Untitled Quiz

Descriptive Epidemiology

• Epidemiology involves describing the who, what, when, where, and why/how of an event, aiming for comprehensiveness like reporting a newspaper story.
• Epidemiologists use synonyms for the 5Ws (what, who, where, when, why) to describe an event, from large pandemics to local increases in accidents.
• Descriptive epidemiology covers time, place, and person.

Advantages of compiling and analyzing data by time, place, and person

• Epidemiologists become very familiar with data, understanding its variables, limitations, and variations.
• Epidemiologists can learn details about a health problem in a population, such as specific neighbourhoods, months, or groups of people.
• Detailed descriptions of health in a population create tables, graphs, maps, which are easily communicated, along with identifying high-risk areas or groups within the population that could help find causes of the problem.

Time

• Occurrence of disease can change over time.
• Regular occurrences- anticipated by officials, like influenza or West Nile virus.
• Seasonal occurrences- expected in certain seasons like influenza in winter.
• Sporadic occurrences- unpredictable, like Hepatitis B.
• Time scale can range from minutes, hours, to days, months, and even decades.
• Examples- chronic diseases, foodborne outbreaks.

Place

• Insight into geographic extent of health problems and variability.
• Relates to location of residence, diagnosis, or reporting and geographic locations relevant to the disease.
• Includes birthplace, place of employment, school districts, hospital units, and urban/rural or domestic/foreign categories.
• Large area of a country, continent, or a smaller category like a street address or hospital wing.

Person

• Personal characteristics are factors in illness.
• Inherent or acquired characteristics of people (age, sex, race)
• Biological attributes (immune, genetic)
• Acquired traits like marital status, activities (occupation, leisure and use of medications/tobacco/drugs) and socioeconomic status.
• Data is displayed in tables or graphs.

Age

• The most important person attribute because health-related events commonly vary with age.
• Susceptibility, exposure opportunity, latency and physiologic response are age-dependent factors.
• Age groups are often used for detailed understanding of disease patterns.
• Chronic diseases may benefit from 10-year or 5-year age groups.

Sex

• Males generally have higher illness and death rates for various diseases.
• Genetic, hormonal, anatomic or other biological differences may explain different susceptibilities or physiologic responses to some diseases.

Ethnic and racial groups

• Differences in susceptibility, exposure, and other factors (like socioeconomic status and health care access) should be considered.
• Some diseases are more or less common in different ethnic or racial groups.

Socioeconomic Status

• This is a difficult variable to measure.
• Relevant variables to include are occupation, income, education, and social standing.

Epidemiologic studies in general

• Epidemiologists are interested in the cause of diseases and in preventative measures to minimize adverse health outcomes.
• They develop and conduct studies on risks of diseases and the effect of interventions.
• Public health officials depend on epidemiology in order to understand risk, prevent occurrence, characterize distributions, investigate, and monitor.

Types of Studies

• Case reports - describe a single patient.
• Case series - describe multiple patients.
• Cross-sectional - examines existing conditions in a group at one point in time.
• Prevalence studies and assessments.
• Ecologic - analyzes characteristics of groups.
• Cohort - involves following a group over time.
• Retrospective cohort - uses existing data.
• Prospective cohort - tracks a group forward in time.
• Case-control - study of individuals with and without a disease.
• Randomized trials - used to test treatments or interventions.