Bioepi PDF - Introduction to Epidemiology

LESSON 1: INTRODUCTION TO EPIDEMIOLOGY: Ms. Ermina/Prelim/1st Semester 1. What is the primary goal of epidemiology? STUDY Th...

LESSON 1: INTRODUCTION TO EPIDEMIOLOGY: Ms. Ermina/Prelim/1st Semester 1. What is the primary goal of epidemiology? STUDY The primary goal of epidemiology is to understand and improve Epidemiology is a scientific discipline with sound methods of population health by studying the distribution, determinants, and control scientific inquiry at its foundation. Epidemiology is date-driven and relies of diseases and health conditions in defined populations. This includes on a systematic and unbiased approach to the collection, analysis, and identifying risk factors, tracking disease patterns, and developing interpretation of data. Basic epidemiologic methods tend to rely on careful strategies for prevention and intervention. observation and use of valid comparison groups to assess whether what 2. How do epidemiologists determine risk factors for a disease? was observed, such as the number of cases of disease in a particular are Epidemiologists determine risk factors for a disease through during a particular time period or the frequency of an exposure among various methods: persons with disease, differs from what might be expected. However, Conducting observational studies (e.g., cohort studies, case- epidemiology also draws on methods from other scientific fields, including control studies) biostatistics and informatics, with biologic, economic, social, and Analyzing data from surveys and health records behavioral sciences. Performing statistical analyses to identify correlations between potential risk factors and diseases occurrence. In fact, epidemiology is often described as the basic science of Designing and implementing experimental studies when ethical public health, and for good reason. First, epidemiology is a quantitative and feasible discipline that relies on a working knowledge of probability, statistics, and Reviewing existing literature and meta-analyses sound research methods. Second, epidemiology is a method of causal 3. Why is it important to study disease patterns in populations rather reasoning based on developing and testing hypotheses grounded in such than individuals? scientific fields as biology, behavioral sciences, physics, and ergonomics Studying disease patterns in populations is important because: to explain health-related behaviors, states, and events. However. It allows for the identification of trends and patterns that may Epidemiology is not just a research activity but an integral component of not be apparent at the individual level public health, providing the foundation for directing practical and Population-level data can reveal risk factors and protective appropriate public health action based on this science and causal factors that influence disease occurrence reasoning. It helps in understanding the overall impact of diseases on public health DISTRIBUTION Population studies enable the development of broader public Epidemiology is concerned with the frequency and pattern of health health strategies and policies events in a population: Frequency refers not only to the number of health events such It allows for comparisons between different populations or subgroups as the number of cases of meningitis or diabetes in a population, but also 4. How can epidemiological data inform public health policies? to the relationship of that number to the size of the population. The Epidemiological data can inform public health policies by: resulting rate allows epidemiologists to compare disease occurrence across different populations. Identifying high-risk populations or areas that require targeted Pattern refers to the occurrence of health-related events by time, interventions place, and person. Time patterns may be annual, seasonal, weekly, daily, Providing evidence for the effectiveness of prevention strategies hourly, weekday versus weekend, or any other breakdown of time that may Guiding resource allocation for health programs influence disease or injury occurrence. Place patterns include geographic Informing the development of screening and vaccination variation, urban/rural differences, and location of work sites or schools. programs Personal characteristics include demographic factors which may be related Supporting the creation of health education and awareness to risk illness, injury, or disability such as age, sex, marital status, and campaigns socioeconomic status, as well as behaviors and environmental exposures. Helping to evaluate the impact of existing policies and Characterizing health events by time, place, and person are activities of interventions descriptive epidemiology, discussed in more detail later in this lesson. 5. What are some challenges in conducting epidemiological studies? Some challenges in conducting epidemiological studies include: DETERMINANTS Ensuring representative sampling and adequate sample size Epidemiology is also used to search for determinants, which Controlling for confounding variables are the causes and other factors that influence the occurrence of disease Dealing with bias (e.g., recall bias, selection bias) and other health-related events. Epidemiologists assume that illness does Ethical considerations, especially in experimental studies not occur randomly in a population, but happens only when the right Long time frames required for some studies (e.g., cohort studies) accumulation of risk factors or determinants exists in an individual. To Difficulty in establishing causality rather than just association search for these determinants, epidemiologists use analytic epidemiology Handling missing or incomplete data or epidemiologic studies to provide the “Why” and “How” of such events. Addressing rapidly changing conditions (e.g., during disease They assess whether groups with different rates of disease differ in their outbreaks demographic characteristics, genetic or immunologic make-up, behaviors, Balancing the need for timely information with the rigor of environmental exposures, or other so-called potential risk factors. Ideally, scientific methods the findings provide sufficient evidence to direct prompt and effective public health control and prevention measures. SECTION 1: DEFINITION OF EPIDEMIOLOGY The word epidemiology comes from the Greek words epi, HEALTH-RELATED STATES OR EVENTS meaning on or upon, demos, meaning people, and logos, meaning the study Epidemiology was originally focused exclusively on epidemics of. In other words, the word epidemiology has its roots in the study of what of communicable diseases but was subsequently expanded to address befalls a population. Many definitions have been proposed, but the endemic communicable diseases and non-communicable infectious following definition captures the underlying principles and public health diseases. By the middle of the 20 th Century, additional epidemiologic spirit of epidemiology: methods had been developed and applied to chronic diseases, injuries, birth defects, maternal-child health, occupational health, and environmental Epidemiology is the study of the distribution and determinants of health- health. Then epidemiologists began to look at behaviors related to health related states or events in specified populations, and the application of and well-being, such as amount of exercise and seat belt use. Now, with this study to the control of health problems. the recent explosion in molecular methods, epidemiologists can make important strides in examining genetic markers of disease risk. Indeed, the Key terms in this definition reflects some of the important principles of term health-related states or events may be seen as anything that affects epidemiology. the well-being of a population. Nonetheless, many epidemiologists still use the term “disease” as shorthand for the wide range of health-related states and events that are studied.  LESSON 1: INTRODUCTION TO EPIDEMIOLOGY: Ms. Ermina/Prelim/1st Semester SPECIFIED POPULATIONS considered the “father of field epidemiology.” Twenty years before the Although epidemiologists and direct health-care providers development of the microscope, Snow conducted studies og cholera (clinicians) are both concerned with occurrence and control of disease, outbreaks both to discover the cause of disease and to prevent its they differ greatly in how they view “the patient.” The clinician is recurrence. Because his work illustrates the classic sequence from concerned about the health of an individual; the epidemiologist is descriptive epidemiology to hypothesis generation to hypothesis testing concerned about the collective health of the people in a community or (analytic epidemiology) to application, two of his investigations will be population. In other words, the clinician’s “patient” is the individual; the described in detail. epidemiologist’s “patient” is the community. Therefore, the clinician and Snow conducted one of his now famous studies in 1854 when an the epidemiologist have different responsibilities when faced with a epidemic of cholera erupted in the Golden Square of London. He began person with illness. For example, when a patient with diarrheal disease his investigation by determining where in this are persons with cholera presents, both are interested in establishing the correct diagnosis. lived and worked. He marked each residence on a map of the area, as However, while the clinician usually focuses on treating and caring for the shown in Figure 1.1. Today, this type of map, showing the geographic individual, the epidemiologist focuses on identifying the exposure or distribution of cases, is called a spot map. source that caused the illness; the number of other persons who many have been similarly exposed; the potential for further spread in the community; Figure 1.1 Spot map of deaths from cholera in Golden Square area, and interventions to prevent additional cases or recurrences. London, 1854 (redrawn from original) APPLICATION Epidemiology is not just “the study of” health in a population; it also involves applying the knowledge gained by the studies to community- based practice. Like the practice of medicine, the practice of epidemiology is both a science and an art. To make the proper diagnosis and prescribe appropriate treatment for a patient, the clinician combines medical (scientific) knowledge with experience, clinical judgment, and understanding of the patient. Similarly, the epidemiologist used the scientific methods of descriptive and analytic epidemiology as well as experience, epidemiologic judgment, and understanding of local conditions in “diagnosing” the health of a community and proposing appropriate, practical, and acceptable public health interventions to control and prevent disease in the community. SUMMARY Epidemiology is the study (scientific, systematic, data-driven) of distribution (frequency, pattern) and determinants (causes, risk factors) of health-related states and events (not just diseases) in specified populations Because Snow believed that water was a source of infection for (patient is community, individuals viewed collectively), and the cholera, he marked the location of water pumps in his spot map, then application of (since epidemiology is a discipline within public health) this looked for a relationship between the distribution of households with cases study to the control of health problems. of cholera and the location of pumps. He noticed that more case households clustered around Pump A, the Broad Street pump, than around SECTION 2: HISTORICAL EVOLUTION OF EPIDEMIOLOGY Pump B or C. When he questioned residents who lived in the golden Although epidemiology as a discipline has blossomed since Square area, he was told that they avoided Pump B because it was grossly World War II, epidemiologic thinking has been traced from Hippocrates contaminated, and that Pump C was located too inconveniently for most through John Graunt, Willian Farr, John Snow, and others. The of them. From this information, Snow concluded that the Broad Street contributions of some of these early and more recent thinkers are described pump (Pump A) was the primary source of water and the most likely source below. of infection for most persons with cholera in the Golden Square area. He noted with curiosity, however, that no cases of cholera has occurred in a Circa 400 B.C. two-block area just to the east of the Broad Street pump. Upon Hippocrates attempted to explain disease occurrence from a investigating, Snow found a brewery located there with a deep well on the rational rather than a supernatural viewpoint. In his essay entitled (On Airs, premises, Brewery workers got their water from this well, and also Waters, and Places,” Hippocrates suggested that environmental and host received a daily portion of malt liquor. Access to these uncontaminated factors such as behaviors might influence the development of disease. rations could explain why none of the brewery’s employees contracted cholera. Epidemiology’s roots are nearly 2,500 years old. To confirm that the Broad Street pump was the source of the 1662 epidemic, Snow gathered information on where persons with cholera had Another early contributor to epidemiology was John Graunt, a obtained their water. Consumption of water from the Broad Street pump London haberdasher and councilman who published a landmark analysis was the one common factor among the cholera patients. After Snow of mortality data in 1662. The publication was the first to quantify patterns presented his findings to municipal officials, the handle of the pump was of birth, death, and disease occurrence, noting disparities between males removed and the outbreak ended. The site of the pump is now marked by and females, high infant mortality, urban/rural differences, and seasonal a plaque mounted on the wall outside of the appropriately named John variations. Snow Pub. 1800 William Farr built upon Graunt’s work by systematically collecting and analyzing Britain’s mortality statistics. Farr, considered the father of modern vital statistics and surveillance, developed many of the basic practices used today in vital statistics and disease classification. He concentrated his efforts on collecting vital statistics, assembling and evaluating those data, and reporting to responsible health authorities and the general public. 1854 In the mid-1800s, an anesthesiologist named John Snow was conducting a series of investigations in London that warrant his being  LESSON 1: INTRODUCTION TO EPIDEMIOLOGY: Ms. Ermina/Prelim/1st Semester Figure 1.2 John Snow Pub, London of the water intake of the Southwark and Vauxhall Company to avoid sources of contamination. Thus, with no knowledge of the existence of microorganism, Snow demonstrated through epidemiologic studies that water could serve as a vehicle for transmitting cholera and that epidemiologic information could be used to direct prompt and appropriate public health action. 19TH AND 20TH CENTURIES In the mid-and-late-1800s, epidemiological methods began to be applied in the investigation of disease occurrence. At that time, most investigators focused on acute infectious diseases. The period since World War II has been an explosion in the development of research methods and the theoretical underpinnings of epidemiology. Epidemiology has been applied to the entire range of health-related outcomes, behaviors, and even Snow’s second investigation reexamined data from the 1854 knowledge and attitudes. The studies by Doll and Hill linking lung cancer cholera outbreak in London. During a cholera epidemic a few years earlier, to smoking and the study of cardiovascular disease among residents of Snow had noted that districts with the highest death rates were serviced by Framingham, Massachusetts are two examples of how pioneering two water companies: the Lambeth Company and the Southwark and researchers have applied epidemiologic methods to chronic disease since Vauxhall Company. At that time, both companies obtained water from the World War II. During the 1960s and early 1970s health workers applied Thames River at intake points that were downstream from London and epidemiologic methods to eradicate naturally occurring smallpox thus susceptible to contamination from London sewage, which was worldwide. This was an achievement in applied epidemiology of discharged directly into the Thames. To avoid contamination by London unprecedented proportions. sewage, in 1852 the Lambeth Company moved its intake water works to a site on the Thames well upstream from London. Over a 7-week period In the 1980s, epidemiology was extended to the studies of during the summer of 1854, Snow compared cholera mortality among injuries and violence. In the 1990s, the related fields of molecular and districts that received water from one or the other or both water companies. genetic epidemiology (expansion of epidemiology to look at specific The results are shown in Table 1.1. pathways, molecules and genes that influence risk of developing disease) took root. Meanwhile, infectious diseases continued to challenge epidemiologists as new infectious agents emerged (Ebola virus, Human Immunodeficiency virus (HIV)/Acquired Immunodeficiency Syndrome (AIDS)), were identified (Legionella, Severe Acute Respiratory Syndrome SARS)), or changed (drug-resistant Mycobacterium tuberculosis, Avian influenza). Beginning in the 1990s and accelerating after the terrorist attacks of September 11, 2001, epidemiologists have had to consider not only natural transmission of infectious organisms but also deliberate spread through biologic warfare and bioterrorism. Today, public health workers throughout the world accept and use epidemiology regularly to characterize the health of their communities The data in Table 1.1 show that the cholera death rate wan more and to solve day-to-day problems, large and small. than 5 times higher in districts served only by the Southwark and Vauxhall Company (intake downstream from London) than in those served only by the Lambeth Company (intake upstream from London). Interestingly, the morality rate in districts supplied by both companies fell between the rates for districts served exclusively by either company. These data were consistent with the hypothesis that water obtained from the Thames below London was a source of cholera. Alternatively, the populations supplied by the two companies may have differed on other factors that affected their risk of cholera. To test his water supply hypothesis, Snow focused on the districts served by both companies, because the households within a district were generally comparable except for the water supply company. In these districts, Snow identified what water supply company for every house in which a death from cholera has occurred during the 7-week period. Table 1.2 shows his findings. This study, demonstrating a higher death rate from cholera among households served by the Southwark and Vauxhall Company in the mixed districts, added support to Snow’s hypothesis. It also established the sequence of steps used by current-day epidemiologists to investigate outbreaks of disease. Based on a characterization of the cases and population at risk by time, place, and person, Snow developed a testable hypothesis. He then tested his hypothesis with a more rigorously designed study, ensuring that the groups to be compared were comparable. After this study, efforts to control the epidemic were directed at changing the location  LESSON 1: INTRODUCTION TO EPIDEMIOLOGY: The Science of Public Health Ms. Ermina/Prelim/1st Semester DEFINITION AND ORIGIN OF EPIDEMIOLOGY specific factors increases the risk of a disease, or it might refute the Etymology: Greek roots “epi” (upon), “demos” (people), hypothesis. “logos” (study of). The word epidemiology has its roots in the study of what befalls a 8. Communication and Application population. The findings are communicated to public health authorities, Definition: The study of the distribution and determinants policymakers, and the scientific community. This information is used to of health-related states or events in specified populations, develop public health interventions, such as vaccination programs, and the application of this study to control health problems. health education campaigns, or regulations to reduce exposure to harmful substances. EPIDEMIOLOGY AS STUDY 9. Replication and Validation Scientific inquiry using systematic methods. Other researchers may replicate the study or conduct further Relies on careful observation and valid comparison groups. research to validate the findings. Consistent results across multiple studies strengthen the evidence for causality. Incorporates methods from biostatistics, informatics, biology, economics, and social sciences. Involves processes and methodologies particularly anchored on the EPIDEMIOLOGY AS BASIC SCIENCE OF PUBLIC HEALTH Scientific Method or Scientific Inquiry. 1. Quantitative Discipline – relies on probability, statistics and sound research methods. SCIENTIFIC METHOD 2. Method of causal reasoning based on developing and testing hypotheses grounded. A systematic approach used by scientists and researchers to investigate phenomena, acquire new knowledge, or correct DISTRIBUTION and integrate previous knowledge. Epidemiology as study of Distribution A continuous process, which usually begins with observations Distribution: Frequency and pattern of health events. about the natural world. Frequency: Number of cases relative to population size STEPS: Pattern: Occurrence by time, place, and person (descriptive 1. Observation epidemiology). The process begins with the observation of a public health issue, such as an increase in cases of a particular disease or an unusual pattern of illness in a community. This might involve routine PREVALENCE RATE VS. INCIDENCE RATE surveillance data, reports from healthcare providers, or firsthand PREVALENCE RATE observations during an outbreak. 2. Formulating a Question Definition: Prevalence rate is a measure of disease frequency Based on the observation, epidemiologists formulate specific in epidemiology. questions. Represents the proportion of a population with a specific For example, “What is causing the outbreak of respiratory condition at a specific point in time (point prevalence) or over illness in a particular city? Or ?Is there an association between smoking a specified period (period prevalence). and lung cancer?” Expressed as a percentage or per 1,000 or 10,000 individuals. Important for assessing disease burden and planning public 3. Developing a Hypothesis health interventions. A hypothesis is generated to explain the observed pattern. This could involve proposing a potential cause of the disease, identifying risk factors, or suggesting a mode of transmission. For instance, “If people consume contaminated water, then they will be at higher risk of Types of Prevalence: developing cholera.” 1. Point Prevalence: Measures disease frequency at a specific point in time. 4. Designing an Epidemiological Study Example: Percentage of university students with flu on a To test the hypothesis, an appropriate study design is chosen. particular day. Common types of studies in epidemiology include: 2. Period Prevalence Descriptive Studies: Describe the distribution of disease in a Measures disease frequency over a defined time period. population (e.g., case reports, cross-sectional studies). Example: Percentage of university students who had flu during Analytical Studies: Test specific hypotheses about the a semester. relationship between exposures and outcomes (e.g., cohort 3. Lifetime Prevalence: studies, case-control studies). Measures the proportion of a population that had the condition Experimental Studies: Test interventions in controlled at any point in their life. settings (e.g., randomized controlled trials). Example: Percentage of adults who have ever experience depression. 5. Data Collection Example: Asthma Prevalence in a City Data is collected through various methods, including surveys, Let’s say you want to determine the point prevalence of medical records, laboratory tests, or field investigations. This data asthma in a city with a population of 200,000 people. includes information on disease occurrence, potential exposures, and Scenario: After conducting a survey, you find that 8,000 other relevant factors. people in the city have asthma on the day of the survey. Calculation: 6. Analysis Prevalence Rate = (Number of existing cases of asthma/Total The data is analyzed using statistical methods to determine if population) x 100 there is an association between the exposure and the disease. In Prevalence Rate = (8,000/200,000) X 100 = 4% epidemiology, measures like relative risk, odds ratios, and incidence Interpretation: The point prevalence of asthma in this city is rates are commonly used. 4%, meaning that 4% of the city’s population has asthma at the specific point in time when the survey was conducted. 7. Conclusion This percentage helps public health officials understand the Based on the analysis, conclusions are drawn about the burden of asthma in the city an can inform decision on healthcare hypothesis. For instance, the study might confirm that exposure to a resources, asthma management programs, and environmental policies aimed at reducing asthma triggers.  LESSON 1: INTRODUCTION TO EPIDEMIOLOGY: The Science of Public Health Ms. Ermina/Prelim/1st Semester Incidence Rate: INCIDENCE RATE Definition: Incidence rate is a measure of the frequency with which new cases of a disease occur in a population over a Prevalence Rate: specified time period. Key concept in epidemiology for understanding disease dynamics and public health trends. Expressed as the number of new cases per population at risk Usage: in a given time period. Incidence Rate: Incidence is useful for understanding the risk of contracting a disease and for identifying new outbreaks or trends over time. Components of Incidence Rate: Prevalence Rate: Prevalence is useful for assessing the 1. Numerator: Number of new cases overall impact of a disease on a population, planning healthcare services, and allocating resources. Only includes newly diagnosed cases within the study period. Excludes pre-existing cases. Purpose: 2. Denominator: Population at risk x Time period. Incidence Rate: Incidence helps determine how quickly a Population at risk: Those capable of developing the disease. disease is spreading. Time period: Duration of observation (e.g., person-years) Prevalence Rate: Prevalence helps determine how 3. Units: Typically expressed per 1,000, 10,000, or 100,000 person- widespread the disease is within the population. years. Types of Incidence Measures: Analogy: Cumulative Incidence: The proportion of a population that Incidence Rate: The Flow of New Cases: Imagine a bathtub develops a disease over a specified period. It’s typically used when the with water running from a faucet. The water coming from the faucet population is stable and there is no loos to follow-up. represents the incidence. It’s the flow of new water (or new cases) Incidence Rate (or Incidence Density): The number of new entering the tub. cases per unit of person-time, which accounts for varying lengths of Prevalence Rate: The Water in the Tub: The water already follow-up for different individuals in a study. in the bathtub represents prevalence. It’s the total amount of water in Example: Incidence of Influenza the tub at any given time, which includes all the water that’s flowed in Suppose you are studying the incidence of influenza in a before (all existing cases). community over one year. Scenario: The community has 10,000 people at the start of the Understanding the Dynamics: year. During the year, 500 people develop influenza for the first time. If the faucet (incidence rate) is turned on very high (many new Calculation: cases), the bathtub (prevalence) will fill up quickly, assuming the water Incidence Rate: (Number of new cases/Population at risk) x isn’t draining (i.e., people aren’t recovering or dying quickly. 1,000 If the incidence rate is low (faucet is slow) but people live with Incidence Rate: (500/10,000) x 1,000 = 50 new cases per the disease for a long time (water drains slowly), the bathtub can still 1,000 people per year. have a lot of water in it (high prevalence). Interpretation: The incidence rate of influenza in this community is 50 new cases per 1,000 people per year. This means that, Why both are important? on average, 50 out of every 1,000 people in the community are expected Public Health Planning: to develop influenza during the year. Incidence helps in planning preventive measures. Like Incidence rates are crucial for understanding the risk of vaccines or screening programs, by showing where and how developing a disease and are used to identify trends in disease fast a disease is spreading. occurrence, evaluate the effectiveness of interventions, and guide public Prevalence helps in planning healthcare resources, like health policy. hospital beds, medication, or lone-term care facilities, by showing how many people need ongoing care. COMPARISON OF PREVALENCE AND INCIDENCE Definition: Key Difference: Incidence Rate: The incidence rate measures the number of Incidence Rate: new cases of a disease or condition that develop in a specific population Measures how many new cases occur during a specific time during a defined time period. period. Prevalence Rate: The prevalence rate measures the total Think of it as the rate at which people get sick. number of existing cases (both new and old) of a disease or condition in Relevant for understanding the risk of catching the disease. a specific population at a particular point in time (point prevalence) or Prevalence Rate: over a specified period (Period prevalence). Measures how many total cases exist at a particular time over a period. Focus: Incidence Rate: It focuses on the risk of developing a disease. Think of it as how many people are sick at that moment or It tells is how quickly people are getting a disease. during that period. Prevalence Rate: It focuses on the burden of disease within Relevant for understanding the burden of the disease on a a population at a certain time. community. It tells us how widespread the disease is in the population. Impact of Duration Time Factor: Diseases with short duration but high incidence (like the flu) Incidence Rate: Incidence is always tied to a time period (e.g., might have a low prevalence because people recover quickly. per year, per month). Diseases with long duration (like diabetes or HIV) might have Prevalence Rate: Prevalence can be point prevalence (at a a high prevalence or even of the incidence is low, because people live specific moment) or period prevalence (over a period). with the disease for many years. Interrelationship A high incidence rate will eventually lead to a higher prevalence rate is people do not recover quickly or if the disease is not Formula: fatal.  LESSON 1: INTRODUCTION TO EPIDEMIOLOGY: The Science of Public Health Ms. Ermina/Prelim/1st Semester Conversely, a disease with a high prevalence might not have a high Challenges: Addressing interconnected determinants for incidence if it’s a chronic condition that doesn’t have many new cases effective public health measures. over time. BIOLOGICAL AND BEHAVIORAL INTERACTIONS DETERMINANTS IN EPIDEMIOLOGY: FACTORS SHAPING Genetic predisposition and lifestyle choices. POPULATION HEALTH Example: Hereditary risk of heart disease amplified by poor diet and lack of exercise. INTRODUCTION TO EPIDEMIOLOGICAL DETERMINANTS Implications: Personalized health recommendations based on Definition: Factors influencing health conditions or diseases genetic and behavioral factors. in populations. Categories: Biological, behavioral, environmental, social, ENVIRONMENTAL AND SOCIAL INTERACTIONS economic, cultural, and political. Living conditions and socioeconomic status. Importance: Key to understanding disease spread, risk Example: Industrial areas air pollution affecting low-income factors, and public health measures. neighborhoods. Interaction: Determines often work together to influence Importance: Environmental justice and equitable health health outcomes. policies. Analytic epidemiology: Provides the “Why” and “How” of health events. CULTURAL AND POLITICAL INTERACTIONS Goal: Direct effective public health control and prevention Health beliefs influencing policy implementation. measures. Example: Cultural attitudes toward vaccination affecting public health campaigns. BIOLOGICAL DETERMINANTS Significance: Developing culturally appropriate health Genetics: Predisposition to specific diseases. policies and interventions. Immune status: Susceptibility to infections. Sex and age: Influence on disease risks. CHALLENGES IN ADDRESSING DETERMINANTS Example: Genetic predisposition to breast cancer (BRCA1/BRCA2 Complexity: Multiple interacting factors influencing health genes) outcomes. Impact: helps identify at-risk populations and tailor interventions. Measurement: Difficulty in quantifying some determinants BEHAVIORAL DETERMINANTS (e.g., cultural factors). Lifestyle choices: Smoking alcohol consumption, diet, physical activity. Long-term effects: Some determinants have delayed health Sexual Behavior: Risk of sexually transmitted infections (STIs). impacts. Substance abuse: Increased risk for various health conditions. Resource allocation: Balancing intervention across various Example: Smoking’s link to lung cancer and cardiovascular diseases. determinants. Importance: Target for public health education and interventions. EPIDEMIOLOGIST VS. CLINICIANS ENVIRONMENTAL DETERMINANTS Epidemiology: Physical environment: Housing, air quality, access to clean water. Focus: Collective health of a community or population. Geography: Climate, location, presence of disease vectors. “Patient”: The community Work Environment: Occupational hazards and exposures. Responsibility: Identify exposure, source, potential spread, Example: Higher asthma rates in urban areas with poor air quality. and interventions. Significance: Guides environmental health policies and regulations. Clinical Medicine: Focus: Health of an individual. SOCIAL AND ECONOMIC DETERMINANTS Patient: The individual Socioeconomic status (SES): Access to healthcare, nutrition, education. Responsibility: Diagnosis, treatment, and care of the Education level: Impact on health literacy and decision-making. individual. Healthcare access: Availability, affordability, and quality of services. Example: Lower life expectancy in areas with high poverty rates. Both share interest in correct diagnosis and disease occurrence. Implications: Addressing health disparities and promoting equity. APPLICATION OF EPIDEMIOLOGY IN PUBLIC HEALTH CULTURAL DETERMINANTS Combines scientific methods with experience and judgment. Cultural beliefs: Attitudes toward healthcare and illness. Health practices: Traditional medicine and religious beliefs. Aims to “diagnose” community health issues. Example: Cultural dietary practices influencing nutrition-related Proposes practical and acceptable public health interventions. diseases. Guides evidence-based decision-making for disease control Importance: Developing culturally sensitive health interventions. and prevention. Addresses various health-related states: chronic diseases, POLITICAL DETERMINANTS injuries, maternal-child health, occupational and Health policies: Government actions on healthcare systems and disease environmental health. control. Examines health-related behaviors and genetic markers of Legislation: Policies on public health issues (e.g., smoking, food disease risk. safety). Serves as the foundation for directing appropriate public Example: Impact of vaccination policies on disease prevention. health actions. Significance: Shaping public health strategies and resource allocation. INTERACTION OF DETERMINANTS Complex interplay between different categories of determinants. Example: Low SES (social) poor housing (environmental) increased disease risk Holistic approach: Considering multiple factors in health interventions.