VITAL STATISTICSRATES AND RATIOS

RATE• Shows the relationship between a vital

event and those persons exposed to the occurrence of said event, within a given area and during a specified unit of time.• It is evident that the persons

experiencing the event (the numerator) must come from the total population exposed to the risk of same event (the denominator)

RATIO• It is used to describe the relationship

between 2 numerical quantities or measures of events without taking particular considerations to time or place.

• These quantities need not necessarily represent the same entities, although the unit of measure must be the same for both numerator and denominator of the ratio

CRUDE OR GENERAL RATES

• These rates refer to the total living population. It must be presumed that the total population was exposed to the risk of occurrence of the event

SPECIFIC RATE

• The relationship is for a specific population, class or group.• It limits the occurrence of the

event to that portion of the population definitely exposed to it

Crude Birth Rate

• A measure of one characteristic of the natural growth or increase of a population.

CBR = Total no. of livebirths registered in a given calendar X 1,000 Estimated population as of July 1 of the same year

CRUDE DEATH RATE

• A measure of one mortality from all causes which may result in decrease of population

CDR =Total no. of deaths registered in a given calendar year x 1,000

Midyear population in a given Calendar year

INFANT MORTALITY RATE

• Measures the risk of dying during the 1st year of life. • It is a good index of the general

health condition of a community since it reflects the changes in the environmental and medical condition of a community

IMR= Total no. of deaths under 1 year of age registered in a given calendar year X 1,000

Total No. of registered live births of same Calendar year

MATERNAL MORTALITY RATE

• It measures the risk of dying from causes related to pregnancy child and puerperium

• It is an index of the obstetrical care needed and received by the women in a community

MMR=Total no. of deaths from maternal causes registered for a given calendar year X1,000

Total no. of live births registered of same Calendar year

FETAL DEATH RATE•Measures pregnancy wastage.• Death of the product of

conception occurs prior to its complete expulsion irrespective of duration of pregnancy

NEONATAL DEATH RATE•Measures the risk of dying

during the 1st month of life•May serve as index of the

effects of prenatal care and obstetrical management on the newborn

NDR=No. of deaths under 28 days of age registered in a given calendar year X 1,000

Total no. of live births registered of the same Calendar year

SPECIFIC DEATH RATE

• Describe more accurately the risk of exposure of certain classes or groups to particular diseases.

• To understand the forces of mortality, the rates should be made specific provided the data are available for both the population and the event in their specifications.

• Specific rates render more comparable results and thus, reveal the problems of public health.

Deaths in a specific class or registered in a given calendar

year Specific Death Rate= --------------------------------------- X

1000 Estimated population as of

July 1 in same specified class or group of the said year

EXAMPLESno. of deaths in a specific cause registered in a given

Cause-Specific Death Rate= calendar year…………………..X 1000

Estimated population as of July 1 in same year

EXAMPLES

No of deaths in a particular age group registered in a

Age-Specific = given calendar year X 1000Death Rate Estimated Population

as of July 1st in same age group of the same year

EXAMPLES

No. of Deaths of a certain sex registered in a

Sex-Specific =given calendar year X 1000Death Rate Estimated population as of

INCIDENCE RATE (IR)

• Measures the frequency of occurrence of a phenomenon in a given period of time

• Deals only with new casesno. of new cases of a particular

disease registered IR = during a specific period of time x

1000Population at risk

PREVALENCE RATE (PR)

• Measures the proportion of the population which exhibits a particular disease at a particular time

• This can only be determined following a survey of the population concerned

• Deals with total (old and new) number of cases

No. of new and old cases of a certainPR = disease registered at a given time X 100

Total no. of person examined at same given year

ATTACK RATE (AR)

• A more accurate measure of the risk of exposure

• Useful in epidemiological investigationsNo. of persons acquiring a disease

AR = registered in a given year X 100No. of exposed in same disease in same year

PROPORTIONATE MORTALITY (DEATH RATIOS)

• Shows the numerical relationship between deaths from a cause (or group of causes), age (or group of age) etc. and the total no. of deaths from all causes in all ages taken together

• Not a measure of risk of dying

No. of registered deaths from a PM = specific cause or age for a given year X 100

No. of registered deaths from all causes, all ages in same year

CASE FATALITY RECORD (CFR)

• INDEX OF THE KILLING POWER OF A DISEASE• IT IS INFLUENCED BY INCOMPLETE REPORTING

AND POOR MORBIDITY RATENo. of registered deaths from a

CFR =specific disease for a given year X 100No. of registered cases from samespecific disease in same year

SWAROOP’S INDEX

• INDEX OF DEATHS ABOVE 50 YEARS OLD

SWAROOP’S INDEX = Total deaths, 50 years and above X 100

Total deaths, all ages in same year