Aside: fascinatingly, a recurring critique this year of the development economists conducting RCTs from my public health professors has been that they are much, much too concerned with randomization.) I'm interested in cost-effectiveness evaluations of health and other interventions, and how politics and evidence from various disciplines -- from epidemiology to economics -- get used and misused to make health and development policy.

I'll wrap up the Epi Scholars program here in New York in August in order to move to Princeton by August 20 to start "Math Camp" -- a three week crash course in math and economics to get us all up to speed before real classes start. I've already started to meet some of my incoming WWS classmates as they pass through NYC and I think it will be an amazing experience.

From the front lines of public health

Rashida is a Peace Corps volunteer in Uganda teaching "teaching life skills/health/whatever at a local secondary school," as well as a blogger. She also happens to be in the same Hopkins global health Masters program as me (but a year or two ahead, so we've never met). Her latest post starts with this:

Since the kids are often shy around the muzungu (and in front of their classmates), I thought it would better to set up an anonymous questions box, where students can ask questions about health, etc. without having to ask them in front of everyone. Well, no one else seemed as excited about this idea as I was, so I thought the box would just be forgotten about, or maybe even stolen by a trouble-making student. Imagine my surprise when I came back to the school two days after setting up the box to find it overstuffed with questions. I was a bit overwhelmed by the volume of questions posed to me, so I told the students to let me take them home and prepare my answers for next week. Well, here are some of the questions that I got:
  • If you have sex during your menstruation, do you get pregnant?
  • Is it true that if you kiss someone who has HIV, you’ll also get HIV?
  • There are some boys who disturb me during my leisure time, but if I see them I feel like vomiting. What can I do, please help me?
  • Is it true that if young people play sex before menstruation begins you can still get pregnant?
  • How can I know when playing sex that sperm is coming through the penis?
  • Is it true that if you delay having sex you become an abnormal person?
  • Is it bad to practice homosexuality?
  • People usually tell us to have sex when we are still young in order to become perfect in sex. What is the meaning of perfect in sex?

There are quite a few more in the rest of the post,  and they just get more disturbing. Personally I wouldn't know where to start, and I greatly admire those who have the patience, courage, and tact to do this badly needed work. It must be especially difficult to do this sort of work as a foreigner.  Alas, I described this post -- and the sample questions -- to a friend who does sex ed in New York City and was told that the questions are remarkably similar to what you get asked here.

Summer plans

My first (and only) full year of coursework for my masters program is drawing to a close. Finals are in mid-May, and comprehensive exams are in early June. Then it's off to New York City! On June 8 I will be joining the 5th class of the Epi Scholars program with the New York City Department of Health and Mental Hygiene. Each scholar (read: grad student in epidemiology) is paired with a staff mentor and given a specific project to work on throughout the summer. The research work is augmented by training on SAS and GIS, educational sessions on health disparities and other topics that touch on the work of the Department. The project I will be working on involves characterizing children with severe lead poisoning in New York to help clinicians better screen for them. I've only heard amazing things about this program from the Hopkins students and alumni who have gone before, so I'm quite excited.

In the fall I will move to an as-yet-undisclosed location and spend the majority of my second year doing 'field work' in global health. One of the reasons I chose this program is that it gives me the chance to get a substantial chunk (6-12 months) of work experience abroad in one place before I complete my degree, and I plan to take full advantage of that. More on where I'll be once things are finalized.

"The Most Important Medical Discovery of the 20th Century"

Just a reminder -- it wasn't open heart surgery or sequencing the human genome:

A massive cholera outbreak in refugee camps on the border of India and Bangladesh in the 1970s exposed the limitations of intravenous treatment and paved the way for a radically different approach to treating dehydration.

In 1971, the war for independence in what is now Bangladesh prompted 10 million refugees to %ee to the border of West Bengal, India. !e unsanitary conditions in the overcrowded refugee camps fueled a deadly cholera outbreak characterized by fatality rates approaching 30 percent.' Health officials from the Indian and West Bengal governments and relief agencies faced a daunting task: Conditions were squalid and chaotic, intravenous fluid was in scarce supply, treatment facilities and transportation were inadequate, and trained personnel were limited.' Mass treatment with intravenous therapy alone would not halt the impending crisis.

Dr. Dilip Mahalanabis, a cholera expert at the Johns Hopkins Centre for Medical Research and Training in Calcutta and head of a health center at one of the refugee camps, proposed an alternative to the intravenous treatment. He suggested the camp use a new method of oral replacement of fluid, known as oral rehydration therapy, that had been developed in the 1960s in Bangladesh and Calcutta.

The science was as ingenious as it was simple: A solution of water, salt, and sugar was found to be as effective in halting dehydration as intravenous therapy. Dr. Mahalanabis’ team recognized the many advantages of oral therapy over the intravenous rehydration: It is immensely cheaper, at just a few cents per dose; safer and easier to administer; and more practical for mass treatment. ORT, however, had still not been tested in an uncontrolled setting, and skeptical health specialists cautioned that only health professionals and doctors should administer the new therapy.)

Mahalanabis’ team moved quickly to introduce the treatment to the 350,000 residents of the camp. Packets of table salt, baking soda, and glucose were prepared in Calcutta at the diminutive cost of one penny per liter of fluid.' The solution was widely distributed, with instructions about how to dissolve it in water. Despite the shortage of trained health personnel, large numbers of patients were treated, with mothers, friends, and patients themselves administering the solution.

The results were extraordinary: At the height of the outbreak, cholera fatalities in the camp using ORT dropped to less than 4 percent, compared with 20 percent to 30 percent in camps treated with intravenous therapy.

From Millions Saved, case study 8: diarrhea in Egypt. Just re-reading it for a class.

"Small Changes, Big Results"

The Boston Review has a whole new set of articles on the movement of development economics towards randomized trials. The main article is Small Changes, Big Results: Behavioral Economics at Work in Poor Countries and the companion and criticism articles are here. They're all worth reading, of course. I found them through Chris Blattman's new post "Behavioral Economics and Randomized Trials: Trumpeted, Attacked, and Parried." I want to re-state a point I made in the comments there, because I think it's worth re-wording to get it right. It's this: I often see the new randomized trials in economics compared to clinical trials in the medical literature. There are many parallels to be sure, but the medical literature is huge, and there's really one subset of it that offers better parallels.

Within global health research there are a slew of large (and not so large), randomized (and other rigorous designs), controlled (placebo or not) trials that are done in "field" or "community" settings. The distinction is that clinical trials usually draw their study populations from a hospital or other clinical setting and their results are thus only generalizable to the broader population (external validity) to the extent that the clinical population is representative of the whole population; while community trials are designed to draw from everyone in a given community.

Because these trials draw their subjects from whole communities -- and they're often cluster-randomized so that whole villages or clinic catchment areas are the unit that's randomized, rather than individuals -- they are typically larger, more expensive, more complicated and pose distinctive analytical and ethical problems. There's also often room for nesting smaller studies within the big trials, because the big trials are already recruiting large numbers of people meeting certain criteria and there are always other questions that can be answered using a subset of that same population. [All this is fresh on my mind since I just finished a class called "Design and Conduct of Community Trials," which is taught by several Hopkins faculty who run very large field trials in Nepal, India, and Bangladesh.]

Blattman is right to argue for registration of experimental trials in economics research, as is done with medical studies. (For nerdy kicks, you can browse registered trials at ISRCTN.) But many of the problems he quotes Eran Bendavid describing in economics trials--"Our interventions and populations vary with every trial, often in obscure and undocumented ways"--can also be true of community trials in health.

Likewise, these trials -- which often take years and hundreds of thousands of dollars to run -- often yield a lot of knowledge about the process of how things are done. Essential elements include doing good preliminary studies (such as validating your instruments), having continuous qualitative feedback on how the study is going, and gathering extra data on "process" questions so you'll know why something worked or not, and not just whether it did (a lot of this is addressed in Blattman's "Impact Evaluation 2.0" talk). I think the best parallels for what that research should look like in practice will be found in the big community trials of health interventions in the developing world, rather than in clinical trials in US and European hospitals.

Behavioral observation: Powerpointia grad-studentus

Slide proliferation is a well-documented evolutionary phenomena that results from cooperative behavior in the species powerpointia grad-studentus. Not observed in solitary p. grad-studentus, but in ecological systems where p. grad-studentus must work together to forage for grades, we observe an arms race to add more slides. Each p. grad-studentus thinks that adding another slide will yield a better grade, when in reality their collective action makes the whole presentation less compelling, and the entire flock may starve (ie, not get an A). By limiting the number of slides, faculty are applying selective pressure which in the end will result in a more fit powerpointia grad-studentus. Punctuated equilibrium for powerpoint.


From a lab assignment for my Professional Epidemiology Methods course:

...but part of this exercise is to remember that public health practice does not happen in a vacuum.  And if you do your job well, nothing happens and you may be blamed for interrupting daily life activities.  If you do not do your job well, people get sick or die--and you still get blamed.

History refresh: AZT and ethics

A professor pointed me to this online history and ethics lesson from the Harvard Kennedy School's Program on Ethical Issues in International Research: The Debate Over Clinical Trials of AZT to Prevent Mother-to-Infant Transmission of HIV in Developing Nations. It's surprisingly readable, and the issues debated are surprisingly current.

In 1994, researchers in the US and France announced stunning news of a rare victory in the battle against the AIDS pandemic. Studies conducted in both countries had shown conclusively that a regimen of the drug AZT, administered prenatally to HIV-positive pregnant women and then to their babies after birth, reduced the rate of mother-to-infant transmission of HIV by fully two-thirds. The results of the clinical trials constituted "one of the most dramatic discoveries of the AIDS epidemic," the New York Times declared, and one of the most heartening as well.

The new regimen--known by its study name, AIDS Clinical Trials Group (ACTG) 076 or, often, simply "076"--offered the epidemic's most vulnerable targets, newborns, their best hope thus far of a healthy childhood and a normal life span. The number of infants who might benefit from this research was significant: according to World Health Organization (WHO) figures, as many as five to ten million children born between 1990-2000 would be infected with HIV. In the mid-1990s, it was estimated that HIV-infected infants were being born at the rate of 1,000 a day worldwide.

So impressive were the findings of ACTG 076--and so substantial the difference in the transmission rate between subjects given AZT and those given a placebo (eight percent versus 25 percent)--that the clinical trials, which were still ongoing, were stopped early, and all participants in the studies were treated with AZT. In June 1994, after reviewing the study results, the US Public Health Service recommended that the 076 regimen be administered to HIV-infected pregnant women in the US as standard treatment to prevent transmission of the virus.

But while 076 was hailed as a major breakthrough, the celebration was somewhat muted. For a variety of reasons, the new treatment regimen would not likely reach those who most desperately needed it: pregnant women in the developing nations of the world and, most particularly, sub-Saharan Africa, where AIDS was wreaking devastation on a scale unimagined in the West.

I think one reason why graduate school can be so overwhelming is that you're trying to learn the basic technical skills of a field or subfield, and also playing catch-up on everything that's been written on your field, ever. True, some of it's outdated, and there are reviews that bring you up to speed on questions that are basically settled. But there's a lot of history that gets lost in the shuttle, and it's easy to forget that something was once controversial. Something as universally agreed upon today as using antiretrovirals to prevent mother-to-child transmission of HIV was once the subject of massive, heart-wrenching debate. I tend to wax pessimistic and think we're doomed to repeat the mistakes of the past regardless of whether we know our history, because we either can't agree on what the mistakes of the past were, or because past conflicts represent unavoidable differences of opinion, certainty, and power. But getting a quick refresher on the history of a is valuable because it puts current debates in perspective.

Hangman for Stata

Yes, you can load a .do file and play Hangman in Stata. But only true stats nerds are allowed to play.

And on a related note, have you ever wondered how a game as morbid as hangman became so popular? Can you imagine if you visited another culture and they had a word game that everyone -- adults and children -- knew how to play, and it was based on the electric chair or decapitation, would you judge them? Wikipedia tells me its origins are obscure...

Academic vs. Applied... Everything

When I posted on Academic vs. Applied Epi I included the following chart:

Then I realized that this breakdown likely works pretty well for other fields too. I sent a link to an economist friend, who responded: "No doubt this is similar with econ. The theoreticians live in a world of (wrong) assumptions, while the practitioners are facing the tough policy challenges. And there are quite a few similarities with the below...such as urgency etc."

You can replace "physicians" with "economists" or many other professions and the chart holds up. Contrasting academic economics researchers with policymakers, the fields for Timeline, Data quality, Scientific values, Outputs, and Competencies needed all hold up pretty well.

Many positions that are basically epidemiological in nature are filled by physicians with clinical training but very little formal public health and epidemiology training, which is strongly paralleled in the policy realm. Some sort of graduate training is generally necessary for many jobs, so those aiming for the applied track tend to get multipurpose 'public policy' degrees often viewed as weak by the more purist academics, while those studying public policy deride the inapplicability of the theoretical work done by academics. And the orientation of many academic fields towards a set of skills primarily useful in pursuits that aren't highly valued by the more applied practitioners may go a long way in explaining animosity between the two camps.

Life expectancy: what really mattered

National Geographic has a great series up on global population growth. We'll hit 7 billion people in 2011 - quite a milestone. One thing to quibble about from the article:

Moreover in 1798, the same year that Malthus published his dyspeptic tract, his compatriot Edward Jenner described a vaccine for smallpox—the first and most important in a series of vaccines and antibiotics that, along with better nutrition and sanitation, would double life expectancy in the industrializing countries, from 35 years to 77 today. It would take a cranky person to see that trend as gloomy: “The development of medical science was the straw that broke the camel’s back,” wrote Stanford population biologist Paul Ehrlich in 1968.

I've read statements like this - about increasing life expectancy and its reasons - many times, and it's almost always done in a certain order. Here, life expectancy increases result from "a series of vaccines and antibiotics that, along with better nutrition and sanitation..." It's hardly the most egregious wording I've seen. Often I'll read that "modern medicine" led to increases in life expectancy, so it's nice that the article specifically mentions vaccines, a preventive measure, instead of only the curative parts of modern Western medicine that we're more familiar with as adults.

But the even the formulation "vaccines and antibiotics along with better nutrition and sanitation" still seems problematic. Why is nutrition and sanitation always an afterthought? I don't have a citation handy, but my impression is that the vast majority of the increase in life expectancy stemmed from advances in sanitation and nutrition, while curative medicine (including antibiotics) played a much more minor role. (I would love to read a good paper outlining the relative contribution of changes in nutrition, sanitation, vaccination, antibiotics to life expectancy improvements - if you know of one, please post it in the comments.)

I think this bias stems in part from a larger bias toward seeing advances in public health as medical advances, rather than societal, economic, or political ones. Many (too many?) people working in the public health field have medical backgrounds. Modern medicine is shiny and fancy and dramatic, and (credit where it's due) has made some incredible advances.

Imagine you're given a Rawlsian choice between being born into:

  • World A, with the nutrition, sanitation and vaccination of modern Europe but with all of the doctors and drugs mysteriously raptured in a giant Hippocratic tribulation, or
  • World B, with the nutrition, sanitation and vaccination of ancient Rome but with Atul Gawande on standby with the latest treatments once you get sick

I'd definitely choose World A. (Though I'm glad we don't have to choose!)

To correct this bias, I think it would helpful if every time we mentioned the dramatic shift in life expectancy over the past few centuries, we emphasized that most of those gains are from reductions in child mortality, and that nutrition and sanitation deserve the lion's share of credit for those improvements. At the least, let's mention them first and then say "along with later, less important developments such as antibiotics."

Mapping Race in Baltimore

The New York Times has a new interactive feature up, called Mapping America: Every City, Every Block. It uses "local data from the Census Bureau's American Community Survey, based on samples from 2005 to 2009." The data includes income and education levels by census tract, which is interesting but not that visually stimulating, and the more striking data on race by household in each census tract. Areas with higher population density are typically easier to work with -- try New York City for starters. My current home, Baltimore, makes a great test case. On these maps, each circle represents 50 households. (As you zoom further out, you start seeing counties instead of census tracks, and each dot represents many more households.)  A screenshot:

By race, blue = black, green = white, red = Asian, yellow = Hispanic.

For those unfamiliar with Baltimore, that's the Inner Harbor at the bottom. As you can see, the neighborhoods just southwest (Federal Hill) and north (Canton, Fells Point) of the harbor are predominantly white. The relatively sparsely populated section in the center is the more commercial downtown. East and West Baltimore are predominantly black. The green (ie, white) strip in the center is Mt. Vernon, whereas the area at the center top with more green (white) and red (Asian) includes the Charles Village neighborhood, where Hopkins' Homewood undergraduate campus is located.

The Johns Hopkins medical campus, including the School of Public Health where I'm a student, is in the predominantly blue (black) area on the middle right of the map above.

One thing that struck me as odd at first is that there are a bunch of green dots (ie, white households) in the middle of Patterson Park, the big green space included in this zoomed in map:

On further thought, I think the maps are showing averages of the data from the entire census tract. The tract that includes Patterson Park also includes some surrounding blocks, which are predominantly white. The distribution of differently colored dots on the map represents the race breakdown within that tract, but the location  of the dots within the tract on this map is completely random. If you play with the tool, you'll find that tracts are highlighted when you mouseover them, and that the spacing of dots within the tract is uniform -- this also accounts for the sudden changes in density you see in some places at the edges between tracts.

Finally, below is a closeup of the area I live in. At the top center of this map is Charles Village (including the Hopkins undergraduate campus). I live near 25th street, which bisects this map horizontally, in the transition between the predominantly white and Asian area in Charles Village and the mostly black neighborhoods in between Mt. Vernon and Charles Village:

h/t @edwardcarr

Grad School Buffet

My program only requires one full academic year of coursework. The second year is a mix of a field practicum, work on a masters paper, and additional courses for those who choose to take some (and many do). But most students complete the core requirements for the degree in the first academic year, which is composed of four quarters. So far I've completed the first two quarters, which included 10 classes and 3 additional seminars for a total of 43 credits. Now I have to decide which classes to take in the 3rd and 4th quarters (January through May), when I have fewer required classes and more electives are offered. Fellow Hopkins GDEC (global disease epidemiology and control) student Kriti at EpiTales describes the selection of public health courses at Hopkins as a buffet. Quite true. I've been trying to narrow down my courses for the 3rd and 4th terms and have come up with a preliminary list, excluding many classes that are redundant, don't fit my interests, or have prerequisites that I haven't taken. After narrowing it down a bit, I'm down a list of a mere 42 courses, or which I'll be able to take 10-11 at most:

Armed Conflict and Health Assessing Epidemiologic Impact of Human Rights Violations Clinical and Epidemiologic Aspects of Tropical Diseases* Clinical Vaccine Trials and Good Clinical Practice* Comparative Evaluation for Health Policy in International Health Current Issues In Public Health Data Management Methods in Health Research Studies Demographic Estimation for Developing Countries Demographic Methods for Public Health Design and Conduct of Community Trials* Econometric Methods for Evaluation of Health Programs Emerging Infections Epidemiologic Inference in Outbreak Investigations Ethics of Public Health Practice in Developing Countries Ethnographic Fieldwork Fundamentals of Budgeting and Financial Management* Fundamentals of Program Evaluation GDEC seminar (required) Global Disease Control Programs and Policies (required) Global Sustainability and Health Seminar Global Tobacco Control History of International Health and Development History of Public Health Infectious Diseases and Child Survival* Intro to SAS Statistical Package Introduction to Urban Health Large-scale Effectiveness Evaluations of Health Programs Nutrition in Disease Treatment and Prevention Pandemics of the 20th Century Poverty, Economic Development, and Heath Professional Epi Methods I Professional Epi Methods II Project Development for Primary Health Care in Developing Countries Public Health Practice* Scientific Grant Writing Spatial Analysis and GIS I Statistical Methods for Sample Surveys Statistical Methods in Public Health III (required) Statistical Methods in Public Health IV (required) Systematic Reviews and Meta-Analysis Vaccine Policy Issues

*Classes noted in bold are required, while those in italics meet some other requirements (I have to choose one from a cluster of courses on a subject area -- it's a bit too complicated to explain here).

Obviously I'll have to narrow it down a bit more. While I would probably enjoy most everything on the list, my strategy is to concentrate on coursework in epidemiology, biostatistics, and statistical software (we use Stata in the required biostatistics series, and I would also like to be familiar with SAS and ArcGIS). Then I'll prioritize courses that provide additional skills in program evaluation and trial design and execution. If I have time left in my schedule I'll get to take the other things -- but it looks like I would need to go back for a second plate at the buffet to be able to take even half of these.

(If you're a prospective student and want to browse for yourself, the JHSPH course search feature is here).

The Changing Face of Epidemiology

Unlike many scientific disciplines, undergraduate training in epidemiology is fairly rare. I've met a lot of public health students over the past few months, but only a few majored as an undergrad in public health or something similar, and I haven't met anyone whose degree was in epidemiology. For the most part, people come to epidemiology from other fields: there are many physicians, and lots of pre-med student who decided they didn't want to be doctors (like me) or still want to be. This has many implications for the field, including a bias towards looking at problems primarily through a biomedical lens, rather than through sociological, political, economic, or anthropological ones. Another interesting consequence of this lack of (or only cursory) study of epidemiology before graduate school is that the introductory courses in epidemiology at most schools of public health are truly introductory. If you're a graduate student in biochemistry and molecular biology (my undergraduate field), my guess is that it's assumed you know something about the structure of nucleic acids, have drawn the Krebs cycle at some point, and may even have heard the PCR song.

In epidemiology we're essentially starting from scratch, so there's a need to move rapidly from having no common, shared knowledge, through learning basic vocabulary (odds ratios, relative risk differences, etc.), all the way to analyzing extremely complex research. This presents pedagogical difficulties, of course, and it also makes it easier to miss out on the "big picture" of the field of epidemiology.

For one of our earliest discussion labs in my epidemiologic methods course, we discussed a couple papers on smoking and lung cancer. While "everyone knows" today that smoking causes lung cancer, it's a useful exercise to go back and look at the papers that actually established that as a scientific fact. In terms of teaching, it's a great case-study for thinking about causality like an epidemiologist. After all,  most people who smoke never get lung cancer, and some people get lung cancer without ever smoking, so establishing causality requires a bit more thought. Two of the papers we read are great for illustrating some changes that have occurred as epidemiology has changed and matured over the last 50 years.

The first paper we looked at is "The Mortality of Doctors in Relation to Their Smoking Habits: A Preliminary Report," written by Richard Doll and Bradford Hill in the British Medical Journal in 1954. (Free PDF here)  Doll and Hill followed up their groundbreaking study with "Mortality in relation to smoking: 50 years' observations on male British doctors" in 2004 (available here).

A few observations: First, the 1954 paper is much shorter: around 4 1/2 pages of text compared to 8 1/2 in the 2004 article. The 1954 paper is much more readable as well: it's conversational and uses much less specialized vocabulary (possibly because some of that vocabulary simply didn't exist in 1954). The graphs are also crude and ugly compared to the computer-generated ones in 2004.

The 2004 paper also ends with this note: "Ethical approval: No relevant ethics committees existed in 1951, when the study began."

Beyond the differences in style, length, and external approval by an ethics committee, the changes in authorship are notable. The original paper was authored by merely two people: a physician and a statistician. The 2004 paper adds two additional authors for a total of 4 (still small compared to many papers) -- and notably, the two new authors are both female. During those 50 years there was of course great progress in terms of women's representation in scientific research.  While that record is still spotty in some areas, schools of public health today are producing many more female scholars than males -- for example, current public health students at Hopkins are 71% female.

There has been a definite shift from the small-scale collaboration resulting in a paper with an individual, conversational style to the large-scale collaboration resulting in an extremely institutional output. One excellent example of this is a paper I read for an assignment today: "Serum B Vitamin Levels and Risk of Lung Cancer" by Johansson et al. in JAMA, 2010 (available here).

The Johansson et al. paper has ~8 pages of text, 47 references, 2 tables and 2 figures (all of which are quite complicated) and a number of online supplements. Its 46 authors have between them (by my count) 33 PhDs, 27 MDs, 3 MPHs, and 6 other graduate degrees! It's hard to tell gender just by name, but by my count at least half of the authors are likely female.

Clearly, epidemiology has changed a lot in the last 50 years. Gone are the days of (at least explicit) male domination. Many of the problems with the field today are related to information management and large-scale collaborations. Gone are the days of one or two researchers publishing ground-breaking studies on their own -- many of the "easy" discoveries have been made. Yet many of the examples we learn from -- and role models young public health researchers may want to emulate -- are from an earlier era.

Grad school is...

Grad school is a battle between curiosity and productivity. Coursework can be conducive to learning -- and especially to skill acquisition. Most students in international health programs -- and all in my GDEC program -- are currently taking Introduction to International Health with Prof. James Tielsch. The class has been excellent so far, with compelling (if sometimes controversial) lectures offering a broad overview of everything in global health. The grades for the course come exclusively from two papers, which are described in an exquisitely detailed 29-page section of the syllabus. The more I work on my paper, which focused on the Guatemalan health system, the more convinced I am that it's excellent preparation for working on grant proposals. That doesn't mean it's fun -- fitting your ideas into someone else's boxes never quite approaches that level of enjoyment -- but it's a great skill to have. But even the best considered assignment pails in comparison to the learning that occurs outside of class, and it feels like the requirement to be productive is always digging into my ability to actively feed my curiosity. During orientation, several professors said that they wished Hopkins would do abolish grades entirely; that worrying about grades was a detriment to their education, and it doesn't really predict who will do well in public health. I can see how this would be true, as the times that I've felt that I'm absorbing the most have been when reading something inspired -- but not required by -- a class, usually something that grew out of a discussion question or a casual aside in a lecture. That, and the conversations and debates we're having amongst ourselves...

Should male circumcision be the default in the US? In Africa? Is it OK to make different policy recommendations for different countries?  If so, how do you explain it to the shafted? Why do people care about maternal mortality more than other types of mortality? How do we think about causality? Are some lives worth more than other? Can a sense of humor survive in a morbid (and mortal) field like public health?

Monday Miscellany

Stuff I like:


As should be obvious now, I got a bit behind on blogging while in Guatemala. I was hopeful that this blog would serve as a reminder to myself to write more regularly, as well as a convenient conduit for sharing travel stories and photos with friends and families. But as I fell more and more behind, I started emailing those stories and photos directly to the friends I felt the greatest need to share them with, and the blog fell behind. I hope to post some photos and additional travel stories from Guatemala in the coming weeks, but mostly I'll try not to make promises I can't keep. So sometimes I'll write about public health and epidemiology, sometimes about politics, about rockets, etc.

I moved to Baltimore about 3 1/2 weeks ago, and a little over a week ago I started classes for a Master in Health Science (MHS) in Global Disease Epidemiology and Control (GDEC) through the Department of International Health at the Johns Hopkins Bloomberg School of Public Health. That's the longest name for a program ever, so we mostly just call it an "MHS in GDEC." Basically, it's an intensive program in international health, especially the epidemiology of infectious diseases and vaccine development and testing. I'll take classes in Baltimore for 4 terms (one academic year), take comprehensive exams in June of 2011, and then head somewhere overseas for 4-12 months for my practicum. I can come back and take additional classes if I want to, but that's optional. GDEC--the program, the people, the pace--is already awesome, and I expect that it will only get more awesome and intense as it goes.