Epidemiology Epidemiology is the study and analysis of the patterns, causes, and effects of health and disease conditions in defined populations. It is the cornerstone of public health, and shapes policy decisions and evidence-based practice by identifying risk factors for disease and targets for preventive healthcare.Epidemiology
What are the three types of epidemiological approaches?
The three main types of epidemiological approaches consist of interventional epidemiology, descriptive epidemiology, and analytic epidemiology (John, 2001 ). Interventional epidemiology uses the results from the descriptive and analytic approaches to implement public health actions and health interventions in communities.
What is epidemiological approach to health management?
Epidemiological approaches to health planning, management and evaluation The promotion of health and the prevention of disease depend to a large extent on the good planning and management of health programmes. Good planning and management in turn depend on the availability of reliable, accurate and timely information about the health situation.
What is the meaning of Epidemiology?
Epidemiology is the study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems ( 1 ). Key terms in this definition reflect some of the important principles of epidemiology.
What is the relationship between epidemiology and public health?
However, epidemiology is not just a research activity but an integral component of public health, providing the foundation for directing practical and appropriate public health action based on this science and causal reasoning. ( 2) Epidemiology is concerned with the frequency and pattern of health events in a population:
What are the different epidemiological approaches?
The three major epidemiologic techniques are descriptive, analytic, and experimental. Although all three can be used in investigating the occurrence of disease, the method used most is descriptive epidemiology.
What are the 3 major types of epidemiologic studies?
Three major types of epidemiologic studies are cohort, case-control, and cross-sectional studies (study designs are discussed in more detail in IOM, 2000).
What are the 5 epidemiological principles of disease control?
The difference is that epidemiologists tend to use synonyms for the 5 W's: diagnosis or health event (what), person (who), place (where), time (when), and causes, risk factors, and modes of transmission (why/how).
What are the four methods of epidemiology?
Epidemiological investigations can be grouped into four broad categories: Observational epidemiology, experimental epidemiology, natural experiments, and Theoretical epidemiology.
What are the two main types of epidemiologic methods?
Epidemiologic studies fall into two categories: experimental and observational.
What are the 3 divisions of epidemiology?
Among the simplest of these is the epidemiologic triad or triangle, the traditional model for infectious disease. The triad consists of an external agent, a susceptible host, and an environment that brings the host and agent together.
What is epidemiology and examples?
The term epidemiology is now widely applied to cover the description and causation of not only epidemic, infectious disease, but of disease in general, including related conditions. Some examples of topics examined through epidemiology include as high blood pressure, mental illness and obesity.
What are the main objectives of epidemiology?
The objective of epidemiology is to figure out what causes different health outcomes in different groups of people. These groups can be as small as a neighborhood or as large as the global population. Epidemiologists look at symptoms, patterns, and other factors.
What are the principles of epidemiology in public health practice?
Principles of EpidemiologyDistribution - Epidemiology is concerned with the frequency and pattern of health events in a population. ... Determinants - Epidemiology is also used to search for causes and other factors that influence the occurrence of health-related events.More items...•
What is epidemiology and types of epidemiology?
By definition, epidemiology is the study (scientific, systematic, and data-driven) of the distribution (frequency, pattern) and determinants (causes, risk factors) of health-related states and events (not just diseases) in specified populations (neighborhood, school, city, state, country, global).
What are the 3 main elements of descriptive epidemiology?
Descriptive epidemiology searches for patterns by examining characteristics of person, place, & time . These characteristics are carefully considered when a disease outbreak occurs, because they provide important clues regarding the source of the outbreak.
What is epidemiology and types of epidemiology?
By definition, epidemiology is the study (scientific, systematic, and data-driven) of the distribution (frequency, pattern) and determinants (causes, risk factors) of health-related states and events (not just diseases) in specified populations (neighborhood, school, city, state, country, global).
What are the different types of study design?
Broadly speaking, there are 2 types of study designs: descriptive studies and analytical studies.
What type of studies are incidence studies?
Incidence studies are usually the preferred approach to studying the causes of disease, because they use all of the available information on the source population over the risk period.
Why is epidemiology important?
Epidemiological research helps us to understand how many people have a disease or disorder, if those numbers are changing, and how the disorder affects our society and our economy. The epidemiology of human communication is a rewarding and challenging field.
What is the burden of disease?
Burden of disease: The total significance of disease for society, beyond the immediate cost of treatment. It is measured in years of life lost to ill health, or the difference between total life expectancy and disability-adjusted life expectancy (DALY). (Adapted from the World Health Organization. (link is external)
What is the definition of incidence?
Incidence: The number of new cases of a disease or disorder in a population over a period of time.
What factors should be taken into account when calculating the cost of illness?
Ideally, the cost of illness would also take into account factors that are more difficult to measure, such as work-related costs, educational costs, the cost of support services required by the medical condition, and the amount individuals would pay to avoid health risks.
What is epidemiology in health?
Epidemiology is the study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems.
How many types of epidemiologic measures of occurrence are there?
There are ONLY five types of epidemiologic measures of occurrence. That's it! No more, no less. The multi-state model depicts a susceptible person becoming infected but not infectious (latent state), becoming infectious (infective state), then recovering (recovery state). At any time the subject can die. We can count the number of events (new infections) during some time interval, or we can count the number of subjects in a health state (e.g., susceptibles) at a point in time. We can measure the waiting time until a subject becomes newly infected. This is also call time-to-event. We can calculate the average (per capita) rate of new infections as the count of new infections divided by person-time at risk. We can calculate the risk for new infection (for a specific time interval) as the count of new infections divided by the number of subjects infection-free at the start of the time interval. Odds is just the numerical transformation of risk: (more on this later). Prevalence is the proportion that are in a specific state (e.g., susceptible) at a point in time. For epidemics, prevalence measures can change significantly over time.
What is the difference between descriptive and analytic epidemiology?
Analytic epidemiology is the complementary process of descriptive epidemiology. Whereas in descriptive epidemiology we measure and describe differences across strata, in analytic epidemiology we measure and test differences across strata (exposed vs non-exposed, for example) in order to test a causal hypothesis. In descriptive epidemiology, epidemiologists rule out chance, bias, and confounding as explanations of observed differences. In analytic epidemiology, epidemiologist control for chance, bias, and confounding in study design and data analysis (more on these later). The conclusions we draw from descriptive and analytic studies is called epidemiologic inference. Chance, bias, and confounding are always threats to making valid inferences in both types of studies. Descriptive epidemiology is backbone of studies (including public health surveillance) conducted at health departments. Analytic studies are more commonly conducted at academic institutions. However, both require require scientific rigor.
What is descriptive epidemiology?
In outbreak investigations, the process of descriptive epidemiology occurs when we describe identified cases. Immediately, we start to consider alternative explanations (chance, bias, and confounding). If the outbreak is real, we generate causal hypotheses base on our observations and on current fund of knowledge. In the ideal scenario, we have sufficient information to implement control measures. Sometimes we don't have enough information to implicate a cause, or control measures are failing. In this case, we might conduct an analytic study to test causal hypotheses. We'll cover this approach in detail in another lecture.
What is an epidemic curve?
This epidemic curve depicts a community outbreak of shigellosis in San Francisco. Epidemic curves most commonly use counts of newly identified cases (also call incident cases or incidence). We avoid the term incidence because there are other terms that use the word incidence but have very different meanings:
How to use ratios in epidemiology?
In epiodemiology we often combine numbers to construct a rate, proportion, or ratio. A rate is the change in one measure (usually counts) per change in another measure (usually person-time). In a proportion, the numerator (usually a count) is part of the denominator. We use proportions to estimate risk (2 out 10 exposed subject got ill) or prevalence (8 out of 10 injection drug users are anti-hepatitis C antibody positive). We use ratios to compare two measures. For example, a ratio of rates is called a rate ratio, and a ratio of risks is called a risk ratio.
What is public health surveillance?
Public health surveillance is the ongoing, systematic collection, analysis, interpretation, and dissemination of data about a health-related event for use in public health action to reduce morbidity and mortality and to improve health.
How did epidemiology come about?
By plotting the incidence of death on maps, he discovered an asso-ciation between deaths in various districts and the sources of drinking water. He went door to door, counting deaths and asking about those homes’ water sources. He hypothesized that the scourge was spread by contaminated water from evacu-ations of infected people. Once these sources were identifi ed, Snow removed the offending pumps’ handles even though he did not understand that it was bacteria that spread the disease. Subsequently, deaths declined.
What is epidemiology in health?
Epidemiology is the study of health and its determinants in specifi ed populations with the often unstated goal of improving health. The root word, “epidemic,” derives its origin from a study of the causes of diseases. The word has been so used for the last 125 years, and epidemiology as a discipline is mainly concerned with illness or disease rather than health and well-being. This chapter traces the historical roots of epidemiology’s evolution, its main concepts, and discusses how the way it is practised limits its potential to improve the health of populations. This chapter considers what health means at various biological and social levels, and the sources of health in populations. It is argued that the gap between rich and poor in a society is the key factor in producing health. The gap likely matters most in early life, somewhere between conception and age fi ve. Discussion of various natural experiments will help the reader to grasp this concept.
What is the positive approach to producing health?
positive and action-oriented approach to producing health would be to publicize and act upon what is known regarding the poor health status of countries such as the U.S., which have large gaps between the rich and poor, relative to other rich countries. These gaps result from lack of an egalitarian policy frame. If Canadians have no interest in producing health, they can continue to pursue policies that will increase the gap between our rich and poor, which will move Canada toward the
What is shoe leather epidemiology?
John Snow went door to door in what is called “shoe leather epidemiology” to collect information on water sources and deaths. Such observational data form the backbone of epidemiologic investigations. For a disease-focused approach, one needs to know whether or not someone has the disease, and then obtain a variety of supplemental information to discern what is going on. Suppose one studied lung cancer in a population where everyone smoked. It would be very diffi cult to identify smoking as a cause of lung cancer if you studied the disease in a population where everyone smoked since you could not compare the incidence of disease between smokers and non-smokers. Smoking as a risk factor for lung cancer would not be apparent. The kinds of questions asked to study health in a population depend on the characteristics of that population and the questions themselves. If you ask the wrong question, or study the wrong population, you will be led astray as sug-gested by our smoking example. Today the term “social epidemiology” refl ects the population or societal level of analysis.
Is medical care the leading cause of death?
Whenever it has been studied, medical care is always one of the leading causes of death (Starfi eld 2000). In studies of doctors’ strikes, the common fi nding is that mortality does not increase. In fact, it tends to go down (Cunningham et al. 2008). The public believes that postmodernism doesn’t apply to medical science. Perhaps half of what is believed to be true in medicine is not. Primary care may be the best part of medical care. Countries that have less of a specialist focus on health care services tend to have better health. Always ask: “Do you want health or health care?”
What is epidemiology in health?
Many definitions have been proposed, but the following definition captures the underlying principles and public health spirit of epidemiology: Epidemiology is the study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems ( 1 ).
What are the behaviors that epidemiologists look for?
Then epidemiologists began to look at behaviors related to health and well-being, such as amount of exercise and seat belt use. Now, with the recent explosion in molecular methods, epidemiologists can make important strides in examining genetic markers of disease risk.
How do epidemiologists and health care providers differ?
Although epidemiologists and direct health-care providers (clinicians) are both concerned with occurrence and control of disease, they differ greatly in how they view “the patient.” The clinician is concerned about the health of an individual; the epidemiologist is concerned about the collective health of the people in a community or population. In other words, the clinician’s “patient” is the individual; the epidemiologist’s “patient” is the community. Therefore, the clinician and the epidemiologist have different responsibilities when faced with a person with illness. For example, when a patient with diarrheal disease presents, both are interested in establishing the correct diagnosis. However, while the clinician usually focuses on treating and caring for the individual, the epidemiologist focuses on identifying the exposure or source that caused the illness; the number of other persons who may have been similarly exposed; the potential for further spread in the community; and interventions to prevent additional cases or recurrences.
What is epidemiology distribution?
Distribution. Epidemiology is concerned with the frequency and pattern of health events in a population: Frequency refers not only to the number of health events such as the number of cases of meningitis or diabetes in a population, but also to the relationship of that number to the size of the population.
What is the definition of determinants in epidemiology?
Determinant: any factor, whether event, characteristic, or other definable entity, that brings about a change in a health condition or other defined characteristic. Epidemiology is also used to search for determinants, which are the causes and other factors that influence the occurrence of disease and other health-related events.
What are the 5 W's of epidemiology?
The difference is that epidemiologists tend to use synonyms for the 5 W’s: diagnosis or health event (what), person (who), place (where), time (when), and causes, risk factors, and modes of transmission (why/how). The word epidemiology comes from the Greek words epi, meaning on or upon, demos, meaning people, and logos, meaning the study of.
What were the epidemiologic methods developed in the 20th century?
By the middle of the 20th Century, additional epidemiologic methods had been developed and applied to chronic diseases, injuries, birth defects, maternal-child health, occupational health, and environmental health.
