Epidemiology and Biostats

Question 1

Epidemiology

Answer 1

the core science of public health
- the study of the distribution of disease amoung populations
- Investigate causes of diseases
- Identify trends in disease (reporting of “notifiable” diseases)
- Evaluate interventions

Question 2

What is Epidemiology?

Answer 2

The study of the distribution and determinants of health and disease-related states in populations, and the application of this study to control health problems.

• distribution
• determinants
• populations

Question 3

What do we mean by distribution?

Answer 3

Standard dimensions used to track the occurrence of a disease/health event
- person
- place
- time

Question 4

Distribution

Answer 4

person
- age, sex, race, occupation marital status

place
- physical, biological, social environment

time
- calendar months

Question 5

Determinants

Answer 5

host
- refers to who has the disease

agent
- anything that causes the disease (chemical, bacteria, nutrition related)

environment
- what in the environment allows this disease to happen and spread?

Question 6

Populations

Answer 6

group of people who share a common characteristics

Question 7

Patterns of disease occurrence (3Ws)

Answer 7

Who is getting the disease?
When did they get the disease?
Where is the disease occurring?

From this information, epidemiologists can infer why the disease is occurring.
- i.e. John Snow followed this procedure

Question 8

Numerator

Answer 8

A measure of the frequency with which an event occurs; Number of people with the health outcome (“disease” broadly”)

Question 9

Denominator

Answer 9

Number of people who are at RISK of getting the disease

Question 10

Incidence (risk)

Answer 10

The number of NEW cases in a population

Question 11

Prevalence

Answer 11

The number of TOTAL cases in a population during a specific time period; a proportion (of the population that has the disease)

Question 12

Incidence (Risk) Formula

Answer 12

(# new cases / # of ppl at risk *excluding existing cases) x 100

Question 13

What information does incidence convey?

Answer 13

conveys information about the RISK of contracting a disease over a certain time period

Question 14

Prevalence Formula

Answer 14

(# of cases in the present population / total # of people in the population) * 100

Question 15

What information does prevalence convey?

Answer 15

the proportion of a population who has the health outcome at a given period of time; conveys information about how WIDESPREAD a disease is during a certain time period

Question 16

Incidence or prevalence?

Answer 16

32,100 new HIV infections per year

Question 17

Incidence or prevalence?

Answer 17

Currently an estimated 1.2 million persons aged 13 years and older are living with HIV

Question 18

If we think of the marble jar, why can prevalence grow?

Answer 18

Prevalence grows when diseases become chronic.

i.e. prevalence of HIV in the US; we are getting better at treating it so people can live with it (less dying and leaving the bucket)

Question 19

Assuming that we begin to measure incidence of breast cancer among women on January 1, 2018, which group in Massachusetts would be counted for the denominator of the incidence measure?

A. All men and women in Massachusetts in 2018
B. All women in Massachusetts in 2018
C. Only women in Massachusetts without breast cancer on January 1, 2018

Answer 19

C. Only women in Massachusetts without breast cancer on January 1, 2018

*for incidence
(only looking for those at risk, so excluding the people who have the disease)

Question 20

Who is the father of epidemiology and what did he do?

Answer 20

John Snow
- cholera epidemic in London 1850

Question 21

Q: What was the risk among those who ate guacamole?

Answer 21

Step 1: Rate among guacamole-eaters: 32/80 = 40%

Step 2: Rate among non-guacamole eaters: 93/170 = 55%

Step 3: Rate ratio: (32/80)/(93/170)= 0.73

Question 22

Endemic

Answer 22

The constant presence and/or usual prevalence of a disease or infectious agent in a population within a geographical area

Question 23

Epidemic

Answer 23

Sudden increase in the number of cases of a disease above what is normally expected in that population in that area

Question 24

Pandemic

Answer 24

An epidemic that has spread over several countries or continents, usually affecting a large number of people

Question 25

Biostatistics

Answer 25

• The numbers that describe the health of the
  population
• The science used to interpret these numbers
  -The uncertainty of science – science is ongoing and statistics can help quantify the degree of uncertainty
• methodological tool
• Translate data into information about causes and effects, health risks, and interventions (policies, cures, etc.)

Question 26

association

Answer 26

presence of a relationship btwn variables… cause?

Question 27

confounding

Answer 27

the “third factor” or a separate factor that may explain an association between exposure and outcome

Question 28

Risk Ratio

Answer 28

Risk Exposed / Risk Unexposed

*risk = incidence

Question 29

Rate Ratio

Answer 29

rate exposed / rate unexposed

Question 30

Rates (types)

Answer 30

• Crude rates
• Adjusted rates
• Group specific rates

Question 31

Rates (definition)

Answer 31

relate the raw numbers to the SIZE of a population

Question 32

Descriptive statistics

Answer 32

describe, show, or summarize data in a meaningful way (who, what, when, where)

Question 33

Inferential statistics

Answer 33

Draw conclusions from samples of data;
i.e. infer what is happening in the population (why?)

Question 34

Case definition

Answer 34

set of uniform criteria to define a disease for public health

Question 35

T/F case definitions can change overtime was we get more data?

Answer 35

T (i.e covid)

Question 36

Surveillance

Answer 36

the ongoing, systematic…
- collection
- analysis
- interpretation, AND
- dissemination
….of health outcome data

(– guides health action – which can be used to guide population healthy programs and policy)

Question 37

Example of exposure / risk –> outcome/disease

Is there a relationship between taking PHCG & Pursuing a masters in PH?

Answer 37

• taking PHCG = exposure (risk factor)
• pursing a masters = outcome or disease