3.2 Rates and Studies

Question 1

Rates

Answer 1

• Number of events that occurred in a population in a specific period of time.

Examples
- Birth Rates
- Death Rates
- Injury/Disease Rates

• Help to determine the risk of a population and help determine the best approach to prevention and limiting transmission

Other Examples
- Morbidity
- Mortality
- Incidence
- Attack
- Prevalence

Question 2

Morbidity Rate

Answer 2

• Rate of illness among a specific population

Calculation
- People with influenza divided by total population

Question 3

Mortality Rate

Answer 3

• Rate of death from an illness (usually per 1000 people per year)

Example (in a month)
- Deaths from influenza in the first month divided by total population at risk

Question 4

Incidence Rate

Answer 4

• Number of newly related cases of influenza in a certain amount of time

Calculation (incident rate in a nursing home in a week)
- New cases in a week divided by total people at risk in nursing home

Question 5

Attack Rate

Answer 5

• Trying to figure out the source (such as a specific event)

Example
- You think influenza was caused by mealtime on a certain day.
- Divide number of ill residents by sum of both ill and well residents in a dining hall times 100.

Question 6

Prevalence Rate

Answer 6

• Used for chronic illnesses to determine how many people have the disease

Example
- Divide all new and pre-existing cases by the total population during the time period.

Question 7

Incidence Vs Prevalence

Answer 7

Incidence (Measures Disease Risk)
- Number of new cases of a disease during a specific time period divided by total number of people at risk for the disease
- Multiply by 1000 to determine new cases per 1000 people
- (How many people got the disease during a specific period of time)

Prevalence (Measures Disease Burden)
- Number of affected people divided by the number of everyone in that population at a specific point in time
- Multiply by 1000 to determine new cases per 1000 people.
- (How many people HAVE the disease during a specific period of time)

• Prevalence takes into account duration of disease. (once a person is cured they are not counted towards prevalence rate)

Question 8

Descriptive Studies

Answer 8

• Identifies patterns among cases
• Typically helps develop hypothesis but does not test them
• Looks at who, what, where, why, when
• Provides information on distribution of disease and health states according to personal characteristics, geographic locations, and time.
• THIS CAN BE USED TO CREATE TARGET PROGRAMS AND RESOURCE ALLOCATION

Question 9

Analytic Studies

Answer 9

• Tests hypothesis by comparing groups to determine risk factors causing health concerns.
• Helps determine what caused a disease along with developing primary, secondary, tertiary prevention.