BIO4503 APPLIED EPIDEMIOLOGY
DATA ON POPULATION AND
MORTALITY
Postgraduate Course Feedback
INTRODUCTION TO BASIC CONCEPTS IN
DEMOGRAPHY
workshop
Dr Carmen Aceijas, PhD
[email protected]
WORKSHOP OUTLINE
• Building from lecture contents:
• Population pyramids transformation. Video watching
• Some key indicators to describe populations:
2. BIRTH RATE, 3. FERTILITY RATE,
4. MORTALITY RATE, AND 5. DISEASE RATE
POPULATION PYRAMIDS
• http://www.youtube.com/watch?fea
ture=player_embedded&v=OpOEH
jndywk
WHAT ARE RATES? WHAT ARE THEY USED
FOR? WHAT ARE THOSE MOST USED IN
EPIDEMIOLOGY?
• Are measures of frequency
• Used when the aim is to know how frequently an event happens within a
given period of time in a given population.
• Most used in PH epidemiology:
–
–
–
–
Birth Rate
Fertility Rate
Mortality [Death] Rate
Disease Rate
• Take into account
– The number of events (e.g. No of deaths, births, cases of a disease)
– The number of people to whom it could potentially happen (Population
at risk)
– Time period within which it happened (often year)
• Reported as “x” [evens/cases] per 1,000 or 100,000 population
BIRTH RATE
• Birth rate:
– Measures number of births within a given
period of time (e.g. Year)
– The denominator is the whole population
– Reported as per 1,000 population
Birth rate
(crude)
=
Number of births in year x 1000
(mid-year) population
FERTILITY RATE
• Measures number of births within a given period of
time (e.g. Year)
• The denominator is the female population 15-44
• Reported as “no. of children per woman”
Fertility rate =
(crude)
Adjusted
Number of births in year
x 1000
(mid-year) female population 15-44
FR is calculated based on current fertility rates in different
age groups
MORTALITY RATE
• Mortality (death) rate:
– Measures number of deaths per 1,000 within a given
period of time (e.g. Year)
– The denominator is the whole population
– Reported as per 1,000 population
Crude Mortality Rate (CMR) = Number of deaths in year x 1000
mid-year population
OTHER MORTALITY RATES. INFANT MORTALITY
RATE, UNDER 5 MORTALITY RATE, MATERNAL
MORTALITY RATE
Infant mortality rate= No. of deaths in children under 1 year of age x 1000
No. of live births in year
Under 5 mortality rate= No. of deaths in children under 5 years of age x 1000
No. of live births in year
Maternal mortality = Number of deaths related to childbearing x 1000
No. of live births in year
DISEASE RATE
• Measures number of event [people getting the disease =
cases] within a given period of time (e.g. Year)
•The denominator is the population at risk [might or might
no be the whole population]
• Reported as per 100,000 population but might vary
depending on extent of disease [often multiplies used
1,000 or 10,000 too]
Disease rate= Number of cases x 100,000
pop at risk
*or other multiplier
BIRTH RATE and MORTALITY RATE [exercise]
Exercise: Calculate the natural increase, the birth and
the mortality rates in a “x” country in 2012:
– Population: 25,000,000
– Number of births in 2008: 3,500
– Number of deaths in 2008: 47,500
NATURAL INCREASE, BIRTH RATE and
MORTALITY RATE [exercise]
Answers:
NI = 3,500 – 47,500 / 25,000,000 x 100 = - 0.176%
[-0.18%]
CMR = 47,500/25,000,000x1,000= 1.9 deaths per
1,000 population
BR = 3,500/ 25,000,000x1,000= 0.14 births per 1,000
population
DISEASE RATE [exercise]
Exercise: Calculate the disease rate of HIV in a
“x” country in 2010 excluding vertical
transmission.
Population: 25,000,000
Population at risk: Calculate it taking into account
the percentage of 0-12 years old = 15%
Cases: 3,000
DISEASE RATE [exercise]
Answer:
Population: 25,000,000
Population at risk: 21,250,000 [85% of whole pop]
Cases: 3,000
3,000/21,250,000x1,000 = 0.14 cases per 1,000 population
3,000/21,250,000x100,000 = 14.11 cases per 100,000 pop
When presenting data
• Always specify Year
• Always specify Source of data
• Make sure you compare data from the
same year and the same source
• Always use units of measurement (years,
people, percentages etc.)
• When presenting rates check multiplier
(per 1000, per 10,000 or 100,000 etc).