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DEMOGRAPHIC INDICATORS. Assoc. Prof. Petko Salchev, MD, PhD. The science of demography. „ Demography ” comes from demos – people and grapho – to write Demography is a science dealing with types , methods and nature of population reproduction and factors affecting this process.
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DEMOGRAPHIC INDICATORS Assoc. Prof. Petko Salchev, MD, PhD
The science of demography „Demography” comes fromdemos – peopleandgrapho – to write Demography is a science dealing with types, methods and nature of population reproduction and factors affecting this process
Structure of the demographic science • Demographic theory • Pure (formal) demography • Analytic demography • Historical demography • Sociological demography
The demographic cycle • Stationary stage • Early growth stage – characterized by a decline in mortality and unchanged birth rate. • Late growth stage – mortality continues to decrease, but there is also a tendency for a decrease in birth rate, although still higher than mortality. • Stationary stage – characterized by low levels of birth rate and mortality. • Decline stage – birth rate lower than mortality.
Early growth stage Stationary stage Late growth stage Decline stage Types of stages in Bulgarian population
Population and population reproduction • Population, people – natural, historically set and constantly renewing itself in the course of life sum of people, the fundamental material component of human society • Population reproduction – this is one of the main processes of reproduction of society and represents a probability process, formed by a mass of random single events of birth and death
Reproductive behavior • Psychic regulator of behavior, personal predisposition governing the harmonization of a stream of activities, subject to positive or negative attitudes towards the birth of a given number of children • Readiness for a certain outcome of a walk of life, the acceptance from the individual of the necessity for giving birth to a given number of children
Main groups of demographic indicators • According to complexity: • simple – reflecting a count (population, births, etc.) • complex – expressing ratios (birth rate, mortality, etc.) • integral – the integration of several health events (life expectancy, healthy life expectancy, etc.) • According to the type of study subject: • static – number, composition and structure of the population in a given moment • dynamic – related to vital processes in human life or population transitions in territory and time.
Indicators of population static • Population number • Average yearly population number Р0 + Р1 Р= ----------------- 2 Where Р0is the population number at the beginning of the year, Р1is the population number at the end of the year
Population number • Present population according to address registration (Population de fait) • Population according to place of residence (Population reference) • Risk exposed population (Population exposee ou risque) – the population with the highest probability of occurrence and development of a certain disease
Demographic transition Stages • Traditional – characterized by high and balanced levels of birthrate and mortality • Transitory– characterized by diminishing the level of mortality while keeping the birthrate • Stable – characterized by low and balanced birthrate and mortality • Population ageing – characterized by a growing proportion of aged people as a result of a lowered birthrate and higher life expectancy • Depopulation – characterized by high migration and mortality among people in active age as a result of trauma, chronic heart diseases, AIDS, wars, etc.
Rate of demographic ageing (Ti) The rate of increase of the relative share of population above work age (according to the defined boundary for men and women) towards the preceding year. Calculated as a percentage.
9000000 8500000 8000000 7500000 1970 1980 1990 2000 2010 Changes in the average population number in Bulgaria for the period 1970-2004 г. Source: World Health Organization, Regional Office for Europe. European health for all database (HFA-DB)
Population structure • Population structure according to gender • Population structure according to age • Analysis of the correlation of dependant contingents • Population structure under, in and above work age • Analysis of the relative shares of persons aged 0-14, 15-49 and above 50 • Ethnic composition, religion, maternal language • Population structure according to level of education
Population gender structure Population as of 31.12.2005 Source: NSI,2006
Population age structure Age classifications • WHO classification • 0-14 – infant age • 15-44 – juvenile age • 45-59 – middle age • 60-74 – aged persons • 75-89 – old people • Above 90 – longevity • Classification for the needs of education and healthcare • Under 1 – nursing age • 1-3 – early infant age • 4-6 – before school age • 7-14 – school age
The population age structure may be characterized in four basic ways • Through building and analyzing of an age pyramid • Through correlation of dependant contingents (relation of children and persons above 65 to working population) • Through comparison of relative shares of persons in the three main groups 0-14, 15-49 and above 50. • Through relative shares of persons above 60 or above 65.
Analysis of the correlation of dependant contingents • Coefficient of age dependency (V) shows the number of people in „dependant" ages (population under 15 and above 65) in relation to 100 people in „independent" age (from 15 to 64). Calculated in percent.
Population structure under, in and above work age Source: NSI,2006
Population, insured persons and retired for the period 2000-2005 Relation of Population above retired work to Population age as of Retired - Insured insured as of 31.12. 31.12. total persons persons 2000 г. 8 149 468 2 027 976 2 379 324 2 303 726 103.3% 2001 г. 7 891 095 1 929 683 2 370 871 2 311 091 102.6% 2002 г. 7 845 841 1 887 036 2 350 900 2 170 061 108.3% 2003 г. 7 801 273 1 845 175 2 336 806 2 393 927 97.6% 2004 г. 7 761 049 1 804 868 2 327 807 2 491 829 93.4% 2005 г. 7 718 750 1 759 875 2 313 744 2 597 061 89.1% Coefficients of dependency 2000-2005 Source: Hr. Mitreva, NII, 2006
Analysis of the relative shares of persons in ages 0-14, 15-49 and above 50. • Progressive type – persons aged 0-14 areabove30%of the total number of population, and these above 50 areunder 20%; • Stationery type – the number of persons in the two age groups 0-14 and above 50 is approximately equal and their percent relation to the total population number is respectively 25% to 25%; • Regressive type – persons in the age group 0-14 constitute under 20%of the total population number, and those above 50 – more than 30%.
Coefficient of demographic replacement The ratio of the population numbers of incoming in the working contingent age group 15-19 and exiting from the working contingent age group 60-64.
Marriage and divorce • The marriage coefficient (b) shows the number of marriages per 1 000 people. It is calculated (per thousand) as the ratio of the number of marriages (B) throughout the year and the average population throughout the same year. • The divorce coefficient (p) shows the number of divorces per 1 000 people. It is calculated (per thousand) as the ratio of the number of divorces throughout the year and the average population throughout the same year.
Distribution of ethnic groups in Bulgaria as of 2001 in % Others Roma 2% 5% Not shown 0% Turks 9% Bulgarians 84% Ethnic composition Source: NSI, 2005
POPULATION DISTRIBUTION ACCORDING TO RELIGION Source: NSI, 2005
Population distribution according to religion as of 2001 in % Other Muslim Not 0,19 12,20 defined 3,57 Not shown Catholic 0,31 0,55 Protestant 0,53 East- orthodox 82,64 Source: NSI, 2005
Population distribution according to education in % No education 0% Higher Primary 24% 20% Secondary 56% Population distribution according to education Source: NSI, 2005
Indicators for mechanical movement of population • External migration • Internal migration • Cyclic movement
Indicators for natural movement of population Main concepts • “Childbirth" means is the process at the end of a human pregnancy that results in a baby being born • Alive birth occurs when a fetus, whatever its gestational age, exits the maternal body and subsequently shows any signs of life • Stillbirth is considered the delivery of child that by the termination of pregnancy didn’t show any signs of lifeand the pregnancy has lasted no less than 28 weeks • Abortionis considered the delivery of child that by the termination of pregnancy didn’t show any signs of lifeand the pregnancy has lasted less than 28 weeks
Children born alive through the year х 1000 Birth rate = Average yearly number of population Birth rate • Birth rate is assessedusing a three-stage scale: • low – below 15%, • medium – 15-25% • high – above 25%.
Children born alive х 1000 Fertility = Average yearly number of women aged 15 - 49 Generalfertilityrate Birthrate and general fertility rate(1990-2005) Year Birthrate (per 1000) General fertility rate3 1990 12.1 1.81 1995 8.6 1.23 2000 9.0 1.27 2001 8.6 1.24 2002 8.5 1.21 2003 8.6 1.23 2004 9.0 1.29 2005 9.2 1.31 Source: NSI, 2006
Age-specificfertilityrate Represents the number of live births per 1000 women of a specified age in one year.
Age-specific fertility rate 210 200 190 180 170 160 150 140 130 120 110 100 Coefficient 90 80 70 60 50 40 30 20 10 0 15-19 20-24 25-29 30-34 35-39 40-44 45-49 80,3 192,8 92,8 32,2 9,7 2,1 0,1 1980 68,3 159,4 78,3 28,8 9,4 1,8 0,1 1990 53,5 100,6 61,8 22,4 7,5 1,5 0,1 1995 45,1 85,2 56,9 22,4 7,3 1,6 0,1 1997 45,5 89,7 72,9 32,3 9,5 1,9 0,1 2000 Age Age-specificfertilityratein Bulgaria for 1980-2000 Source: NSI, 2006
Specific indicators for assessment of population reproduction • Total fertilityrate – represents the average number of children, that a woman would give birth to, through her entire fertile period, if the age-specific fertility rate remains the same as at the present moment for which it is calculated; • Gross fertility rateof population is a complex indicator, representing the average number of girls born of a mother in her fertile age; • Net fertility rateof population is the average number of girls born of a mother in her fertile age (15-49), which will live up to the age their mother had by the moment of their birth.
An example of calculating total fertility rate and gross fertility rate We use the data for age-specific fertility rate for each year. The coefficients for each age group are multiplied by 5 (column 3 of the table), which will give us information ho many live births would produce 1000 women for the 5-year interval. The products of column 3 are summed (the sum is 1259,6) – this is the number of live births per 1000 women for the next 5-year interval after 2000.
An example of calculating total fertility rate (continuation) Finally, we divide this sum by 1000 and get the total fertility rate, which is 1,26, meaning that if no changes occur in age-specific fertility rate, a woman from the offspring of 15-year old, which by 2000 have reached reproductive age, will have an average of 1.26 children by their 49 anniversary. If we keep in mind that a family couple reproduces if it has at least to children, it becomes clear that by the year 2000 Bulgaria is in the stage of narrowed reproduction. The sumof column (3) is1259,6. 1259,6 : 1000 = 1,26. Total fertility rate = 1,26. The gross rate is calculated by multiplying the total fertility rate by the relative share of girls in the structure of live born for the year. For 2000 the relative share of girls is 0,488. Consequently, the gross rate for the year 2000 is: Gross fertility rate = 1,26 х 0,488 = 0,61.
Number of stillbirths х 1000 Number of abortions for a given territory in a given period х 1000 Stillbirth rate = Abortions rate = Number born (alive and stillbirths) Number of women (15-49) on the same territory for the same period Stillbirth and abortion rate
Total number of abortions in all ages 200000 150000 100000 50000 0 1970 1975 1980 1985 1990 1995 2000 2004 Source: World Health Organization, Regional Office for Europe . European health for all database (HFA-DB)
Reasons for death „All those ailments, pathological states or trauma that have lead to the occurrence of death or have facilitated death, as well as circumstances that have lead to incidents or acts of violence causing such trauma”
Primary cause of death Primary cause of death can be defined as : „а) illness or trauma causing a number of pathological processes directly leading to death or б) circumstances that have lead to an incident or act of violence causing mortal trauma.”
International form of medical certificate for cause of death
An example of defining the cause of death The medical certificate of death, comprising four events in a chain leading directly to death, should be filled in the following way [1]: а) Pulmonary artery embolism б) Pathological fracture в) Secondary femoral cancer г) Mammal cancer [1]Example from ICD-X, tome ІІ.
Mortality Groups of indicators • Not standardized – intensive indicators, measuring the frequency of a health event in a given year and territory. • Standardized – when comparing gross coefficients or specific indicators by reasons (calculated for the entire population), but under existing differences in age structure of the population in compared populations. • Standardization aims to eliminate the differences in these factors and show what would be the health event if the compared populations would have identical age structure. • Specific coefficients – measuring the frequency of health events in different subgroups of population or by different causes. • Proportions – structural or extensive indicatorsshowing the distribution of causes of death
Number of deceased х 1000 Total mortality = Yearly average number of population Not standardized indicators of mortality • When assessing total mortality a scale of three stages may be used : • low – below 10 ‰, • medium – 10-15 ‰ • high – above 15 ‰.
Total mortality in ‰ in Bulgaria (1965-2005) with calculated trend Source: NSI, 2006
Fig. 10. Standardized mortality coefficient in Bulgaria per 100000 1500 1400 1300 1200 1100 1000 1980 1985 1990 1995 2000 2005 2010 Standardized mortality indicators Source: World Health Organization, Regional Office for Europe . European health for all database (HFA-DB)