33. Demographic indicators: measures describing population groups. Population pyramids

Dependency ratio is the ratio of the population who are economically inactive to those who are economically active:
- Dependency ratio = population < 15 and > 65 / population between 15 and 65
Population size – the number of individuals in the population
Population density – the number of individuals in the population per unit of area
Age structure – the age structure of a population is shown by the population pyramid
- Most developed countries have contracting population pyramids
- Most developing countries have expanding or stationary population pyramids
Population pyramids
- Population pyramids are formed according to age and gender
- They change shape according to the epidemiological stage
Major demographic characteristics of developing countries
- High fertility
- High infant mortality
- High prevalence of HIV/AIDS
- High level of out-migration
Major demographic characteristics of developed countries
- Low levels of fertility – often lower than the replacement level of 2.1
- Women have babies at later ages
- High level of in-migration
Trends in age groups
- In Europe, people < 15 are decreasing, 15 – 60 are decreasing, > 60 are increasing rapidly
- In Asia, people < 15 are stable, 15 – 60 are increasing rapidly, > 60 are increasing
- In Africa, all age groups are increasing rapidly. 15 – 60 are increasing the fastest
The stages of epidemiologic transition
- Describe the change from when our demographics were determined by epidemics and famines to now, where out demographics are mostly determined by non-communicable diseases, like cancer and cardiovascular disease
- Pestilence and famine
  - High mortality rate, wide swings in mortality rate due to pestilence and famine, little population growth, low life expectancy
- Receding pandemics
  - Epidemics and infectious diseases become less frequent, non-communicable diseases begin to appear
- Degenerative and man-made diseases
  - Mortality due to non-communicable and man-made diseases becomes higher than mortality due to infectious diseases and famine