IH5426_Gutschmidt_J_EPI Final Exam, Concept Map

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Images from Bing Search, Creative Commons License, Free to modify, share, and use commercially. Text, Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Epidemiology: "The study of how disease is distributed in populations and the factors that influence or determine this distribution" (Gordis, 2014) History of Epidemiology adapted from "Table 2-2, Selected Historical Contributions of Men and Women to Epidemiology: From "Essential Epidemiology" by William A. Olenckno, copyright 2002, Waveland Press, page 16." Photos obtained using "Bing Search Engine. All photos are covered under the Creative Commons license. Free to modify, share, and use commercially. John Snow (1813-1858). Used in- person interviews, maps, and keen observational skills to tie a London cholera outbreak to a water pump located on Broad Street. Hippocrates (460-377 BCE) was the fist person known to offer rational explanations for disease that were not supernatural in nature. He considered environmental and other factors in his analysis. Ignas Semmelweis (1818-1865) used epidemiological theory to identify the cause of childbirth fever Girolamo Fracastoro (1478 - 1553) was the first person known to offer a formal theory of disease that used the contagion theory of disease transmission. Edward Jenner (1749-1823): Invented a vaccine against small pox through observational and experimental skills. William Farr (1807-1883), used statistics to describe epidemiology problems John Gaunt (1620-1674), described disease occurrence systematically using Bills of Mortality. Peter Ludwig Panum (1820-1885) showed that people could acquire immunity to measels through infection. Thomas Sydenham (1624-1689), insisted that the natural history of disease be guided by observation instead of by theory alone. Robert Koch (1843-1910), credited, along with Pasture for the Germ Theory of Disease. Established criteria for bacterial disease causation. Anna Wessels Williams (1863-1954), made a antitoxin against diphtheria by isolating the bacterium. Joseph Goldberger (1874-1929), showed that pellagra was caused by a diet deficient in protein through observation and experiment. James Lind (1716- 1794), showed how to treat and prevent scurvy using an experimental approach. Louis Pasture (1822-1895), demonstrated the veracity of the germ theory of disease and showed that vaccines could be used to control them. Florence Nightingale (1820-1910), Improved hygiene at military hospitals using mortality statistics as a justification. Image Bing.com search, Creative Commons License,Free to modify, share, and use commercially Study Types: Adapted from Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Scientific Studies Randomized Trials: A trial where, from the total population, a defined population is identified and a subset of that defined population is studied (Gordis, 2014). Validity Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version Internal: Valid only within study population. # External: Validity outside of study population ## Design Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version Methods Random Number Table Computer Selection Possible Effects Stratification by age, for instance, may increase validity of results, or by sex? Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version Masking (blinding): Hiding from subjects and researchers who is in the treatment versus control group to mitigate the placebo effect. (Gordis, 2014) Crossover: Planned versus unplanned. When patients in the treatment group cross over to the non-treatment group and vice versa. (Gordis, 2014) Non-Compliance: Effects of patients not complying with assigned treatments. Testing: Do Treatments Differ? Type I Error # Type II Error # Image, copyright, Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Number of patients needed in each group to establish Alpha and Beta at different confidence intervals. (The symbol "/" for this purpose stands for the mathematical operator for division.) One sided Test Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Two sided test Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. NNT: Number needed to treat [NNT=1/(ratein untreated)-(rate in treated)] How many patients needed to treat to prevent one adverse outcome. (Gordis, 2014) Efficacy: (rate in those who received a placebo)-(rate in those who received a vaccine)/(Rate in those who received the placebo) Tells of the extent reduction in disease by use off treatment. (Gordis, 2014) Alpha = probability of making a Type I error # Beta = probability of making a type II error # Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version Clinical Trials: Used in the US to test new drugs (Gordis, 2014) Phase II: Clinical investigation of 100-300 patients to determine efficacy of new drug or treatment (Gordis, 2014) Phase III: Large scale randomized controlled trials meant to assess effectiveness relative to safety (Gordis, 2014). Phase I: Clinical, pharmalogical studies of 20-80 patients to assess safety of new drug or treatment (Gordis, 2014) Phase IV: Post marketing surveillance is used to determine if drug or treatment has any long-term negative effects after final approval in phase III. Phase IV is not a randomized study (Gordis, 2014). Studies without comparisons: Case Study or Case Series for example. (Gordis, 2014) Descriptive Studies:Time, Place, and Person Adapted from Centers for Disease Control and Prevention, Principles of Epidemiology in Public Heath Practice, Third Edition An to Applied Epidemiology and Bio statistics, Lesson1: Introduction to Epidemiology, Section 6: Descriptive Epidemiology, November 2016 Time Secular Trends: Annual cases graphed over a period of years (CDC, 2016). Seasonality: Graphed over weeks or months, or a year or more to show seasonal characteristics (CDC, 2016) Two dimensional graph showing number or rate versus time in weeks, days, or months (CDC, 2016) EPI Curve Continuous exposure example. Image, Bing.com search, Creative Commons License, Free to modify, share, and use commercially. Singe exposure, common vehicle outbreak example Epi Curve: Image, Bing.com search, Creative Commons License, Free to modify, share, and use commercially. Place Contain the 5 W's: Who, what, where, when, and why/how (CDC, 2016) Person: Age, Race, Ethnicity, Socio-Econonmic Status. Study Types Case-Control Study: Compares diseased to non- diseased. Easier to administer, less expensive, better for comparing rare diseases. (Gordis, 2014) Selection bias: If subjects are selected from a single hospital, for instance, risk factors observed may be specific to that institution. (Gordis, 2014) Bias: Incident versus prevalent cases usage: prevalent cases are more abundant but risk factors associated with the study of prevalent cases may be more associated with living with the disease than from having caused it. (Gordis, 2014) Information bias # Problems with recall. Limitation in recall: Can't remember answer to question during interview. Recall bias: Affected subjects recalling a perceived triggering event that non-affected subjects forgot about but did happen. Matching Group: Controlling for proportionality of characteristics between cases and controls. (Gordis, 2014) Individual: Pairing case subjects with similar control subjects each of whom has similar characteristics with only the disease status differentiating them. Matches case/control pairs. (Gordis, 2014) Choosing to use multiple controls? Same? Increases statistical power of the study. (Gordis, 2014) # Different?: Choose to use over concern that pool of exposed persons (i.e. a hospital setting) do not represent the population and for that reason may choose to use more controls that differ in terms of traits. (Gordis, 2014) Use when an association is suspected and more evidence is needed to suggest an association between a risk factor and an outcome. (Gordis, 2014) Ecologic: Looks at and compares data for populations and not individuals. Ecologic fallacy: Results for groups cannot necessarily be transferable to individuals in groups. Cannot draw conclusions about individuals. (Gordis, 2014) Cohort: Compares exposed population to non-exposed. Either prospective or retrospective. Prospective studies follow participants for years and can be very expensive especially for comparing rare conditions.(Gordis, 2014 Selection bias: Bias of non-participation or non- response. (Gordis, 2014) Information bias:bias based on the quality of the information obtained and the bias on the part of the person who assigns diseased or non status based on known exposure. (Gordis, 2014) Intervention: Compares the effects of an intervention on subjects, for instance, the effects of smoking cesassion intervention on pregnant women who smoke. (Gordis, 2014) Cross-Sectional Place and time interview. Captures a snapshot. Scientific Studies : Drug Trials, for example. (Gordis, 2014) # Agents of human disease/conditions: Adapted from Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. # Paracites/Prototzoal infections Malaria Rocky Mountain Spotted Fever Giardia Heart Attack/Stroke Mental Illness Schitzophrenia Post-traumatic Stress Disorder Bipolar Disorder Depression Accidents/Injuries Broken bones Sprains and strains Lasserations Cancer/Tumor Example: Smoking and lung cancer Colon Cancer Uterine Cancer Prostate Cancer Bacterial Infections Typhoid: Typhoid Mary Image form Bing Search, Creative Commons License. Free to modify, share, and use commercially. E. Coli from contaiminated food. Legionella Siphalis: Treponema pallidum Graham Negative bacillus associated with virulance Viral Infections Marburg Influenza Ebola Hepatitus Addiction/Substance Abuse Heroine Nicotine Alcohol Cocaine Genetic and Environmental Factors Genetic Associated with Leukemia, Down's Syndrome, and Alzheimer's Disease Human genome project. Concordance vs. discordance measures in twin studies. Environmental Likely the cause when observed changes in populations are over short periods of time like decades. Occurance Measurments: (Symbol "/" used in the context of an example equation is intended to denote mathematical division) Adapted form Riccetti-MastersonK, Lopes B, Yeatts KB, Summary of Epidemiologic Measures. UNC Giddings School of Global Public Health 2/14 and Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Image, intended as a reference for equations listed in this section and taken from from Bing Search, Creative Commons License. Free to modify, share, and use commercially. Odds: Ratio of cases and non-cases (Ricchetti et al, 2014) Exposed Odds (EO) PO: (a+c)/(b+d) or diseased divided by non-diseased; EO: (a+b)/(c+d) or exposed divided by non-exposed Prevalent Odds (PO) Denominator does not typically include diseased subjects. Only in EO are diseased subjects included in the denominator. AKA: Incidence Odds (Ricchetti et al, 2014). Associated with: Cast-Control Study; Cross Sectional Study (PO); Cohort Study; Experimental Study; and Ecologic Study (group level), Associated with: Cohort Studies; Experimental Studies; and Ecologic Studies (group-level), (Ricchetti et al, 2014). Rate: Proportion of population who develop condition per unit time at risk (Ricchetti et al, 2014) # (a+c)/(total person-time at risk). Numerator is incident cases (Ricchetti et al, 2014). Denominator does not include diseased subjects. AKA: Incidence Rate or Incidence Density (Ricchetti et al, 2014). # Associated with: Cohort Studies; Experimental Studies; and Ecologic Studies (group-level), (Ricchetti et al, 2014). Risk: Proportion of population who, over a specified amount of follow-up time develop the heath condition (Ricchetti et al, 2014). AKA: Cumulative Incidence (Ricchetti et al, 2014). (a+c)/(a+b+c+d). Numerator is incident cases. Denominator is total at-risk baseline study population (Ricchetti et al, 2014). Denominator does not include diseased subjects (Ricchetti et al, 2014). Associated with: Cohort Studies; Experimental Studies; and Ecologic Studies (group-level), (Ricchetti et al, 2014). Prevalence: At a point in time the proportion of a population living with a health condition (or with a history of the same condition), (Ricchetti et al, 2014). Period Pravalence: How many people have a given disease at any point during a time period (Gordis, 2014) Point Prevalence: The prevalence of a disease at a particular point and time (Gordis, 2014) Denominator includes diseased subjects: Yes! (a+c)/(a+b+c+d) AKA: Prevalence Proportion (Ricchetti et al, 2014). Associated with: Cross-sectional Study; Cohort Study (baseline/non-outcome variables); Ecologic Study (group-level), Associated with: Cohort Studies; Experimental Studies; and Ecologic Studies (group- level), (Ricchetti et al, 2014). Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Prevalence = Incidence x duration. (Gordis, 2014) Person Time:When each individual in the denominator is not followed for the full length of the study person time is sometimes used as a surrogate. Person time can be expressed as person years, days, months, etc. (Gordis, 2014) # Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Terns Vector: According ot Merriam Webster "an organism (as an insect) that transmits a pathogen from one organism or source to another <fleas are vectors of plague>" [ Merriam Webster # Agent: According to CDC "The agent is the cause of the disease. When studying the epidemiology of most infectious diseases, the agent is a microbe an organism too small to be seen with the naked eye. Disease causing microbes are bacteria, virus, fungi, and protozoa (a type of parasite). They are what most people call “germs.”" CDC # Endemic: According to Gordis endemic refers to the presence of a disease within a geographic area that is habitual. Epidemic: According to Gordis an epidemic the presence of disease in a community or region clearly in excess of normal expectancy. According to a current example of an epidemic in the US is the Heroine epidemic. CDC Pandemic: According to Gordis a pandemic is an a worldwide epidemic. 1968 Pandemic of H3N2, according to CDC 1957 pandemic of H2N2, according to CDC 2009 pandemic of H1N1 pandemic, according to CDC 1918 pandemic of H1N1, according to CDC Immunity: According to Gordis, refers to people in a population that are not susceptible for acquiring a particular disease. Herd immunity, according to Gordis is the resistance toward acquiring a particular disease by a group of people, due to immunity, by a large proportion of that group. Incubation Period: "the interval from the receipt of infection to the time of onset of clinical illness." (Gordis, 2014) Resevoir: According to CDC, "A reservoir of an infectious agent, such as a virus, is any animal, person, plant, soil, substance—or combination of any of these — in which the infectious agent normally lives. In addition, the infectious agent must primarily depend on the reservoir for its survival, and must be able to multiply there. It is from the reservoir that the infectious substance is transmitted to a human or other susceptible host." . CDC Image from Bing.com, Creative Commons License. Host: According to Merriam Webster "a living animal or plant on or in which a parasite lives." Merriam Webster # Environment: According to Merriam Webster "the complex of physical, chemical, and biotic factors (as climate, soil, and living things) that act upon an organism or an ecological community and ultimately determine its form and survival" Merriam Webster # Public Health: According to , "Public health is the science of protecting and improving the health of families and communities through promotion of healthy lifestyles, research for disease and injury prevention and detection and control of infectious diseases." CDC Etiology: Cause of disease. (Gordis, 2014) Passive and active surveillance: Passive surveillance uses available data, active surveillance uses program staff to collect data. (Gordis, 2014) Ratio, according to :"The quantitative relation between two amounts showing the number of times one value contains or is contained within the other: ‘the ratio of men's jobs to women's is 8 to 1"’ Oxford Dictionary on-line Proportion according to : "The relationship of one thing to another in terms of quantity, size, or number; ratio: ‘the proportion of examination to coursework’ ‘the bleach can be diluted with water in the proportion one part bleach to ten parts water’" Oxford Dictionary on-line Rate according to : "A measure, quantity, or frequency, typically one measured against another quantity or measure: ‘the island has the lowest crime rate in the world’ ‘buying up sites at a rate of one a month’" Oxford Dictionary on-line Screening Tests: Adapted from Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version # Specificity ## Predictive Value Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version Positive Predictive Value Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version Dichotomous results Positive versus negative result Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version Tests for pregnancy, HIV status, cancer screening Continuous variables Establish cut-off level Bllood pressure screening, blood glucose level screening Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version Sensitivity # Prevalence Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version # Validity versus Reliability Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version Effectivemess? # Natural history of disease? Primary, Secondary, or Tertiary Intervention? Outcome measures Improvement to quality of life in screened individuals Prevention of or reduction in recurrences. Rection in complications. Increase in percent of cases detected earlier Reduction in case-fatality Reduction in mortality Effects of lead time bias on five-year survival? May make screening appear to extend life but only actually reduces years of perceived heath with no change in outcome. Effects of randomized screening trials versus non- randomized: Randomized is usually better but may be difficult to carry out or precluded for ethical reasons. Occurrence of Disease adapted from Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Where: Geographic distribution is not random, is localized by time and place in a region - clustering. (Gordis, 2014) When: Certain diseases occur periodically: Annually, seasonally, etc. (Gordis, 2014) Who: Age, sex, and race of human host? (Gordis, 2014) Disease Transmission from Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Direct.Person to person. (Gordis, 2014 Indirect: Through common vehicle, such as contaminated water or air. (Gordis, 2014) Type of organism: Characteristics of organism/rate of growth (Gordis, 2014). Mode of transmission/portal of entry: skin, respiratory tract, urogenital tract, alimentary tract, arthropod, conjunctiva, etc. (Gordis, 2014) Individual characteristics: Scratches, injuries, susceptibility (immunity), (Gordis, 2014) Clinical versus sub-clinical disease Bing.com search, Creative Commons License. Clinical disease = signs and symptoms. (Gordis, 2014) Noncliniccal disease = preclinical or subclinical disease. Either not yet clinically apparent and either destined or not destined to progress to clinical disease. (Gordis, 2014). Peristent disease is a lingering condition that lasts for years or life. An example is polio myelitis. (Gordis, 2014) Carrier status: Person with disease who does not develop symptoms. (Gordis, 2014) # Measures of Morbidity and Mortality adapted from Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. For the purposes of this discussion the symbol "/" represents the mathematical operation of division. Morbidity: Incidence Rate per 1,000 = (No. of new cases of a disease occurring in a population during a period of time/No. of persons who are at risk of developing the disease during that period of time) x 1,000 (Gordis, 2014) Morbidity - a transition from non-disease to disease. (Gordis, 2014) Mortality Rate: Annual mortality rate for all causes (per 1,000 population) = (Total no. of deaths from all causes in a year/No. of persons in the population at midyear) x 1,000. (Gordis, 2014) Case Fatality Percent: (No. of individuals dying during a specific period of time after disease onset/No. of individuals with the specified disease) x 100. (Gordis, 2014) # Mortality data may be inaccurate due to how deaths are coded on death certificates. (Gordis, 2014) Mortality rates can be adjusted to a standard population (today the year 2000 census is used in the US). Applying standardization to mortality rates eliminates population effects on differences between rates. (Gordis, 2014) Indirect age adjustments are used when ages of subject population are unknown. Here a standard age distribution in the standard population is used as an surrogate of the population of interest. (Gordis, 2014) Rates indicate the speed of disease progression in a population. Proportions tell us the fraction of the people who are impacted. (Gordis, 2014) YPLL: Years of potential life lost: Age at death subtracted form perdetermined age at death or standard age. (Gordis, 2014) The cohort effect: A potential error that results form cross-sectional reading of data that relates to different cohorts that age together over time. When comparing mortality data could be effected by: 1) Changes in survivor-ship without changes in incidence; 2) Changes in incidence; 3) Changes in the age composition of the populations; 4) A combination of factors. (Gordis, 2014) Quality of life: impact of disease on individuals beyond mortality. (Gordis, 2014) Future burden of disease: Measured in DALY (disability adjusted life years) or years of life lost to premature death and years of life lived with disability. (Gordis, 2014) Outbreak adapted from Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. # Cross Tabulation .Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Attack rate: The number of people at risk, in whom a certain illness develops divided by the total number of people at risk. (Gordis, 2014) Food specific attack rate is based on the number of people who at the food and became ill divided by the total number of people who at the food. (Gordis, 2014) Natural History of Disease, Adapted from Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Outcome Cure Death Control Signs and Symptoms Clinical Phase # Seeks Medical Treatment Treatment Preclinical Phase ## Biological Onset Pathological Evidence Expression of outcomes in terms of Case-Fatality Person Years Life Table # Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Use of life tables assumes no secular (temporal) changes in treatment over calendar time and lack of knowledge of outcomes due to loss to follow-up (outcomes do not necessarily need to be mortality). (Gordis, 2014) Kaplan-Meirer Method Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Median Survival Time: Average of survival times. Relative Survival: Ratio of observed survival to expected survival # Lead time bias: Bias that results from an earlier diagnosis that does not affect actual survival and may rob someone of years of perceived health. Related to early screening tests that do not actually increase survival rates. (Gordis, 2014) Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Stage Migration: Apparent improvements from earlier diagnosis may be misleading? (Gordis, 2014) Image copyright Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Estimating Risk Adapted from Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Relative Risk: is the risk in the exposed divided by the risk in the non-exposed. Use ratio of risks or incidence rates. Bing.com search, Creative Commons License. Odds Ratio # Bing.com search. Creative Commons License. Use when? Controls studied are representative (Gordis, 2014) Disease studied does not occur frequently. (Gordis, 2014) Cased studied are representative (Gordis, 2014) Attribution risk: Incidence in exposed group minus incidence in non-exposed group. (Gordis, 2014) Evaluating Health ServicesAdapted from Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Effectiveness: Dose the agent produce the right result in real world trails? Efficient: What is the ratio of cost to benefit? Efficacy: Dose the intervention/agent work under ideal conditions. Studies of outcome Studies of process Randomized versus non-randomized? PreventionAdapted from Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Secondary: Early detection. Tertiary: Reducing impact. Primary: Prevent disease Prevention Adapted from Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Looks at factors that determine exposure (help select for risk factors) along with social psychological, family, economic, and community effects (come about as a result of disease). Environmental and social factors that influence suseptability? Genetic factors influencing susceptibility or vulnerability Population Approach Direct intervention toward population. High Risk Approach Direct intervention toward high risk persons within the population. Risk AssessmentAdapted from Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Dose-Response Assessment Exposure Assessment: Review records Physician records. Hospital records. Disease registry records Employment records Interview both subject and surrogate Death certificates. Hazard Identfiication Risk Characterization Metal Analysis: Aggregation of separate trials to uncover associations and make inferences. However, these aggregate studies have drawbacks and can come to erroneous conclusions. Does the study include all published data or is it cherry picked? Are non-randomized trials included? Publication Bias: Tendency to only report concordant data. Ethics Use of race versus ethnicity? Conflicts of interest? Who owns the data? Jeffrey Gutschmidt, December 12, 2016 – IH5426: Advanced Epidemiology – Final Exam, Concept Map. Current Issues in Epidemiology Breaking Issues in Epidemiology US Heroine Epidemic Global issues in epidemilogy Cholera in Haiti. Post Matthew, CNN Ebola in Africa. . CDC Zika in Central and South America. Is Southern US safe, Zika 101 by NPR , December 6, 2016 Private sector implements measures to avert 1m malaria deaths by 2020 US Based Infectious Disease Outbreaks Raw Milk – Listeria monocytogenes, announced March 2016, . CDC Elizabethkingia anophelis in the Midwest, announced January 2016, . CDC Dairy Bull Calves – Multidrug-resistant Salmonella HeidelbergAnnounced November 2016, CDC International Outbreaks Affecting Travelers Zika in Bahamas, Nov 2016, . CDC Zika in Palau, November 2016, . CDC Measels in Romania, November 2016, . CDC Association to Causation Adapted from Epidemiology by Leon Gordis, Saunders, 2014, Amazon Kindle Version. Causal Direct: Factor to disease, no intermittent steps. Indirect: factor + step 1 + step 2 = disease Determining Cuasality Cessation of exposure. Consideration of alternate explanations. Biological plausibility Replication of findings. Dose response relationship Strength of association as measured by the risk or odds ratio. (Gordis, 2014) Temporal relationship Confounding Third factor X confounds the causation of risk factor A in a study if: X is a known risk factor for the disease X is associated with factor A. Control for confounding by Stratify data and adjust data to a standard population. Conduct individual or group matching

Transcript of IH5426_Gutschmidt_J_EPI Final Exam, Concept Map

Page 1: IH5426_Gutschmidt_J_EPI Final Exam, Concept Map

Images from Bing Search,Creative Commons License, Free to modify,

share, and use commercially. Text,Epidemiology by Leon Gordis, Saunders,

2014, Amazon Kindle Version.

Epidemiology:"The study of how disease is distributed

in populations and the factors thatinfluence or determine this distribution"(Gordis, 2014)

History of Epidemiology adapted from "Table 2-2, Selected Historical Contributions of Men and Women to Epidemiology: From"Essential Epidemiology" by William A. Olenckno, copyright 2002, Waveland Press, page 16." Photos obtained using "Bing SearchEngine. All photos are covered under the Creative Commons license. Free to modify, share, and use commercially.

John Snow (1813-1858). Used in-person interviews, maps, and

keen observational skills to tie aLondon cholera outbreak to awater pump located on Broad

Street.

Hippocrates (460-377 BCE)was the fist person known tooffer rational explanations for

disease that were notsupernatural in nature. Heconsidered environmental

and other factors in his

analysis.

Ignas Semmelweis (1818-1865) usedepidemiological theory to identify the cause of

childbirth fever

Girolamo Fracastoro (1478 - 1553) was the firstperson known to offer a formal theory of disease

that used the contagion theory of diseasetransmission.

Edward Jenner (1749-1823): Invented a vaccine against small pox

through observational and experimental skills.

William Farr (1807-1883), used statistics to describe

epidemiology problems

John Gaunt (1620-1674), described disease occurrence systematically using Bills of Mortality.

Peter Ludwig Panum (1820-1885) showed thatpeople could acquire immunity to measels through

infection.

Thomas Sydenham (1624-1689), insisted that thenatural history of disease be guided by observationinstead of by theory alone.

Robert Koch (1843-1910), credited, along withPasture for the Germ Theory of Disease.

Established criteria for bacterial disease causation.

Anna Wessels Williams (1863-1954), made aantitoxin against diphtheria by isolating thebacterium.

Joseph Goldberger (1874-1929), showed thatpellagra was caused by a diet deficient in proteinthrough observation and experiment.

James Lind (1716-1794), showed how to

treat and preventscurvy using an

experimentalapproach.

Louis Pasture (1822-1895), demonstrated theveracity of the germ theory of disease and showedthat vaccines could be used to control them.

Florence Nightingale(1820-1910),Improved hygiene atmilitary hospitalsusing mortalitystatistics as ajustification.

Image Bing.comsearch, CreativeCommonsLicense,Free tomodify, share, anduse commercially

Study Types: Adapted from Epidemiology byLeon Gordis, Saunders, 2014, Amazon

Kindle Version.

Scientific Studies

Randomized Trials: A trial where, from the totalpopulation, a defined population is identified and a

subset of that defined population is studied (Gordis,2014).

Validity

Image

copyright Epidemiology by LeonGordis, Saunders, 2014, Amazon

Kindle Version

Internal: Valid only within study population. #

External: Validity outside of study population # #

Design

Image copyrightEpidemiology by Leon

Gordis, Saunders, 2014,Amazon Kindle Version

MethodsRandom Number Table

Computer Selection

Possible Effects

Stratification by age, for instance, may increase validityof results, or by sex?

Image copyrightEpidemiology by Leon

Gordis, Saunders, 2014,Amazon Kindle Version

Masking (blinding): Hiding from subjects andresearchers who is in the treatment versus control group

to mitigate the placebo effect. (Gordis, 2014)

Crossover: Planned versus unplanned. When patients inthe treatment group cross over to the non-treatment

group and vice versa. (Gordis, 2014)

Non-Compliance: Effects of patients not complying withassigned treatments.

Testing: Do Treatments Differ?

Type I Error #

Type II Error #

Image, copyright,Epidemiology byLeon Gordis,Saunders, 2014,Amazon KindleVersion.

Image copyrightEpidemiology byLeon Gordis,Saunders, 2014,Amazon

Number of patients needed in each group to establishAlpha and Beta at different confidence intervals. (Thesymbol "/" for this purpose stands for the mathematicaloperator for division.)

One sided Test

Image copyright Epidemiologyby Leon Gordis, Saunders,

2014, Amazon Kindle Version.

Two sided test

Image copyrightEpidemiology by

Leon Gordis,Saunders, 2014,

Amazon KindleVersion.

NNT: Number needed to treat [NNT=1/(rateinuntreated)-(rate in treated)]How many patients needed to treat to prevent one

adverse outcome. (Gordis, 2014)

Efficacy: (rate in those who received a placebo)-(rate inthose who received a vaccine)/(Rate in those whoreceived the placebo)Tells of the extent reduction in disease by use off

treatment. (Gordis, 2014)

Alpha = probability of making a Type I error #

Beta = probability of making a type II error #

Image copyrightEpidemiology byLeon Gordis,Saunders, 2014,Amazon KindleVersion

Clinical Trials: Used in theUS to test new drugs(Gordis, 2014)

Phase II: Clinical investigation of 100-300 patients todetermine efficacy of new drug or treatment (Gordis,

2014)

Phase III: Large scale randomized controlled trialsmeant to assess effectiveness relative to safety (Gordis,

2014).

Phase I: Clinical, pharmalogical studies of 20-80 patientsto assess safety of new drug or treatment (Gordis, 2014)

Phase IV: Post marketing surveillance is used todetermine if drug or treatment has any long-term

negative effects after final approval in phase III. PhaseIV is not a randomized study (Gordis, 2014).

Studies without comparisons: Case Study or CaseSeries for example. (Gordis, 2014)

Descriptive Studies:Time, Place, and PersonAdapted from Centers for Disease Control and

Prevention, Principles of Epidemiology in PublicHeath Practice, Third Edition An to AppliedEpidemiology and Bio statistics, Lesson1:

Introduction to Epidemiology, Section 6: DescriptiveEpidemiology, November 2016

Time Secular Trends: Annual cases graphed over a period ofyears (CDC, 2016).

Seasonality: Graphed over weeks or months, or a yearor more to show seasonal characteristics (CDC, 2016)

Two dimensional graph showing number or rate versustime in weeks, days, or months (CDC, 2016)

EPI Curve

Continuousexposure example.

Image, Bing.comsearch, CreativeCommons License,Free to modify,share, and usecommercially.

Singe exposure, commonvehicle outbreak exampleEpi Curve:

Image, Bing.com search,Creative Commons License,Free to modify, share, anduse commercially.

Place

Contain the 5 W's: Who, what, where, when, andwhy/how (CDC, 2016)

Person: Age, Race, Ethnicity, Socio-Econonmic Status.

Study Types

Case-Control Study: Compares diseased to non-diseased. Easier to administer, less expensive, better for

comparing rare diseases. (Gordis, 2014)

Selection bias: If subjects are selected from a singlehospital, for instance, risk factors observed may be

specific to that institution. (Gordis, 2014)

Bias: Incident versus prevalent cases usage: prevalentcases are more abundant but risk factors associatedwith the study of prevalent cases may be moreassociated with living with the disease than from havingcaused it. (Gordis, 2014)

Information bias #

Problems with recall.

Limitation in recall: Can't remember answer to questionduring interview.

Recall bias: Affected subjects recalling a perceivedtriggering event that non-affected subjects forgot aboutbut did happen.

MatchingGroup: Controlling for proportionality of characteristicsbetween cases and controls. (Gordis, 2014)

Individual: Pairing case subjects with similar controlsubjects each of whom has similar characteristics withonly the disease status differentiating them. Matchescase/control pairs. (Gordis, 2014)

Choosing to use multiple controls?

Same?Increases statistical power of the study. (Gordis, 2014) #

Different?: Choose to use over concern that pool ofexposed persons (i.e. a hospital setting) do notrepresent the population and for that reason maychoose to use more controls that differ in terms of traits.(Gordis, 2014)

Use when an association is suspected and moreevidence is needed to suggest an association between a

risk factor and an outcome. (Gordis, 2014)

Ecologic: Looks at and compares data for populationsand not individuals.

Ecologic fallacy: Results for groups cannot necessarilybe transferable to individuals in groups. Cannot drawconclusions about individuals. (Gordis, 2014)

Cohort: Compares exposed population to non-exposed.Either prospective or retrospective. Prospective studiesfollow participants for years and can be very expensiveespecially for comparing rare conditions.(Gordis, 2014

Selection bias: Bias of non-participation or non-response. (Gordis, 2014)

Information bias:bias based on the quality of theinformation obtained and the bias on the part of theperson who assigns diseased or non status based onknown exposure. (Gordis, 2014)

Intervention: Compares the effects of an intervention onsubjects, for instance, the effects of smoking cesassionintervention on pregnant women who smoke. (Gordis,2014)

Cross-SectionalPlace and time interview. Captures a snapshot.

Scientific Studies : Drug Trials, for example. (Gordis,2014)

#

Agents of human disease/conditions:Adapted from Epidemiology by Leon Gordis,Saunders, 2014, Amazon Kindle Version. #

Paracites/Prototzoal infectionsMalaria

Rocky Mountain Spotted Fever

Giardia

Heart Attack/Stroke

Mental IllnessSchitzophrenia

Post-traumatic Stress Disorder

Bipolar Disorder

Depression

Accidents/InjuriesBroken bones

Sprains and strains

Lasserations

Cancer/Tumor

Example: Smoking and lung cancer

Colon Cancer

Uterine Cancer

Prostate Cancer

Bacterial Infections

Typhoid: Typhoid Mary

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Search, Creative Commons License. Free to modify,share, and use commercially.

E. Coli from contaiminated food.

Legionella

Siphalis: Treponema pallidum

Graham Negative bacillus associated with virulance

Viral InfectionsMarburg

Influenza

Ebola

Hepatitus

Addiction/Substance AbuseHeroine

Nicotine

Alcohol

Cocaine

Genetic and Environmental Factors Genetic

Associated with Leukemia, Down's Syndrome, andAlzheimer's Disease

Human genome project.

Concordance vs. discordance measures in twin studies.

EnvironmentalLikely the cause when observed changes in populationsare over short periods of time like decades.

Occurance Measurments: (Symbol"/" used in the context of anexample equation is intended todenote mathematical division)Adapted form Riccetti-MastersonK,Lopes B, Yeatts KB, Summary ofEpidemiologic Measures. UNCGiddings School of Global PublicHealth 2/14 and Epidemiology byLeon Gordis, Saunders, 2014,Amazon Kindle Version.

Image,

intended as a reference forequations listed in this section andtaken from from Bing Search,Creative Commons License. Freeto modify, share, and usecommercially.

Odds: Ratio of cases and non-cases (Ricchetti et al,2014)

Exposed Odds (EO)

PO: (a+c)/(b+d) or diseased divided by non-diseased;EO: (a+b)/(c+d) or exposed divided by non-exposed

Prevalent Odds (PO)

Denominator does not typically include diseasedsubjects. Only in EO are diseased subjects included in

the denominator.

AKA: Incidence Odds (Ricchetti et al, 2014).

Associated with: Cast-Control Study; Cross SectionalStudy (PO); Cohort Study; Experimental Study; and

Ecologic Study (group level), Associated with: CohortStudies; Experimental Studies; and Ecologic Studies

(group-level), (Ricchetti et al, 2014).

Rate: Proportion of population who developcondition per unit time at risk (Ricchetti et al, 2014) #

(a+c)/(total person-time at risk). Numerator is incidentcases (Ricchetti et al, 2014).

Denominator does not include diseased subjects.

AKA: Incidence Rate or Incidence Density (Ricchetti etal, 2014). #

Associated with: Cohort Studies; Experimental Studies;and Ecologic Studies (group-level), (Ricchetti et al,

2014).

Risk: Proportion of population who, over a specifiedamount of follow-up time develop the heathcondition (Ricchetti et al, 2014).

AKA: Cumulative Incidence (Ricchetti et al, 2014).

(a+c)/(a+b+c+d). Numerator is incident cases.Denominator is total at-risk baseline study population

(Ricchetti et al, 2014).

Denominator does not include diseased subjects(Ricchetti et al, 2014).

Associated with: Cohort Studies; Experimental Studies;and Ecologic Studies (group-level), (Ricchetti et al,

2014).

Prevalence: At a point in time the proportion of apopulation living with a health condition (or with ahistory of the same condition), (Ricchetti et al,2014).

Period Pravalence: How many people have a givendisease at any point during a time period (Gordis, 2014)

Point Prevalence: The prevalence of a disease at aparticular point and time (Gordis, 2014)

Denominator includes diseased subjects: Yes!

(a+c)/(a+b+c+d)

AKA: Prevalence Proportion (Ricchetti et al, 2014).

Associated with: Cross-sectional Study; Cohort Study(baseline/non-outcome variables); Ecologic Study

(group-level), Associated with: Cohort Studies;Experimental Studies; and Ecologic Studies (group-

level), (Ricchetti et al, 2014).

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Version.

Prevalence = Incidence x duration. (Gordis, 2014)

Person Time:When each individual in thedenominator is not followed for the full length of thestudy person time is sometimes used as asurrogate. Person time can be expressed as personyears, days, months, etc. (Gordis, 2014) #

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Gordis, Saunders,2014, Amazon Kindle

Version.

Terns

Vector: According ot Merriam Webster "an organism(as an insect) that transmits a pathogen from one

organism or source to another <fleas are vectors ofplague>" [ Merriam Webster #

Agent: According to CDC "The agent is the cause of the disease. Whenstudying the epidemiology of most infectious diseases, the agent is a

microbe an organism too small to be seen with the naked eye. Diseasecausing microbes are bacteria, virus, fungi, and protozoa (a type of

parasite). They are what most people call “germs.”" CDC #

Endemic: According to Gordis endemic refers to thepresence of a disease within a geographic area thatis habitual.

Epidemic: According to Gordis an epidemic thepresence of disease in a community or regionclearly in excess of normal expectancy.

According to a current example of an epidemic inthe US is the Heroine epidemic.

CDC

Pandemic: According to Gordis a pandemic is an aworldwide epidemic.

1968 Pandemic of H3N2, according to CDC

1957 pandemic of H2N2, according to CDC

2009 pandemic of H1N1 pandemic, according to CDC

1918 pandemic of H1N1, according to CDC

Immunity: According to Gordis, refers to people in apopulation that are not susceptible for acquiring a

particular disease.

Herd immunity, according to Gordis is the resistancetoward acquiring a particular disease by a group ofpeople, due to immunity, by a large proportion of thatgroup.

Incubation Period: "the interval from the receipt ofinfection to the time of onset of clinical illness."(Gordis, 2014)

Resevoir: According to CDC, "A reservoir of aninfectious agent, such as a virus, is any animal,

person, plant, soil, substance—or combination ofany of these — in which the infectious agent

normally lives. In addition, the infectious agent mustprimarily depend on the reservoir for its survival,and must be able to multiply there. It is from the

reservoir that the infectious substance is transmittedto a human or other susceptible host." .CDC

Image

from Bing.com, Creative Commons License.

Host: According to Merriam Webster "a living animalor plant on or in which a parasite lives."

Merriam

Webster #

Environment: According to Merriam Webster "thecomplex of physical, chemical, and biotic factors (as

climate, soil, and living things) that act upon anorganism or an ecological community and ultimatelydetermine its form and survival" Merriam Webster #

Public Health: According to , "Public health isthe science of protecting and improving the healthof families and communities through promotion ofhealthy lifestyles, research for disease and injuryprevention and detection and control of infectiousdiseases."

CDC

Etiology: Cause of disease. (Gordis, 2014)

Passive and active surveillance: Passivesurveillance uses available data, active surveillanceuses program staff to collect data. (Gordis, 2014)

Ratio, according to :"Thequantitative relation between two amounts showing

the number of times one value contains or iscontained within the other:

‘the ratio of men's jobs to women's is 8 to 1"’

Oxford Dictionary on-line

Proportion according to : "Therelationship of one thing to another in terms of quantity,

size, or number; ratio:‘the proportion of examination to coursework’

‘the bleach can be diluted with water in the proportionone part bleach to ten parts water’"

Oxford Dictionary on-line

Rate according to : "Ameasure, quantity, or frequency, typically one

measured against another quantity or measure:‘the island has the lowest crime rate in the world’

‘buying up sites at a rate of one a month’"

Oxford Dictionary on-line

Screening Tests: Adapted from Epidemiologyby Leon Gordis, Saunders, 2014, Amazon

Kindle Version #

Specificity # #

Predictive Value

Image copyrightEpidemiology byLeon Gordis,Saunders, 2014,Amazon KindleVersion

Positive Predictive Value

Image copyrightEpidemiology byLeon Gordis,Saunders, 2014,Amazon KindleVersion

Dichotomous results

Positive versus negative result

Image copyright Epidemiologyby Leon Gordis, Saunders,2014, Amazon Kindle Version

Tests for pregnancy, HIV status, cancer screening

Continuous variables Establish cut-off levelBllood pressure screening, blood glucose level

screening

Image copyrightEpidemiology byLeon Gordis,Saunders, 2014,Amazon KindleVersion

Sensitivity #

Prevalence

Image copyrightEpidemiology byLeon Gordis,Saunders, 2014,Amazon KindleVersion

#

Validity versus Reliability

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Effectivemess? #Natural history of disease?

Primary, Secondary, or Tertiary Intervention?

Outcome measuresImprovement to quality of life in screened individuals

Prevention of or reduction in recurrences.

Rection in complications.

Increase in percent of cases detected earlier

Reduction in case-fatality

Reduction in mortality

Effects of lead time bias on five-year survival?May make screening appear to extend life but onlyactually reduces years of perceived heath with nochange in outcome.

Effects of randomized screening trials versus non-randomized: Randomized is usually better but may bedifficult to carry out or precluded for ethical reasons.

Occurrence of Disease adapted fromEpidemiology by Leon Gordis, Saunders,2014, Amazon Kindle Version.

Where: Geographic distribution is not random, islocalized by time and place in a region - clustering.

(Gordis, 2014)

When: Certain diseases occur periodically:Annually, seasonally, etc. (Gordis, 2014)

Who: Age, sex, and race of human host? (Gordis,2014)

Disease Transmission from Epidemiology byLeon Gordis, Saunders, 2014, Amazon

Kindle Version. Direct.Person to person. (Gordis, 2014

Indirect: Through common vehicle, such ascontaminated water or air. (Gordis, 2014)

Type of organism: Characteristics of organism/rateof growth (Gordis, 2014). Mode of transmission/portal of entry: skin, respiratory

tract, urogenital tract, alimentary tract, arthropod,conjunctiva, etc. (Gordis, 2014)

Individual characteristics: Scratches, injuries,susceptibility (immunity), (Gordis, 2014)

Clinical versus sub-clinical disease

Bing.com search,Creative Commons

License.Clinical disease = signs and symptoms. (Gordis, 2014)

Noncliniccal disease = preclinical or subclinical disease.Either not yet clinically apparent and either destined ornot destined to progress to clinical disease. (Gordis,2014). Peristent disease is a lingering condition thatlasts for years or life. An example is polio myelitis.(Gordis, 2014)Carrier status: Person with disease who does not

develop symptoms. (Gordis, 2014) #

Measures of Morbidity and Mortality adaptedfrom Epidemiology by Leon Gordis,Saunders, 2014, Amazon Kindle Version.For the purposes of this discussion thesymbol "/" represents the mathematicaloperation of division.

Morbidity: Incidence Rate per 1,000 = (No. of newcases of a disease occurring in a population duringa period of time/No. of persons who are at risk ofdeveloping the disease during that period of time) x1,000 (Gordis, 2014)Morbidity - a transition from non-disease to disease.

(Gordis, 2014)

Mortality Rate: Annual mortality rate for all causes(per 1,000 population) = (Total no. of deaths from

all causes in a year/No. of persons in the populationat midyear) x 1,000. (Gordis, 2014)

Case Fatality Percent: (No. of individuals dyingduring a specific period of time after disease

onset/No. of individuals with the specified disease)x 100. (Gordis, 2014) #

Mortality data may be inaccurate due to how deathsare coded on death certificates. (Gordis, 2014)

Mortality rates can be adjusted to a standardpopulation (today the year 2000 census is used inthe US). Applying standardization to mortality rateseliminates population effects on differencesbetween rates. (Gordis, 2014)

Indirect age adjustments are used when ages of subjectpopulation are unknown. Here a standard age

distribution in the standard population is used as ansurrogate of the population of interest. (Gordis, 2014)

Rates indicate the speed of disease progression ina population. Proportions tell us the fraction of the

people who are impacted. (Gordis, 2014)

YPLL: Years of potential life lost: Age at deathsubtracted form perdetermined age at death or

standard age. (Gordis, 2014)

The cohort effect: A potential error that results formcross-sectional reading of data that relates to

different cohorts that age together over time. Whencomparing mortality data could be effected by: 1)

Changes in survivor-ship without changes inincidence; 2) Changes in incidence; 3) Changes in

the age composition of the populations; 4) Acombination of factors. (Gordis, 2014)

Quality of life: impact of disease on individualsbeyond mortality. (Gordis, 2014)

Future burden of disease: Measured in DALY (disabilityadjusted life years) or years of life lost to prematuredeath and years of life lived with disability. (Gordis,

2014)

Outbreak adapted from Epidemiology byLeon Gordis, Saunders, 2014, AmazonKindle Version. #

Cross Tabulation

.Image copyrightEpidemiology by Leon

Gordis, Saunders, 2014,Amazon Kindle Version.

Attack rate: The number of people at risk, in whoma certain illness develops divided by the totalnumber of people at risk. (Gordis, 2014)

Food specific attack rate is based on the number ofpeople who at the food and became ill divided by the

total number of people who at the food. (Gordis, 2014)

Natural History of Disease, Adapted fromEpidemiology by Leon Gordis, Saunders,2014, Amazon Kindle Version.

OutcomeCure

Death

Control

Signs and Symptoms

Clinical Phase #Seeks Medical Treatment

Treatment

Preclinical Phase # #Biological Onset

Pathological Evidence

Expression of outcomes in terms ofCase-Fatality

Person Years

Life Table #

Image copyrightEpidemiology by Leon

Gordis, Saunders, 2014,Amazon Kindle Version.

Use of life tables assumes no secular (temporal)changes in treatment over calendar time and lack of

knowledge of outcomes due to loss to follow-up(outcomes do not necessarily need to be mortality).

(Gordis, 2014)

Kaplan-Meirer Method

Image copyrightEpidemiology byLeon Gordis,Saunders, 2014,Amazon KindleVersion.

Median Survival Time: Average of survival times.

Relative Survival: Ratio of observed survival to expectedsurvival #

Lead time bias: Bias that results from an earlierdiagnosis that does not affect actual survival andmay rob someone of years of perceived health.Related to early screening tests that do not actuallyincrease survival rates. (Gordis, 2014)

Image copyrightEpidemiology by Leon

Gordis, Saunders,2014, Amazon Kindle

Version.

Stage Migration: Apparent improvements fromearlier diagnosis may be misleading? (Gordis, 2014)

Image copyrightEpidemiology by

Leon Gordis,Saunders, 2014,

Amazon KindleVersion.

Estimating Risk Adapted from Epidemiologyby Leon Gordis, Saunders, 2014, Amazon

Kindle Version.

Relative Risk: is the risk in the exposed divided bythe risk in the non-exposed. Use ratio of risks or

incidence rates.

Bing.com search,Creative CommonsLicense.

Odds Ratio #

Bing.com search.Creative Commons

License.

Use when?Controls studied are representative (Gordis, 2014)

Disease studied does not occur frequently. (Gordis,2014)

Cased studied are representative (Gordis, 2014)

Attribution risk: Incidence in exposed group minusincidence in non-exposed group. (Gordis, 2014)

Evaluating Health ServicesAdapted fromEpidemiology by Leon Gordis, Saunders,

2014, Amazon Kindle Version.

Effectiveness: Dose the agent produce the rightresult in real world trails?

Efficient: What is the ratio of cost to benefit?

Efficacy: Dose the intervention/agent work underideal conditions.

Studies of outcome

Studies of process

Randomized versus non-randomized?

PreventionAdapted from Epidemiology byLeon Gordis, Saunders, 2014, AmazonKindle Version.

Secondary: Early detection.

Tertiary: Reducing impact.

Primary: Prevent disease

Prevention Adapted from Epidemiology byLeon Gordis, Saunders, 2014, Amazon

Kindle Version.

Looks at factors that determine exposure (helpselect for risk factors) along with socialpsychological, family, economic, and communityeffects (come about as a result of disease).

Environmental and social factors that influencesuseptability?

Genetic factors influencing susceptibility orvulnerability

Population ApproachDirect intervention toward population.

High Risk ApproachDirect intervention toward high risk persons within thepopulation.

Risk AssessmentAdapted from Epidemiology byLeon Gordis, Saunders, 2014, Amazon Kindle

Version.

Dose-Response Assessment

Exposure Assessment: Review recordsPhysician records.

Hospital records.

Disease registry records

Employment records

Interview both subject and surrogate

Death certificates.

Hazard Identfiication

Risk Characterization

Metal Analysis: Aggregation of separate trials to uncoverassociations and make inferences. However, these

aggregate studies have drawbacks and can come toerroneous conclusions.

Does the study include all published data or is it cherrypicked?

Are non-randomized trials included?

Publication Bias: Tendency to only report concordantdata.

EthicsUse of race versus ethnicity?

Conflicts of interest?

Who owns the data?

Jeffrey Gutschmidt, December 12, 2016 – IH5426:Advanced Epidemiology – Final Exam, Concept Map.

Current Issues inEpidemiology

Breaking Issues in Epidemiology USHeroine Epidemic

Global issues in epidemilogyCholera in Haiti. Post Matthew, CNN

Ebola in Africa. .CDC

Zika in Central and South America. Is Southern USsafe, Zika 101 by NPR

, December 6, 2016Private sector implements measures to avert 1m malariadeaths by 2020

US Based Infectious Disease Outbreaks Raw Milk – Listeria monocytogenes, announced March2016, .CDC

Elizabethkingia anophelis in the Midwest, announcedJanuary 2016, .CDC

Dairy Bull Calves – Multidrug-resistant SalmonellaHeidelbergAnnounced November 2016, CDC

International Outbreaks Affecting TravelersZika in Bahamas, Nov 2016, .CDC

Zika in Palau, November 2016, .CDC

Measels in Romania, November 2016, .CDC

Association to Causation Adapted fromEpidemiology by Leon Gordis, Saunders, 2014,

Amazon Kindle Version.

CausalDirect: Factor to disease, no intermittent steps.

Indirect: factor + step 1 + step 2 = disease

Determining CuasalityCessation of exposure.

Consideration of alternate explanations.

Biological plausibility

Replication of findings.

Dose response relationship

Strength of association as measured by the risk or oddsratio. (Gordis, 2014)

Temporal relationship

Confounding

Third factor X confounds the causation of risk factor A ina study if:

X is a known risk factor for the disease

X is associated with factor A.

Control for confounding byStratify data and adjust data to a standard population.

Conduct individual or group matching