Introduction to demography definition, scope and sources of information

1. Introduction to demography ( definition, scope and sources of information)

2. 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. teenage fertility, immigrant fertility, Malay fertility, infant mortality, maternal mortality

3. DEMOGRAPHY Composition of population --- ethnic, age, sex (also, how many are non-citizens) Distribution --- % rural, % urban, % suburban. Also, how many citizens live overseas Growth --- rapid growth, slow growth, population decline

4. DEMOGRAPHY Population is affected by fertility, mortality and migration rates Final population = Initial population + (Births � Deaths) + (Immigration � Emigration)

5. (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

6. (1) FERTILITY Fertility rates can be affected by: Public policy e.g. some governments pressure couples to have fewer kids, other governments encourage them to have more! Culture e.g. religion and contraception Economics e.g. expense of having kids in industrial versus agricultural societies Technology e.g. are effective contraceptive methods available?

7. FERTILITY AND HEALTH High fertility can increase maternal and child mortality Continuous child-bearing can have a negative impact on maternal health Closely-spaced births (<18 months apart) & low birth weight babies (<2,500g) at higher risk Illegal abortions and maternal mortality �Female genital mutilation� & maternal mortality Sex-selective abortion in China and India

8. FERTILITY AND HEALTH Problem of teenage pregnancies STDs such as gonorrhea can lead to infertility in women Use of condoms reduce transmission of STDS e.g. HIV/AIDS Monogamous women at risk of being infected with HIV by husbands and boyfriends

9. INFERTILITY AND �ASSISTED REPRODUCTION� Infertility = inability to conceive children Options for infertile couples: Adoption In some societies: second spouse, or even divorce or even abandonment of �infertile� spouse Treatment for infertility Ethical issues e.g. surrogate motherhood, , sperm donors and sperm banks

10. (2) MORBIDITY AND MORTALITY The Epidemiological Transition This refers to the change in disease patterns from mostly infectious diseases to mostly chronic and degenerative diseases Cancer, heart disease, stroke, injuries, diabetes, arthritis etc versus HIV/AIDS, SARS etc

11. MEASURES OF MORTALITY Infant mortality rate (deaths of babies under 1 year old) Neonatal mortality rate (<28 days after birth) Postneonatal mortality rate (between 28 days and 1 year old) IMR = Deaths of babies under 1 year X 1,000 Total live births

12. MEASURES OF MORTALITY IMR = Neonatal Mortality Rate + Postneonatal Mortality Rate Low Birth Weight (<2.5 kg at birth) greatly increases the risk of infant mortality

13. OTHER MEASURES OF MORTALITY Under 5 mortality rate Life expectancy at birth Age-specific mortality rates Cause-specific mortality rates Maternal mortality rate

14. MEASURES OF MORBIDITY Very important: Incidence rate Prevalence rate

15. INCIDENCE RATE No. of NEW cases in fixed time period X 1,000 Population at risk

16. PREVALENCE RATE No. of people with a disease X 1,000 Population at risk

17. (3) MIGRATION Involuntary: slavery, ethnic persecution, wars, natural disasters, famines Voluntary: to seek jobs (skilled or unskilled), to get an education, because of marriage, upon retirement ------------------------------ Internal migration: within a country e.g. rural to urban International migration: skilled professionals to other countries

18. MIGRATION AND 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)

19. Demographic data and vital statistics are useful tools in: Determining a community�s health status Deciding what�s the best way for providing health services Planning a public health program Evaluating a program�s effectiveness Epidemiology, as a public health discipline, prides itself in using scientific principles in studying health problems. Since the world is not a big laboratory, public health practitioners cannot conduct scientific experiments as researchers can, and would, in a laboratory. Public health practitioners use what is available first, and then collect whatever additional data they need through mostly observational studies. Fortunately, there are many good sources of information available - if you know where to look. Epidemiology, as a public health discipline, prides itself in using scientific principles in studying health problems. Since the world is not a big laboratory, public health practitioners cannot conduct scientific experiments as researchers can, and would, in a laboratory. Public health practitioners use what is available first, and then collect whatever additional data they need through mostly observational studies. Fortunately, there are many good sources of information available - if you know where to look.

20. Sources of Vital Statistics & Demographic Data . Census Registration of Vital Events Morbidity Surveys These sources are usually provided for defined populations (i.e., cities, states, political entities). Morbidity data have usually been hospital and clinic data, which means the populations of reference may not be easy to define. Changes in health care delivery will have an impact on hospital and clinic data. In the U.S., the trend has been to hospitalize only the most sickest, and then for the shortest length of time. For example, �length of stay� may no longer be truly reflective of �severity of illness.� These sources are usually provided for defined populations (i.e., cities, states, political entities). Morbidity data have usually been hospital and clinic data, which means the populations of reference may not be easy to define. Changes in health care delivery will have an impact on hospital and clinic data. In the U.S., the trend has been to hospitalize only the most sickest, and then for the shortest length of time. For example, �length of stay� may no longer be truly reflective of �severity of illness.�

21. Demographic Data: Sources of Morbidity Data Reportable diseases National Health Survey Hospital records data Industrial hygiene records School health records Medical care subgroups (i.e.,prepaid health insurance plans) Chronic Disease Registries (i.e., tumor registries) Insurance industry data National Health Survey - Mandated by an Act of Congress in 1956. An annual nationwide survey of a representative sample of 40,000 persons. Include: National Health Interview Survey National Health & Nutrition Examination Survey (HANES) National Hospital Discharge Survey National Ambulatory Medical Care Survey National Nursing Home Survey Includes the incidence or prevalence rates for many diseases, length of hospital stays, hospitalization by cause, number of days of disability, and patterns of ambulatory care. Published in Vital and Health Statistics, known as the �Rainbow Series�. Hospital/clinic data - hard to define population served. Chronic Disease Registries - mostly cancer (tumor) oriented, but there are some for cardiovascular disease, TB, diabetes, and psychiatric disease. Can be population-based (i.e., CT), or hospital -based. National Health Survey - Mandated by an Act of Congress in 1956. An annual nationwide survey of a representative sample of 40,000 persons. Include: National Health Interview Survey National Health & Nutrition Examination Survey (HANES) National Hospital Discharge Survey National Ambulatory Medical Care Survey National Nursing Home Survey Includes the incidence or prevalence rates for many diseases, length of hospital stays, hospitalization by cause, number of days of disability, and patterns of ambulatory care. Published in Vital and Health Statistics, known as the �Rainbow Series�. Hospital/clinic data - hard to define population served. Chronic Disease Registries - mostly cancer (tumor) oriented, but there are some for cardiovascular disease, TB, diabetes, and psychiatric disease. Can be population-based (i.e., CT), or hospital -based.