Transcript What kills us?: Yesterday, today & tomorrow

What kills us?:
Yesterday, today &
tomorrow
How much have mortality patterns
changed and why?
R.Fielding
Learning objectives
• Define incidence, prevalence,
morbidity and mortality
• Give examples of major ratios used
to define morbidity and mortality
• Describe changes in cause of death
in HK over the past century
• Give valid explanations for these
changes
Learning objectives
• Describe the allocation of mortality
to different categories of biology,
environment, lifestyle, health care
and contrast this with the
expenditure in these areas;
• Describe the major determinants
of health at the community level
Definitions
• Morbidity: all ill-health, sickness, etc.
• Mortality: all deaths.
• Incidence: (number of new cases of a
disease) / (popn. at risk) per unit time.
• Prevalence: all cases (new and old) of a
disease/ total population per unit time.
• Ratio: proportion of those affected
relative to a given unit of population or
events
Common ratios
• Mortality rate: Number of deaths per unit
of population (10,000 or 100,000)
• Infant Mortality Rate:
deaths among children < 1 year old
total number of children < 1 year.
• Standardized Mortality Ratio (SMR):
product of (number of observed deaths
x100)/(number of expected deaths). >100
indicates excess deaths, < 100 indicates
a lower mortality.
Leading causes of death, HK.
1912
Plague
T.B.
Pneumonia
Smallpox
Paralysis /
convulsion
Malaria
Diarrhoea
Developmtl
Old age
Unknown
1948
1993
379
239
238
121
119
Pneumonia
T.B.
Enteritis
Perinatal
Ill-defined
175
109
98
67
45
Cancer
Heart
CVD
Pneumonia
Accident
9,311
4,707
3,247
2,209
1,694
92
82
81
76
71
Violence
Heart
Cancer
G.U.
Digestive
43
32
22
19
18
Nephritis
Septicemia
Liver
Bronchitis
Diabetes M.
(TB)
851
560
498
436
425
396
5.04
rate/1,000 7.8
(0.414)
80
Expectation of life at birth, men,
1871-1971 (UK)
75
1961
70
65
60
1931
life expectancy
trend
55
50
1901
45 1871
40
19
61
19
31
19
01
18
71
35
Age-standardized annual mortality
rates 1851-1930 (UK)
10,000
TB
B, P, I
1,000
100
'51 '61 ''71'81 '91 '01 '11 '21
Whooping
cough
Measles
Epidemiological model for disease
evaluation
%
allocation of mortality
% of Cause of medical Life
deaths mortality
care
style
34.0 Heart dis.
12
54
14.9 Cancer
10
37
13.4 CVD
7
50
8.0
Accident
13
60
3.8
Influenza
18
23
pneumon
2.7
Respiratory 13
40
Enviro Biology
nment
9
28
24 29
22 21
25 2
20 39
24
24
Comparison of US Federal expenditure to
allocation of mortality according to
epidemiological model
Epidemiological Federal health
model
expenditure
1974-1976 (%)
90.2
 System of
medical care
organization
1.3
 Lifestyle
Allocation of
mortality (%)
11
43
 Environment
1.6
19
 Human biology
6.9
27
Questions
1. How has mortality changed in HK
since 1900?
2. Why have these changes
occurred?
3. What does this tell us about the
important influences on mortality?
4. How should we be spending our
health budget?
1. How has the pattern of mortality
changed?
• From acute to chronic degenerative
causes and (in children and
younger adults) accidents.
• Life expectancy at adulthood little
changed, but childhood survival
improved during last 100 years.
How has mortality changed?
(cont.)
• Infectious disease mortality
declined before causes (and Rx)
were identified,
–so medical interventions not
responsible
–what else happened in Europe
1830-1930 and HK 50 years
later?
2. What has contributed to
these changes? (a)
• Changes in the nature of work
• Food hygiene laws, improved
income => better nutrition
• Infrastructure development =>
–better living conditions
–clean drinking water
–sewage disposal
2. What has contributed to
these changes?(a)
• Decline in fertility rate altered family
size, birth spacing and age
distribution; =>
• increase in median age of infection
and lower case fatality rate; =>
• More children survived, so the mean
age of the population increased.
80
Expectation of life at birth, men,
1871-1971 (UK)
75
1961
70
65
60
1931
life expectancy
trend
55
50
1901
45 1871
40
96
1
93
1
90
1
87
1
35
2. What has contributed to
these changes?(b)
• From W.W.II onwards change in
activity levels: less manual labour
more motorized transport.
• Increases in
– disposable income
– food availability & marketing strategies
– dietary and other substance intake
2. What has contributed to
these changes?(b)
• Increase in body mass
(DM, CHD, HT)
• Tobacco / alcohol use /
environmental degradation > rise in
chronic disease prevalence.
• Economic developments, loss of
control, competitiveness.
3. What does this tell us about
important influences on mortality?
• Improvements in life expectancy
small despite massive expenditure
on health care delivery.
• Most mortality declines due to
economic, cultural, behavioral and
domestic changes
• Societal, cultural and behavioural
influences have been more
important that medical care.
4. How should we be spending our
health budget to improve health further?
• Many current causes of mortality
incurable.
• Prevention best approach to further
reductions in mortality
• Economic and occupational
improvements are among most important
developments.
• Environmental degradation (consumer
behaviour) is now most important threat.
Mortality from coronary heart
disease, men (20-64) UK
Professional
Managerial
Skilled nm
Skilled m
Part skilled
Unskilled
0
50
100
150
200
250
300
European age-standardized mortality rate/100,000
Conclusions
• Economic/political, social &
individual behaviour impacts on
environment and behaviour,
disturbing systemic homeostasis
(ecosystem),
• result is increased risk exposure
and heightened vulnerability.
Conclusions
• Mortality primarily influenced by socioeconomic factors through opportunity
and personal behaviour.
• Future declines in mortality will derive
mostly from social-level changes (e.g.
legislation on drink-driving, smoking,
pollution, education) and personal
behaviour.
• Preventive measures offer better value
for money.