Epidemiology Notes for Module 3 PDF

Epidemiology and the Policy Arena - Chapter 8 Notes 1. Introduction to Epidemiology in the Policy Arena Role of Epidemiologists: ○ Provide expertise relevant to policy development. ○ Conduct research and share findings. ○ Take part in policy-making and legal pro...

Epidemiology and the Policy Arena - Chapter 8 Notes 1. Introduction to Epidemiology in the Policy Arena Role of Epidemiologists: ○ Provide expertise relevant to policy development. ○ Conduct research and share findings. ○ Take part in policy-making and legal proceedings. ○ Advocate for specific health policy initiatives. 2. Definitions Policy: A plan or course of action to influence decisions and actions. Health Policy: Policies linked to healthcare services, dentistry, medicine, or public health, focusing on: ○ Water quality, food safety, health promotion, and environmental protection. 3. Policy Cycle Stages: ○ Problem Definition: Identifying and analyzing issues. ○ Agenda Setting: Prioritizing issues to address. ○ Policy Establishment: Adopting and legislating policies. ○ Policy Implementation: Enforcing and executing policies. ○ Policy Assessment: Evaluating effectiveness and making adjustments. Epidemiologists' Contributions: ○ Assist at every stage using their expertise. 4. Evidence-Based Public Health Relies on empirical data to adopt policies, laws, and programs. Randomized Controlled Trials (RCTs) are considered the most reliable evidence source. 5. Risk Assessment and Management  Risk: Likelihood of experiencing adverse effects. Risk Assessment: ○ Hazard Identification: Determining harmful agents and their impact. ○ Dose-Response Assessment: Measuring the relationship between exposure and health effects. ○ Exposure Assessment: Identifying populations at risk and analyzing exposure levels. ○ Risk Characterization: Estimating potential health effects over time. Risk Management: ○ Actions to control or minimize harmful exposures, e.g., limiting toxic chemicals in the environment. 6. Cost-Effectiveness Analysis Evaluates and compares costs and benefits of health programs and interventions. Identifies least costly alternatives for maximizing health outcomes. 7. Ethics in Epidemiology Ethical principles ensure fairness, accountability, and public trust. Guidelines by the American College of Epidemiology (ACE): ○ Minimize risks and protect subjects. ○ Obtain informed consent. ○ Ensure ethical review of studies. ○ Promote equitable distribution of risks and benefits. Ethical Violations: ○ Example: Tuskegee Syphilis Study: Participants were not given informed consent. Treatment was withheld despite the availability of penicillin. Resulted in a class-action lawsuit in 1973. 8. Public Health Policies Examples include: ○ Healthy People: National goals for health improvement. ○ Health in All Policies: Collaborative approach incorporating health considerations across sectors. ○ Laws for smokefree bars, banning trans fats, and addressing distracted driving. 9. Stakeholders and Policy Actors Policy Actors: Legislators, citizens, lobbyists, and advocacy group representatives. Stakeholders: People or groups affected by policies, including community members, advocacy groups, and organizations. 10. Key Concepts for Memorization 1. Policy vs. Health Policy: ○ General policy: Government or business-related actions. ○ Health policy: Specific to health services and public health. 2. Policy Cycle: ○ Remember the stages: Define → Set agenda → Establish → Implement → Assess. 3. Risk Assessment Steps: ○ Hazard → Dose-response → Exposure → Risk characterization. 4. Ethical Guidelines: ○ Focus on fairness, informed consent, and public trust. 5. Examples of Public Health Policies: ○ Healthy People, smoke-free laws, distracted driving regulations. CHAPTER 9 1. Introduction to Screening Screening involves testing populations to identify diseases early, often before symptoms appear. It is crucial for public health, disease prevention, and health promotion. Screening tests should be reliable (consistent results) and valid (accurately measure what they are supposed to). 2. Types of Screening Mass Screening: Tests for the entire population, regardless of risk. Selective Screening: Targets high-risk groups, e.g., for STDs, and is more efficient. 3. Appropriate Situations for Screening The disease must be significant and prevalent.  The test should offer a high cost-benefit ratio. Effective treatments should be available for the disease. Tests should be reliable and valid. 4. Controversies and Issues in Screening False Positives: Can cause unnecessary anxiety. Overdiagnosis: Identifying benign conditions that don't need treatment. Lead-time Bias: Appears to improve survival because screening detects diseases earlier. Length Bias: Tends to detect slower-growing, less aggressive diseases. 5. Examples of Screening Newborns: Tests for hearing defects, heart defects, and blood disorders like PKU and Sickle Cell. Children/Adolescents: Screening for developmental delays, tobacco use, alcohol use, and sexual activity. Adults: Screening for cancer, diabetes, HIV, cholesterol levels, depression, etc. 6. Natural History of Disease Diseases progress in stages: ○ Prepathogenesis: Before the disease has interacted with the host. ○ Pathogenesis: After the disease has started; can be early (before symptoms) or late (after symptoms). 7. Levels of Prevention Primary Prevention: Preventing disease before it occurs (e.g., vaccination). Secondary Prevention: Detecting the disease early, before symptoms appear (e.g., screening). Tertiary Prevention: Managing disease after it’s progressed (e.g., treatment). 8. Measures Used in Screening Reliability: The consistency of test results.  Validity: The accuracy of the test in measuring the condition it’s meant to detect. 9. Validity in Screening Tests Sensitivity: The ability to identify true positives (correctly identifying sick people). Specificity: The ability to identify true negatives (correctly identifying healthy people). Positive Predictive Value (PPV): The likelihood that those who test positive actually have the disease. Negative Predictive Value (NPV): The likelihood that those who test negative actually don’t have the disease. 10. Fourfold Table for Test Results True Positives (a): Correctly identified as having the disease. False Positives (b): Incorrectly identified as having the disease. False Negatives (c): Incorrectly identified as not having the disease. True Negatives (d): Correctly identified as not having the disease. Formulas: Sensitivity = a / (a + c) Specificity = d / (b + d) Positive Predictive Value = a / (a + b) Negative Predictive Value = d / (c + d) 11. Conclusion Screening tests are vital for early disease detection but require follow-up diagnostic tests for confirmation. Reliability and validity are crucial for the accuracy of screening tests, with sensitivity and specificity being key measures. Screening is considered secondary prevention, aiming to detect diseases before symptoms appear. CHATPER 10 Key Concepts in Infectious Diseases  1. Infectious (Communicable) Diseases: ○ Caused by agents like bacteria, viruses, fungi, and parasites. ○ Examples: COVID-19, Amebiasis. 2. Epidemiologic Triangle: ○ Agent: The microorganism causing the disease (e.g., bacteria, viruses). ○ Host: The organism (human or animal) that harbors the agent. ○ Environment: External conditions that allow disease transmission (e.g., climate, social settings). 3. Host Characteristics: ○ Immunity: Active: Long-term immunity from natural infection or vaccination. Passive: Short-term immunity from transferred antibodies (e.g., maternal antibodies). ○ Herd Immunity: Resistance in a community due to a high proportion of immune individuals. ○ Other factors: Incubation period, carrier status, subclinical illness. 4. Infectious Agent Properties: ○ Infectivity: Ability to enter and multiply in a host. ○ Pathogenicity: Ability to cause disease. ○ Virulence: Severity of disease symptoms. ○ Toxins: Substances produced by agents causing illness (e.g., botulism). Disease Transmission 1. Direct Transmission: ○ Person-to-person contact. 2. Indirect Transmission: ○ Vehicle-borne: Contaminated objects (e.g., doorknobs, water). ○ Airborne: Spread of droplet nuclei (e.g., COVID-19). ○ Vector-borne: Insects or animals (e.g., malaria via mosquitoes). 3. Key Concepts: ○ Portal of Entry/Exit: Pathways for agents to enter or leave the body (e.g., respiratory tract, skin). ○ Reservoirs: Places where agents live and multiply (e.g., humans, animals, soil). ○ Zoonosis: Diseases transmitted from animals to humans (e.g., rabies). Outbreak Investigation Steps 1. Define the Problem: ○ Identify patterns and symptoms (e.g., fever, rash). ○ Use epidemic curves to visualize case distributions.  2. Data Analysis: ○ Incubation Period: Time between agent invasion and symptom onset. ○ Attack Rate: Formula: Attack Rate=(IllIll + Well)×100\text{Attack Rate} = \left(\frac{\text{Ill}}{\text{Ill + Well}}\right) \times 100Attack Rate=(Ill + WellIll​)×100. 3. Formulate Hypotheses: ○ Use case mapping and other tools to hypothesize potential causes. 4. Test Hypotheses: ○ Confirm using laboratory results or statistical analysis. 5. Conclusions and Prevention: ○ Plan for prevention of future outbreaks. Significant Infectious Diseases 1. Sexually Transmitted Infections (STIs): ○ Examples: HIV/AIDS, Gonorrhea. 2. Foodborne Diseases: ○ Agents: Salmonella, E. coli. 3. Vector-Borne Diseases: ○ Examples: Lyme disease (ticks), malaria (mosquitoes). 4. Zoonotic Diseases: ○ Examples: Rabies, anthrax. 5. Emerging Infections: ○ Examples: Ebola, MPox. 6. Bioterrorism-Related Diseases: ○ Example: Anthrax as a weapon. Conclusion Infectious diseases remain a global challenge due to new diseases, bioterrorism risks, and antibiotic resistance. CHATPER 12 Key Topics and Definitions 1. Molecular and Genetic Epidemiology: ○ Molecular Epidemiology: Uses molecular biology to improve exposure-disease measurements.  ○ Genetic Epidemiology: Focuses on inherited factors influencing disease and their interaction with the environment. ○ Human Genome Project (HGP): A breakthrough for studying genetic-environmental interactions. 2. Environmental Epidemiology: ○ Studies diseases linked to environmental factors. ○ Key issues: air pollution, toxic chemicals, heavy metals, global warming, and radiation from nuclear facilities. 3. Occupational Epidemiology: ○ Focuses on work-related health hazards (e.g., noise, toxic chemicals, stress). ○ COVID-19 highlighted healthcare workers' risks. 4. Unintentional Injuries: ○ Major causes: poisoning (e.g., drug overdose), motor vehicle accidents, falls, drowning. ○ Falls: Leading cause of injuries for individuals 65+. Detailed Concepts 1. Genetic Markers: ○ Host factors increasing disease susceptibility after exposure. ○ Example: BRCA1/BRCA2 genes linked to higher cancer risks. 2. Environmental Health Topics: ○ Air Pollution: Linked to heart disease, lung cancer, and asthma. Examples include the 1948 Donora smog and London’s 1952 fog. ○ Global Warming: Causes include fossil fuels and deforestation; impacts include disease spread and extreme weather. ○ Toxic Chemicals: DDT: Prohibited due to health impacts. PFAS: Persistent environmental contaminants. ○ Heavy Metals: Lead: Found in old paints, fuels, linked to neurological damage. Mercury: Hazardous, especially for unborn children. 3. Radiation Incidents: ○ Three Mile Island (1979): No immediate deaths, psychological impact. ○ Chernobyl (1986): Thyroid cancer spike due to exposure. ○ Fukushima (2011): Displacement led to mental health challenges. 4. Other Applications: ○ Pharmacoepidemiology: Studies drug/vaccine effects (e.g., thalidomide). ○ Disaster Epidemiology: Evaluates disaster impacts and priorities. ○ Screen-Based Media Use: Linked to metabolic issues and cognitive effects. ○ Violence Epidemiology: Includes high school dating violence and bullying. Figures and Examples Fall Mortality: Increasing, especially among the elderly. Global Warming Graph: Earth’s temperature rises by ~0.2°C/decade. Chapter 11 Leading Causes of Death & Health Factors Major preventable causes: tobacco, poor diet/inactivity, alcohol, toxic agents 3 Key Models & Frameworks Biopsychosocial Model: Integrates biological, psychological, and social factors in disease 7 Ecological Model: Five influence levels affecting health behavior: Individual, interpersonal, institutional, community, and policy levels 8 Mental Health & Stress Stress definition: Physical, chemical, or emotional factor causing bodily/mental tension 10 Mental disorders show patterns by person, place, and time 22 Social support from friends/family helps during stress periods 11 Behavioral Factors Lifestyle choices significantly impact chronic diseases 10 Individual behavior and social influences affect health outcomes