DEMOGRAPHY/

DEMOGRAPHY

Definition

The science of population concerned with not only the people but also the social and natural history of the human spp, The mathematical knowledge of the population, the population, the political, moral and intellectual as well as the changes of this population.

Human population is dynamic thus the need for all this information. Can also be defined from 2 perspectives:-

Narrow definition , wide definition

Narrow definition

Called formal demography

Concerned with: - the size of the people.

Distribution

Biological composition age, sex composition.

Demographic variable

3 variables: - fertility, mortality, migration.

Balancing equation/simple demographic equation

Pt2= Pt1 + B1-2 - D1-2 M

Population change = normal processes + net migration

The population pyramid

The population pyramid is typical of developing countries where fertility is high and mortality is also high.

It depicts age, sex composition in relation to fertility and mortality.

Wide definition

Take into account additional characteristics of the population. These include:-

Income

Ethicinity

Mother tongue

Literacy

Marital status

Occupation

Religious affiliation

Nationality

It depicts population change on one hand vis--vis development many issues e.g.

Population versus urbanisation

Population versus income distribution

Population versus environmental degradation.

Growth rate in Kenya is 2.9% p.a. (? 2.6%)Kenyas population 1997 28.7m

2001- 30 m.

Less than 5yrs 20%

Less than 15yrs 44%

More than 60yrs 4%.

This has implications in terms of health.

Population programmes and measures in many countries south of the Sahara have been incorporated in development plans.

DEMOGRAPHIC MEASURES

1. Rates

Events e.g. births, death

Measured per period of time usually p.a.

E.g. crude birth rate

2. Ratio

Relationship between two parameters.

M: f = 1.04: 1.0 at birth

Thereafter there is a disproportionally high mortality among men than women. By 5 yrs m:f = 96:100. It continues decreasing.

3. fraction/proportion

Expressing a parameter as part of a whole express proportion with decimals

Role of demography in health

Ensures planning is done accurately. It is carried out for specific age groups as their needs are highly specific.

1. Children under 5 years have the highest morbidity and mortality rate.

Enables one to find the

DeterminantsConsequences

Interventions/ solutions of morbidity pattern.

-Births may also be examined using therefore TFR average number children of women in her life time. It is currently at 4.7. It is increased in some areas.

-This rate varies due to socio-economic reasons and environmental reasons.

-Culture may also contribute towards diseases.

-These needs include: immunization, nutrition, Health education for the mothers.

2. School age population (6-15)

Their needs include:- counseling HIV Aids awareness.

Maternal mortality ration is 590 100,000 live births. This is due to lack of availability, affordability, accessibility.

3. Adult population

Mortality is increased due to HIV/Aids, malaria, cancer, overcrowding, OH.

Life expectancy

Life span optimal number of years one would expect to live given ideal conditions of 100yrs.by elderly

Have institutions to care for them e.g. add age institutions.

Sources of demographic data.

Primary sources

Secondary sources

1.Primary sources include: census, vital registration

Sample surveys.

2.Secondary Sources processed data e.g. Journals, books, atlas, newspapers, research reports, pamphlets.

Census An official enumeration of the entire population

-Government is the major sponsor

-Is official

-Data is for planning and projecting needs of the people. The census is the benchmark statistics for planning in local, provincial and district levels in many fields.

Limitations

-Cumbersome exercise

-Expensive undertaking thus taken once every 10 years (decennial census)

Census seeks to determine:- age, sex, religion, marriage, head of family, sanitation and disposal, occupation, education, ophanhood, water source, electricity source, migration.

-some people are missed.

-Poor coverage especially in communities who are nomadic.

-Analysis faulty machines (scanners)

-Wrong entry in computer (human error)

-there is a big time lapse between time of census being taken and release data therefore data become obsolete and outdated.

-under enumeration therefore one has conduct a post enumeration.

Advantages

Fiscal support from donors if a country conducts a regular census.

Sample surveys

-Periodic forms of stock taking.

-Used for monitoring population trends.

-The surveys could be economic, political or population.

-In Kenya, Kenya Demographic and Health surveys (KDHS) are under NCPD (National Council for Population and development.

-Kenya fertility survey.(KFS)Kenya contraceptive prevalence survey. (KCPS)-Are done more regularly than census.

-Are sponsored by either the government or private sponsors.

-Monitors variables e.g. birth, fertility, trend analysis, labor force, income, unemployment, attitudes, behavior.

Limitations

Lack representativeness, pay particular attention to a group of people thus leading to bias.

Vital registration system

-Registration of births, deaths, marriage, divorce, annulment, baptism.

-Events that occur regularly and require documentation.

-May be incomplete because of inaccurate data.

Population registers

Common in Nordic countries

Are able to tell when people have migrated, job change, arrested entered their countries (foreigners)

Advantage

Administrative purposes

Update ones census.

Secondary information is as accurate as the source.

Very useful for teachers and students.

Measurement of fertility

1. Child: woman ratio

2. Crude birth rate

3. General fertility rate

4. Age specific fertility rate.

5. Total fertility rate.

Fertility

Def: the number of live births a woman has actually had.

Post partum death is irrelevant therefore what happens after birth isnt important. What is important is whether or not the child was alive at birth.

Cultural practices in many African communities dictate what happens soon after birth.

Fecundity

Def: the physiological ability to conceive or the potential to conceive. This potential is measured using indirect methods as it is quite difficult to quantify.

Measurement of fertility

Period fertility

Fertility is measured in reference to a particular period usually one year.

Cohort fertility

Measurement of fertility in a life time i.e. over a long period of time.

A) Period fertility

1. Child to woman ratio

Advantages

It is easy and feasible to calculate because it only requires information on age-sex structure.

In developing countries with inadequate birth registration system, this measure provides a rough estimate of fertility performance.

Disadvantages

1. Greatly affected by fertility and child mortality levels in the country and is sensitive to reporting error (in birth registrations). It is therefore not used when comparing two or more countries.

2. Because children under five are survivors of the past fertilitythose computed do not represent those who were born live but die within the span of 0-5 years.

- If infant and child mortality is high, this ratio would under estimate the fertility levels prevalent in the country because some of the children have died. A similar effect is observed in under reporting of young children or misclassifications e.g. live births then death after 5 days labeled as still births.

Information for this ratio is obtained from the population census which gives the age-sex structure of the country.

- Demographic surveys can also provide information e.g.

Kenya Demographic and Health surveys 1993, 1998 by national

Counsel for population and development with central Bureau of statistics child woman ratio in

Bangladesh is 900/1000

USA 250/1000

Crude birth rate

Supposed to be a ratio.

Mid year estimated to be July first.

Called rate because it deals with total births and total population.

Indicate the frequency of live births occurring in the entire population.

Formula is total births in a year * 1000 Total pop at mid year

Advantages

Its an easy concept to understand because it is a single indicator of fertility.

Data is easy to collect and process to get the rate.

It used in the basic demographic equation:

Disadvantage

1. It is a crude measure because it is affected by the composition of population with regard to age and sex.

-Countries with young people in reproductive age (high fecundity) have a high crude birth rate compared to countries with low fecundity.

-It is therefore misleading if used for comparing two or more people unless you standardize the population.

2. Many developing countries have incomplete registration of vital events CB Rate for many developing countries is 30-40/ 1000

Kenya 37.5/1000 91.2/30 million

Most developed countries less than 10/1000

-Source of data is the census and other surveys.

It is affected by marital pattern.

General Fertility rate

Advantages

1. Concepts easy to understand.

2. Easy availability of data from census on age sex group.

3. Easy to calculate.

4. Is a refinement of the previous rate has control by female sex and partially by age (15-49 years) by relating births to those at risk of having them i.e. at specific age and sex.

5. Can be computed in situations where registration of births and enumeration of census are unsatisfactory.

Disadvantages

1. Still crude and doesnt control totally for age structure because it lumps all women together, Young, middle and old. Hence variation cannot be told.

2. Doesnt tell the pattern of fertility.

GFR for developing countries 200/1000

Age specific fertility rate.

-Best measurement of fertility, most important and most refined and are used as fertility models.

-It involves seven indications and is much more complex.

-It is calculated for each five years age group.

NB. Actual number of children born depends on age, duration of marriage etc.

The ASFR successfully controls for the effects of age. The variation of fertility by age can be seen.

Disadvantage

-Interpretation is difficult because you are dealing with seven age groups because for each of them, you must establish the determinants with consequences.

-Requires very specific data (births classified by age of mother) which are often unavailable or unreliable in developing countries.

-Comparison of schedule of ASFR is not easy given each set of ASFR provides at least 7 values of interpretation.

ASFR has full control of age-sex structure hence comparison between two or more people is allowed.

Total fertility rate

The sum of ASFR

Most important measure used by demographers.

The average number of children a Kenyan woman would have if she goes through the

ASFRis 4.7

TFR in 1993 is 54

TFR 1989 is 67

1977 is 8.1

-It is declining.

- Formula is TFR= ASFR * 5 1000Gross reproduction rate

-Looks at one half of the people. It is a one sex measurement therefore it is artificial and mathematical.

-It is special case of TFR.

-TFR measures total number of children. GRR measures total number of daughter a cohort of women will have in their life time if no woman died. There is therefore an assumption of no mortality.

-In Kenya GRR is 2.3.

-This suggests the mothers of the next generation. This indicates people growth.

Net reproduction rate

-mathematical

-Is a measurement of daughter cohort of female would have in a lifetime if they followed a fixed schedule of age, specific mortality rate and ASFR.

-Life tables are used.

NRR=1

Less than 1 people is replacing itself in the next generation.

More than 1 people not replacing itself in the next generation.

-Kenya approximately 2.0

Other specific fertility rates

-Are minor

1.General marital fertility rate (GMFR)

Information assumes that children come only from married mothers.

All births in a year * 1000 Total pop of married women (15-49 yrs)2.General legitimate fertility rate.(GLFR)

Legitimate births only.

Legitimate births * 1000 Tot pop of married women (15-49)3.General illegitimate fertility rate.(GIFR)

All illegitimate births * 1000 Single, widowed, divorced women 15-49B) cohort fertility

It considers the experience of one group of people over time. It include: marriage cohort, age cohort.

Numbers change due to death, migration

Measurement of mortality.

-Mortality is easy to measure as it is a one time exit.

-Mortality has a longer history and is more developed than fertility therefore the government is more aware of longevity than fertility.

-Crude death rate (CDR)

Advantages

1. Easy to compute with minimal data.

It requires on age sex distribution from the census registration of deaths.

2. It is easy to communicate to lay people.

3. Helps us understand about the growth of the people.

Disadvantage

1. Affected by age, sex composition of a country. As most people in a country are young, the CDR is decreased e.g. Mexico 7/1000

USA x/1000

Therefore two populations can be compared as their age sex structure is different.

Kenya according to 1998 survey

CDR=11/1000 CBR=40/1000 thus CGR=29/1000=2.9%

-CDR can go as high as 25-30/1000 in countries with civil strife and can be as low as 4/1000 e.g. In Costa Rica.

Age specific mortality rate.(ASMR)

-It is necessary for

1. Policy makers

2. Research purposes

3. To know prevalence rates (use epidemiology) and incidences rates and relate it to age.

-Mortality is not uniform in the whole countries it is influenced by this factor;

-Mortality indicators

(a) Infant mortality rate (IMR).

All deaths in infants less than one year

-Its the only measurement that has total live births as a denominator

-IMR in Kenya 74/1000 live births (LB)

Tanzania 88/1000 LB

Uganda 90/1000 LB

-Developed countries < 10/1000 LB

-As an MOH, identify the factors leading to increase in IMR.

-It is the single most important indicator as it tells about:

1. The quality of life

2. Quantity of health services.

3. Socioeconomic status of people.

1. Neonatal mortality.

Occur within the first 28 days of birth.

Are usually due to biological or clinical factors e.g. congenital malformations, suffocations etc occurring during birth process.

2.Post neonatal mortality.

-Between the age of one month to one year.

-Causes: - Environnemental e.g. diarrheal diseases, infections, malaria etc.

Most children are immunized against diseases.

-Lack of immunization on time.

3. Perinatal mortality rate (PNMR)

Deaths between 28 weeks to 1 week after birth.

4. Under 5 mortality rate (U5MR)

-Under 5s are one people at risk of dying from common cold. Noncommunicable diseases

-U5MR in Kenya = 112/1000 has risen from 1996

Reasons for increase HIV/AIDS, low SES, dwindling nutrition levels

-Infant mortality is associated with:

1. Mothers age and birth order of child.

2. Mothers reproductive history.

3. Marital status of mother.

4. Socio economic status of mother.

Less 2500 gm children tend to have increased mortality.

5. Adult mortality rate

-Increase of mortality as one grows old.

-Many die due to diseases e.g

Malaria, aids.

Accidents occupational related accidents RTL homicides etc.

Cancers

CVs problems

Diabetes etc.

-To decrease this mortality rate, control causes.

6. Adolescent mortality rate

-Many are dying from HIV/Aids

7. Maternal mortality RATIO (MMR)-Deaths of mothers upto 42 days after delivery are included. Kenya, 590/100000 live births. (?414/100000)8. Maternal mortality RATE.

LIFE TABLES.

- These are statistics used to measure primary mortality. They also measure fertility, widowhood etc. And other aspects of public health importance

- The mortality measured is of a hypothetical group from birth until death.

- The group of people is also known as cohort i.e. people sharing the same characteristics and of a particular age. This cohort is diminished gradually by deaths. It begins from birth and ends when all the members die.

- The number of people who will die at each age are predetermined in the table.

- Thus these tables present an artificial situation; however they are constructed using census data and are therefore a near mirror image of reality.- These tables are mainly used by insurance companies in order to estimate premiums.

Types of life tables

1. Generation life tables or cohort life tables.

- Look at the generation of the cohort i.e. measure the mortality of a cohort

- They use series date i.e. data collected over a long period of times

- Can include people born in a decade a marriage cohort.

2. Current or period life tables

- These tables are based on the mortality rates over a short period of time 1, 2, 3 years where the values are almost the same.

- Can observe the pattern of death by the age groups thus the age specific death rate is observed.

3. Complete life tables or unabridged

-These have data presented in one year intervals and has a lot of information.

4. Abridged life tables.

-Have summarized data with 5 years intervals.

-It is the most common of the two complete life tables and more comprehension therefore less accessible for poor countries.

5. Standard life tables

- Only measure mortality

- They are the commonest type of life table.6.Multiple decrement life tables

-Measure more than one variable it multiple and two variable.

-They describe the separate and combined effects of two factor e.g. Marriage mortality, widowhood and mortality.

History of life tables

Began approximately 300yrs ago and were generally used for cities. Most are published by the U.N.

Table

x- Exact Age

n Width of age interval.

There are 5 basic assumptions that must be made in order to interpret.

1. The cohort is closed to in and out migration. (No losses except due to death)2. People die at each age according to a schedule/arrangement thats fixed in advance and doesnt change. (Most important assumption)3. This cohort originates/starts from some standard number of live births called the radix of the life table, set at a certain figure (100000, 10,000, 1 M). This is to enable comparison with other life tables.

This is placed in column 3.

4. The cohort normally contains members of only one sex due to the differences in mortality at each age for the different sexes.

5. At each age (except for the first years of life) deaths are evenly distributed between one birthday and the next.

Qx is the probability of dying between ..

E.g. Where x= 10 =10

In this case survivals is 99.1748%

Lx is the number of survivors of a progressive cohort, began with 100,000 (radix) left now with 100,000 825 = 99.175. These are the number of children to reach one year.

Called the total persons lived within the indicated age intervals x(x+1)

Tx is the total person years lived after the beginning of the indicated age interval x and all subsequent intervals.

eX.is the life expectancy column (life expectancy at a particular age).

- Describes the average remaining life time in years for a person who survives to the beginning of the age interval x

- Also called life expectancy or complete years to go.Derived by:

- All these functions are interrelated

- Of the 6, qx is the most important.( its the initial function from which all other functions are derived)Px-probability of lifeMEASUREMENT OF MIGRATION

- 3rd demographic variable.

- Migration greatly influences population in terms of:

- Migration is a form of geographic or spatial mobility involving a change of usual residents through two clearly defined geographic units. These units are described by countries e.g. Administration units.

Short movements include: change of domicile (within the same compound/ sublocation /neighborhood)

Types of migration

1. International migration

Cross national borders emigrants

_ immigrants2. Internal migration

Within the same country- inmigrants outmigrants

-Net migration is the balance between in and out migration.

- Depopulation occurs when there is more moving out than in.

- In Kenya, population growth is 2.9%.

- Growth rate of Nairobi is 4.8%. In migration is 1.9%.

- Gross migration is either in or out migration turnover considered separately. It is not the total which is called Turnover. It involves a change of physical residence between two clearly defined geographical

- In Kenya every movement is out migration with respect of where you coming from and the area one moves into is known as in migrating (descrination).

History of Migration

1950 : 150,000

1999 : 2,134,000

2001 : 2,400,000

Theory of migration

-1885-E.G Ravestein.

Migration has definite laws:-

1. Migration and distance. The longer the distance, the fewer the migration people mostly move to centers of commercial.

2. Stream and counterstream. Movement in one direction creates movement in the opposite direction.

3. Urban rural differences in propensity to migrate. Migration of rural dwellers to urban areas is more than vice versa.

4. Technology and migration. Migration increases with technological breakthrough.

5. Dominance of the economic motive. This surpasses many other motives i.e. climate, bad governance, taxation, apartheid.

6. People move in stages.

-migration is not always permanent.

Microtheories of migration

- Movement of people at a family/ household/ individual level. Its more interested in explaining the migrating behavior (way) education, marriage, rite of passage (initiation), economic disputes, networking.

- Must also study the non movers. These are mainly young singe 19-25yrs mainly move males above high school, University graduates.

- There is also rural-rural migration in Kenya. This is mainly duet to landlessness.

Macrotheories of migration

- The focus is on identifying patterns and trends in migration.

Superior in describing broad as migration and provide an aspect of demographic change.

Data sources include census an surveys like KDHS (1989,93,98)

Socioeconomic and ecological factors are assoc with systems of pop movt.

Its not interested with individual based data.

Units of analysis: districts, provinces.

Mesotheories of migration

- Tries to intergrate micro and macro theory factors.

- Awareness of these broad factors are important in decision making at any level.

Models

1. Tadaro Harris model (economic model)2. Pull push model i.e. certain factors at the area of origin, push people and certain factors at the area of destination pull people.

Push factors include:

Metrological disasters floods, droughts

Demographic/population pressure

Social factors: insecurity

Social organization: these running away from the extended family system.Pull factors

The city, entertainment, communication, health, employment.

3. Everett lee model

It is just like Todaro Harris model only that those migrating encounter intervening obstacles. Obstacles encountered by married people are more than those encountered by unmarried people.

4. Rites de passage model.

Questions: 1. What is the public health implication of migration? 2. What policy issues should be put in place to counter migration? 3. Discuss The Future of Migration

Health consequences of movement

Immunization

Transporting or spreading dx.

Riots and wars.

BIRTH PREVENTION METHODS

METHODS OF CONTROLLING FETILITY

History

Family planning was introduced in India in 1952. Family planning was introduced in Kenya in 1966-67.

In the 1950s, private organizations had family planning service mainly for the expatriates in Kenya. The FPAK (Family Planning Association of Kenya was introduced in 1957.

A family planning policy was initially introduced by the ministry of economic planning.

The ministry of Health then realized that a high population growth rate signifies a highly dependent population.

In 1978, the M.O.H trained family planning field educators approximately 800.

The programme was not forceful. It targeted family planning Acceptors. The number of acceptors was very low. Government support was however lukewarm and the M.O.H could not therefore train individuals effectively.

The guiding principle was to reduce Kenyas crude birth rate.

Church leaders were also against the FP. campaigns.

Cultural/traditional leaders were against the concepts of having smooth families as this was contrary to what they were used to.

Financial incentives, abortions and sterilization were excluded from the programme.

There was no reduction in the CBR for approximately ten years

In 1977/78 a Kenya fetility surveys (KFS) revealed that only 7% of female were using a form of family planning.

Population growth rate was 4.1% p.a. TFR was 8.1 children per woman.

Population growth rate is 2.9% p.a. TFR is 4.9

CPR.has increased from 7% in 1978 to 39% in 1998

Concepts

1.Unmet needs of family planning.

- This refers to sexually active people (fecund women who are married) who would like to space their births or stop but use no method of family planning.

- Up to 12%of the population have unmet needs.

2.Desired family sizeThis refers to the number of children a woman would like to have.

It includes both male and female children.

Kenyan women: 3.9 children Men: 4.3 children

It is a preference indicator.

3. Deficit fertility Woman reports that she has got fewer children than she had desired.

4. Excess fertility

One has more children than desired.

5. Unwanted births

Did you want to have this pregnancy/birth? The answer is NO

It could be due to mistiming.

Family planning and its influence on fertility

1. There is both direct and indirect influence on fertility.

2. There is an inverse relation between family planning and fertility therefore when family planning increase, fertility decrease.

3. There are however intermediates e.g.Education, age, marital status, race/ethinicity sociocultural factors, occupation, residence.

4. These factors influence the use of family planning.

5. Education particularly influences fertility in :-

-Inculcating values and advantage of small families.

-Delaying the age of marriage

-Use of effective methods of family planning.

Models of family planning

1. Vertical

2. Horizontal

1. Vertical

Seen as one programme on its own and dont interact with other programmes

Use one service, unipurpose and separate funding and adminstration.

Other vertical programmes include: malaria, schistosomiasis, trypanosomiasis, MCH.

2. Horizontal

Programmes are interacted

Are multipurpose, share same funding administration and service components.

Advantages

1. Workers in the vertical model become very efficient in dealing with the programme.

2. In horizontal model, both worker and system are used for many programmes therefore are cost efficient.

3. With regard to vertical models duties are repetitious and are therefore easy to remember.

4. With regard to the horizontal models duties are varied therefore the worker does not get bored. Duties are complimentary therefore also easy to remember.

Disadvantages

1. Competition between programmes for funds, other resources is a way towards horizontal programmes.

2. Horizontal programmes also have internal competition for resources and managerial infrastructure may become overloaded.

Factors influencing family size in Kenya

Age at first marriage

Marriage conjugation

Time spent after and between marriages

Voluntary abstinence

Involuntary abstinence

Involuntary infecundity

Voluntary infecundity

Use of contraceptives

Abortions

Female education

Religion

Race

Attitudes/ awareness/ practices

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