Population Dynamics - Health - Lecture Slides, Slides of Public Health

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POPULATION DYNAMICS

AND HEALTH

DEMOGRAPHY

Scientific study of population



Births (Fertility)



Sickness (Morbidity)



Deaths (Mortality)



Population movements (Migration)



Other e.g. abortion rates, divorce rates etc.



Scholars often focus on subtopics e.g. teenagefertility, immigrant fertility, Malay fertility, infantmortality, maternal mortality

DEMOGRAPHY

Population is affected by fertility, mortality

and migration rates

Final population = Initial population +

(Births – Deaths) + (Immigration –Emigration)

AGE-SEX COMPOSITION OF A

POPULATION

Depicted by the Population Pyramid 

“Young” population: pyramid is triangular



“Ageing” population: pyramid becomesmore and more rectangular

“AGEING” POPULATION



Elderly rises from 5% to more than 20% of totalpopulation



Due mainly to low fertility e.g. Japan, Singapore



“Young-old” versus “old-old”



More and more elderly women



More chronic & degenerative diseases



Multiple health problems are common in elderlypeople

THE DEMOGRAPHIC

TRANSITION

This 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.

(1) FERTILITY

Fertility rates differ by social variables:Differ by religious group e.g. Catholic

Church and contraception

Differ by social class – lower classes tend to

have higher fertility

Differ by region – people in rural areas tend

to have higher fertility

Differ by country – people in poor countries

tend to have higher fertility

(1) FERTILITY

Fertility rates can be affected by: 

Public policy e.g. some governments pressurecouples to have fewer kids, other governmentsencourage them to have more!



Culture e.g. religion and contraception



Economics e.g. expense of having kids inindustrial versus agricultural societies



Technology e.g. are effective contraceptivemethods available?

FERTILITY AND HEALTH



Problem of teenage pregnancies in USA



STDs such as gonorrhea can lead toinfertility in women



Use of condoms reduce transmission ofSTDS e.g. HIV/AIDS



Monogamous women at risk of beinginfected with HIV by husbands andboyfriends

INFERTILITY AND “ASSISTED

REPRODUCTION”

Infertility = inability to conceive childrenOptions for infertile couples:

AdoptionIn some societies: second spouse, or even

divorce or even abandonment of “infertile”spouse Treatment for infertility



Ethical issues e.g. surrogate motherhood, Baby M case in USA, sperm donors and sperm

banks

MEASURES OF MORTALITY



Infant mortality rate (deaths of babies under 1year old)



Neonatal mortality rate (<28 days after birth)



Postneonatal mortality rate (between 28 daysand 1 year old)

IMR = Deaths of babies under 1 year

X

1,

Total live births

MEASURES OF MORTALITY



IMR = Neonatal Mortality Rate +Postneonatal Mortality Rate



Low Birth Weight (<2.5 kg at birth)greatly increases the risk of infantmortality

MEASURES OF MORBIDITY

Very important: 

Incidence rate



Prevalence rate

INCIDENCE RATE

No. of NEW cases in fixed time period

X

Population at risk