Elena A. AbumuslimovaPh.D., Associate Professor

Department of Public Health and Health Care,Northern-West State Medical University named after I.I.

Mechnikov, Saint-Petersburg

Demography is the scientific study of human populationDemography studies 3 aspects of a

population Changes in population sizeComposition of populationDistribution of population on the territory

Before we plan any health intervention or programs for the community we should know the size and composition of the community

We also need to know the changes that will occur to the size and composition to the population

IMPORTANCE OF DEMOGRAPHIC STATISTICS:Estimation of health indices of the population

(birth rate, death rate, average life expectancy, final parameters of reproduction);

Estimation of laws and regularity of population reproduction forming structure;

Planning, accommodation and forecasting of staff network of public health service on the basis of amount and structure of the population;

Estimation of efficiency of planning and forecasting of medico-social actions;

Deep statistical analysis of its health condition, activity of medical institutions, precisely to plan their work.

STATICSSTATICS studies amount and structure of population according to age, gender, profession, etc.

Sources of Demographic informationSources of Demographic information

Population censusVital statisticsMigration

POPULATION CENSUSPOPULATION CENSUS

POPULATION CENSUS POPULATION CENSUS is the special scientifically organized state statistical operation for account and analysis the size of the population, its structure and distribution around the territory.

is the main method for estimation of population static.

Features of population censusFeatures of population census

PeriodicityPeriodicity (in the majority of the countries PCs are carried out in every 10 years, in economically advanced - in 5 years).

GeneralityGenerality (scope of all population).Unity of a technique Unity of a technique (presence of the

uniform program of census as census sheet).Single character Single character (the population is taken

into account for the certain moment when the population conducts the most settled way of life).

Collecting data by method of interrogation method of interrogation by means of copyists without obligatory documental confirmation.

Centralized method Centralized method of data processing.

Importance of population censusImportance of population census

perspective population calculations;planning development of branches of

national facilities (economy), including public health service;

estimation of sanitary condition of the population and calculation of various parameters of health;

estimation of sanitary - epidemic condition of area, for development of forecasts of an epidemic situation, etc.

Population sizePopulation sizerefers to the number persons in the

population.By the beginning of the 21st century,

world population reached 6 billion. Most of the growth has occurred in the past 200 years.

World populationWorld populationAbout ¾th of world population lives in

the developing countriesChina and India are the two most

populous countries in the worldThe world population growth rate was at

the peak in 1970About 95% of the population growth is

occurring in the developing countries

Amount of World-Population 500CE-2150(United Nations Statistics Division)

Total population in RussiaTotal population in Russia

The unprecedented population growth of modern times heightens interest in the notion of doubling time. Calculation of population doubling time is facilitated by the Law of 70Law of 70.

Low of 70Low of 70If a population is growing at a

constant rate of 1% per year, it can be expected to double approximately every 70 years

If the rate of growth is 2%, then the expected doubling time is 70/2 or 35 years.

StructureStructure is the distribution is the distribution of population among its sex & of population among its sex & age groupingsage groupings

Age-sex composition of a populationAge-sex composition of a population

Depicted by the Population PyramidPopulation Pyramid

“Young” population: pyramid is triangular

“Ageing” population: pyramid becomes more and more rectangular

Age-Sex Composition of a Age-Sex Composition of a populationpopulation

Refers to the proportion of males & females in different age-groups.

It has a direct bearing on social, economic, health needs of communities or countries.

In an “old” population“old” population, for example, the society has to arrange for the care of the elderly, & the country’s health system must be organized accordingly.

In a “young” population“young” population, on the other hand, the country has to provide more schools, immunizations, & economic support for the young

Age-sexual structure of the population

The ages

groups

The type of age structure of population

RegressiveRegressive StationaryStationary ProgressiveProgressive

Till 14 years (A) A < C A = C A > C

From 15 to 49

years (B) ~ 50% ~ 50% ~ 50%

50 years old

and older (C) C > A A = C C < A

Distribution Distribution refers to the refers to the arrangement of the population arrangement of the population in space at a given timein space at a given time

Global population densityGlobal population density

Mechanical movementIt is understood as a process of

population migration. Depending on duration, migration is

divided into constantconstant and seasonalseasonal. It includes:It includes:Emigration;Immigration;Urbanization;Movement of population in depend on

socio-political and others courses

Migration Migration InvoluntaryInvoluntary: slavery, ethnic persecution,

wars, natural disasters, famines

VoluntaryVoluntary: to seek jobs (skilled or unskilled), to get an education, because of marriage, upon retirement

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Internal migrationInternal migration: within a country e.g. rural to urban

International migrationInternational migration: skilled professionals to other countries

Migration & HealthMigration & Health

Migrants (workers, prostitutes, truck drivers) may spread infectious diseases e.g. HIV/AIDS, TB, diphtheria

Jet travel speeds up disease transmission

Migrants often live in urban slums and experience adjustment problems (these can affect their physical or mental health)

Urbanization

It is a demographic process which is characterized by growth of number of cities;

increasing in their capacity;prevalence of a share of city dwellers

among all population.

Urbanization level in the worldUrbanization level in the world

Natural movement of the population

It is a set of such demographic phenomena as birth rate, death rate, a natural increase of the population, infantile death rate, the data on marriages, divorces, average duration of a forthcoming life, which registered in medical institutions and establishments of civil registration.

Index of average duration of a forthcoming life / life expectancy

It is hypothetical number of years which should be lived by the given generation born or to number of contemporaries of the certain age if on all extent of their life death rate in each age group will be the same it was that year for which calculation was made.

Life expectancyLife expectancyLife expectancy is the average number of

years which a person of a particular age may expect to live

It is one of the best indicators of a country’s level of development and overall health status

The life expectancy of people all over the world has been increasing

Life expectancyLife expectancy

This parameter characterizes viability of the population as a whole: it does not depend on features of age structure of the population and is suitable for the analysis in dynamics and comparisons of the data of different countries.

Life expectancy Life expectancy ≠≠ middle age of died middle age of died people people

Life expectancy Life expectancy ≠≠ middle age index of middle age index of the populationthe population

Parameters of reproduction of the population

Birth rateDeath rateIndex of natural increase

Birth rate

Birth rate is the major component of natural movement of the population.

Recently was marked significant decrease of decrease of birth rate birth rate level in all economically advanced countries that entails a lot of undesirable undesirable consequencesconsequences:

increase of deficiency of a manpower, decrease in rate of population growth, change of its age structure (population ageing

and reduction of a share of fertile age women), increase the quantity of the single-child families,

etc.

Developed countries have low birth rates Developed countries have low birth rates because because

It is expensive to look after large families More women prefer to concentrate on their

careers Increasing sexual equality has meant women

have more control over their own fertility There is a ready availability of contraception

and family planning advice

Profound characteristic of birth rateGeneral birth rateFertile indexAge-specific birth rateFactor of total prolificacy Gross – factorNet - factor

THE FACTORS INFLUENSING BIRTH RATEsocial position of women, - their employment in manufacture,- level of satis faction of their material needs,- cultural level,- living conditions,- degree of legislation security,- level of children's death rate,- provision of pensions,- urbanization,- national features,- psychological and religious factors,- ageing of population,- State demographic policy, ets.

English clergyman, Thomas Thomas Robert MalthusRobert Malthus, was the first person to draw widespread attention to the two components of natural increase, births births and deathsdeaths (fertility and mortality).

In his “Essay on the Principle of Population”, initially published in 1798, Malthus postulated that population tended to grow geometrically while the means of subsistence (food) grew only arithmetically.

The Malthusian TrapThe Malthusian Trap:Arithmetic Arithmetic growth (food): 1, 2, 3, 4, 5, 6, 7, 8, 9,

10…

GeometricGeometric growth (population): 1, 2, 4, 8, 16, 32, 64, 128, 256, 512…

Malthus argued that the difference between geometric and arithmetic growth caused a tension between the growth of population and that of the means of subsistence.

This gap could not persist indefinitely. Owing to war, disease, hunger, and vice,

mortality would serve as a positive check positive check on population growth.

Definition of Key Words Size refers to the number persons in the

population

Distribution refers to the arrangement of the population in space at a given time

Structure is the distribution of population among its sex & age groupings

Solution to the Malthusian TrapSolution to the Malthusian TrapPreventive checks: birth control

through o later age at marriage.o abstinence from sex outside marriage.

(Malthus opposed artificial methods of birth control on moral grounds. Viewed contraception as a vice)

Population ExplosionPopulation ExplosionContrary to Malthus’s prediction,

mortality has not yet risen to curb world population growth.

< 1 billion people in 1800 / 6 billion by the end of the 20th century

Why was Malthus unable to foresee the population explosion (also known as the population bombpopulation bomb)?

He did not recognize the force of the Industrial RevolutionIndustrial Revolution, which produced exponential growth in the means of subsistence.

The demographic transitionThe demographic transitionThis refers to the change from:

High rates (births and deaths) toLow rates (births and deaths)

Death rates drop before birth rates: therefore, there is a period of rapid population growth. This ends when birth rates finally drop.

The demographic transitionThe demographic transition

Falling death rates are due to better nutrition and higher standards of living

Falling birth rates are due to social and economic changes:

1) Women stay in school longer2) More women work outside the home3) Women marry later4) Women postpone childbearing5) People choose to have fewer kids

Source: Ian R.H. Rockett. Population and Health: An Introduction to Epidemiology. Second edition. Population Reference Bureau 54(4); 1999: 9

Death rate

Death rate of the population is regarded as the major demographic index revealing sanitary conditions of the population.

Medical death certificateMedical death certificate

Medical registration of the reasons of death is physician responsibility.

The medical death certificate is the legal and medical document certifying the fact and the reason of death.

Developing countries have high death rates Developing countries have high death rates becausebecause

Dirty, unreliable water supplies Poor housing conditions Poor access to medical sevices Endemic disease in some countries Diets that are short in calories and/or protein

Developed countries have low death rates Developed countries have low death rates becausebecause

Good housing conditions Safe water supplies More than enough food to eat Advanced medical services which are easy to access Some developed countries have a high death rate

as they have an ageing population with many older people.

Structure of the death reasons

Blood circulation system.Malignant tumours.Traumas and poisoning

Infantile death rate

Index of infantile death rate is considered as operative criterion for an estimation of sanitary well-being of the population, level and quality of the medical-social help, an overall performance obstetrical and pediatric service.

Criteria of foetus (newborn) viability recommended by the WHO

term - 22 weeks and more, body weight- 500 g and more,body height – 32 sm and more.

Live-born criteria: Live-born criteria:

extra-uterine lung breath, palpitation, pulsation of large vessels, reduction of separate groups of muscles.

Infant mortality rate

Infantile death rate during the various Infantile death rate during the various periods of childperiods of child- Early neonatal death rate- Late neonatal death rate - Neonatal death rate- Post-neonatal death rate, etc.

The structure of reasons The structure of reasons of infantile death rateof infantile death ratesome causes of perinatal period , mainly

intrauterine hypoxia of a fetuscongenital developmental of anom aliesrespiratory organ diseasesinfection diseasestraumas and poisoningotheres