1.0 Demography and Populations Flashcards Preview

MedST IB: Human Reproduction (HR) > 1.0 Demography and Populations > Flashcards

Flashcards in 1.0 Demography and Populations Deck (29)
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What is demography?

Study of age structure and growth of population
Encompasses current stock and flow


What is stock?

The age and sex structure of a population


What is flow?

Flow of vital events
Usually summerised using rates or expectancy (e.g. life expectancy)


What is a rate? (true rate)

Frequency of an event occurring per person time
(number of x per 1000 people over a given period[year])

E.g. 10.6 deaths per 1000 person years


What is a risk?

Probability of a specified event occurring within a specified period


Define crude birth rate:

Number of births per unit of person time


Define crude death rate:

Number of deaths per unit of person time


Define crude rate of national increase (or decrease):

Crude birth rate - crude death rate


What is the usual range given to reproductive life?

15-45yrs old


What is the total fertility rate?

Total number of babies born per average reproductive lifetime

Sum of probabilities of giving birth in each year of reproductive life (15-45yrs)

In UK this is ~ 2


What is gross reproductive rate?

Total number of daughters per average reproductive lifetime

Proportion of female births x total fertility rate


What is net reproductive rate?

Average number of daughters per mother who are expected to survive to reproductive age


Define infant mortality 'rate':

"Probability of dying before 1st birthday



Define child (under 5) mortality 'rate':

Probability of child dying before 5yrs old.

Done by asking:
1) How many births have you had?
2) How many are still alive?


Define adult mortality 'rate':

Probability of dying between ages of 15 and 60


Why is it important to age standardise birth and death rates?

Because values are sensitive to age structure (esp. death rate)

Death rates within each age group could be lower in population A compared to population B. Crude death rate could, however be the same if population A has a more ageing population


What is q(x)?

Probability of dying during age interval
(this info is given to us)


What is l(x)?

Number living at beginning of interval

l(x+1) = l(x) - d(x)


What is d(x)?

Number of deaths during interval

d(x) = l(x)*q(x)


What is L(x)?

Number of person-years of life lived in this age intervals
L(x) = l(x+1) + 0.5*d(x)


What is T(x)?

Number of person-years of life lived in this and all subsequent age interval

T(x) = L(x) + from x to final row


What is e(x)?

Life expectancy at beginning of interval

e(x) = T(x) / l(x)


Why is it better to separate childhood and adult mortality?

Because there is limited association between child and adult mortality risks


When were biggest gains achieved for childhood mortality?

Early 20th century

Child mortality reduce by 50% in the first 3 decades of 20th century (1900-1930)


When were biggest gains achieved for adult mortality?

Late 20th century


What are possible explanations for these changes in mortality?

"1) Better food
Increased incomes led to better nutrition (this wasn't as much the case in the UK, but other European countries saw poor people suffer when food prices went up due to poor harvest)

2) Professional medicine
Played little role in reducing mortality

3) Advancement and Diffusion of useful knowledge
""Domestic medicine""
Better understanding of how to protect and restore health"


What was the link between social class and mortalilty in the 20th century?

There was a weak link between social rank and child survival.

When data was adjusted for environment - it seemed that the only benefit was living in a safer area-


What scientific knowledge has become public health agendas to improve childhood mortality?

1) Cleanliness
Breast milk, boil cows milk, control flies, wash hands, keep infected people away from children

2) Mass participation
Books used to disseminate into
Baby weeks in local communities

3) Increased role of the mother figure


What two improvements played a big role in improvement of adult mortality?

1) Decline in Tb
- Improvements were seen well before the vaccine was developed

2) Decline in tobacco caused disease
- Responsible for 3/4 decline in total risk
- Tobacco control occurred in late 20th century