Epidemiology Primer: Focus on Disease Prevention

Vocabulary flashcards covering fundamental epidemiological terms, disease definitions, measurement metrics, and statistical concepts from the lecture.

Epidemiology

The study of the distribution and determinants of health-related states or events (including disease), and the application of this study to the control of diseases and other health problems.

Descriptive Studies

Epidemiological investigations used to study the distribution of health-related states or events.

Analytical Studies

Epidemiological investigations used to study the determinants of health-related states or events.

Acute Disease

A deterioration in health with rapid onset that lasts hours to weeks and resolves, transitions into a chronic condition, or results in death.

Chronic Disease

Impaired health that continues controlled or progressing for long periods of time, with symptoms generally less severe than the acute phase.

Period Life Expectancy

The number of years the average person born in a certain year would live if they experienced the same chances of dying at each age as people did that year.

Ratio

An expression of the relationship between two numbers in the form of $x:y$ or $\frac{x}{y}$.

Proportion

A specific type of ratio where the numerator is included in the denominator and the result is expressed as a percentage.

Rate

A special form of proportion that includes a specification of time.

Mortality Rate

A measure of the number of people dying in a given time period per $100,000$ population.

Survival Rate

The percentage of people with a specific condition who live for a given period of time after diagnosis.

Prevalence Rate

A measure of the number of people in a population who have a disease at a given time, calculated as $\frac{\text{number of existing cases}}{\text{total population at a point in time}}$.

Incidence Rate

A measure related to the probability that healthy people will develop a disease during a specified period of time, calculated as $\frac{\text{number of new cases}}{\text{population at risk over a period of time}}$.

Prognosis

The outcome of a disease, which includes both morbidity and mortality (M&M).

Aging

A normal, progressive, and irreversible process that affects all individuals.

Age-Dependent Diseases

Diseases that will occur to some extent in all individuals with time, such as senile degeneration of the skin, degenerative arthritis, osteoporosis, presbyopia, and endocrine changes.

Age-Related Diseases

Diseases that occur as an individual ages but do not occur in all people and are not part of the normal aging process, such as atherosclerosis, hypertension, and Alzheimer's disease.

Type 1 Error

An error made when concluding that comparison groups are different when in truth they are not, represented by $p\text{-values}$ or $\alpha$.

Type 2 Error

An error made when concluding that there is no difference between comparison groups when a difference actually exists.

Statistical Power

Calculated as $1 - P(\text{Type 2 error})$, representing a study's ability to rule out false negative findings, with adequate power generally being in the $80\%\text{--}90\%$ range.

Confidence Interval

An estimated range of values calculated from a set of sample data that is likely to include an unknown population parameter, commonly set at $95\%$.

Relative Risk (Risk Ratio)

The probability of an event when exposed divided by the probability of the event when not exposed, calculated as $RR = \frac{\frac{a}{a+b}}{\frac{c}{c+d}}$.

Odds Ratio (OR)

A statistic used to compare the relative odds of the occurrence of an outcome of interest given exposure to a variable of interest.

Validity of Screening Tests

The ability of a test to distinguish between who has a disease and who does not, composed of sensitivity and specificity.

Sensitivity

The ability of a test to identify correctly who has the disease, defined as the proportion of diseased people who are correctly identified (True Positive Rate).

Specificity

The ability of a test to identify correctly who does not have the disease, defined as the proportion of non-diseased people who are correctly called negative (True Negative Rate).

Ecological Fallacy

The assumption that a population average has a simple interpretation when considering likelihoods or outcomes for an individual.