The document discusses the measurement of health and disease, including definitions and formulas for morbidity and mortality rates. It elaborates on tools such as incidence and prevalence rates, crude and specific death rates, and various indicators of health. The document provides exercises and examples to illustrate the calculations related to these measures.

1. MEASUREMENT OF HEALTH
AND DISEASE
Ms. Jyoti Chand
MSc Nursing
AIIMS RISHIKESH

2. Objectives
◦ Explain the measurement of health and disease
◦ Define measurement of morbidity
◦ Elaborate measurement of mortality

3. Tools of measurement
The basic tools of measurement in epidemiology are:
Rate
Ratio
Proportion

4. Rates
◦ A rate measures the occurrence of some particular event
(development of disease or the occurrence of death) in a population
during a given period of time.
◦ It indicates the change in some event that takes place in a
population over a period of time.

5. ◦ A rate comprises the following elements:
Numerator
 denominator
 time specification and
Multiplier
RATE= Numerator (a) is a part of denominator (b) and multiplier is
1000 or 10,000 or 100,000

6. Types of rates
Crude rate
Specific Rate

7. Crude rate
“These are the actual observed rates such as the birth & death rates.”
CDR= No. of deaths in one year in a specified area
× 1000
mid year population of the specified area during the same year

8. Exercise
If,
total number of deaths is, 4000
Mid year population at that time = 2,000,000
Calculate the crude death rate??

9. Specific Rates
◦ These are actual observed rates due to specific causes (e.g.
tuberculosis); or occurring in specific rates (e.g. age-sex groups)
or during specific time periods (e.g. annual, monthly or weekly
rates).

10. Cause specific death rate=
No. of deaths from specific cause in an area during a year
× 1000
mid year population of the same area during the same year

11. Exercise
Total no of deaths from an age 20-40 = 1500
Mid year population at risk= 5,550
Calculate the specific death rate??

12. Ratio
◦ Another measure of disease frequency is ‘ratio’.
◦ It expresses a relation in size between two random quantities. The
numerator is not a component of denominator. It is expressed in the
form of x y or x/y
◦ Example: The ratio of white blood cells relative to red cells is 1:600
or 1/600, meaning that for each white cell, there are 600 red cells.

13. RATIO= Numerator is not a part of denominator and both
numerator and denominator are unrelated

14. Proportions:
◦ Expressed in percentage
◦ Numerator is a part of denominator.
◦ Multiplier is only 100
Example- in skin OPD, number of patients attended on 24/7/2022
was 60, out of which 48 were female.
= 48/60
=0.8% or 80%

15. Indicators of health
Mortality indicators
Morbidity indicators

16. MEASUREMENT OF MORBIDITY
Morbidity has been defined as any departure, subjective or
objective, from a state of physiological well-being. The term is used
equivalent to such terms as sickness, illness, disability, etc.
Three aspects of morbidity are frequency, duration and severity.
Disease frequency is measured by incidence and prevalence rates.

17. Morbidity
Indicators
1. Incidence rate
2. Prevalence rate

18. Incidence
◦ Incidence rate is defined as “the number of new cases occurring
in a defined population during a specified period of time”. It is
given by the formula:
◦ Incidence= No. of new cases of a disease in a year
× 1000
Total Population at risk

19. if,
There had been 500 new cases of an illness in a population of
30,000 in a year
Calculate the incidence rate?

20. Prevalence
◦ The term 'disease prevalence' refers specifically to “all the current
cases (old and new) existing at a given point in time, or over period of
time in a given population”.
◦ Prevalence= No. of total(new+old) cases of a disease in a year
× 100
Total population

21. Types of prevalence
◦ Point prevalence:- number of all cases ( old and new cases)
that exist at a given point in time
◦ Period prevalence: number of all cases that exist in a
population during a specified period of time

22. Q) In a population of 5000 number of new cases of TB is 500; old
cases in the same population are 150. what is the prevalence of
TB?

23. Measurement of Mortality
Mortality indicators: -
◦ Crude death rate(CDR)
◦ Specific death rate
◦ Case fatality rate
◦ Proportional mortality rate
◦ Survival rate

24. Crude Death Rate (CDR)
Definition: Number of deaths (from any cause), per 1000 population,
in one year, in a defined population.
CDR= No. of deaths in one year in a specified area
× 1000
mid year population of the specified area during the same year

25. Specific death rate
a. Cause specific death rates: TB death rate, death rate due to
accidents etc.
b. Group specific death rates: Age specific death rate, sex

26. Uses of Cause Specific Death Rate
◦ Comparison between different populations
◦ For monitoring the control measures for a disease
◦ Disease surveillance

27. GROUP SPECIFIC DEATH RATES
Age specific death rate:
No. of deaths in the specific age groups in the defined
population/ midyear population of the same age group in the
same year X 1000

28. Infant Mortality Rate (IMR):
IMR= number of deaths of infants (0-1yr age) in an year in a specified
population
x1000
No. of live births in the same year in the same population

29. Q) In a population of 5000, with birth rate of 30/1000
population, 15 children died during first year life in a year: of
these 9 died during first month of life. What is the infant
mortality rate in this population?
a)100
b)60
c)150
d)45

30. Neonatal Mortality Rate (NNMR):
No. of deaths up to 28 days of life in a year in a specified population
x1000
No. of live births in this population in the same year

31. CASE FATALITY RATE (RATIO):
◦ Total no. of deaths due to a particular disease/Total no. of cases
due to the same disease x100
◦ It measures the 'killing power' of a disease
◦ Case fatality rate is a Proportion : always expressed in
percentage

32. Proportional mortality rate
◦ Proportional mortality rate (PMR) is defined as "the ratio of
deaths due to a specific cause or in a specific age or sex or sub-
area, to the total number of deaths, multiplied by 100".
◦ Under-5 Proportional Mortality Rate
No. of deaths in 0-4 years of age in one year in a specified
population /Total no. of deaths in the same year in the same
population *100

33. ◦ It is the proportion of survivors in a group (e.g. of patients)
studied and followed over a period (e.g. a 5-year period).
◦ Total number of patients alive after 5 years /Total number of
patients diagnosed or treated× 100
◦ is used to describe prognosis in certain disease conditions
Survival Rate

34. Practice Exercise

35. ◦ A study was done to assess the health status of a community with
a total population of 50000. it was seen that 1 year:
◦ Live births= 2000
◦ Total deaths= 500
◦ Neonatal deaths= 300
◦ Deaths due to leukemia= 15
◦ Cases of leukemia = 45
Calculate the main fertility, morbidity, and mortality measures of
this community.

36. Q) The following is true about prevalence and incidence:
a)Both are rates
b)Prevalence is a rate but incidence is not
c)Incidence is a rate but not prevalence
d)Both are not rate

37. Q) Case fatality rate is a method of measuring:
◦ a) Infectivity
◦ b) Pathogenicity
◦ c) Virulence
◦ d) Average duration of disease

38. Q) If the prevalence is very low as compared to the incidence for a disease, it
implies:
a) Disease is very fatal and easily curable
b) Disease is non- fatal
c) Calculation of prevalence & incidence is wrong
d) Nothing can be said, as they are independent

39. Q) Which one of the following is a better indicator of the severity of an acute
disease?
a) Cause specific death rate
b) Case fatality rate
c) Proportional mortality rate
d) Five year survival rate

40. Q) The mid year population during 2013 was 50,000. the no. 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