PHLT 103 Exam 1 Review Session

Question 1

What is epidemiology?

Answer 1

study of the distribution (who/when) and the determinants (why) of health and disease

Question 2

What are the uses of Epidemiology

Answer 2

• Historical Use: documents patterns, types, and causes of morbidity and mortality over time.
• Community health use: diagnose the dimensions an distributions of diseasie
  witjin of the community.
• Health services use: Studies the working of health services.
• Helps to provide quantitative information
  regarding the availability and cost of
  healthcare services, needed services, etc.
• Provides relevant information to help
  maximize cost effectiveness.
• Risk Assesment use: estimates individuals’ risks ofdisease, accident, or defect
• DISEASE CAUSALITY USE: contributes to
  the search for
  the causes of
  health and
  disease.

Question 3

Define epidemic.

Answer 3

within population and geographic area of case of health-related event or behavior that exceeds normal, expected levels or the background rate

Question 4

What is an endemic?

Answer 4

Level of disease present in a population or geographical area all of the time. (Baseline level of disease)

Question 5

What characterizes a pandemic?

Answer 5

An epidemic occurring worldwide, crossing international boundaries, usually affecting a large number of people.

Question 6

What is the difference between descriptive and analytical epidemiology?

Answer 6

Descriptive: Characterizing the amount and distribution of health and disease. Analytical: Examining causal hypotheses regarding exposures and health outcomes.

Question 7

What is a population in epidemiology?

Answer 7

The complete set of all individuals, objects, or measurements of interest for a particular study.

Question 8

Define sample in the context of epidemiological studies.

Answer 8

A subset of the population selected for study when it’s not practical to study the entire population.

Question 9

What is a parameter?

Answer 9

A numerical value that describes a characteristic of an entire population.

Question 10

What is a statistic?

Answer 10

A numerical value that describes a characteristic of a sample.

Question 11

What does representativeness refer to?

Answer 11

The degree to which a sample accurately reflects the characteristics of the population it was drawn from.

Question 12

What is estimation in epidemiology?

Answer 12

The process of using sample statistics to make educated guesses about population parameters.

Question 13

What is simple random sampling?

Answer 13

A method where each individual has an equal chance of being selected.

Question 14

Define stratified sampling.

Answer 14

A sampling method where the population is divided into subgroups and samples are drawn from each.

Question 15

What is convenience sampling?

Answer 15

A sampling method that selects individuals who are easiest to reach.

Question 16

What is incidence rate?

Answer 16

The number of new cases in a time period/ the total population at risk during that time.

Question 17

What is point prevalence?

Answer 17

The number of existing cases of a disease at a specific point in time.

Question 18

What is cumulative incidence?

Answer 18

• The proportion of a population that becomes diseased over a specified period.
• used when all individuals in the population are at risk
• (Number of new cases over a time period)/ (people who do not have disease)–> Total population at risk at the start of the time period

Question 19

What does attack rate measure?

Answer 19

• Number who became ill/ Total population(ill +well)
  The proportion of an exposed population that becomes ill.

Question 20

Define Ratio

Answer 20

Result of dividing one quantity by another

Question 21

Define proportion

Answer 21

ratio in which the numerator is incuded in the denominator

Question 22

Define Rate

Answer 22

similar to proprtion but the dnominator involves a measure of time

Question 23

What is a case-fatality rate?

Answer 23

The proportion of individuals diagnosed with a disease who die from that disease.
* ▪ Number of deaths due to
a disease that occur
among people who are
afflicted with that
disease.
* number of deaths
due the disease X within a
specified period of time/number of
cases of that disease during
the same period of time

Question 24

What is a cause-specific rate?

Answer 24

number of deaths from a specific cause/ population size at the midpoint of the time period

• **in the denominator everyone in the populatin must be able to die from the disease **

Question 25

What is an adjusted rate?

Answer 25

A rate that has statistical procedures applied to allow fair comparisons across populations.

Question 26

True or False: An epidemic occurs when cases of a health-related event exceed normal levels.

Answer 26

True

Question 27

Fill in the blank: The _______ is the level of disease that is consistently present in a population.

Answer 27

endemic

Question 28

What type of graph is used for categorical vs categorical data?

Answer 28

Contingency table

Question 29

What is the difference between period prevalence and lifetime prevalence?

Answer 29

Period prevalence refers to existing cases during a time period; lifetime prevalence refers to cases at any point during a lifetime.

Question 30

What is the primary focus of epidemiology?

Answer 30

Population focus;Epidemiology primarily studies health-related states or events in populations.

Question 31

Name the key characteristics of epidemiology.

Answer 31

* Population focus: * Unique focus of epidemiology: population * All the inhabitants of a given country or area considered together. * Different from clinical medicine * Distribution: *The occurrence of diseases and other health outcomes varies in populations with some subgroups of the population more affected than others. * Determinants: *A collective or individual risk factor that is causally related to a health condition, outcome, or other defined characteristic * Includes exposures **and ** risks * e.g: bioligical agents, chemical agents * Outcomes *All the possible results that may stem from exposure to a causal factor. * Expressed as types and measures * Morbidity * Mortality * Quantification *Epidemiology is a quantitative discipline. * Counting of the number of events, e.g., illness or death * It means the use of statistical measures to describe the occurrence of a health outcome or to measure the strength of an association * Control of Health Problems * Health promotion * Alleviation of adverse health outcomes * Prevention of disease * Needs assessments * Design of preventive programs * Formulation of public health policies * Evaluation of programs These characteristics help define the scope and purpose of epidemiological studies.

Question 32

Explain difference between determinant, exposure, and risk factor

Answer 32

* Determinant: A collective or individual risk factor that is causally related to a health condition, outcome, or other defined characteristic * Exposure: Related to being in contact with a disease- causing factor or to the amount of the factor that impinges upon a group or an individual. *Risk factor: Exposure that increases the probability of a disease or adverse health outcome.

Question 33

What type of data displays are used for univariate analysis?

Answer 33

* Tables * Data table * Graphs * Bar chart * Histogram * Line graph * Pie chart

Question 34

When is a bar chart vs histogram used

Answer 34

* histograms are charts that are used to display the frequency distributions for grouped categories of a continuous variable. * A bar chart is a type of graph that shows the frequency of cases for categories of a discrete variable.

Question 35

Which graphical display is used for continuous vs continuous data?

Answer 35

Scatter plot;Scatter plots show the relationship between two continuous variables.

Question 36

What is the formula for calculating Prevalence?

Answer 36

Prevalence = # of **existing** cases or deaths/ total population Prevalence measures how widespread a disease is within a population.

Question 37

What is the difference between point prevalence and period prevalence?

Answer 37

* Point prevalence: cases at a specific point in time * Period prevalence: cases over a specified period These measures help to understand the burden of disease in a population. ## Footnote These measures help to understand the burden of disease in a population.

Question 38

What does Cumulative Incidence measure?

Answer 38

It reflects the risk of developing a disease over a specified time period. * (# new cases in time period) / (total population at risk during time period) Incidence proportion with Population AT RISK as denominator

Question 39

Define Incidence Rate.

Answer 39

This rate helps measure the occurrence of new cases of a disease. * Incidence Rate = (# new cases in time period) / (total population at risk during time period)

Question 40

What is the formula for Incidence Density Rate?

Answer 40

This formula accounts for varying time at risk among individuals. Incidence density rate = (# new cases in time period) / (total person- time of observation during the time period)

Question 41

What is the Attack Rate?

Answer 41

A measure of the proportion of a population that develops a disease during an outbreak ## Footnote It is often used in outbreak investigations.

Question 42

What is a Crude Rate?

Answer 42

A rate of morbidity or mortality in a population without adjustment for demographic factors * number of deaths in a given year/ reference population (during midpoint of the year). * multiplier * Crude rates provide a general overview but may not reflect true risk as they are not an adjusted rate ## Footnote Crude rates provide a general overview but may not reflect true risk.

Question 43

What does Case Fatality Rate represent?

Answer 43

Expressed as a percentage of how many people die from a disease among those diagnosed * number of deaths due to disease/ number of case of the same disease ## Footnote It indicates the severity of a disease.

Question 44

What is the Proportional Mortality Ratio?

Answer 44

Proportional Mortality Ratio (%) measures the proportion of deaths from a specific cause relative to total deaths * mortality due to a specific cause/ mortality due to all causes dueing the same period * 100 * is a percentage ## Footnote This ratio helps assess the impact of a specific disease on mortality.

Question 45

What is a Cause-Specific Rate?

Answer 45

* Mortality/frequency of a given disease / the population size at the midpoint of a time period times a multiplier ## Footnote It provides insight into the frequency of specific causes of death.

Question 46

What is an Adjusted Rate?

Answer 46

Rate of morbidity or mortality adjusted to allow fair comparisons across populations. * An adjusted rate is a rate of morbidity or mortality in a population in which statistical procedures have been applied to permit fair comparisons across populations by removing the effect of difference in the composition of various populations. ## Footnote Adjustments remove the effects of demographic differences.

Question 47

How do you calculated age-specific rate

Answer 47

Number of deaths among those in a certain age range / total ppl in that age range

Question 48

how do you calculate a sex-specific rate

Answer 48

number of deatsh in sex group/ total numnber of persons in the sex group

Question 49

Fill in the blank: Prevalence = (Incidence) * _______.

Answer 49

Duration ## Footnote This relationship shows how prevalence is influenced by both incidence and the duration of the disease.