Theoretical Frameworks - Disease Frequency and Biopsychosocial Models

Vocabulary practice flashcards covering measures of disease frequency, morbidity, mortality, burden of disease metrics, Bronfenbrenner's bioecological model, and Engel's biopsychosocial framework.

Epidemiology

The field of study examining relationships between physiological, psychological, social, and environmental events and the incidences (new cases) and prevalence (total number of cases) of chronic and infectious diseases.

Counts

A measure of disease frequency representing the total number of individuals with a specific disease.

Proportions

A measure of disease frequency representing the fraction of a population that is affected by a disease, which lacks an explicit time dimension.

Rates

A dynamic measure showing how fast a disease occurs in a population, explicitly incorporating time into the denominator.

Ratios

Measures that compare different population groups to identify which groups are at a higher risk of disease relative to others.

Prevalence

The proportion of individuals in a population who have a disease at a given point in time, calculated as the number of people with the disease at that point divided by the total population.

Prevalent Cases

All existing cases of a disease present within a population at baseline or a designated point in time.

Period Prevalence

The proportion of people in a population who have a disease at any time during a specified period, encompassing individuals with the disease at the start plus those who develop it during the period.

Incident Cases

Newly developed or newly detected cases of a disease that occur in a population over a specified period of follow-up.

Incidence Rate (Incidence Density)

A measure of how quickly individuals develop a disease, calculated as the number of new cases divided by the total person-time at risk (or the average population in the same year).

Population at Risk

The subset of a population susceptible to contracting a specific disease, excluding individuals who are incapable of developing it (e.g., excluding women who have undergone a hysterectomy when evaluating uterine cancer risk).

Incidence-Prevalence Relationship

Under steady-state conditions where population rates are stable and prevalence is low, prevalence ($P$) is approximated by the product of the incidence rate ($IR$) and the duration of disease ($D$): $P \times IR \times D$.

Incidence Proportion (Cumulative Incidence or Risk)

The proportion of healthy individuals at risk who develop a disease during a specified time period, calculated as the number of new cases divided by the number of individuals at risk at the start of the period.

Person-Time

An epidemiological denominator measuring the total duration of time (e.g., person-years, person-months) that individuals contribute while being at risk for developing a disease.

Case-Fatality

The proportion of individuals diagnosed with a specified disease who die from that disease within a specified period, calculated as: $\text{Case-fatality} = \frac{\text{Number of deaths from specified disease}}{\text{Number of individuals with specified disease}} \times 100$

Annual Mortality Rate for All Causes

The total death rate from all causes in a population per $100,000$ people, calculated as: $\text{Annual mortality rate (all causes)} = \frac{\text{Total deaths from all causes in } 1 \text{ year}}{\text{Number of persons in the population at midyear}} \times 100,000$

Annual Mortality Rate for a Specified Disease

The death rate resulting from a specific disease per $100,000$ people, calculated as: $\text{Annual mortality rate (specified disease)} = \frac{\text{Total deaths from specified disease in } 1 \text{ year}}{\text{Number of persons in the population at midyear}} \times 100,000$

Proportionate Mortality

The percentage of total deaths within a population attributable to a specific disease over a designated time period, calculated as: $\text{Proportionate mortality} = \frac{\text{Total deaths from specified disease}}{\text{Total deaths from all causes}} \times 100$

Burden of Disease

A quantitative measurement of the gap between a population's current health status and an optimal state where all individuals attain full life expectancy without suffering major ill-health.

Years of Potential Life Lost (YPLL)

A measurement of premature mortality calculated by subtracting the age at death from a predetermined average lifespan (e.g., $75$ or $80$) and summing the values across a population.

Disability-Adjusted Life Years (DALYs)

A composite metric representing the loss of the equivalent of $1\text{ year}$ of full health, calculated as: $\text{DALYs} = \text{YLLs} + \text{YLDs}$ where $\text{YLLs}$ are Years of Life Lost due to premature mortality and $\text{YLDs}$ are Years Lived with Disability.

Health-Adjusted Life Expectancy (HALE)

A population-based indicator estimating the average number of years a person can expect to live in good health given current morbidity and mortality conditions.

Bronfenbrenner's Bioecological Model of Human Development

A theoretical framework conceptualizing human development as influenced by interactions across multiple nested environmental systems, ranging from immediate surroundings to broader societal and historical forces over time.

Microsystem

In Bronfenbrenner's model, the innermost environment containing direct interactions, roles, and relationships experienced by an individual in immediate settings like family, school, peers, and neighborhood.

Mesosystem

In Bronfenbrenner's model, the layer comprising interactions and linkages between two or more of an individual's microsystems (e.g., the relationship between family and school).

Exosystem

In Bronfenbrenner's model, external settings and social structures that do not contain the individual directly but indirectly influence their microsystem (e.g., parental workplace, social services, laws, policies).

Macrosystem

In Bronfenbrenner's model, the overarching cultural framework containing social ideologies, cultural values, norms, and economic systems.

Chronosystem

In Bronfenbrenner's model, the temporal component representing changes, transitions, and historical events over the course of an individual's life.

Biopsychosocial Model

A broad healthcare framework introduced by Drs. George Engel and John Romano (1977) asserting that health and illness stem from complex interactions among biological, psychological, and social/environmental factors.

Hierarchy of Natural Systems

Engel's conceptual continuum organizing nature from subatomic particles, molecules, cells, and organs up to person, family, community, culture, and biosphere, placing the person at the nexus of biological and social systems.