Final exam - Week 2 Flashcards
What is the science for studying population health?
epidemiology
What is the study of the distribution and determinants of health-related states in populations?
epidemiology
What kind of discipline is epidemiology?
quantatitive
What is epidemiology based on?
statistics and research methods
What is the goal of epidemiology?
is to control health problems
What do some of epidemiology have a focus on?
morbidity/mortality
What does epidemiology most recently include?
lifestyles, health,-promotion strategies, injury, environmental conditions.
What are contributions of epidemiology?
Identification of risk factors Pinpoint modifiable risk factors Promotes lifestyle changes Public policy modifications Promotes a healthy environment Injury and disease prevention Health promotion
How do people characterize epidemiology?
descriptive or analytic
Descriptive epidemiology is what?
person, place and time of the health problem.
What 2 things does descriptive epidemiology involve?
- distribution of frequencies
2. patterns of health events according to person, place, and time
What does descriptive epidemiology compare?
affected groups and unaffected groups
What does descriptive epidemiology suggest?
suggests hypotheses for further study
What precedes what when it comes to descriptive studies and analytic ones?
Descriptive studies usually precede analytic ones
What does descriptive epidemiology generate ?
morbidity and mortality statistics
Descriptive epidemiology can answer which of the following questions? (select all that apply)
a. Which municipalities in Puerto Rico (PR) have been most severely affected by Zika virus infections?
b. What percent of the lab confirmed cases of Zika virus in PR were in women?
c. How does sexual transmission effect the gender disparity in Zika virus transmission?
d. Why is Zika virus emerging now in PR?
A and B; , because the questions ask for a description of the person (gender) and place (locations) of the outbreak .
What is the “how” and “why” of health and disease?
analytic epidemiology
What does analytic epidemiology specifically look at?
determinants of disease and causality
What does analytic epidemiology test?
hypotheses or seeks answers to specific questions
What kind of design can analytic epidemiology be?
retrospective or prospective
Analytic epidemiology can answer which of the following questions?
A. Which municipalities in Puerto Rico (PR) have been most severely affected by Zika virus infections?
B. What percent of the lab confirmed cases of Zika virus in PR were in women?
C. How does sexual transmission effect the gender disparity in Zika virus transmission?
D. Why is Zika virus emerging now in PR?
C and D; C asks How and D asks Why, which are questions that analytic epidemiology studies can answer.
What do descriptive measures of health do?
assess and report risk in populations
What do descriptive measures of health include?
- demographics
2. morbidity and mortality statistics
What 3 things are included in morbidity and mortality statistics?
- incidence and prevalence
- ratios, proportions, OMR and case fatality rates
- true rates
What is a statistical study of human populations?
demography
What is included with the demography?
size, density, distribution, vital statistics
What is the “how” of demography?
How population characteristics influence community needs and delivery of health care services
What are descriptions and comparisons made according in demography?
according to age, race, sex, socio-economic status, geographic distribution, birth, death marriage and divorce
What is a comprehensive descriptive demographic study?
the US census
What are demographics that may affect health outcome?
Age Race Sex Ethnicity Ancestry Income Educational level Language spoken at home Occupation/Employment status Marital status/household type
define incidence
the number of people who develop a condition during a specified time period
What is specifically incidence?
- new cases (new diagnoses)
2. events (falls, heart attacks, deaths)
What does incidence allow?
the estimation of risk necessary to asses the casual association (relative risk)
What is generally required to determine incidence?
a prospective study
What is incidence and incidence rates used to track?
effectiveness of primary and secondary prevention
define prevalence
total number of people in the population who have a condition at a particular point in time
When can prevalence be calculated?
in a one-shot crossectional or retrospective study
What is prevalence influenced by>
by rate of new cases, number of existing cases, new treatments, and deaths
What is prevalence used to describe?
scope of problem and need for services
define period prevalence:
Total number of people who have the condition during a specified period of time.
true or false: period prevalence is always used.
false; rarely used
What is a measure the amount of disease, injury, or death within a unit of the population and within a unit of time?
rates
What do rates enable researchers to do?
to compare different populations in terms of health risk
When are rates less reliable?
when based on small numbers
What are rates usually based on?
data from a calendar year
What are commonly used rates?
- measures of natality
2. measures of morbidity and mortality
What is an example of incidence?
3,370 (new) cases of acute Hepatitis B virus (HBV) infection were reported to the CDC in 2015.
What is an example of an incidence rate?
There were 1.1 (new) cases of HBV infection per 100,000 population in 2015.
What is an example of prevalence?
Based on a 2013 national survey, there were 15,908 people identified as living with amyotropic lateral sclerosis (ALS)
What is an example of a prevalence rate?
Estimated as 5.0 people per 100,000 population at the time of the survey
You are asked to provide the number of patients with an active case of the COVID in a long-term care setting on October 9, 2020. This is an example of:
a. Incidence
b. Incidence rate
c. Prevalence
d. Prevalence rate
Answer: c
The prevalence of a disease or condition refers to the total number of people in the population who have the condition at a particular time. Thus, prevalence may be calculated in a “one-shot” cross-sectional (“slice of time”) or retrospective (backward looking) study.
What are crude-rates computed for?
for a population as a whole, irrespective of age
crude mortality rate equals what?
crude death rate
What are specific-rates computed for?
subgroups
What is an example of an age specific rate?
75yrs old and over mortality rate
what is an example of a cause specific rate?
Breast cancer mortality rate
What are adjusted rates?
summary measures in which statistical procedures remove the effect of differences in the composition of the various populations
define ratio
one number divided by another in which the numerator is not part of the denominator
define proportion
one number divided by another in which the numerator is a subset of the denominator and is usually expressed as a percentage
define proportion mortality rate
Proportion of deaths from a specific cause
true or false: proproprtion mortality rate is a true rate
false; it’s a proportion
What is PMR usually expressed as?
percent
What is the numerator and denominator usually?
Numerator is the number of deaths from a specific cause, such as cancer. Denominator is total number of deaths
What does PMR differ from?
Differs from cause specific death rate where the denominator is population at risk
What is the percentage of people diagnosed with a specified illness who die as a result of that illness within a given period?
case-fatality rate
What is the case-fatality rate usually used for?
Usually used for measuring mortality in outbreaks.
How is case-fatality rate calculated?
of people who die from the illness/# of people who are dx with illness
What is case-fatality rate different from?
Different from cause-specific mortality rate because of denominator!
define the dependent variable:
the outcome or result that the investigator is studying
What 3 factors are included in the dependent variable?
- health status
- knowledge
- behavior
define the independent variable:
the presumed cause or contributor to the variation in the dependent variable
define the confounding variable:
an extraneous factor that is statistically related to the independent variable thus possibly affecting the outcome or dependent variable.
What are criteria for evaluating causation?
Association is strong
Association is consistent
Association is temporally correct
Association is specific
Association is not the result of a confounding variable
Association is plausible and consistent with current knowledge
Association does not imply what?
causation
define association is strong
the strength of the relationship is usually measured statistically with RR, or the odds ratio
define association is consistent
the same association exists repeatedly in other studies, in other settings, and with other populations.
define association is temporally correct
the hypothesized cause of a health condition should occur before the onset of the condition. (i.e. exposure to the risk factor should precede the onset of disease)
define the association is specific
specificity measures the degree to which one particular exposure produces one specific disease.
define the association is not the result of a confounding variable
although not all potential intervening variables are identified, the alternate explanations for the association are examined carefully before considering an association casual
define the association is plausible and consistent with current knowledge
Any disease or injury causation association should be congruent and compatible with current biomedical and scientific knowledge and information. This depends on the state of scientific information, at a given time. An association that contradicts current scientific views should be evaluated very carefully. However, associations may be inconsistent with current knowledge simply because current knowledge is not as advanced as a new discovery.
What is the purpose of a screening test?
- to rapidly and economically identify asymptomatic people who have a high probability of having or developing an illness
- So they can be referred for diagnosis and treatment
What do screenings not do?
diagnose
Positive screens are referred for what?
further workup and diagnosis
What are considerations in deciding to screen?
- early diagnosis and treatment can favorably alter the course of the illness
- Definitive diagnosis and treatment facilities are available, either through the screening agency or through referral
- the group being screened is at risk for the illness
- the screening procedures are reliable and valid
What are the two types of screening tests available?
- high-sensitivity
2. low-sensitivity
To save the most lives, which test is essential?
high-sensitivity
What does high-sensitivity tests guarantee? what is bad about it?
a, low rate of false negatives.
b. low specificity means that one will have a high rate of false positives
What is bad about high sensitivity?
many people could be alarmed needlessly
What should decisions regarding screening involve?
seeking the most favorable balance of sensitivity and specificity
What is consistency or repeatability of test results?
reliability
what is the ability to measure what it’s supposed to?
validity
What 2 things are under validity?
- Sensitivity ability to identify those who have it
2. Specificity ability to identify those who don’t
What are 3 epidemiological models?
- The Epidemiologic Triangle
- The Person-Place-Time Model
- The Web of Causation
Which model asks the following questions:
- Who is affected (characteristics of people; similar to host of epi model)?
- Where were the people affected (environment or location)?
- When were they affected (the time period involved)?
- What type of epidemiological study uses this model, analytic or descriptive?
The Person-Place-Time Model
What views health problems as complex interrelationships of numerous factors?
web of causation
true or false; web of causation is increase or decrease risk of disease
true
what does the web of causation attempt to identify?
all possible influences on health and illness processes
what is the whole is more than the sum of its separate parts
synergism
