Measures of Mortality&

Mortality in Different Populations

Mortality is a term which means “death” or describes

death and related issues

Mortality Table

Selected Mortality Rates

Maternal Mortality

Rates

• With rates, the numerator is included in the denominator

• Rate is the number of or frequency of a disease per unit size of population

Ratio

Ratios

• Ratio – the relation in number, degree or quantity existing between two similar things

25 ♀ : 30 ♂

• Ratio as a fraction

25/30 or 5/6

Proportions• Compare like populations or like

illnesses within a populationFor example, 40 children are currently

ill with measles, while 80 children all together have or have had the measles

Mortality

• Deaths; describes death; related issues

• Graunt 1600s – Bills of Mortality

• Farr (1807-1883) Registrar general; vital statisticsCausesRegistration

Types of Mortality Rates/Ratio• annual death rate• crude death rates• infant mortality rates (ratio)• neonatal mortality rates• postneonatal mortality rates• perinatal mortality rates• fetal death rates• fetal death ratios• abortion rates• maternal mortality rates• adjusted mortality rates• standardized mortality ratio• specific death rates• proportionate mortality rate- case fatality rate• mortality crossover – mortality time trends

Your Assignment: familiarize yourself with the definitions

of these terms

Three Levels of Rates

• Crude rates

• Adjusted rates

• Specific rates/ratios

Annual Death Rates• “General” (crude) mortality rate

a population group exposed to risk of death

a time period

• Crude Mortality Rate = # of deaths occurring in that population during that period of time

Crude Death Rates• Does NOT account for differences of

age, sex, etc. in any aspect of death

• Info needed: total deaths total population a given period of time

Crude Death Rates(cont’d)

Cause Specific Mortality Rate

Cause Specific Mortality Rate

Case Fatality Rate

Specific Death Rates• For example: Early life mortality measures

Specific Death Rates

• For example: infant mortality

Infant Death Rates in the U.S.

Specific Death Rates

• Neonatal mortality rate

(cont’d)

• Postneonatal mortality rate

Neonatal & Postneonatal Death Rates

Specific Death Rates

• Perinatal mortality rates

(cont’d)

Specific Death Rates

• Fetal death rate

(cont’d)

Maternal Mortality Rates

Maternal Mortality Rates(cont’d)

Adjusted Death Rates• Allows comparisons by controlling

for differences in some variablesStandardized Mortality Ratio (SMR)Proportionate Mortality Ratio (PMR)Specific Mortality Rates

• Does NOT account for differences of age, sex, etc. in any aspect of death

• Info needed: total deaths total population a given period of time

Adjusted Death RatesAge Adjusted Rates

• Direct Method

Adjusted Death RatesAge Adjusted Rates

• Direct Method(cont’d)

Adjusted Death RatesAge Adjusted Rates

• Direct Method(cont’d)

Adjusted Death RatesAge Adjusted Rates

• Indirect Method Standard Mortality Ratio

(cont’d)

Standardized Mortality Ratio (SMR)

Standardized Mortality Ratio (SMR)

Standardized Mortality Ratio (SMR)

Specific Mortality Rates

• Age specific mortality rate

Age-Specific Mortality Rates

Other Issues Related to Mortality

• Mortality Cross-overDeath of a subject that started in one group

but “crossed over” to another group during course of study

• Mortality Time Trends

• Years of Potential Life Lost (YPLL)YPLL Rate

Years of Potential Life Lost