Health Measures 2 (Sept 11)

Question 1

Surveillance

Answer 1

• can give disease spread patterns (ex: crow sightings increase and a few days later, human cases of west nile virus increase)
• how diseases spread and progress

Question 2

Public health surveillance

Answer 2

• provides and interprets data to facilitate the prevention and control of disease
• should have clear objectives about what needs to be achieved

Question 3

Characteristics of surveillance program

Answer 3

Timeliness: to implement effective control measures (have enough time when we can actually do something to control a disease)
Representation: to provide an accurate picture of the temporal trend of the disease (population that is representative of average cases of disease)
Sensitivity: to allow identification of individual persons with disease to facilitate treatment, quarantine, or other appropriate control measures (identify people who truly have the disease to treat appropriately)
Specificity: to exclude persons not having the disease

Question 4

Goal of surveillance measures

Answer 4

-help public health set priorities

Question 5

Most common surveillance measure

Answer 5

Mortality: measure of number of deaths in particular population and typically scaled to the size of that population

Question 6

Crude death rate

Answer 6

total deaths in any population per year typically per 1000

Question 7

Perinatal mortality

Answer 7

neonatal deaths or fetal deaths

Question 8

Maternal mortality ratio

Answer 8

number of deaths per 100 000 live births (for every 1 birth, how many maternal deaths are there then multiply by 100 000)

Question 9

Maternal mortality rate

Answer 9

number of women who die during childbirth in child bearing age

Question 10

Infant mortality rate

Answer 10

number of deaths of children less than 1 year old per 1000 live births

Question 11

Child mortality rate

Answer 11

number of deaths of children less than 5 years old per 1000 live births

Question 12

Measuring mortality (conceptual universe)

Answer 12

• calculate mortality rates for Canadians

- these mortality rates apply to Canadians no matter where you live

Question 13

Proportionate mortality

Answer 13

• what are people dying of in a specific country?
• of all of the deaths what causes are the most common
• number of people dying of certain causes compared to total deaths in population

Question 14

Absolute mortality

Answer 14

-proportionate mortality multiplied by number of deaths in each country
-ex:
Total deaths per 100 000 in USA: 711
PM of cancer in USA: 34.48
AM of cancer in USA: 0.3448 x711= 245
Therefore 245 deaths could be prevented with a cure for cancer

Question 15

Case fatality rate

Answer 15

-% of people who die of a certain disease
-ex:
influenza death rate is 0.7 per 100 000 people/year
incidence rate for influenza is 40 per 100 000 people/year
case fatality rate= 0.7/40 x 100 =1.75% therefore 1.75% of people who get influenze die of it

Question 16

Issue with crude mortality

Answer 16

• comparing white and black death rate and see that death rate is almost double in black than white
• however overall death rate is lower in blacks
• this is because mortality is heavily weighted by older age groups since this group tends to die more
• this happened because this population consisted of a lot of white old people so it made the overall death rate increase whereas there were less old black people dying

Question 17

Direct standardization

Answer 17

• adjust the observed population mortality rates to that of a standard reference population with known age (and sex) distribution
• take percentages of population in each category of standard reference population and multiply this percentage by deaths per 100 000 in the other countries
• get expected amount of deaths if they had the same age distribution

Question 18

Indirect standardization

Answer 18

• calculate an expected mortality rate
• then compare the observed mortality against the expected
• use average death rate in each age group per 100 000 and calculated expected death rate by dividing expected death rate per 100 000 by 100 000 and multiplying it by the number of people in the study in that age group
• collect observed deaths and calculate SMR

Question 19

Standardized Mortality Ratio

Answer 19

• observed deaths/expected deaths
• if SMR = 100 then observed and expected deaths are equal
• if SMR>100 then observed deaths are greater than expected deaths
• if SMR<100 then observed deaths are less than expected deaths