Test Your Knowledge of Epidemiology

Epidemiology: The Study of Health and Disease Within a Population

• Epidemiology is the study and analysis of the distribution, patterns, and determinants of health and disease conditions in a defined population.

• Epidemiology is a cornerstone of public health, shaping policy decisions and evidence-based practice by identifying risk factors for disease and targets for preventive healthcare.

• Epidemiologists help with study design, collection, and statistical analysis of data, amend interpretation and dissemination of results, and rely on other scientific disciplines like biology, statistics, social sciences, and engineering.

• Major areas of epidemiological study include disease causation, transmission, outbreak investigation, disease surveillance, environmental epidemiology, forensic epidemiology, occupational epidemiology, screening, biomonitoring, and comparisons of treatment effects.

• The term "epidemiology" appears to have first been used to describe the study of epidemics in 1802 by the Spanish physician Villalba in Epidemiología Española.

• 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 such as high blood pressure, mental illness, and obesity.

• The Greek physician Hippocrates, known as the father of medicine, sought a logic to sickness and is the first person known to have examined the relationships between the occurrence of disease and environmental influences.

• Modern epidemiological studies can use advanced statistics and machine learning to create predictive models as well as to define treatment effects.

• Epidemiologists employ a range of study designs from the observational to experimental and generally categorized as descriptive, analytic, and experimental.

• Case-series may refer to the qualitative study of the experience of a single patient or small group of patients with a similar diagnosis or to a statistical factor with the potential to produce illness with periods when they are unexposed.

• The former type of study is purely descriptive and cannot be used to make inferences about the general population of patients with that disease, while the latter is used to compare the incidence rate of a given outcome between exposed and unexposed periods.

• Case-control studies select subjects based on their disease status and compare a group of individuals that are disease positive (the "case" group) with a group of disease-negative individuals (the "control" group).

• The statistic generated to measure association is the odds ratio.Epidemiology: Understanding Disease and Health

• Case-control studies select subjects based on their disease status while cohort studies select subjects based on their exposure status.

• The odds ratio (OR) is used in case-control studies to assess the likelihood of exposure in cases compared to controls.

• If the OR is significantly greater than 1, then those with the disease are more likely to have been exposed.

• Cohort studies follow a group of subjects over time to assess their outcome status while accounting for their exposure status.

• The relative risk (RR) is used in cohort studies to assess the probability of disease for a person in the exposed group over the probability of disease for a person in the unexposed group.

• Epidemiological studies aim to establish causal relationships between exposures and outcomes but correlation does not imply causation.

• The Bradford Hill criteria provide a series of considerations to assess evidence of causation.

• Epidemiological studies can be used to investigate specific causation of disease or injury in legal settings.

• Epidemiological analysis makes a significant contribution to emerging population-based health management frameworks.

• Applied field epidemiology involves using epidemiological methods to investigate communicable and non-communicable disease outbreaks, mortality and morbidity rates, and nutritional status.

• The methodologies used to report data in humanitarian crisis situations can compromise the surveillance and reporting of diseases and other health factors.

• Validity in epidemiological studies is dependent on the degree of systematic error, including selection bias, information bias, and confounding.Epidemiology: The Study of Disease Distribution and Control

• Confounding is a major issue in epidemiology as it stems from real causal effects and can affect study results.

• Epidemiology is not commonly offered as an undergraduate course but can be taken as a graduate-level course or through Masters or Doctoral programs.

• Formal training programs in epidemiology can be set in either schools of public health or medical schools.

• Epidemiologists work in various settings, including community health protection services, non-profit organizations, and government entities.

• Epidemiologists can also work in for-profit organizations such as pharmaceutical and medical device companies.

• The COVID-19 pandemic has brought epidemiology to the forefront of scientific disciplines across the globe.

• Epidemiology studies the incidence, distribution, and control of disease in a population.

• Johns Hopkins University offers an undergraduate program in public health that includes epidemiology courses.

• Formal training programs in epidemiology include Master of Public Health, Master of Science of Epidemiology, and Doctor of Public Health, among others.

• Epidemiologists who work in the field are often at the forefront of investigating and combating disease outbreaks.

• Epidemiologists can work for organizations such as the Centers for Disease Control and Prevention, World Health Organization, or Public Health Agency of Canada.

• Epidemiologists study diseases in populations and are responsible for identifying the causes and patterns of disease.