Epidemiology Basics Quiz

Epidemiology Statistics Overview

• Epidemiology is the study of the distribution and determinants of health-related states in populations.
• This involves the application of this towards the prevention and control of health problems (diseases).
• Key figures like AIDS, caused by HIV, illustrate real-world examples.
• Globally, an average of 39.9 million people were affected by AIDS in 2023, with 1.4 million being children under 15.
• Estimated AIDS-related deaths in 2023 stood at 630,000.

Epidemiology and Public Health

• Epidemiology is integral to public health practice and individual decision-making.
• It plays a role in monitoring population health, responding to emerging public health problems through disease investigation, promoting research and evidence-based interventions, evaluating public health programs, setting research priorities, and determining priorities for public health action.
• Epidemiological methods include monitoring the health of a population, responding to emerging public health problems, promoting research, evaluating existing programs, setting funding priorities, establishing research priorities, targeting interventions, studying the natural history of diseases, and surveillance of disease occurrence.
• Disease distribution is not random in populations.

Types of Epidemics

• Endemic: Diseases consistently present within a population at predictable rates. Examples include malaria in Africa and chickenpox in the US.
• Epidemic: A sudden increase in disease cases exceeding the expected normal rate. For instance, the SARS event.
• Pandemic: Widespread epidemic spreading across multiple countries or continents in human populations. Examples include HIV/AIDS in the early 20th century and COVID-19 in 2020.
• Outbreak: A sudden increase in case numbers but within a localized geographic area, like an Ebola outbreak in a region.
• Sporadic: infrequently occurring diseases within a community.
• Cluster : an aggregation of cases that exceed the expected number in a particular place and time.

Levels of Prevention

• Primary prevention aims to prevent diseases before they occur by promoting health, providing health education, and implementing health protection measures (lifestyle, good behavioral practices, proper nutrition, and sanitation).
• Secondary prevention focuses on early detection and screening to halt disease progression and prevent further impairment or disability.
• Tertiary prevention aims to mitigate further impairment or disability for those already affected by the disease, providing rehabilitation and support services.

Epidemiological Investigations

• Epidemiologic investigations involve descriptive and analytical methods for identifying determinants of diseases within a population (using frequencies, rates, proportions, percentages, geographical locations, ethnicity, and time).
• Example: In 1981, the Centers for Disease Control and Prevention (CDC) reported cases of pneumonia in young men, and later classified this illness as AIDS linked to HIV.

Data Types

• Risk factor: A condition associated with an increased probability of a health-related state (e.g., smoking increases risk of chronic diseases).

Measuring Disease Frequency

• Morbidity: The unhealthy state of an individual or population
• Mortality: The state of being dead in an individual or population
• Data points like rates of death and cases are measures of disease frequency.

Study Designs

• Descriptive Studies: They can include case reports or series (individual-based data), cross-sectional studies (population-based), and correlational studies.
• Analytical Studies: Analytical designs include cohort and case-control studies.
• Interventional Study Designs: These employ the same approach as experimental designs, with subjects being randomly assigned to different intervention groups.

Study Timeframes

• Prospective Studies: look forward in time to study future events, following a specific condition or disease to the future.
• Retrospective Studies: look back in time to study past events that have already taken place.

Validity and Reliability

• Reliability: (or robustness) describes the degree of stability when a measurement is repeated under identical conditions. Measurements are considered reliable if they correlate well under those conditions. Factors like divergence between observers or instruments, and instability in the measured attribute, can undermine reliability. Reliability assesses instruments for test-retest, alternate-form, and internal consistency.
• Validity: a measure of the accuracy of data obtained using a particular method. Face, content, criterion, and construct validity are commonly assessed components to confirm accuracy.

Calculating Prevalence and Incidence Rates

• Prevalence Rate: (P): The total number of cases during a specified time period divided by the total number of people in the population.
• Incidence Rate: (IR): The number of new cases during a specified time period divided by the total person-time at risk.

Calculating Odds Ratios / Relative Risk

• Relative Risk: (RR): This compares the risk of an event in one group to that of another.
• Odds Ratio: (OR): It compares the odds of an event occurring in one group with the odds of it happening in another group.

Test your knowledge on key concepts in epidemiology, including disease prevention levels and rates of morbidity and incidence. This quiz covers definitions, classifications, and characteristics of diseases and epidemics. Perfect for students and health professionals alike!