Epidemiology Measuring Disease Frequency-Death Rates

1. EPIDEMIOLOGY
Lecture 4
Death Rates

2. 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.

4. Crude death rate
Number of deaths during the year
Mid-year population
X 1000

5. What is the disadvantage of a crude
death rate?
Population A
Age group Population No. of
deaths
0-15 300 3
15-60 200 1
>60 500 5
Total 1000 9
Age group Population No. of
deaths
0-15 100 1
15-60 800 4
>60 100 1
Total 1000 6
Population B

6. 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????)

7. 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 group
X 1000

9. 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 4
10-20 300 3
20-30 300 2
30-40 350 3
40-50 400 5
50-60 250 7
60-70 150 5
70-80 50 7
Total 2000 36
6.67
18

10. 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

11. 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

12. 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 population
X 1000

14. 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.
12
1

15. 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.

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

20. EXERCISE 5

21. EXERCISE 5

22. EXERCISE 5

23. EXERCISE 5

24. EXERCISE 5

25. EXERCISE 6

26. EXERCISE 6

27. EXERCISE 6