Principles of Epidemiology for Public Health (EPID600)
Victor J. Schoenbach, PhD home page
Department of Epidemiology Gillings School of Global Public Health University of North Carolina at Chapel Hill
www.unc.edu/epid600/
Announcements
Minority health events and resources at UNC – www.minority.unc.edu
UNC School of Public Health Annual Minority Health Conference
Annual Summer Public Health Research Videoconference on Minority Health
Why Men Are Not Secretaries
12/2/2001
Role of epidemiology in public health
Husband’s note on refrigerator to his wife:
“Someone from the Guyna College called: They said Pabst beer is normal”
12/2/2001
Role of epidemiology in public health
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I’m not tired anymore!
12/2/2001
Role of epidemiology in public health
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Poor understanding of the patients perspective!!!
12/2/2001
Role of epidemiology in public health
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Guilt by association!
12/2/2001
Role of epidemiology in public health
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Excerpts from (allegedly) actual student history essays collected by teachers from 8th grade through college Richard Lederer, St. Paul's School
12/2/2001
Role of epidemiology in public health
“Soon the Constitution of the United States was adopted to secure domestic hostility. Under the constitution the people enjoyed the right to keep bare arms.”
Excerpts from (allegedly) actual student history essays collected by teachers from 8th grade through college Richard Lederer, St. Paul's School
12/2/2001
Role of epidemiology in public health
“Meanwhile in Europe, the enlightenment was a reasonable time. Voltaire invented electricity and also wrote a book called Candy. Gravity was invented by Isaac Walton. It is chiefly noticeable in the autumn when the apples are falling off the trees.”
From A Prairie Home Companion Pretty Good Joke Book, 4th Edition
12/5/2006
Role of epidemiology in public health
The secretary was leaving the office when she saw the CEO standing by a shredder with a piece of paper in his hand. “Listen,’ said the CEO, ‘this is a very important document. Can you make this thing work?”
From A Prairie Home Companion Pretty Good Joke Book, 4th Edition
12/5/2006
Role of epidemiology in public health
The secretary turned the machine on, inserted the paper, and pressed the start button.
“Great,” said the CEO as his paper disappeared inside the machine. “I just need one copy.”
p177
“Getting better all the time.”
9/24/2001
A little girl was sitting on her grandfather's lap as he read her a bedtime story. From time to time, she would take her eyes off the book and reach up to touch his wrinkled cheek. She was alternately stroking her own cheek, then his again. Finally she spoke up, “Grandpa, did God make you?”
“Yes, sweetheart,” he answered, “God made me a long time ago.”
“It’s getting better all the time.”
9/24/2001
“Oh,” she paused, “Grandpa, did God make me too?”
“Yes, indeed, honey,” he said, “God made you just a little while ago.”
Feeling their respective faces again, she observed, “God's getting better at it, isn't he?”
How to remember what you’ve learned – how to tell others
12/2/2001
Role of epidemiology in public health
10 fundamentals of epidemiology
1. Epidemiology studies populations
12/2/2001
Role of epidemiology in public health
Epidemiology is the study of health and disease in populations for the purposes of (i) understanding disease dynamics, (ii) controlling disease, and (iii) promoting health.
Comparison across and within populations is the key strategy of epidemiologic inquiry.
2. Populations are diverse
12/3/2002
Role of epidemiology in public health
Populations (meaningful collections of people) are diverse, heterogeneous, dynamic, and interconnected.
Epidemiology depends on these qualities in order to make useful comparisons.
Comparisons must not be confounded by uncontrolled diversity.
3. Measures for studying populations
7/29/2002
Role of epidemiology in public health
Counts of people – rates, proportions, and ratios, e.g., birth rate, death rate, incidence, prevalence, abortion ratio;
Distributions of characteristics of people, e.g., mean age, mean education, mean cholesterol level;
Characteristics of groups or environment, e.g., sexual networks
Incidence rate measures the process of disease occurrence; incidence proportion measures the result of a process.
5. Measurement
12/2/2001
Role of epidemiology in public health
Observation and measurement are fundamental to scientific advances.
Choosing a measure – objective, conceptual model, and availability of data (technology, feasibility, and ethics).
6. Error
12/2/2001
Role of epidemiology in public health
All measurement involves error.
Science seeks to minimize error and to quantify it as a guide to interpreting data.
Sources of error include random error (e.g., variability from sampling) and systematic error (e.g., selection bias, information bias).
7. Epidemiology is mass production
12/3/2002
Role of epidemiology in public health
Collection, processing, management, and analysis of epidemiologic data (medical records, questionnaires, interviews, biological specimens, environmental measurements) involve mass production.
Skillful management and quality control are key though often unadvertised components of epidemiology.
8. Health and disease are processes
12/2/2001
Role of epidemiology in public health
Health and disease are complex, dynamic processes affected by multiple, interacting factors acting at multiple levels.
Can be challenging to define and to measure.
Interpretation must take this complexity into account but not become lost in it.
We are the source of our data and their spokesperson. Conclusions from data require inference and the weighing of evidence. One of the most difficult decisions is deciding when to act. Action should be accompanied by monitoring.
10. Awareness and humility
12/2/2001
Role of epidemiology in public health
Breadth of awareness and humility are important assets.
More factual knowledge but major public health problems and failings.
Good people can make mistakes, resist new knowledge, take deplorable actions.
When confronting the unfamiliar, how can we tell fact from illusion, insight from fantasy?
Where have we come from, where do we need to go?
12/2/2001
Role of epidemiology in public health
Epidemiology in the 19th century – focus on acute infectious disease
• Denied medical benefits for on-the-job injuries.
"… the closest thing I've ever seen to slavery." [Congressman Charles Rangel]
Behavior toward others has profound effects – domination
12/2/2001
Role of epidemiology in public health
Persecution, discrimination, favoritism by race, ethnicity, religion, language,…, in relation to land, jobs, housing, water, education, …
Behavior toward women
5/5/2009
Role of epidemiology in public health
“Missing” infants in China
Bride burning in India
Extreme female subjugation in many countries
Trafficking in women from Asia and Eastern Europe www.pbs.org/wgbh/pages/frontline/slaves/
Material sex
12/5/2006
Role of epidemiology in public health
Commercial sex work – the oldest profession
Material sex - 40% of women at prenatal clinic in rural Haiti had at least one STD; 30% had sex from financial need (Fitzgerald, Behets, et al.)
World poverty and underdevelopment
12/5/2006
Role of epidemiology in public health
Rye Barcott, UNC-CH, May 2001, as an undergraduate in Kibera, Kenya (UNC-CH Endeavors, Spring 2001, p14)
Malnourished children
10/29/2009
Role of epidemiology in public health
Source: “Response to hunger tests new priorities”, Population Today, Nov-Dec 2001:8
The rich get richer and the poor get . . .
4/20/2009
Role of epidemiology in public health
“Wealthy countries give 1 billion U.S. dollars per year in agricultural aid to developing countries, while they subsidize their own agriculture with nearly 1 billion U.S. dollars per day {(10), p. 130}.”
10: UN Development Programme, http://hdr.undp.org/en/reports/global/hdr2005/
Quoted by Per Lindskog,Science 16 Dec 2005;310:1768
The right to health
12/2/2001
Role of epidemiology in public health
“The enjoyment of the highest attainable standard of health is one of the fundamental rights of every human being without distinction of race, religion, political belief, economic or social condition.” 1946 Constitution of the World Health Organization, AJPH Dec 2001:1923
Universal Declaration of Human Rights
12/2/2001
Role of epidemiology in public health
“a standard of living adequate for the health and well-being of himself and his family, including food, clothing, housing and medical care and necessary social services, and the right to security in the event of unemployment, sickness, disability, widowhood, old age or other lack of livelihood in circumstances beyond his control.” AJPH Dec 2001:1923
Can these goals be attained?
12/5/2006
Role of epidemiology in public health
Is it only a matter of priorities?
What will change them?
> The collision course between humanity and our ecosystem.
Behavior toward the environment
8/5/2002
Role of epidemiology in public health
Two key epidemiology books:
Planetary Overload (1993)
Human Frontiers, Environments and Disease Past Patterns, Uncertain Futures (2001)
Species extinction Can we defy Nature’s end? Stuart L. Pimm et al., Science 21 Sept 2001;293:2207-8
12/8/2009
Role of epidemiology in public health
Is saving remaining biodiversity still possible?
Is protecting biodiversity economically feasible?
Should effort concentrate on protection or on slowing harm?
Do we know enough to protect biodiversity?
Economics and environment
12/2/2001
Role of epidemiology in public health
June 2001 report from Asian Development Bank (www.adb.org) describes the high environmental cost of Asia’s economic development over past few decades, including pollution, deforestation, inadequate sanitation, threatening depletion and degradation of forests, fisheries, and other natural resources.
Environment – air
12/2/2001
Role of epidemiology in public health
Nearly 100,000 premature deaths/year in southern Asian cities
12 of the 15 cities with highest levels of particulate matter are in Asian and Pacific regions.
Environment - land
10/26/2009
Role of epidemiology in public health
William Wallace Covington. Helping western forests heal. The prognosis is poor for US forest ecosystems. Nature 9 Nov 2000 p135
Environment - water
12/2/2001
Role of epidemiology in public health
One in three Asians lack access to safe drinking water near their homes - contamination by sewage, urban and agricultural runoff and saline infusion.
Urban health
12/2/2001
Role of epidemiology in public health
“Over 600 million people in cities of developing countries cannot meet their basic needs for shelter, water, food, health and education”
– Population Reports, Johns Hopkins Bloomberg SPH, www.jhuccp.org [quoted in the Nation’s Health Aug 2001, p11]
Urbanization
11/29/2005
Role of epidemiology in public health
Number of cities with population >=10 million in developing countries is expected to rise from 3 in 1975 to 19 in 2015 - Bombay, Lagos, Dhaka, Sao Paolo will have > 20 million
Within 5 years, half of world’s population will live in cities. Nearly all population growth will be in the cities of developing countries.
Urbanization in the developing countries
12/2/2001
Role of epidemiology in public health
Population of such cities will double by 2030, to 4 billion (size of total 1990 population of developing world)
Standing at the edge of disaster
12/2/2001
Role of epidemiology in public health
“Our societies haven't imploded yet only because most of the world lives at a level of privation Westerners would not accept, beyond the reach of the very resources Westerners cannot live without.”
(from David Morens’ review of McMichael, 2001)
Government matters
12/2/2001
Role of epidemiology in public health
Angola (30,000 dead since independence in 1975, AJPH Dec 2001:1921), Zaire (Laurie Garrett, Betrayal of public health)
9.7 million men missing in Russia
AIDS Catastrophe in South Africa
Economic resources and government
World economic inequality
12/2/2001
Role of epidemiology in public health
Marked increase in world income inequality
20% of world population has 84% of world income; 20% has 1.2% of income
International inequality in wealth and power underlies the degradation of the biosphere.
Adam Smith’s Invisible Hand
4/24/2010
Role of epidemiology in public health
“. . . By directing his industry in such a manner as to produce its greatest value, he intends only his own gain but is led by an invisible hand to promote . . . The interests of society more effectively than when he really intends to promote it.”
Adam Smith in The Wealth of Nations, quoted in John Bogle, Enough. p202
Adam Smith’s Impartial Spectator
4/24/2010
Role of epidemiology in public health
“. . . This impartial spectator . . . Shows us the propriety of generosity and the deformity of injustice; the propriety of reining the greatest interests of our own, for the yet greater interests of others . . . In order to obtain the greatest benefit to ourselves.”
Adam Smith in The Wealth of Nations, quoted in John Bogle, Enough. p203
Evolution values cooperation
12/8/2009
Role of epidemiology in public health
Groups that cooperate are more likely to succeed. Cheaters get edged out.
Phages (bacterial viruses)
Pseudomonas aeruginosa
Slime molds
Yeast (cell-adhesion protein FLO1 enables clumping, protecting those on the inside).
Many people exhibit fairness in anonymous interactions and punish unfairness
Societies with greater market integration (households buy more of their food) had higher levels of fairness (higher average awards in the “Dictator game”)
British leadership in the Industrial Revolution may have benefited from “class solidarity” enforcing trust among businessmen.
(Karla Hoff. Fairness in modern society. Science 19 March 2010;327:1467-8)
What can epidemiology contribute?
10/25/2009
Role of epidemiology in public health
McMichael, according to Morens, makes “a strong if understated case for broader thinking and broader planning…”
We need to understand human behavioral and cognitive tendencies
Can we understand how humans think and behave?
“To err is human?”
4/24/2010
Role of epidemiology in public health
Because of incorrect drawings, engineers installed critical sensors upside down in the Genesis sample return capsule, causing it to crash into the Utah desert.
(Science, 10/22/2004:306:587)
Mars Climate Orbiter (metric vs. English units) and the Mars Polar Lander (software error)
(Science, 10/22/2004:306:587)
Primary cause of offshore oil rig accidents is most often human error (US Minerals Management Service)
The Model aims, over time, to achieve higher total return than the market with less volatility by not always being 100% invested in stocks. Of course, this does not guarantee the Model will anticipate the correct time to move into or out of stocks, bonds or cash in the future.
As Barneby points out, “there have been 15 previous times when the Model has returned to a 100% investment in equities. Over the ensuing 12-month periods, the S&P 500 has had an average return of 28%."
"There has never been a negative return over the 12 months following the Model's return to a full equity allocation," says Barneby. . . . “we are bullish at the current time.”
“Under (almost) any profit outlook, stocks look cheap.” UBS PaineWebber newsletter, Oct 7, 2001.
Optimism?
3/25/2008
Role of epidemiology in public health
“There is a lot of money to pay for this that doesn't have to be US taxpayer money, and it starts with the assets of the Iraqi people. We are talking about a country that can really finance its own reconstruction and relatively soon.”
Paul Wolfowitz, Deputy Secretary of Defense, testifying before the defense subcommittee of the House Appropriations Committee, March 27, 2003
This one and many more at: www.thenation.com/doc/20080331/navasky_cerf
Human tendencies
12/2/2001
Role of epidemiology in public health
West Coast men who have sex with men have resumed high HIV risk behavior
U.S.: Billions spent on entertainment, need to promote consumption to keep economy going
Can we maintain affluence without overconsumption?
Human tendencies
Role of epidemiology in public health
“The strong scientific consensus on the causes and risks of climate change stands in stark contrast to widespread confusion and complacency among the public (1,2).”
[John Sterman. Science 24 Oct 2008;322:]
Human tendencies
Role of epidemiology in public health
“Nearly two-thirds of the participants asserted that atmospheric GHGs can stabilize even though emissions continuously exceed removal--analogous to arguing a bathtub continuously filled faster than it drains will never overflow. Most believe that stopping the growth of emissions stops the growth of GHG concentrations. The erroneous belief that stabilizing emissions would quickly stabilize the climate supports wait-and-see policies but violates basic laws of physics.” [John Sterman. Science 24 Oct 2008;322:]
Human tendencies
Role of epidemiology in public health
"Training in science does not prevent these errors.“
“When "common sense" and science conflict, people often reject the science (3).”
[John Sterman. Science 24 Oct 2008;322:]
Are academics a breed apart?
Role of epidemiology in public health
“The obstacles to entering the academic profession are now so well known that the students who brave them are already self-sorted before they apply to graduate school. . . . The result is a narrowing of the intellectual range and diversity of those entering the field, and a widening of the philosophical and attitudinal gap that separates academic from non-academic intellectuals. . . . There is less ferment from the bottom than is healthy in a field of intellectual inquiry. Liberalism needs conservatism, and orthodoxy needs heterodoxy, if only in order to keep on its toes.”
(Louis Menand, The Ph.D. Problem, Harvard Magazine, Nov-Dec 2009: p31)
Children can predict election results
4/19/2009
Role of epidemiology in public health
Evaluations from facial appearance should be modified based on information.
University students rating candidates’ competence from photos had 72% probability of choosing the one elected.
Children choosing a captain for an imaginary boat trip had 71% probability.
(Science 27 Feb 2009;323:1183)
Red and blue thinking
4/19/2009
Role of epidemiology in public health
Red (versus blue) induces an avoidance (versus approach) motivation & enhances performance on a detail-oriented task
Blue enhances performance on creative task
Effects occur outside of consciousness
Activation of alternative motivations mediates
[Ravi Mehta and Rui (Juliet) Zhu, Science 27 Feb 2009;323:1226-1229]
Attitudes and international terrorism
12/8/2009
Role of epidemiology in public health
Alan B. Krueger and Jitka Malecková. Attitudes and Action: Public Opinion and the Occurrence of International Terrorism. Science 18 Sept 2009: 1534-1536.
Fig. 1 Attitudes and international terrorist attacks. Shown are the numbers of attacks per pair of countries by public disapproval of foreign leaders. Calculations were made by the authors from Gallup World Poll data and NCTC WITS data.
In 143 pairs of countries, controlling for other relevant variables, we “found a greater incidence of international terrorism when people of one country disapprove of the leadership of another country.”
Choice architecture
12/8/2009
Role of epidemiology in public health
Choices/preferences influenced by many subtle details of how a question is asked
Default choice tends to get selected more often
(Eric J. Johnson. Tilt the table toward good choices. Science 11 July 2008;321:203. Review of Nudge: improving decisions about health, wealth, and happiness. Richard H. Thaler and Cass R. Sunstein. Yale, 2008)
Comparison of suicide victims with and without a history of child abuse found decreased levels of and differences in glucocorticoid receptor mRNA in brain.
Epigenetic regulation of hippocampal glucocorticoid receptor expression.
(McGowan PO et al., Epigenetic Regulation Brain Child Abuse, Nature Neuroscience, March 2009;12(3):241-3)
Under the influence of hormones
4/19/2009
Role of epidemiology in public health
“… hormones alter emotional states (such as fear), bias attention (for example, toward sexual stimuli), or change the pleasantness or aversiveness of stimuli (such as infant odors) to alter behavioral probabilities in ways that depend on prior experience.” p1146
“The basic endocrine mechanisms and brain structures have been remarkably conserved in the course of evolution . . .”
(Elizabeth Adkins-Regan. Under the influence of hormones. Science 29 May 2009;324:1145. Review of Peter T. Ellison and Peter B. Gray, eds. Endocrinology of social relationships. Harvard, 2009)
Breast milk helps babies sleep – or not
4/24/2010
Role of epidemiology in public health
Breast milk contains nucleotides that promote sleep, especially at dusk and overnight.
Babies fed morning breast milk in the evening might not sleep as well as babies given breast milk at the time it is produced.
(Sanchez C, et al. The possible role of human milk nucleotides as sleep inducers. Nutritional Neuroscience 12:2-8 (Feb 2010) in American Scientist Jan-Feb 2010, p27.
Intervention reduces risk behavior in youth at genetic risk
12/5/2009
Role of epidemiology in public health
The Strong African American Families (SAAF) program attenuated the link between 5-HTTLPR status and risk behavior initiation.
Brody et al. Prevention Effects Moderate the Association of 5-HTTLPR and Youth Risk Behavior Initiation: Gene × Environment Hypotheses Tested via a Randomized Prevention Design. Child Development 2009;80(3):645-661
Score on risk behavior initiation index
SAAF youth with genetic risk
Consumer consciousness
12/7/2009
Role of epidemiology in public health
“Can America afford the ‘vanity tax’ of glitter and glitz? (Steve Salerno, author of SHAM: How the self-help movement made America helpless, in The Los Angeles Times, reprinted in The Herald-Sun, 12/1/2009, A7)
“We are a nation that specializes in producing and consuming items that have little purpose except to facilitate extravagance . . . Although bemoaning taxes . . . The one tax nobody really considers is this ‘vanity tax’”
But who gets to decide? The need for consciousness.
Consumer consciousness – green economics
4/24/2010
Role of epidemiology in public health
Consumer consciousness has increased sales and marketing of “green” products
Sales of “green” products up 15% since 2006 (Dan Sewell, AP, Herald-Sun 4/24/2010; source: Mintel International)
GreenBiz index finds incremental change, but in many cases too incremental for meaningful progress in reducing energy, water, materials, carbon and toxic intensity of the U.S. economy
Consumer consciousness – workers rights
4/26/2010
Role of epidemiology in public health
Workers Rights Consortium
Nike now employs 50 people assigned to monitor compliance
United Students Against Sweatshops vs. Mexmode
1993 Wal-Mart sweatshops in Bangladesh
When banned child labor, children ended up in the streets
Consciousness of leaders
4/26/2010
Role of epidemiology in public health
Corporate leaders
Statesmen (“Statespeople”)
Philanthropists
Social entrepreneurs
Collective intelligence
11/1/2010
Role of epidemiology in public health
Collective intelligence (c): group’s general ability to perform a wide variety of tasks.
c depends on composition of group (e.g., average member intelligence) and on the way group members interact.
c correlated with average social sensitivity of group members and turn-taking.
Anita William Woolley et al., Evidence for a Collective Intelligence Factor in the Performance of Human Groups. Science 29 October 2010;330:p686-688) www.sciencemag.org/cgi/content/short/330/6004/686
Fig. 1. Standardized regression coefficients for collective intelligence (c) and average individual member intelligence when both are regressed together on criterion task performance in Studies 1 and 2 (controlling for group size in Study 2). Coefficient for maximum member intelligence is also shown for comparison, calculated in a separate regression because it is too highly correlated with individual member intelligence to incorporate both in a single analysis (r = 0.73 and 0.62 in Studies 1 and 2, respectively). Error bars, mean ± SE.
Evolution is still here
12/8/2009
Role of epidemiology in public health
Everything that exists has either endured from the past or arisen anew. Only what adapts and succeeds can remain.
Adaptation means trying something different – new or since abandoned.
Humans are a product of evolution and remain subject to its forces.
Having lasted a “long time” is not a guarantee, and a “long time” is quite short.
Goals for public health
12/8/2009
Role of epidemiology in public health
In the light of evolution, what should be the goals for public health? Our individual professional goals? Our personal goals?
Survival as a species?
A comfortable ride?
Survival of other species?
Truth, justice, beauty, wealth,. . .?
Aphorism from John Bogle: “whoever dies with the most toys wins” (Enough, 2009, p185)
Is this epidemiology?
8/2/2002
Role of epidemiology in public health
Epidemiologists lack appropriate training and methodology
Epidemiology is “occurrence research”; disease and exposure occur in individuals.
Historically, epidemiologists have not shied away for lack of adequate methods
Why epidemiology?
8/5/2002
Role of epidemiology in public health
“There is a need for innovative, transdisciplinary approaches. Epidemiology is already transdisciplinary. Epidemiology is well placed to take leadership."
(John M. Last, accepting the Abraham Lilienfeld Award at the American College of Epidemiology Annual Meeting, Boston, September 22, 1997).
The role of epidemiology
12/2/2001
Role of epidemiology in public health
“Epidemiology is fundamentally engaged in the broader quest for social justice and equality.”
John Cassel, a founder of the UNC Department of Epidemiology and a revered figure among epidemiologists
Thank you so much for taking EPID600. You have been a wonderful class.
May you all have fulfilling careers and lives.
Please visit me at www.epidemiolog.net
American Airlines for exporting to Mexico the advertisement for its new leather first class seats (“Fly In Leather”), rendered as “Vuela en cuero” (“Fly Naked”).
American Airlines for exporting to Mexico the advertisement for its new leather first class seats (“Fly In Leather”), rendered as “Vuela en cuero” (“Fly Naked”).
Advertising in the global economy: speaking literally
