1. Demography
Prof Iain Crombie

2. Demography Study of populations
size and density, growth, age distribution, fertility, mortality,, migration and vital statistics
the interaction of all these with social and economic conditions.

3. Our focus size growth age distribution fertility vital statistics
births
deaths
IMR
PYLL
DALY
Population size and
structure has important
implications for patterns
of health and disease

4. Population size World population estimates: 2008: 6.7 billion
Of 78 million people added to the world every year, 95% live in less developed countries

5. Growth in population by region

6. % population in urban areas

7. Population size Interplay of births, deaths and migration
P2 = P1 + Births – Deaths + Net migration

8. Scotland’s population:1855- 2002

9. Net migration and natural changes

10. Projecting the future

12. Scotland’s Population

13. Scotland’s Population: a spike

14. A wedge

16. A barrel

17. Scotland’s Population

18. Trends in births and birth rate

19. Infant mortality rates: Scotland

20. Scotland’s Population: a spike

21. Overall deaths and death rates

22. Trends in death rates among younger women

23. Trends in death rates among older women

24. A wedge

25. A barrel

26. Population pyramids
a graphic presentation of the age and sex composition of the population
types
Spike: high birth rate, high death rate, low growth rate, in equilibrium
Wedge: high birth rate, low death rate, high growth rate, in transition
Barrel / beehive: low birth rate, low death rate, low growth rate, in equilibrium

27. Demographic transition
a theory/ model to explain shift from SPIKE to BARREL population pyramids
transition from high birth and high death rates to low birth and low death rates
often seen in change from rural (poor) to industrialized (wealthy) society
Note: changes in birth rate and mortality in infancy and childhood are very important

28. Demographic transition
1. Population has high birth rates and high death rates (particularly at young ages)
2. Death rates begin to fall (improved environmental conditions)
3. Population increases rapidly
4. Birth rates begin to fall but population has increased greatly
5. Population has low birth and death rates

29. Reasons for mortality decline
improved nutrition and food distribution
better environmental conditions and sanitation (public health movements of 19th Century)
better housing, less overcrowding
reduced infectious disease
Note medical advances most marked after 1930

30. Tuberculosis mortality over time

32. Dependency ratio the proportion of economically inactive (due to age)
Under 18 plus over 65 years
Dependency
Ratio* =
population aged 18 – 64 years
* minimum age varies from
maximum age sometimes 60, may rise to 70
Is this a useful measure? Why?

33. Calculating the dependency ratio
Pakistan, which is a developing country, has
41% of its population <15,
4% over 65.
55% between the ages of 15 and 64.
41 + 4 55
Dependency ratio = = 81.8
New Zealand, a developed country, has
23% of its population <15
12% over 65
65% between 15 and 64.
23+12 65
Dependency ratio = = 53.8

34. Predicted changes in Age structure: Scotland 2003 - 2028

35. Predicted changes in factors influencing the dependency ratio

37. Exploring key death rates
Infant mortality rates
Under five mortality rates
Maternal mortality ratio

38. Infant mortality rate No of deaths of infants aged 0 –1 year
No. of live births
for specific time period per 1,000
276 infant deaths * 1,000
55,147 live births
in Scotland in 1999
Very useful measure in a population.
Often used as an overall summary measure of the health status of a population and indicator of public health standards and consitions.
Infant mortality rate 5.0 per 1,000

39. 1841
1866
1891
1916
1941
1966
1991

40. Infant mortality rate measure of population’s state of health
general - food, sanitation, overcrowding
quality of health care – especially when rates low
international indicator
UK turn of century: IMR = 140
Sub-Saharan Africa today: IMR = 100
Developed countries today: IMR = 5-10
Very useful measure in a population.
Often used as an overall summary measure of the health status of a population and indicator of public health standards and consitions.

41. Comparing the health status of countries
Country
Infant mortality rate
Per capita health care expenditure (US$)
Singapore
2.31
816
France
3.3
2109 UK
4.85
1835
Cuba
5.72
185 US
5.82
4887
Mexico
18.42
370
Morocco
36.88 59
Yemen
54.7 20
Ethiopia
80.8 3
Afghanistan
151.95 8
Angola
180.21 31
2001

42. An alternative measure: under-five mortality
Why is under-five mortality one of the Millenium Development Goals?

43. Millenium Development Goals for 2015
189 Countries – September 2000 – Declartion at the UN

44.  Child mortality target: to reduce by two-thirds, between 1990 and 2015, the under five years old mortality rate, from 93 children of every 1,000 dying to 31 of every 1,000

45. % of under 5 deaths by region

46. Factors associated with Child Mortality

47. Evaluation of progress 2010
On track
Insufficient progress
No progress

48. Maternal mortality ratio
deaths during pregnancy or within 42 days of termination
associated with or aggravated by pregnancy
expressed per 100,000 live births per year - ratio
What does the graph show?

49. Under-5 mortality rate 1970-2013
Lancet, Wang et al 2014

50. Fact sheet 2010
350,000 women die annually from complications during pregnancy or childbirth
99 per cent — in developing countries
maternal mortality rate is declining only slowly
the vast majority of deaths are avoidable
Risk
sub-Saharan Africa -1 in 30
developed regions - 1 in 5,600

52. More population measures
fertility rate
life expectancy
healthy life expectancy
PYLL
DALY

53. Fertility rates live births per 1,000 women per year
aged 15 – 44 years
aged 15 – 49 years
age specific fertility rates
total period fertility rate

54. Scotland fertility rate 1861-2001

55. Age specific fertility rates E&W 2004
per 1000
Age group

56. Fertility rates in Scotland
Two main findings?

57. Total Period Fertility Rate (TPFR)
the average number of children that would be born to a woman over her lifetime
assumes that a woman
has the same fertility as the population on average
lives beyond the maximum age of giving birth
UK: 1.84
TPFR > 2.1 population increasing
TPFR < 2.1 population decreasing }
why?

58. Age-specific fertility rate per 1,000 women
Calculating TPFR
Age
Age-specific fertility rate per 1,000 women
Rate x 5 years
< 20
26.9
134.5
20-24
73.3
366.5
25-29
98.6
493
30- 34
99.4
497
35-39
48.9
244.5
40+
10.4
52.0
1787.5
1,787.5 per 1000 women
TPFR=1.78 (per woman)

60. Round the world TPFR Hong Kong 1.02 Japan 1.21 Cuba 1.61 China 1.79
United States
2.05
Ecuador
2.51
Ghana
3.68
Sierra Leone
5.88
Niger
7.75

61. Total period fertility rates

62. Factors associated with high fertility
Poverty
Extended family structure
Pastoral / agrarian economy
Religion
Low socio-economic status
Ignorance
Early marriage
Pro-natalist policies

63. Factors associated with low fertility
Affluence
Nuclear family structure
Industrial economy
Religion
High socio-economic status
Education
Deferred marriage
Anti-natalist policies

65. Expectation of life at birth: 1861-2001

66. Life expectancy
the number of years a baby born today can be expected to live IF it experienced the current age-specific mortality rates
an average for the whole population
some people will live longer other less
apply age specific mortality rates
0-1, 1-4, 5-9,
in sequence to a population of 100,000
add up the total number of years lived / 100,000
the calculation is not examinable

67. Male life expectancy
Russian Fed
59.4
Belarus 62
Ukraine
62.6
Slovenia
71.9
Chile
72.5
SCOTLAND
72.8
Costa Rica
73.4
Cuba
73.7
England
75.4
Iceland
77.1
Sweden
77.3
Japan
77.5

68. UK Life expectancy 2006 What do these data show? At birth At age 65
Male
Female
England
77.2
81.5
17.2
19.9
Wales
76.7
81.7
16.9
19.6
Scotland
74.8
79.7
16.0
18.7
Northern Ireland
76.2
81.2
16.8
19.7
What do these data show?

69. Life expectancy at birth, England and Wales, 1980-1982 to 2009-2011

70. Life expectancy at age 65, England and Wales, 1980-1982 to 2009-2011

71. Percentage Change in Life Expectancy, England and Wales 1980-1982 to 2009-2011

73. Healthy life expectancy
expected years of life in good or fairly good general health
two types
life expectancy in good general health
disability-free life expectancy (no long term limiting illness)
assumes current patterns of mortality and morbidity remain unchanged
calculation similar to life expectancy

75. UK Health expectancies
Life expectancy
Healthy life expectancy
Disability-free life expectancy
At birth
Male
76.9
68.2
62.4
Female
81.3
70.4
63.0
At age 65
16.9
12.8
10.1
19.7
14.5
10.6
What do these data show?

77. Potential years of life lost: PYLL
a measure of the relative impact of various diseases and lethal forces on society.
highlights the loss to society from early deaths.
should live to 75
die at 40
lose 35 years
JM Last

78. Calculating the PYLL
the number of years of life "lost" when a person dies "prematurely" i.e. before age 75
dies at 25, loses 50 years
dies at 57, loses 18 years
calculate average number lost
can use a different maximum age
65, 70 or 85
all causes or death or specific causes
cardiovascular
cancer

79. PYLL Index Deaths in male due to road traffic accidents in Tayside
: set maximum age at 70 years
Age a)
Remaining
years d)
Deaths
a) x d)
0-4
67.5 5
337.5
5-9
62.5 3
187.5
10-14
57.5 4
230.0 -
65-69
2.5 10
25.0
Total
3380
Total pop = 192,500
PYLL = 3380 / 192,500 = 17.6 per 1,000

80. PYLL data: US 2005

81. Disability-adjusted life years (DALYs)
measure of burden of disease
extent to which disease reduces healthy years of life
1 DALY= 1 healthy year of life lost
calculated for specific diseases

82. DALYs disability plus mortality disability mortality DALY
= incidence x duration x disability
mortality
years lost through early death
DALY
= years lost (death) plus years spent with disability (allowing for the amount of disability)

83. Adjustment for DALYs example disputed
women lives for 10 years in moderate pain, disability weighting 0.4. Dies 5 years younger than life expectancy
DALY= 0.4x = 9
disputed
the adjustment for the amount of disability

84. Leading Causes of Mortality and Burden of Disease World, 2004
DALYs %
Ischaemic heart disease
Cerebrovascular disease
Lower respiratory infections
COPD
Diarrhoeal diseases
HIV/AIDS
Tuberculosis
Trachea, bronchus, lung cancers 2.3
Road traffic accidents
Prematurity, low birth weight %
Lower respiratory infections 6.2
Diarrhoeal diseases 4.8
Depression 4.3
Ischaemic heart disease 4.1
HIV/AIDS 3.8
Cerebrovascular disease
Prematurity, low birth weight 2.9
Birth asphyxia, birth trauma 2.7
Road traffic accidents
Neonatal infections and other 2.7
WHO. Global Burden of Disease 2004 Update

85. What you should know Population pyramids Dependency ratio
Infant mortality rate
Fertility rates
Life expectancies
PYLL
DALY
what they are – definition
what they mean – interpretation
what influences them

86. No. of deaths from suicide
Mid Pt
Years lost
No. of deaths from suicide
0-14 yrs
7.5
67.5 3
15-24 yrs 20 55 90
25-34 yrs
167
35-44 yrs
138
45-54 yrs 93
55-64 yrs 70
65-74 yrs 47

87. No. of deaths from suicide
Mid Pt
Years lost
No. of deaths from suicide
0-14 yrs
7.5
67.5 3
202.5
15-24 yrs 20 55 90
4950
25-34 yrs 30 45
167
7515
35-44 yrs 40 35
138
4830
45-54 yrs 50 25 93
2325
55-64 yrs 60 15 70
1050
65-74 yrs 5 47
235
Total years lost = 21,067.5
Total pop = 5,120,000
PYLL = 21,067.5 ÷ 5,120,000 = 4.12 per 1000

88. Age-specific fertility rates
Rate x 5
< 20
43.0
215
20-25
97.2
486
25-29
112.9
564.5
30-34
118.3
591.5
35-39
55.6
278
40+
14.4 72
Cumulative birth rate 2,207 per 1000 women
TPFR = 2.2 (per woman)