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Epidemiology

Epidemiology. Introduction Types of Studies. Definition of Epidemiology. Recall Epidemiology literally means “the study of what is upon the people.” It puts the individual's condition in a population context and is the path to disease prevention. Key words. Study Distribution

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Epidemiology

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  1. Epidemiology Introduction Types of Studies

  2. Definition of Epidemiology • Recall • Epidemiology literally means “the study of what is upon the people.” It puts the individual's condition in a population context and is the path to disease prevention.

  3. Key words Study Distribution Determinants Health-related states Populations Control

  4. Epidemiology key words: • Study • Epidemiology is the basic science of public health. • It's a highly quantitative discipline based on principles of statistics and research methodologies.

  5. Epidemiology key words: • Distribution • Epidemiologists study the distribution of frequencies and patterns of health events within groups in a population. • They use descriptive epidemiology, which characterizes health events in terms of time, place, and person. – Questions: who, what, where, when

  6. Epidemiology key words: • Determinants • Epidemiologists also attempt to search for causes or factors that are associated with increased risk or probability of disease. • This type of epidemiology is referred to as analytical epidemiology • Questions: how and why

  7. Virtual Field Trip http://www.whatispublichealth.org/what/index.html

  8. Epidemiologic Process WHO was affected? WHERE were they affected? WHEN were they affected? HOW and WHY?

  9. Why are the who, when, and where questions useful in determining the causes of disease? The epidemiologist attempts to determine who is prone to a particular disease; where risk of the disease is highest; when the disease is most likely to occur and its trends over time; what exposure its victims have in common; how much the risk is increased through exposure; and how many cases of the disease could be avoided by eliminating the exposure.

  10. Why are the who, when, and where questions useful in determining the causes of disease? The study of the distribution of diseases in populations and of factors that influence the occurrence of disease. Epidemiology examines epidemic (excess) and endemic (always present) diseases; it is based on the observation that most diseases do not occur randomly, but are related to environmental and personal characteristics that vary by place, time, and subgroup of the populationRead more:

  11. WHO was affected?Person Age Sex Race/Ethnicity Socio-Economic Status Behaviors

  12. WHERE were they affected?Place • Geographic Distribution • Clustering, uniform, scattered • Home • Work • School • Hospital room

  13. Geographic Distribution of LaCrosse

  14. Clustered

  15. Scattered

  16. WHEN were they affected?Time • Onset of symptoms • Incubation Period • Infectious Period • Seasonality • Epidemic • Interval • Long-term trends • Shorter for environmental exposure

  17. Health-related states Health-related states Epidemiology is applied to the whole spectrum of healthrelated events: – chronic diseases, – environmental problems, – behavioral problems, – injuries, – infectious diseases.

  18. Epidemiology key words: • Populations • One of the most important distinguishing characteristics of epidemiology is that it deals with groups of people rather than with individual patients.

  19. Epidemiology key words: Control Epidemiology can be used simply as an analytical tool for studying diseases and their determinants. Epidemiological data also steers public health decision making and aids in developing and evaluating interventions to control and prevent health problems.

  20. How is Epidemiology Used? • Population/community health assessment • Personal decision-making • Complete clinical picture • Evaluate interventions • Search for cause • Exposure and relationship to disease • Outbreak investigation

  21. Aim of Epidemiological studies To determine distribution of disease To examine determinants of a disease To judge whether a given exposure causes or prevents disease.

  22. Establishing a cause-and-effectrelationship: Five criteria Strength of association—the relationship must be clear. Consistency—observation of the association must be repeatable in different populations at different times. Temporality—the cause must precede the effect. Plausibility—the explanation must make sense biologically. Biological gradient—there must be a dose-response relationship

  23. Explain the interaction between incidence, prevalence

  24. Incidence • Number of new events occurring in a defined population during specific period of time • Incidence = New cases/ Pop at risk/time • Used to measure current disease activity • Allows comparison between areas with different populations.

  25. Contrasts with Prevalence • Prevalence = • (new cases + existing cases) / Total Population • Can be expressed as percent • Can give a picture of disease burden within a population

  26. What has epidemiology contributed to people’s understanding of: • Heart disease? • Decline in CVD Death Rates • Advances in Prevention • Lung cancer? • Contemporary epidemiologic research on lung cancer now focuses on a new set of issues,

  27. Heart Disease established the major risk factors of high blood cholesterol, high blood pressure, and smoking and dietary factors (particularly dietary cholesterol, fat, and sodium). The risk factor concept--that particular biologic, lifestyle, and social conditions were associated with increased risk for disease

  28. Lung Cancer Smoking changes in tobacco products Diet Questions have also been raised about possible differences in susceptibility to lung cancer by sex and race.

  29. Tuskegee Syphilis Study A forty year study of syphilis by the US Government that didn't reveal the disease to those infected. In 1932 the American Government promised 400 men - all residents of Macon County, Alabama, all poor, all African American - free treatment for Bad Blood, a euphemism for syphilis which was epidemic in the county

  30. . Treatment for syphilis was never given to the men and was in fact withheld. The men became unwitting subjects for a government sanctioned medical investigation, The Tuskegee Study of Untreated Syphilis in the Negro Male. The Tuskegee Study, which lasted for 4 decades, until 1972, had nothing to do with treatment.

  31. No new drugs were tested; neither was any effort made to establish the efficacy of old forms of treatment. It was a non therapeutic experiment, aimed at compiling data on the effects of the spontaneous evolution of syphilis on black males. What has become clear since the story was broken by Jean Heller in 1972 was that the Public Health Service (PHS) was interested in using Macon County and its black inhabitants as a laboratory for studying the long term effects of untreated syphilis, not in treating this deadly disease.

  32. Why was it unethical? The subjects of the study bear witness to the premise that the burden of medical experimentation has historically been borne by those least able to protect themselves. The Tuskegee Study symbolizes the medical misconduct and blatant disregard for human rights that takes place in the name of science. The studies principal investigators were not mad scientists, they were government physicians, respected men of science, who published reports on the study in the leading medical journals

  33. Using Human Beings as Laboratory Animals What has become clear since the story was broken by Jean Heller in 1972 was that the Public Health Service (PHS) was interested in using Macon County and its black inhabitants as a laboratory for studying the long term effects of untreated syphilis, not in treating this deadly disease.

  34. Daily Ethical Encounters Participants who are vulnerable from: Abuse from Doctor-patient relationship “whatever you say, doc” syndrome Indigent patients

  35. Daily Ethical Encounters • Financial Pressures and Conflict of Interest • Financial • Income for Department • Bonuses • Structure of grant (pay per visit or end-loaded) • Pay for screening • Pay for quality of data, rather than # of patients • Avoid disincentives for dropping a patient (e.g., due to adverse reaction • Pressure re prestiege, publication, tenure

  36. Tuskegee Syphilis Study What influence has it had on the conduct of clinical trials? , and prognosis.

  37. Milestones in Ethical Development 1932–72 Tuskegee experiment on syphilis 1939–45 Nazi experiments 1944–74 Human radiation experiments by U.S. government 1946 Nuremberg Trial of doctors responsible for the Nazi experiments 1947 Nuremberg Code outlining ethical principles required for research 1948 United Nations adoption of Universal Declaration of Human Rights

  38. Milestones in Ethical Development • 1953 NIH policy, the first U.S. federal policy introducing independent reviewers to • examine research, forerunners of the IRBs • 1963–66 Willowbrook Study, involving hepatitis research on mentally retarded children, • raising issues access to care, consent, and coercion • 1964 Declaration of Helsinki international agreement on recommendations for the ethical • conduct of medical research • 1972 Public exposure of Tuskegee syphilis study • 1974 First federal protections for human research participants

  39. Milestones in Ethical Development • 1979 Belmont Report promoting three principles for research • 1980 Food and Drug Administration regulations (CFR 21 (50) • 1982 Council for the International Organization of Medical Sciences (CIOMS) publication of the International Ethics Guidelines for Biomedical Research Involving Human Subjects • 1985 U.S. Public Health Service Task Force on Women’s Health issues report encouraging inclusion of women in research • 1990 Society for Women’s Health Research

  40. Milestones in Ethical Development • 1993 Public exposure of U.S. human radiation experiments • 1993 NIH Revitalization Act mandating inclusion of women and minorities in research • 1993 NIH Office of Research on Women’s Health

  41. Milestones in Ethical Development • 1997 Food and Drug Modernization Act (FDAMA) requiring the FDA, NIH, and pharmaceutical industry to develop guidance on the inclusion of women and minorities in trials • 1998 Pediatric Rule passed by Congress, stipulating that new drugs for children must include specific pediatric labeling information • 2000 Further publicized ethical abuses prompting establishment of the Office of Human Research Protections (OHRP)

  42. Belmont Report • National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research • 3 basic principles for research

  43. Belmont Report Respect for persons, or an individual’s autonomy- elements of the informed consent requiring that: • Information necessary to make a decision must be presented that is,the risks and benefits, if any, of participation. • The information must be presented at a level that can be understood by the patient or study subject. • Participation must be voluntary.

  44. Belmont Report Benificience, or benefit to the participant Who decides whether there is benefit?

  45. Belmont-Beneficence Loss of substantial benefits that might be gained from research Paternalism Pregnancy Life-threatening illness (AIDS/Cancer)

  46. Belmont-Justice • Risks and benefits should be equitably distributed among different populations • “Do onto others…” rather than taking advantage of Vulnerable populations

  47. Vulnerable Populations • Military • 1944-1979: radiation, chemical, • Mustard gas, lewisite • Venezuelan equine encephalitis virus and the nerve gas agent VX • Operation Whitecoat (tularemia, anthrax, Q fever) • 1994 Congressional review: the Department of Defense “has demonstrated a pattern of misrepresenting the danger of various military exposures that continues today”

  48. Vulnerable Populations • Unsuspecting civilians • Radiation experiments: atomic weapons testing in • South Pacific • Oak Ridge • Los Alamos • Hanford, Washington • Plutoniaum injections (ACHRE report)

  49. Vulnerable Populations What studies are being done now under the guise of counter terrorism, hidden from the public by the “Patriot Act?”

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