Public health exam 2 notes PDF

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03/01 Class Notes- Assignment 3: The public health approach applied to obesity and proposed soda tax Thursday, March 1, 2018

2:56 PM

• Proposed legislation ○ 20% sales tax on sugar sweetened beverages (soda tax or sugar tax) ○ A $1,00 bottle of soda would be taxed 20% and cost $1.20 • Public health approach to solve problems : obesity and soda tax ○ Going through each step and give solutions ○ Step 1 --> identify or define the problem ▪ Describe the public health significance of overweight/obesity and associated health problems ○ Step 2--> identify risk and protective factors ▪ Discuss the relationship between consumption of sugary drinks and obesity and other health problems ○ Step 3 --> develop and test prevention strategies ▪ Discuss how effective a 20% price increases on sugar-sweetened beverages is likely to be in reducing consumption ○ Step 4 --> assure widespread adoption ▪ Discuss the political acceptability of the proposed law and stakeholder support of opposition ○ Make a recommendation as to whether or not the state legislature should pass the proposed law and provide your rationale

0301 Class Notes- As... Audio recording started: 3:12 PM Thursday, March 1, 2018

Research = conversation C-currency R-relevance A- Authority A- Accuracy P- Purpose AMA style

Chapter 4. Epidemiology: The Basic Science of Public Health Saturday, April 7, 2018

3:51 PM

• Epidemiology --> studies the patterns of disease occurrence in human populations and the factors that influence these patterns ○ who, when, where (shoeleather epidemiology) ○ Diagnostic discipline of public health ○ Major part of the assessment function ○ Investigates causes of disease; Identifies trends in disease occurrence ○ Evaluates effectiveness of medical and public health interventions ○ Observational science • Patterns of Disease Occurrence ○ Who is getting the disease ○ When did they get the disease Where is the disease occurring? ○ Ultimate goal is to use this knowledge to control and prevent the spread of disease • Foodbourne Disease Outbreaks (types of data) ○ Epidemiologic ○ Patterns in where and when people got sick, and past outbreaks caused by the same germ ○ Interviews w/ sick people to look for foods or other exposures occurring more often than expected ○ Discovery of clusters of unrelated sick people who ate at the same restaurant shopped at the same grocery store, or attended the same event); ○ Traceback --> A common point of contamination in the distribution chain from farm to fork, identified by reviewing records collected from restaurants or stores where sick people ate or shopped) Inspections in food production facilities, on farms, and in restaurants that identify food safety risks; ○ Food and environmental testing --> The germ that caused illness is found in a good item collected by a sick person's home, a retail location, or in food production environment ▪ The same DNA fingerprint linking germs found in foods or production environments to germs found in sick people ○ Actions to stop the outbreak ▪ health officials warn the public ▪ companies recall contaminated products ▪ temporary closure of restaurant or food production facility • Outbreak Investigation ○ verify the diagnosis ○ construct a working case definition; ○ find cases systematically ○ apply active surveillance ○ ask who, where, and when questions to describe the epidemic by person, place, and time ○ consider the incubation period ○ look for a common source of exposure • Epidemic --> an increase in the frequency of a disease above the usual and expected rate (endemic rate) • John Snow ○ The father of modern epidemiology ○ hypothesis: cholera was spread by polluted drinking water from one water company ○ "natural experiment.. people of both sexes, every age & occupation, rank, station... were divided into two groups without their choice & without their knowledge" ○ Southwark and Vauxhall Company: source of Cholera, not Lambeth

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▪ 1st example of use of epidemiology to study and control a disease was by Snow for cholera (infectious, often fatal bacterial disease of the small intestine, typically contracted from infected water supplies and causing severe vomiting and diarrhea) ▪ Most deaths were associated w/ 1 water supply company ○ data on births, deaths, and other vital statistics Epidemiological surveillance ○ endemic vs epidemic ▪ Endemic --> the usual and expected rate of disease in a population ○ requires that certain "notifiable" diseases be reported as soon as they are diagnosed ○ Major line of defense in protecting the public against disease ○ System was created to control spread of known disease and recognize new disease ○ Importance has increased with the continual thereat of bioterrorism "Notifiable" diseases --> infectious diseases whose spread can be prevented if the appropriate actions are taken ○ about 60 in US (tuberculosis, hepatitis, measles, and syphilis) ○ birth defects, cancer, & other noninfectious conditions Legionnaires' Disease ○ July 1976: American Legion 4 day convention in Philadelphia at Hotel Bellevue-Stratford ○ Symptoms: fever, muscle aches, and pneumonia ○ August 150 cases ○ Airborne, no person-to-person in patient's families ○ Legionella bacteria in the water of cooling tower ○ Federal air-conditioning standards changed Eosinophilia-Myalgia Syndrome ○ Infectious or toxic disease ○ 1989 in New Mexico/Santa Fe ○ Symptoms: fatigue, debilitating muscle pain, rashes, shortness of breath, blood test: high count of white cells/eosinophils ○ L-Tryptophan-dietary supplement ○ New Mexico State Health Department ○ Toxic contamination- recent change of production in one factory ○ individual variations in susceptibility ○ 1981: Madrid/Spain similar to EMS ▪ More than 20,000 people/ more than 300 died in a few months ▪ Households bought oil for cooking from salesperson (oil for industry purposes) ▪ chemicals that cause body's immune system to attack it's own tissues ▪ toxic oil syndrome ○ *to find root of disease- must find common denominator Chronic Disease ○ Identify risk factors, no single causes ○ Observe long-term trends ○ Heart disease: leading cause of death in U.S. ○ Framingham Study- started in 1948 ○ Lung cancer and smoking- early 1950s ○ British Physicians' Study ○ Hammond-Horn study in U.S Heart Disease (Framingham Study) ○ 1920: heart disease leading cause of death in USA ○ 1948: first major epidemiologic study: Framingham, Massachusetts ○ 5000 healthy people, examined and data recorded: weight, BP, smoking habits, blood tests… ○ Every 2 years repeated ○ 10 years: identification of major risk factors: high BP, high blood cholesterol, smoking

○ HDL, LDL,... • Lung Cancer (British Physician's Study)(Hammond and Horn Study) ○ 1950/1952: lung cancer and tobacco smoking ○ Questionnaire to physicians in UK: smokers, past smokers, non-smokers (age started to smoke, amount of tobacco smoked, when they quit smoking) ○ Death rate from lung cancer 20x higher among smokers ○ Death rate among non-smokers lower than of smokers and declined as the length of time increased since they had quit smoking ○ Cigarette smokers: 5x more to die from other cancers- tongue, pharynx, larynx, esophagus then non-smoker ○ Heavy smokers (2 or more packs/day) were 2.4x more likely to die from heart disease than non-smokers

Chapter 5. Epidemiologic Principles and Methods Saturday, April 7, 2018

4:01 PM

• case-control study --> persons who have a disease are questioned about past exposures and are compared with exposures of persons who do not have the disease ○ faster and cheaper ○ least accurate ○ choose people who have disease and then choose healthy control group of individuals as similar as possible to cases ○ interview and ask for previous exposures ○ estimate strength of association between exposure and disease by calculating odds ratio • cohort study ○ most accurate ○ subjects are all healthy when the study begins ○ are studied over a period of time to see whether those who were exposed to the factor being studied are more likely to develop the disease than those who were not ○ use when intervention study too difficult or unethical ○ choose large # of healthy people, collect data on exposures, and track outcomes over time ○ people choose own exposures* • control group --> in a clinical trial, those who are not exposed to substance being tested ○ in a case-control group, the subjects who don't have the disease • descriptive epidemiology ○ answers who, when, and where ○ tells causes of disease or source of outbreak • Disease ○ undesirable health outcome ○ must be defined at start of an epi study • distribution of diseases --> frequency of occurrence of disease by person, place, and time • Epidemiology --> study of the distribution and determinants of disease frequency in human populations • Frequency --> occurrence of disease ○ calculated by: incidence and prevalence and size of population being studied • Hypothesis --> proposed explanation made on basis of limited evidence ○ starting point for future investigation • Incidence --> the rate of new cases of a disease in a defined population over a defined period of time • intervention study --> an experiment where the experimenter assigns subjects to the treatment group or the control group ○ epidemiologists do not perform the experiments ○ experimental group ○ control group ○ watch over time, compare outcomes ○ groups similar as possible so intervention is the only difference ○ randomized, double blind, placebo control is ideal • odds ratio --> a measure of the strength of association between the exposure and the disease used in case-control studies ○ a ratio of exposed to nonexposed subjects in the case group divided by ratio of exposed to non-exposed subjects in the control group • Placebo --> inactive substance given to rule out psychological response • population at risk --> total individuals potentially susceptible to disease of interest

• Prevalence --> # cases of disease existing in defined population at a specific time ○ depends on incidence and prognosis ○ most useful in assessing societal impact of a disease and planning for healthcare services ○ causes/risk factors increase, incidence and prevalence increase ○ ability to diagnose increases, incidence and prevalence appear to increase • prospective studies --> monitor groups of people into future ○ or start at point in time in past and look forward from there • Rate --> # of cases of disease per population at risk • randomized double-blind controlled clinical trial ○ "gold standard" ○ subjects assigned to treatment or control group randomly ○ subject and doctor both don't know which treatment is being given • relative risk --> measure of strength of association between exposure and disease used in intervention studies and cohort studies ○ ratio of incidence rate for exposed persons to incidence rate of unexposed persons • retrospective studies --> look into the past for causes of diseases from which people currently suffer • define the disease ○ death easy to determine, because death certificate states cause of death ○ blood test/stool sample needed to verify diagnosis of certain diseases ○ some diseases hard to define (EMS, SARS) ○ sometimes definition changes as more is learned (AIDS) ○ other health outcomes include injuries and risk factors • disease frequency --> # of people with a disease out of population at risk (PAR) ○ 2 ways to measure disease frequency ▪ incidence (# of new cases) --> used for studying causes of disease ▪ prevalence (# of existing cases) • incidence and prevalence ○ incidence measures change from non-disease to disease; newly diagnosed cases/population at risk ○ prevalence: proportion of total population which has disease; existing cases/total population • bathtub example for prevalence vs incidence ○ incidence: measure of the flow of water into the tub ○ prevalence is the proportion of the tub filled with water ○ prevalent cases leave prevalence pool by recovery or death • distribution of disease ○ who: (age, sex, occupation, race, and economic status) ○ when: (season, year, elapsed time since exposure) ○ where: neighborhood, latitude, urban v rural, regions of countries states etc • determinants of disease ○ why is distribution as it is? ○ can make inferences from distribution ○ risk factors ○ e.g. colon and rectum cancer more common in america than china because of our diet • human population ○ epidemiology studies of human population usually through observational studies rather than experimental ▪ ethics-- experiments usually not done on humans • biomedical approach uses --> animal models to investigate causes of disease • kinds of epidemiologic studies ○ goal to determine association btwn exposure and a disease or other health outcome ○ studies may be prospective or retrospective

○ intervention, cohort, and case-control study

03/06 Class Notes - Epidemiology Tuesday, March 6, 2018

2:56 PM

• Data are essential at every step of the process ○ Data = information • Epidemiology ○ The study of the distribution and determinants of disease frequency in human populations ▪ Determinants = risk factors/causes ○ The study of the patterns and causes of diseases and injury (health conditions) in populations Incidence (Risk) • ○ Measure of new cases of a disease or injury occurring in a population during a specified period of time ▪ Infectious disease ▪ Incidence per 1000 = 1000 #cases of occurring during a specified period of time / #persons at risk for disease or injury during that period of time (X1000) ○ Prevalence (proportion)--> measure of persons in the population suffering from a disease or injury cases at a specified point in time ▪ Chronic disease ▪ Prevalence per 1000 = 1000 #cases present in the population at one point in time / #person in the population at that point in time (X1000) • Step 2 : identify risk factors or causes ○ Is X associated with increased risk of Y? ○ Does X cause Y? ○ How do we determine this? What kind of data do we need? Where/how do we obtain those data? ▪ Cohort study ○ Formal epidemiologic studies ▪ Cohort studies ▪ Case control studies ○ Data sources ▪ Researchers collect primary data ▪ Surveillance data can sometimes be used • Cohort study ○ Start with healthy people ○ Compare incidence of disease or injury over some follow-up time period in exposed and non-exposed individuals ○ Calculate relative risk (RR) ▪ Relative Risk (RR) = incidence rate in exposed / incidence rate in non-exposed

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○ Example : smoking and lung cancer ▪ Study sample: 1000 □ Smokers: 200  Lung cancer: 50  No long cancer: 150 □ Non- smokers: 800  Lung cancer:10  No lung cancer: 790 □ Incidence rate of exposed: 50/200 = 0.25 □ Incidence rate of non-exposed 10/800=0.0125 □ RR= 0.25/0.0125=20.0  A smoker has 20x more risk of developing lung cancer than someone who does not smoke ◊ Incidence of lung cancer in smokers is 20 times greater than the incidence of lung cancer in no-smokers Case control studies • ○ Start by identifying cases, then find healthy controls ○ Compare past exposure in cases and controls ○ Calculate odds ratio (OR) ▪ Odds ratio (OR) = odds of exposure in cases/ odds of exposure in controls

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○ Odds = ratio of number of cases ▪ Odds of exposure cases = #cases exposed/#cases not exposed ▪ Odds of exposure control cases = #controls exposed/# controls not exposed ▪ OR = Odds exposure cases / odds of exposure control cases □ e.g. odds ratio = 10  Among people with the disease,… (?) • Case control vs. cohort ○ Cohort takes a long period time ○ Case control - looking at people who are already sick and looking into their past ▪ Doesn't take as much time ▪ Less expensive ○ What happens if lots of studies both cohort and case control on one topic and the numbers don't agree ▪ Usually depends on how the study was done □ e.g. looked at different populations □ e.g. measurement of variables were different • Step 3: develop and test interventions ○ Does X cause improvement in Y? ○ Evaluation studies or interventions studies ▪ Experimental studies □ Also known as randomized controlled trials □ You hear about this one the most  Used for drug testing all the time

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▪ Quasi experimental studies □ Also called observational studies □ Some things just can’t be randomly assigned --> comparing communities ○ Data sources ▪ Researchers collect primary data ▪ Surveillance data can sometimes be used • Step 4: assurance widespread adoption ○ Policy research ▪ What kinds of policies or programs assure that interventions reach people who can benefit from them (policy analysis) ▪ What package of policies or programs gives us the best outcomes for a given amount of resources (cost-effectiveness analysis) Implementation research ○ ▪ What factors facilitate the implementation of policies and programs ▪ What barriers hinder the implementation of policies and programs

Chapter 6. Problems and Limits of Epidemiology Saturday, April 7, 2018

4:02 PM

• Problems With Studying Humans: Interventions Study ○ Subjects may not follow prescribed behavior throughout study period. • Problems With Studying Humans: Cohort Study ○ Sometimes hard to isolate which of many factors are responsible for health difference • Problems With Studying Humans: Case-Cohort Study ○ Control group may not be truly comparable; also errors in reporting or recall, bias. • Sources of Error ○ Random variation (association is really due to chance, small sample size). Confounding variables. • Bias --> Selection response, and recall/self-report. • Factors that Lend Validity to Results ○ Strong association and Dose ○ Known biological explanation ○ Large study population ○ Consisted results from several studies. • Ethical Issues ○ Nazi experiments on humans. ○ Tuskegee syphilis study. ○ Guatemala syphilis experiment/STD inoculation study. ○ Sex workers, soldiers, prisoners, and mental hospital patients infected with STD's (e.g., syphilis and gonorrhea) and only some were treated ○ No informed consent, some deception. Funded by US NIH. • New Rules ○ Informed consent ○ Institutional review boards. • Conflicts of Interest in Drug Trials ○ Drug companies required to conduct randomized controlled trials on any new drug before it can be approved ○ Evidence that drug companies sometimes supposes negative findings ○ All clinical trials must now be registered in public database. • Clinical Trials --> considered to yield the most accurate results, and cohort studies the next most accurate • Tuskeegee study --> conducted by the US Health Service for 40 years that exploited mostly poor, black men and their families to syphilis • Institutional Review Board --> Current studies on humans funded by the federal government must obey strict ethical rules including informed consent by the patients and review of the study design • Confounding variables --> A factor or explanation other than the one being studied that may affect a result or conclusion. • Dose-response relationship --> The relationship between the dose of some agent, or the extent of some exposure, and a physiological response ○ A dose-response effect means that the effect increases with the dose. • Random variation --> The way a coin will successively turn up heads or tails if flipped in just the same way. • Stroke --> A loss of blood flow to part of the brain caused by a blood vessel bursting or becoming clogged by a blood clot or some other particle. • Association due to chance ○ Disease causality (infection vs. chronic)

○ Weaker relationship needs larger study • Selection bias --> selection of individuals, groups or data for analysis in such a way that proper randomization is not achieved, thereby ensuring that the sample obtained is not representative of the population intended to be analyzed • Reporting bias --> selective revealing or suppression of information by subject • Recall bias --> systematic error caused by differences in the accuracy or completeness of the recollections retrieved ("recalled") by study participants regarding events or experiences ...