3. Tools of measurements
1. Rates: a rate measures the occurrence of some particular
event
number of deaths in one year
Death rate= ------------------------------------x1000
mid- year population
Elements of rates:
numerator, denominator, time specification and multiplier
Categories of rates:
โข Crude rates/unstandardized-actual observed rates
โข Specific rates-actual observed rates due to specific causes,
groups, or time
โข Standardized rates
4. 2. Ratio: Ratio expresses a relation in size between two
random quantities.
x
x:y or ---- eg. Sex ration
y
Proportion: a proportion is a ratio which indicates the
relation in magnitude of a part of the whole
No of children with scabies at a certain time
Eg. ----------------------------------------------------- x 100
Total no of children in the village at the same time
5. Measurement of mortality:
1. Death certificate
2. Uses of mortality data: mortality data
a. Explains trends and differentials in overall mortality
b. Indicates priority for health action and the allocation of
resources
c. Employed in designing intervention programs
d. Helps in monitoring of public health problems and
programs
e. Gives clue for epidemiological research
3.Limitations of mortality data:
a. Incomplete reporting of deaths
b. Lack of accuracy
6. c. Lack of uniformity
d. Choosing a single cause of death
e. Changing
f. Disease with low fatality
Mortality rates and ratios
1.Crude death rate
The no of deaths (from all causes) per 1000 estimated
mid-year population in one year, in a given place
No of death during the year
Crude death rate= ------------------------------------x1,000
mid year population
CDR lack comparability for communities with populations
that differ by age, sex, race, etc.
7. 2. Specific death rates:
specific death rates may be
a. Cause or disease specific e.g; TB, Cancer
b. Related to specific groups e.g; age specific, sex-specific
No of deaths from TB during a calendar year
specific death rate due to TB= ------------------------------------------x1,000
mid-year population
No of deaths in a particular population
Age specific death rate=------------------------------------------------x 1,000
Mid year population of that age group
8. No of deaths of person aged 15-20 during a
calendar year
Specific death rate in age group= ------------------------------------x 1,000
15-20 years Mid year population of person aged 15-20
Male deaths
Sex specific death rate=---------------------x 1, 000
Mid year population of males
No of deaths among males during a calendar year
Specific death rate for males= -----------------------------------------x1,000
mid-year population of males
9. Female deaths at specific aged 15-20 years
Age-Sex specific death rate=-----------------------------------------x 1,000
Female population aged 15-20 years
Deaths in January x 12
Death rate for January= -----------------------x 1,000
Mid- year population
Deaths in the week x 52
Weekly death rate = ---------------------------- x 1,000
Mid- year population
10. 3. Case fatality rate (Ratio)
Total number of deaths due to a particular disease
= ---------------------------------------------------------x100
Total number of cases due to the same disease
4. Proportional mortality rate (Ratio)
a. Proportional mortality from a specific disease
No of deaths from the specific disease in a year
= ---------------------------------------------------------x100
Total deaths from all causes in that year
b. Under -5 proportionate mortality rate
No of deaths under 5 years of age in the given year
= --------------------------------------------------------------x100
Total no of deaths during the same period
11. 5. Proportional mortality rate for aged 50 years and above
No of deaths of persons aged 50 years and above
= -------------------------------------------------------------x 100
Total deaths of all age groups in that year
d. Survival rate:
Total no patients alive after 5 years
= ------------------------------------------x100
Total no of patients diagnosed or treated
12. Measurement of morbidity
Morbidity is defined as โany departure, subjective, or
objective, from a state of physiological well-beingโ
Morbidity=sickness, illness, disability
Morbidity could be measured in terms of 3 units
a. persons who were ill
b. the illnesses (spells of illness) that these persons
experienced and
c. the duration of these illnesses
Morbidity rates:
Disease frequency=incidence and prevalence
Duration of illness=average duration/case or the disability rate
Severity of illness=case fatality rate
13. Value of morbidity data
a. They describe the extent and nature of the disease load in
the community and thus assist in the establishment of
priorities
b. They provide more comprehensive and more accurate and
clinically relevant information on patient characteristics
and therefore essential for basic research
c. They serve as starting point for etiological studies, and
thus play a crucial role in disease prevention
d. They are needed for monitoring and evaluation of disease
control activities
14. Incidence: โNo of new cases occurring in a defined
population during a specified period of timeโ
No of new cases of specific disease during a
given time period
Incidence= -----------------------------------------------------------------x1,000
population at risk during that time
eg., New cases of an illness 500
population at risk 30,000
Incidence rate= 500/30,000x1000= 16.7 per 1000 per year
Incidence rate refers
* only to new cases
โข during a given period
โข In a specified population
15. Prevalence
โAll current cases (new and old) existing at a given point time,
or over a period of time in a given populationโ
Types of prevalence
a. Point prevalence
b. Period prevalence
Point prevalence: the no of current cases of a disease at one
point in time in relation to a defined population
No of all current cases of a specified disease existing at a
given point in time
--------------------------------------------------------------------------------------------x100
Estimated population at the same point in time
16. Period prevalence:
Frequency of all current cases existing during a defined
period of time
No of all existing cases of a specified disease during a
given period of time interval
--------------------------------------------------------------------------x100
estimated mid interval population at risk
Prevalence = incidence x duration (P=I x D)
Uses of prevalence:
1. Helps to estimate the magnitude of health problems and
identify potential high risk population
2. Useful for administrative and planning purposes eg;hospital
beds, manpower needs, rehabilitation facilities
17. LEVELS OF HEALTH PREVENTION
๏ฎ 1. PRIMORDIAL PREVENTION
๏ฎ 2. PRIMARY PREVENTION
๏ฎ 3. SECONDARY PREVENTION:
๏ฎ 4.TERTIARY PREVENTION
18. 1. PRIMORDIAL PREVENTION :
๏ฎ It includes measures for prevention of
emergence of risk factor.
๏ฎ primary prevention for evidence of development
and continuation of such practices in the day to
day life which will lead to initiation of disease
๏ฎ E.g. Overeating, too much salt intake, smoking
of tobacco, alcohol consumption.
19. 2. PRIMARY PREVENTION:
๏ฎ Primary prevention can be defined as โaction taken prior to
the onset of disease, which removes the possibility that a
disease will ever occurโ.
PRIMARY PREVENTION:
A. Health Promotion
B. Specific Protection
20. A. Health Promotion
1. Health education to improve health consciousness
2. Improvement in standard of nutrition with relation to age, sex, occupation,
physiological condition and environment to promote and maintain growth
and development and health
3. Provision of socio-cultural environment for development of good personality
4. Better physical environment through adequate housing, water supply and
waste disposal facility.
5. Proper environment at the occupation
6. Good, usable, feasible recreational facilities
7. Marriage counseling
8. Sex and population education.
9. Application of principles of genetics to improve health
10. Periodic selective examination of general population and at risk population.
21. B. Specific Protection:
1. Use of specific immunizations
2. Use of specific drugs as chemoprophylactic agents
3. Use of specific nutrients e.g. vitamin A at the age of nine months with
measles vaccine for prevention of upper respirators infections by
strengthening respiratory mucosa and prevention of night blindness;
prevention against nutritional anaemia by provision of iron folic acid tablets
during childhood and antenatal period.
4. Protection against accidents and morbidity by use of helmets,
preventive maintenance of machinery and up-to-date cleaning of work place.
22. 3. SECONDARY PREVENTION:
๏ฎ Secondary prevention can be defined as โAction which
halts the progress of a disease and prevents
complicationsโ.
๏ฎ Interventions:
1. Early diagnosis and prompt treatment.
2. To cure and prevent the disease process.
3. To prevent the spread of communicable disease.
4. To prevent the complications.
5. To shorten the period of disability.
23. 4.TERTIARY PREVENTION
Tertiary prevention can be defined as โall patientโs adjustment
to irremediable conditionsโ. Measures available to reduce or limit
impairments and disabilities, minimise suffering caused by existing
departures from good health.
1. Disability limitation
Disease - Infection ( pathogen in body)
Impairment - Any loss
Disability - unable to carry daily work
Handicap - result of disability
24. 2. Rehabilitation
๏ฎ Medical rehabilitation โ restoration of the capacity to earn a
livelihood.
๏ฎ Vocational rehabilitation โrestoration of family and social relationships
๏ฎ Social rehabilitation โ restoration of family and social relationships.
๏ฎ Psychological rehabilitation โ restoration of personal dignity and
confidence.
