exam 1 Flashcards
fecundity rate
of births / # of birthing age women
What is Epidemiology?
Study of distributions and determinants of disease frequency in human populations and the application of this study to control health problems.
What are the epidemiological units of study?
Distribution includes Person (Age, Sex, SES), Place (where did the study take place), and Time (at what point in time?).
What are Determinants in Epidemiology?
Risk Factors that cause some people to get disease and some people not to get the disease.
Example: Running can be considered a causal factor for heart disease.
What is Disease Frequency?
The number of cases in a given population over a specific time period.
What is a Population in Epidemiology?
A group of people with common characteristics.
What is the Null Hypothesis?
claim that the effect does not exist
What are the branches of Public Health?
Policy, Scientific (epidemiology), Clinical, Activist.
What is Primary Prevention?
The actual prevention of a specific outcome (ex: vaccines).
What is Secondary Prevention?
Identifying an outcome at an early stage leading to improved outcomes (ex: mammograms).
Individual: this means changing the path / plan for treatment
Public health: Tuft’s screening program - even though it did not change treatment plans
What is Tertiary Prevention?
The limiting of the mortality, morbidity and/or disability after an outcome has occurred.
What is Diagnosis?
Problem.
What is Prognosis?
Outcome.
What is Causal Theory?
Assessing how x causes y.
What is a Necessary Cause?
Must be present for phenomenon to occur.
What is a Contributing Cause?
Risk factor that makes an outcome more or less likely.
What is a Sufficient Cause?
When all contributing and necessary causes needed to bring about a certain outcome in a given individual are present.
What is Rothman’s Causal Pie?
Method for visualizing necessary contributing and sufficient cause.
What are Hill’s Causal Criteria?
Strength of Association, Consistency of Association, Temporal Sequence of Association, Dose-Response Association, Analogy, Biological Plausibility.
What is an example of effective primary prevention related to measles?
In the 1950-60s, there were 450 deaths per year from measles, with people developing brain swelling. By the 2000s, the US was prepared to declare measles conquered, although vaccination efforts haven’t been entirely successful.
What did the HiB vaccine program achieve?
The HiB vaccine program basically eliminated deadly bacterial meningitis.
What did Jenner discover about cowpox and smallpox?
Jenner observed that milkmaids who had cowpox did not contract smallpox. This led to the development of inoculations against smallpox using cowpox, which is milder.
What are the 4 components of measuring disease frequency?
Populations, Cases of Disease (Numerator), Size of Population (Denominator), Time (must be explicit)
What is a Fixed Population?
A population of which membership is permanent (e.g., Veterans of Vietnam, people being born in 2002)
What is a Dynamic Population?
A population whose membership is defined by being in a state of condition.
What does ‘Disease’ refer to?
Any possible health outcome.
What is Disease Ascertainment?
Determining if a case has occurred through clinical records, diagnostic tests, surveillance programs, self-reports, or disease registries.
Why is Time necessary in measuring disease frequency?
It can be measured at a single point in time or over an interval.
What is Prevalence?
Who has the disease and who does not have the disease at baseline.
What is Incidence?
Of a sample who did not have the disease at baseline, who got the disease over time.
GET NOT HAVE
GET
GET
What is Cumulative Incidence / Risk?
Number of individuals who get a condition divided by the number of individuals in the population at the start of a study period.
Assumption: All people in the population have been followed for the entire time period.
What is Incidence Rate?
Number of new cases during a specified time period divided by total person-time observation during the given time period.
Incidence Rate is NOT RISK.
What is Person-Time?
Used when studies are staggered and subjects are not all studied at the same time; it is the sum of how long all subjects were studied.
What is Point Prevalence?
One point in time is the measure; it indicates who has the disease right now.
Calculated as the number of individuals with a condition at a specific time divided by the number of individuals in a population at that point in time.
What is Period Prevalence?
Who has had the disease over the past two months? Unlike Cumulative Incidence, period prevalence does NOT only include new cases.
What are Absolute Measures of Association?
The difference between two measures of disease frequency.
What are Relative Measures of Association?
The ratio between two measures of disease frequency.
What are Orphan Diseases?
Deeply harmful, but do little damage from a public health perspective and thus are generally neglected.
What are the types of Absolute Measures?
Prevalence Difference, Risk Difference, Rate Difference.
How is Prevalence Difference calculated?
Prevalence in exposed - prevalence in unexposed.
How is Risk Difference calculated?
Cumulative Incidence Exposed - Cumulative Incidence Unexposed.
What is the formula for Risk Difference?
Number of individuals who get a condition / # of individuals in the population at the start of a study period (exposed) - Number of individuals who get a condition / # of individuals in the population at the start of a study period (unexposed).
How is Rate Difference calculated?
of new cases during a specified time period / total person time observation during the given time period (exposed) - # of new cases during a specified time period / total person time observation during the given time period (unexposed).
What are the Relative Measures of Association?
Risk Ratio (CI Ratio), Rate Ratio, Odds Ratio.
How is Risk Ratio calculated?
CI in exposed / CI unexposed.
What is the Incidence Ratio?
The same thing but in person time → Incidence rate exposed / incidence rate unexposed.
How is Odds Ratio calculated?
Outcome in exposed / outcome in unexposed.
Outcome exposed = Number w outcome exposed / number w out outcome unexposed
outcome in unexposed = number w outcome exposed / number w out outcome unexposed
When is Odds Ratio used?
In cases where someone already has or had the outcome.
What are the Strengths of Association categories?
Weak (0.8 - 1, 1 - 1.5), Moderate (.5 - .8, 1.5-3), Strong (less than .5, more than 3).
Relative Measure of Association
How is Attributable Risk % (Ape) calculated?
(Risk Ratio - 1) / Risk Ratio.
What is the formula for Attributable Risk?
Risk exposed - Risk unexposed
What is Population Attributable Risk?
How much risk could we eliminate from a population of both exposed AND unexposed if we eliminated an exposure altogether.
How is Population Attributable Risk calculated?
AR * f (frequency of exposure).
How is Population Attributable Risk % calculated?
(PAR / (PAR + 1)) * 100.
What is Preventative Fraction?
Used when an exposure helps prevent a disease, not cause it.
Used w/ vaccines
Runexposed - R exposed )/ Runexposed = 1 -RR
What is the formula for Preventative Fraction?
(Runexposed - R exposed) / Runexposed = 1 - RR.
What does Years of Life Lost measure?
How many years would you have lived. How many years does a public health issue cost a society.
How is Years of Life Lost calculated?
75 - age of death that is less than 75.
What does Years of Productive Life Lost measure?
Years of working life lost essentially.
What is Survival Rate?
Used when many people survive for long periods.
Calculation: Number of people who don’t die of a disease / number of people with the disease.
What is Case Fatality?
People dying in the short term.
Calculation: # of deaths over a given time period / # of cases of the disease over a given time period.
What is the difference between Survival Rate and Case Fatality?
Survival Rate measures long-term survival, while Case Fatality measures short-term deaths.
What is Case Fatality Burden?
A measure related to the impact of a disease in terms of fatalities.
What is Birth Rate?
Calculation: # of births / population size at mid interval.
What is Infant Mortality Rate?
A key population health indicator.
Calculation: Number of deaths in 0-1 age group over time / # of live births.
What is Mortality Rate?
Calculation: Deaths / Size of population over a given time period.
What is Dengue Fever?
A mosquito borne illness with a 1% case fatality rate in well treated patients and 10% if treatment is substandard.
What is the case fatality rate (CFR) of Influenza?
Influenza has a CFR of about 0.1%.
How does the number of infections affect Influenza’s impact?
The number of infections matters; there are about 100 million cases.
What was notable about the Influenza Pandemic of 1918-1919?
Case fatality rates were higher among the young, with infant deaths being more disruptive for society.
What are the characteristics of the COVID-19 Pandemic regarding gender?
The incidence rate is similar between genders, but mortality is significantly higher among men.
How did COVID-19 affect infants?
COVID-19 did not significantly affect infants.
What was the outcome of Mass’s War on Heart Disease?
It reduced deaths and demonstrated that public health interventions work!
What is Descriptive Epidemiology used for?
To generate hypotheses, evaluate success of interventions, and monitor public health.
What types of studies fall under Descriptive Epidemiology?
Case Reports & Series, Ecological Studies, Cross Sectional Studies.
What is Analytic/Causal Epidemiology focused on?
Evaluating hypotheses and success of interventions.
What types of studies are included in Analytic/Causal Epidemiology?
Clinical Trial, Experimental Study, Case-Control Study, Cohort Study.
What is a Case Report?
A detailed report on one patient experiencing a new or unusual symptom/problem.
What are the purposes of a Case Report?
Recognizing new diseases/symptoms, detecting drug side effects, and providing information to help with hypotheses.
What is a Case Series?
A detailed report on a group of patients with the same new or unusual problem.
What is an Ecological Study?
A study examining rates of disease in relation to a population-level factor, with the group as the unit of observation.
What are the advantages of Ecological Studies?
They are cheap, fast, and cover a wide range of exposures.
What is a limitation of Ecological Studies?
They cannot adjust for complicating factors.
What is the difference between Vertical and Horizontal Case Series?
Vertical Case Series involves one doctor with multiple cases; Horizontal Case Series involves multiple doctors with multiple cases.
What is the Ecological Fallacy?
The limitation that large groups cannot be controlled.
What do Cross Sectional Studies and Surveys examine?
The relationship between exposure and disease at a single point in time.
