EPIDEMIOLOGY

Lecture 4Death Rates

Learning Objectives

1. Understand specific and proportional death

rates

2. Understand the need for standardization

3. Describe the TWO methods of

standardization

4. Calculate age-standardized death rates.

Crude death rate

Number of deaths during the year

Mid-year populationX 1000

What is the disadvantage of a crude death rate?

Population AAge group Population No. of

deaths

0-15 300 315-60 200 1>60 500 5Total 1000 9

Age group Population No. of deaths

0-15 100 115-60 800 4>60 100 1Total 1000 6

Population B

Specific Death Rates

• Cause or disease specific• Age-specific• Sex-specific• Age and sex-specific• Related to specific groups (Remember

incidence rates for smokers, ex-smokers, never-smokers????)

Age-specific death rate

Total number of deaths in a specified age group in a defined area during a specified period

Mid-year population of the specified age groupX 1000

EXERCISE 1• Calculate age-specific death rate for the age group 20-

30 years and compare it with the crude death rate.

Age group Population Number of deaths

0-10 200 410-20 300 320-30 300 230-40 350 340-50 400 550-60 250 760-70 150 570-80 50 7Total 2000 36

6.67

18

Sex-specific death rate

Total number of deaths in males (or females) in a defined area during a specified period

Mid-year population of males (or females)X 1000

EXERCISE 2

• In the year 2013, the mid-year population of a town was 100,000. Calculate the specific death rate for males in the town for the year 2013, given that:– Number of male deaths in 2013=500– Sex ratio=1000 males per 1000 females.

10

Disease-specific death rate

Total number of deaths due to a disease (e.g., Cancers) in a defined area during a specified

period

Mid-year populationX 1000

EXERCISE 3

• The mid-year population during 2013 was 50000. The number of deaths during this year was 600 out of which 50 died due to cancer. Calculate:– The crude death rate.– Specific death rate due to cancer.

121

Proportional Mortality

• The number of deaths from a given cause per 100 or 1000 total deaths in the same period.

• Relative importance of specific disease or disease group, as a cause of death.

EXERCISE 4Number of deaths for Leading Causes of Death – United States, 2003

EXERCISE 5

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EXERCISE 5

EXERCISE 5

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EXERCISE 6

EXERCISE 6

EXERCISE 6