Demography and Health

Dr.Rajkumar PatilAsstt. Prof., Community Medicine

AVMCH, Pondicherry

Demos + graphein

Demography is scientific study of human population

Community Medicine and Demography

Community medicine is vitally concerned with population as the health of the people depends upon:

the number of people the space they occupy the skill that they have acquired

Major sources of demographic data

• Census

• Registration of vital events

• NFHS

Three phenomena in Demography

• Changes in population size• Composition of population• Population distribution in space

Five demographic processes

• Fertility• Mortality• Marriage• Migration• Social mobility

There are four ways in which the number of people

in an area can change during two time periods

Population Growth

Natural Increase (Births-Deaths) + Net Migration (Immigration-emigration)

Demographic cycle

Demographic cycle

Phase/Stage

BR DR Natural Increase

Examples

High Stationary

0-very slow India was in this stage till 1920

Early Expanding

+ Slow South Asia & Africa

Late Expanding

Rapid India, China,Singapore

Low Stationary

Slow UK, Denmark, Sweden, Belgium

Declining Declining Germany & Hungary

Distribution of world population

World Population Trend

Year Population

1800 978 million

1900 1650 million

1950 2.5 billion

1970 3.6 billion

1980 4.4 billion

1985 4.8 billion

2000 6 billion

Trend-Population of world

(2001 estimates)

1. China – 20.43%2. India – 17.01%3. U.S.A. – 4.61% 4. Indonesia – 3.42%5. Brazil – 2.81%6. Pakistan – 2.39%7. Russia – 2.25% 8. Bangladesh – 2.21%9. Nigeria – 2.20%10.Japan – 2.01%

10 most populous countries of the world

On 2.4% of world’s land area,17% of the world’s population (2004-1080 million)

1921-Year of “big divide”, India’s population has been steadily increasing since 1921

India will become the most populous country by the year 2050 (1.53 billion)

Population trend in India

1901-2001 Population trend in India

Year Total popu. (millions)

Average annual

Growth rate (%)

Decadal Growth rate

(%)

1901 238.4 - -

1911 252.1 0.56 0.75

1921 251.3 -0.03 -0.31

1931 279.0 1.04 11.00

1941 318.7 1.33 14.22

1951 361.1 1.25 13.31

1961 439.2 1.96 21.64

1971 548.2 2.20 24.80

1981 683.3 2.22 24.66

1991 843.9 2.14 23.86

2001 1027.0 1.93 21.34

Population trend in India

Most populous states of India

Rank

State Population (million)

Percentage(%)

1 Uttar Pradesh 166.1 16.2

2 Maharashtra 96.8 9.4

3 Bihar 82.9 8.1

4 West Bengal 80.2 7.8

5 Andhra Pradesh 75.7 7.4

6 Tamil Nadu 62.1 6.6

7 Madhya Pradesh 60.4 5.9

8 Rajasthan 56.5 5.5

9 Karnataka 52.7 5.1

10 Gujarat 50.6 4.9

Proportion of males & females in different age-groups

Direct bearing on social, economic, health needs of communities

In an “old” population, for example, the society has to arrange for

the care of the elderly, & the country’s health system must be

organized accordingly.

Age & Sex composition

Table-Distribution of population by age & sex (SRS–2003)

Age group (yr)

Male (%) Female (%) Total (%)

0-4 11.3 10.8 11.0

5-9 10.6 10.3 10.5

10-14 11.0 10.7 10.9

15-19 11.0 10.4 10.7

20-24 9.5 9.7 9.6

25-29 8.4 8.3 8.3

30-34 7.4 7.5 7.5

35-39 6.6 7.0 6.8

40-44 5.8 5.7 5.7

45-49 4.9 5.0 4.9

50-54 3.9 3.7 3.8

55-59 3.1 3.2 3.2

60-64 2.3 2.5 2.4

65-69 1.9 2.2 2.0

70+ 2.5 3.1 2.8

Total 100 100 100

It is a pictorial presentation (double histogram) of the age-sex composition of a population

Male & Female are compared for age

Under-developed/developing country: Broad base & tapering top (pyramid shape)

Developed countries: Bulge in the middle and has a narrow base (spindle shape)

Age pyramid

Population/age pyramid of India, SRS estimates1996

Spindle shape

Age pyramid, World Population Prospects 1998 (UN)        

Dependency Ratio is the ratio of economically dependant population to economically independent population

Total Dependency Ratio = Children (<15 yr) + Elderly (>65 yr) X 100

Working Age(15-64)

Young age dependency ratio

Old age dependency ratio

Dependency Ratio

Trends in Dependency ratio in India (per 100 persons)

Year Total(Societal)Dependency

Young age dependency

Old age dependency

1990 68 61 7

2000 62 54 8

2004 64 56 8

2010 54 45 9

Ratio of males to females in the population

Sex Ratio = Number of Males X 1000 Number of Females

Sex ratio of:

India : 933 females/1000 males Kerala : 1058 females/1000 males Punjab : 874 females/1000 males

Factors affecting sex ratio: 1. Difference in mortality conditions of males &

females 2. Female foeticide and infanticide

Sex Ratio

Sex ratio trend in India

CBR & CDR of selected countries (2004)

Country CBR(per1000 mid yr pop.)

CDR( per1000 mid yr pop.)

India 24.1 7.5

Bangladesh 27 8

Pakistan 31 8

Sri Lanka 16 6

Thailand 16 7

Nepal 30 8

China 13 7

Japan 9 8

Singapore 9 5

UK 11 10

USA 14 8

World’s average birth rate is 21/1000 population

Source: SRS 1998

CBR

Rate at which a given population is expected to increase in a given period of time

CBR-CDR = GR (in %, excluding migration) 10

Approximately 95% of population growth occurs in developing countries

Growth RateGrowth Rate

Relation between growth rate & population

Rating Annual rate of growth %

Population doubling time in years

Stationary Population

No growth -

Slow growth Less than 0.5 More than 139

Moderate growth 0.5 to 1.0 139-70

Rapid growth 1.0 to 1.5 70-47

Very rapid growth 1.5 to 2.0 47-35

Explosive growth 2.0 to 2.5 35-28

Explosive growth 2.5 to 3.0 28-23

Explosive growth 3.0 to 3.5 23-20

Total number of children borne by a women during

her child bearing age (15 to 45 years)

Total fertility rate (TFR) gives an idea of total family size

TFR in India: 2.68 (NFHS-3)

Family size depends upon –

Duration of marriage

Education of couple

No. of live births

No. of living children

Preference of male child

Family Size

Mass migration of rural population into urban

centers resulting in increasing the urban population & growth of cities

Cause of urbanization: Better employment and social services

MEGA CITY: City with population of 10 million or more

Urbanization

Number of persons living per square kilometer

Density in India:

Year 1901 – 77 persons/km2

Year 2001 – 324 persons/km2

Year 2004 – 363 persons/km2

Density of Density of populationpopulation

A person (7 yr or more) is considered as literate if he or she can read & write with understanding in any language.

State Male lit.(%)

Female lit.(%)

Totallit.(%)

Tamil Nadu

82 65 73

Kerala 94 88 91

India 76 54 65.38

Literacy & education

Literacy rates

Female literacy

Expectation of life at a given age is the average number of years which a person of that age may expect to live, according to the mortality pattern prevalent at that age

Indicator of country development & overall health

Expectation of life at birth – World 1950 : 46.5 years

2002 : 63 years

Expectation of life at birth – India

Year Males Females Total

1901 23.63 23.96 23.8

2001 63.90 66.90 65.4

Life expectancyLife expectancy

Approximately 95% of population growth is in developing countries

Currently,1/3 of the world population is under 15yr, & will soon enter the reproductive bracket, giving more potential for population growth

The expected number of births per woman, at current fertility rate is:

– Africa 6.1

– Asia 3.2

– Latin America 3.4

– North America 2.0

– Europe 1.6

Population Explosion

•Economic implications •Demographic Implications

In population with low birth and death rate, 9-13% is 65yr or more. There is increased demand for senior citizen

•Environmental / Ecological Implications

•Social / Political Implications

Fertility Actual bearing of child

Factors affecting fertility

1. Age at marriage

2. Duration of married life

3. Spacing of children

4. Education

5. Economic status

6. Caste & religion

7. Nutrition

8. Family planning

9. Others – biological, physical, social, cultural, housing, breast feeding, industrialization, urbanization, health conditions etc.

• Great impact on fertility

• Early marriages- increased births

• Age of marriage:• In 1930’s:13 years• In 2001: 21years

YEARS AFTER MARRIAGE

% OF BIRTHS

1-5 10-25 %

5-15 50-55 %

25 very few

• Well fed society- low fertility

• Poorly fed society- high fertility

• Education is inversely proportional to fertility

• “economic status is inversely proportional to fertility”

• Economic development is the best contraceptive

• Total fertility rate1. Muslims ---3.592. Hindus ---2.783. Christians ---2.44

• MBC/SC/ST-higher fertility rate

• Physical, social, and cultural factors

Place of women in society Opportunities for women and

local community involvement Value of children in society Widow remarriage

Breast feedingCustoms and beliefsIndustrialization and

urbanizationBetter health conditions

Replacement Level Fertility When a couple has two births during their reproductive

life, just enough to replace themselves.

Replacement level is considered when there are, on the

average, 2.1 births per woman (TFR), to compensate for

child deaths

Fertility Indicatorsa. Original rates

1.Crude Birth rate (CBR)

CBR=Live Births x 1000/mid year population

2.General fertility rate (GFR)

GFR = Live Births x 1000/mid year female pop. (15-49yr)

3.General marital fertility rate (GMFR)

GMFR= Live Births x 1000

mid year married female pop.(15-49yr)

4. Age specific fertility rates (ASFR)

Indicator of Fertility pattern & family planning

Live births in specific age group x 1000 Midyear population of women in that age group

5. Age specific marital fertility rate (ASMFR)

Live births in specific age group x 1000 Midyear population of married women in that age

group

b. Derived rates

6. Total fertility rate (TFR)

Average number of live births a woman is expected

to undergo during her reproductive life.

TFR = 5 x ƩASFR

1000

7. Total marital fertility rate (TMFR)

TFR = 5 x ƩASMFR 1000

8. Gross reproduction rate (GRR)

Average number of girls born to a woman during her reproductive life, if she experiences the current fertility pattern throughout the reproductive life (15-49) assuming no mortality

GRR = 5 x ƩASFR for female Live Births 1000

GRR = TFR x newborn sex ratio

9. Net reproduction rate (NRR)

Average number of girls born (and survived) to a woman during her reproductive life, if she experiences the current fertility pattern throughout the reproductive life (15-49) and assuming current mortality pattern

NRR = Number of girls born and survived Number of the women survived after the end of reproductive life

c. Related rates and ratios

10. Child-woman ratio

Number of children < 4 yrs of age per 1000 women of child bearing age.

11. Pregnancy rate

Ratio of no. of pregnancy in a year to married women in the ages (15 – 49)

12. Abortion rate No. of abortions per 1000 women of child bearing age group.

13. Abortion ratio No. of abortions performed/ no. of live births

14. Marriage rate

Crude MR = Number of marriages in a yr x 1000

Mid Year Population

General MR = Number of marriages in a yr x 1000

Number of unmarried persons in 15–49 age gp.

Exercise-I

In a PHC with a population of 28000,the age wise break up of women population in reproductive age group and the live births in these age groups are given below.Age (yr) Women

populationLive births

15-25 1850 140

25-35 3210 352

35-45 1400 72

Calculate:1.Age specific fertility rates2.General fertility rate3.Crude birth rate

Following are the age specific fertility rates among reproductive age group women in 1991 and 2001 in a country. a. Calculate Total Fertility Rate (TFR) for 1991and 2001yr. b. Whether this country has achieved replacement level fertility in the year 2001?

Age group (years)

ASFR (1991)

ASFR(2001)

15-19 70.1 58.2

20-24 220.0 188.2

25-29 179.0 165.5

30-34 112.0 98.0

35-39 64.5 52.1

40-44 28.7 18.9

45-49 12.4 6.3

Exercise-II

Fertility trends

TFR and CBR in Indian states(2003-04)

universality of marriage early marriage early puberty low standard of living low rate of literacy additional customs and

habits absence of family planning

habit

Reasons for High Birth Rate in India

1. Absence of natural checks2. Mass control of diseases3. Advance in medical science4. Better health facility5. Impact of national

programmes6. Improvements in food supply7. International aid8. Development of social

consciousness among masses

Reasons for declining Death Rate