M1: Epidemiology Flashcards
Often there is a frustrating delay between acquiring ___________ and applying this evidence to health policy.
Epidemiological evidence
A fundamental science of public health. Has made major contributions in improving population health. Essential to the process of identifying and mapping emerge diseases. Study of causes and distribution of disease in human population.
Epidemiology
Epidemiology uses _________ methods to study diseases in human populations to inform prevention and control efforts.
Quantitative
Defined by Last as the study of the distribution and determinants of health-related stated or events in specified populations and the application of this study to the prevention and control of health problems. Concerned not only with death, illness and disability but also with more positive health states and most importantly with the means to improve health.
Epidemiology
In epidemiology, the assumption is that the disease do not occur ________, but follow ________ patterns that can be studied and expressed in terms of what, where, who, when, how, why and what’s next.
Randomly. Predictable.
The goal of Epidemiology is to identify subgroups of the population who are at ___________ for disease than usual and who will benefit the most from disease specific interventions.
Higher risk
Features of Epidemiology: all findings must relate to a defined _________.
Population
Features of Epidemiology: A target population is specified about which the _________ are to be drawn.
Conclusions
Features of Epidemiology: Occasionally, measurements can be mad e on the ___________.
Full target population
Features of Epidemiology: more commonly, ________ can only be made on a study sample selected from the target population.
Observations
Features of Epidemiology: confidence in the conclusions drawn from the sample depends in part on the __________.
Sample size
Features of Epidemiology: ________ can be unrepresentative just by chance but these errors can be computed statistically.
Small samples
Features of Epidemiology: systematic sampling errors can be avoided through ___________ process by which member of the target population has a known probability of being included. However, the process requires an ___________ of all members of the target population, which may not be feasible in all cases.
Random selection. Enumeration/census.
Features of Epidemiology: the selection is thus often partially random meaning within the target population, an accessible subset(aka _______) is defined. The study sample is then _________ chosen from the study population.
Study population. Randomly.
Features of Epidemiology: Oriented to the ______ rather than individuals.
Groups
Features of Epidemiology: May guide decisions to individuals but they relate primarily to ______.
Groups
Epidemiology as a tool: searching for _________. Ex: genetic & environmental factors affects good health which may lead to ill health.
Causality
Epidemiology as a tool: Determining the ________. Ex: good health to subclinical changes to clinical disease which may either lead to death or recovery.
Natural history
Epidemiology as a tool: Determining the ________ of the population. Pie charts & graphs.
Health status
Epidemiology as a tool: Evaluating __________. Ill health, treatment of medical care and health promotion, preventive measures & public health services all affects Good Health.
Interventions
Epidemiologic Studies: Choosing the appropriate __________ is a crucial step in epidemiological investigation.
Study design
Epidemiologic Studies: Each study designs has its _______ and ________.
Strengths. Weaknesses.
Epidemiologic Studies: ________ must consider all sources of bias and confounding and strive to reduce them.
Epidemiologists
Epidemiologic Studies: __________ are important in epidemiology, as in other sciences.
Ethical issues
Allow nature to take its course. The investigator measures but does not intervene.
Observational
Kinds of Observational Studies: limited to a description of the occurrence of a disease in a population. Usually the first step in epidemiologic study.
Descriptive
Types of Descriptive studies
Case report & Case series
Kinds of Observational Studies: Analyses the relationship between health status and other variables.
Analytical
Involves an active attempt to change a disease determinant, such as an exposure or a behaviour- or the progress of a disease through treatment, and are similar in design to experiments in other sciences. Subject to extra constraints, because health of the population may be at stake.
Experimental/Interventional
Examples of Experimental/Interventional
RCT, Field trials & Community trials “RFC”
A state of complete physical, mental and social well being and not merely the absence of disease or infirmity.
Health
Measuring Health & Disease. Fundamental to the practice of __________. A variety of measures are used to characterize overall health of the population.
Epidemiology
is not fully measured in many parts of the world, and this lack of information poses a major challenge to epidemiologists
Population health status
People who are susceptible to a given disease and can be define by demographic, geographic or environmental factors.
Population at risk
Represents the rate of occurrence of new cases arising in a given period in a specified population
Incidence
Frequency of existing cases in a defined population at a given point of in time
Prevalence
Denominator for incidence & prevalence
Population at risk
Numerator is # of new cases of disease in a specified period of time
Incidence
of existing cases of disease at a given point of time
Prevalence
Focus is on the presence or absence of the disease. Time period is arbitrary, rather a snapshot in time.
Prevalence
Focuses whether the event is a new case. Time of onset of the disease.
Incidence
Expresses the risk of being ill. The main measure of acute disease or conditions, but also used for chronic diseases. More useful for studies of causation.
Incidence
Estimates the probability of the population being ill at the period of time being studied. Useful in the study of burden of chronic diseases and implication for health services.
Prevalence
Is often expressed as cases per 100 (percentage) or per 1000 population and P has to be multiplied by the appropriate factor
Prevalence
Prevalence data was collected for one point of time
Point prevalence rate
Total # of cases at any time during a specified period dived by the number of cases at any time during a specified period, divided by the population at risk midway through the period.
Period prevalence rate
Total number of persons known to have had the disease for atleast some part of their lives
Lifetime prevalence
Prevalence studies do not usually provide strong evidence of _______ because it is influenced by a lot of factors unrelated to the cause of the disease.
Causality
The units of incidence rate must always include a unit of
Time
Done by dividing number of people who gets a disease during a specified period to number of people free of the disease in the population at risk at the beginning of the period.
Cumulative Incidence
A measure of disease severity and is defined as the proportion of cases with a specified disease or condition who die within a specified time. Usually expressed in percentage.
Case Fatality
Does not take into account that the chance of dying varies according to age, sex, race, socioeconomic class and other factors. Comparisons of mortality rates between groups of diverse age structure are usually based on age-standardized rates.
Crude Mortality Rate
Death rates expressed for specific groups in a population defined by age
Age Specific Death Rates
Is a ratio of the number of deaths from a given cause per 100 or 1000 total deaths in the same period. It does not express the risk of members of a population contracting or dying from a disease.
Proportionate Mortality (PMR)
Multiplier for PMR
100
Number of deaths in a year of children less than 1 year of age divided by number of live births in the same year multiplied by 1000
Infant mortality rate
Number of maternal deaths in a given geographic area in a given year divided by number of live births that occurred among the population of the given geographic area during the same year
Maternal mortality rate
Variables for Epidemiological Information
Person, Place & Time “PPT”
Most important factor considered when describing the occurrence of any disease because this specific death rates usually show greater variation than rates defined by almost any other personal attribute.
Age
Numerous epidemiological data have shown the difference of this in a wide array of health phenomena, including morbidity & mortality.
Sex
It has become an important variable because of ambiguous characteristics that tend to overlap with nativity or the place of origin of the individual and religion. It is believed that this is a social and cultural construct.
Race/Ethnicity
It is a descriptive term for a person’s position in society formulated as a composite measure of three interrelated dimensions; a person’s income level, education level and type occupation.
Socioeconomic status
Refer to gradual changes in the frequency of disease over long periods of time usually noted in chronic diseases
Secular trends
Are increases and decreases in the frequency of the disease or other phenomenon over a period of several years or within a year usually exhibited by many infectious diseases.
Cyclic/Seasonal trends
May indicate the response of a group of circumscribed in place to a common source of infection, contamination or other etiologic factor to which they were exposed almost simultaneously.
Point epidemics
Is a closely grouped series of events or cases of a disease or other health related phenomena well defined distribution patterns in relation to time or place or bothxddssewswse
Clustering
Harmful effects of an outbreak: High _______ & _______.
Morbidity & Mortality
Harmful effects of an outbreak: Decrease in _______.
Economy
Harmful effects of an outbreak: Bad _______.
Publicity
Harmful effects of an outbreak: Outbreaks are _______.
Expensive
