Definitions Flashcards
Epidemiology
The study of the occurrence and distribution of health-related events, state or processes in specified populations
Population health
The health outcomes of a group of individuals including the distribution of such outcomes within the group
NZDep
Area bases measure of deprivation
Absolute poverty
Income level blow which a minimum nutritionally adequate diet plus essential non-food requirements is not affordable
Relative poverty
The amount of income a person, family, or group needs to purchase a relative amount of basic necessities of life; these basic necessities are identified relative to each society and economy
Social gradient
More deprived = poorer health
Social determinants of health
The social determinants of health are the conditions in which people are born, grow, live, work and age, and the wider set of forces and systems shaping the conditions of daily life
Communicable disease
Illnesses caused by viruses or bacteria that people spread to one another through contact with contaminated surfaces, bodily fluids, blood products, insect bites, or through the air
Non-communicable disease
Disease that is not transmissible directly from one person to another
Disability-adjusted life years (DALYs)
The sum of the years of life lost due to premature mortality (YLLs) and the years lived with a disability (YLDs) due to prevalent cases of the disease or health condition in a population.
Demographic transition
Changes in a population death and birth rates over time
Epidemiological transition
Changes in population disease patterns over time
Prevalence
The proportion of a population who have the disease at a point in time
Incidence
The occurrence of new cases of an outcome in a population during a specific period of follow up
Incidence proportion
The proportion of an outcome-free population that develops the outcome of interest in a specified time period
Incidence rate
The rate at which new cases of the outcome of interest occur in a population
Age standardisation
Takes into consideration both population size and age-structure
Internal validity
Extent to which the study findings are an accurate estimate of the actual value in the source populaiton
External valditiy
Extent to which the study findings are applicable to a broader or different population
Generalisability
Parameter
A number that describes a whole population
Chance
Sampling error from random error and variation
P-values
The probability of getting a study estimate when there is really no association just because of sampling error (chance)
Ho
No difference / association
Ha
Difference / association
Type 1 error
Rejects a null hypothesis that is actually true
Type 2 error
Fails to reject a null hypothesis that is actually false
Power
How many participants are needed to minimise chance of a type 2 error
Arbitrary threshold
A value that is set without regard to specific circumstances (no consideration of clinical importance)
Bias
Any systematic error in an epidemiological study that results in an incorrect estimate of the association between exposure and risk of disease
Selection bias
A systematic difference between the people who are included in a study and those who are not, or when study and comparison groups are selected inappropriately or using different criteria
Information bias
Results from systematic differences in the way data on exposure or outcomes are obtained from the various study groups
Accuracy
How close results are to the true or known value
Precision
How close results are to one another
Non-differential misclassificaion
When measurement error and any resulting misclassification occur equally in all groups being compared
Differential misclassification
When measurement error and any resulting misclassification occur unequally in groups being compared
Recall bias
Systematic error due to differences in accuracy or completeness of recall to memory of past events or experiences
Publication bias
The results of the tendency of authors to submit, organisations to encourage, reviewers to approve and editors to publish articles containing ‘positive’ findings
Confounding
A mixing of effects when the relationship we are interested in is confused by the effect of something else
Sufficient cause
A complete causal mechanism that inevitably produces disease
Component cause
The individual factors making up a sufficient cause
Necessary cause
A component that is present in every sufficient cause of a disease
Biological plausibility
Likelihood of a cause-and-effect relationship between a biological factor and a disease or adverse event
Experimental evidence
RCT
Specificity
A single risk factor is strongly correlated with a single medical outcome
Temporal sequencing
Exposure must come before outcome
Consistency
Being consistent with other studies
Dose-response relationship
Does more of the exposure cause worse outcomes?
Strength of association
Stronger, less likely due to confounding or bias. >2
Systematic review
A scholarly process that evaluates and summarises all relevant studies on a topic to answer a specific research question
Narrative review
A type of literature review that summarises and interprets existing research on a topic
Critical appraisal
The process of carefully and systematically examining research to judge its trustworthiness and its value and relevance in a particular context
Primary prevention
Interventions that attempt to prevent disease from occurring
Secondly prevention
Reduce the impact of disease by shortening its duration, reducing severity or preventing recurrence
Tertiary prevention
Reduce the number or impact of complications and improve rehabilitation
High risk strategy
Individuals in special need are identified… works to control levels of exposure to a cause or to provide protection against the consequence of exposure
Population strategy
Aims to reduce the health risks of the entire population
Prevention paradox
A large number of people at small risk may give rise to more causes of disease than the small number who are at high risk
Evidence based practice
A process used to review, analyse, and translate the latest scientific evidence
Surveillance
Ongoing systematic collection, analysis, interpretation and dissemination of data regarding a health event for use in public health action to reduce morbidity and mortality and to improve health
Indicator based surveillance
Specific selected indicators are under surveillance e.g. infectious diseases or cancers passively notified by clinician to report of rates of disease by demographic characteristics of affected individuals
Event-based surveillance
Organised monitoring of reports, media stories, rumours and other information about health events that could be a serious risk to public health
Passive surveillance
Routine reporting of health data which is low cost, allows data linkages but can cause under reporting
Active surveillance
Serosurveillance (monitoring of presence or absence of specific substance in the blood serum of a population) and health surveys
Sentinel surveillance
Health data collected from selected institutions or groups to monitor diseases or trends and detect outbreaks
Screening
The widespread use fo a simple test for a disease in an apparnetly healthy populaiton
Screening programme
An organised system using a screening test among asymptomatic people in the population to identify early cases of disease to improve outcomes
Sensitivity
Proportion of people with disease who test positive
Specificity
Proportion of people without disease who test negative
Positive predictive value
Proportion of people who test positive and have the disease
Negative predicted value
Proportion of people who test negative and don’t have the disease
Pathogenicity
Ability of an organism to produce clinical symptoms and illness
Virulence
Ability of an organism to produce serious disease (case-fatality rate)
Epidemic
Unexpected increase in the incidence of disease
Endemic
Constant presence of disease or infectious agent within a geographical area or population group
Holoendemic
All year, mainly children
Hyperendemic
Waves of infection, all ages infected
Pandemic
Affects a large number of people and crosses many international boundaries
Clusters
Aggregation of relatively uncommon events or disease in space and/or time that are thought to be greater than could be expected by chance
