Module 11

Question 1

what are types of health indicators?

Answer 1

• Physical disease
• Mental illness (limited functional ability for activities of daily living due to a medical condition such as severe Alzheimer’s disease)
• Impairment or disability (limited functional ability for activities of daily living due to a medical condition such as cerebrovascular accident)
• Social well-being
• Service availability and provision
• Resource availability

Question 2

types of statistics used in descriptive epidemiology

Answer 2

• Counts
• Ratios
• Proportions
• Percentages
• Rates

Question 3

descriptive epidemiology: counts

Answer 3

• Number of cases
• Count
• Frequency
• No denominator

**when health indicators are reported as counts, it is important to know the number of cases and number of frequencies

Question 4

descriptive epidemiology: ratios

Answer 4

• Ratios compare two things
• Divide the numerator by the denominator
• Expressed as X/Y or X:Y
• Numerator may or may not be part of the denominator
• The numerator and denominator may or may not be related

**key feature: ratio has a numerator and denominator

Question 5

what are rates

Answer 5

• Frequency of an event in a population during a specified period of time
• Numerator is the number of people who experience an event
• Denominator is the number of people in the population
• Population is always specified
• Time period is always specified
• In a true rate, person-time is the unit (person-years)

**rates are important when you’re comparing the disease cases, occurrences, outbreaks in two different populations, groups at two different points in time at two different geographical areas

Question 6

vitals sign

Answer 6

essential measures of health for individual patients

Question 7

vital statistics

Answer 7

essential measures of health for a population

Question 8

what are the three major categories of vital statistics

Answer 8

• Mortality
• Morbidity
• Natality
• The indices used are typically related to births and deaths because these data are more readily available than morbidity data

Question 9

what is mortality rate?

Answer 9

a measure of the frequency of occurrence of death in a defined population during a specified interval

Question 10

what is the crude mortality rate

Answer 10

the mortality rate from all causes of death for a population

Question 11

what is infant mortality rate?

Answer 11

• Deaths of infants < 1 year of age
• Denominator is number of live births in the given time period
• Per 1,000 live births
• Single most widely used health indicator to compare nations

Question 12

what is neonatal mortality rate?

Answer 12

• Deaths of infants < 28 days of age
• Denominator is number of live births in the given time period
• Live birth has a specific definition
• Per 1,000 live births

Question 13

what is maternal mortality rate?

Answer 13

Deaths of cis-gender females due to pregnancy related causes anytime during pregnancy or during the first 42 days after pregnancy termination (regardless of the
duration of the pregnancy)
* Denominator is number of live births in the given time
period
* Per 100,000 live births

Question 14

what is pregnancy related mortality?

Answer 14

• Death of a cis-gender female while pregnant or within 1 year of the end of a pregnancy (regardless of the duration) from any cause related to or aggravated by the pregnancy or its management, but not from accidental or incidental causes.
• Denominator is number of live births in the given time period
• Per 100,000 live births

Question 15

what is morbidity?

Answer 15

a measure of the frequency of
occurrence of disease or injury in a defined population during a specified interval.

Question 16

what are rates adjusted to control?

Answer 16

to control confounding factors/variables

Question 17

what are the two major measures of disease frequency?

Answer 17

incidence and prevalence

Question 18

what is prevalence

Answer 18

Prevalence refers to the status of disease, not the onset
Prevalence measures all cases (old and new) at a specified period of time

Question 19

what is point prevalence?

Answer 19

assessed at one specific point in time
- Single point in time
- Number of existing cases (old and new cases) on a certain date (e.g., January 1, 2015)

Question 20

what is period prevalence

Answer 20

assessed during a certain period
- Period of time – days, weeks, months, years
- Start and finish times are specified (e.g., January 1, 2015 through December 31, 2015)

Question 21

what are prevalence statistics often use for?

Answer 21

• policy and administrative decisions
• informs policy makers and the public about the burden of disease
• used in planning health services, both direct care and preventative services
• Prevalence statistics can provide some insight about possible factors associated with disease
• But, the causal relationship cannot be verified by prevalence data
• Useful for generating hypotheses

Question 22

what is incidence?

Answer 22

• Incidence measures the rate at which people without a disease develop the disease during a specified period
• Incidence is a measure of the onset of disease
• Incidence measures the appearance of disease
• Incidence means new
• Note: The word “disease” can be substituted with injury or disability* Incidence describes only the number of new cases that occur during that time period of interest
• Measures the number of new cases of the health-related state (disease, injury) that occur during the specified time
• Does not include the pre-existing cases

Question 23

what is the incidence proportion?

Answer 23

number of new cases of a disease in a specified time period/population at risk of the disease at the start of that time period

also called:
- risk
- attack rate
- probability of developing a disease

Question 24

what is the incidence rate?

Answer 24

number of new cases of a disease in a specified time period/ time that each person was observed, totaled for all persons
* Also known as “Person-Time Rate”
* More difficult to calculate
* More accurate estimate of risk
* Accounts for incomplete data

Question 25

Incidence Proportion vs Incidence Rate: incidence proportion

Answer 25

• Difference between the 2 measures is a matter of precision
• The difference is in the denominator
• The incidence proportion measures the number of new cases that occur in a population over a specified time period of time
• The denominator is the number of people in the population at the start of the study period

Question 26

Incidence Proportion vs Incidence Rate: incidence rate

Answer 26

• The incidence rate measures the number of new cases that occur in a population over a specified time period
• The numerator is the number of new cases during the specified time period
• The denominator is the number of people and the exact amount of time each person in the population was studied. This is what makes it a more precise measure. In any population people will move away, die from other causes, or even get the disease of interest. So, the rate is calculated exactly for the number of
  people and the length of time each contributed.

Question 27

what is crude birth rate

Answer 27

Number of births during a specified time interval/
Total population at the middle of the time interval

Question 28

what is crude fertility rate?

Answer 28

Number of births during a specified time interval/
Number of cis-gender females aged 15-44
at the middle of the time interval