The Demographic/ Epidemiologic
Transitions and Social Determinants of
Health
Gloria Macassa MD, MPH, PhD
University of Gävle and Karolinska Institute
January 2011
Figure 1. Mechanisms by which social determinants of health affect
health outcomes (Dahlgren and Whitehead, 1991)
The Demographic Transition
Definition: the change of a population from high birth and death rates to low
birth and death rates (Landry A, 1934 France; Notestein F, 1945 US)
Four stages
- First stage: high death and birth rates (slow and steady population growth)
- Second stage: death rates begin to decline and birth rates remain high
(faster population growth)
- Third stage: death rates continue to decline and birth rates begins to decline
- Fourth and final stage:death and birth rates balance and population growth
stabilise : In some cases, (eg. Italy) population may cease to grow
altogether)
Figure 2. The Classic Demographic
Transition
Stage 1
Stage 2
Stage 3
Stage 4
Birth rate
Natural
increase
Death rate
Time
Note: Natural increase is produced from the excess of births over deaths.
Demographic transition
The Classical demographic transition
.
.
.
.
It occured in Western countries (US; Europe) through 18 -2o century (earlier)
The death rate had a long and gradual decline (agricultural and industrial revolution).
Improvement in Public Health
No major medical breakthroughs
Japan (an exception) in the classical model
The Present (Contemporary) demographic transition
. Developing countries in the middle of the 20 and 21 th century
. Birth and death rates start at higher levels (compared to historical Europe)
. Dramatic decline in death rates (public health and medical technologies)
. High birth rates and fertility decline (contraceptive technology)
. Very Little or substantial economic development
The Second Demographic Transition ? (Lesthaeghe R, 2004,2006, 2007)
. Europe of today- sub-replacement fertility
Very important!
. The demographic transition has occured (and still occurs) in different paces and
paths in different countries and sometimes within countries.
Figure 3. Demographic Transition in
Sweden and Mexico
Births/Deaths per 1,000
60
50
40
Sweden
Birth Rate
Mexico
Birth Rate
30
Death Rate
20
Death Rate
10
0
1750 1775 1800 1825 1850 1875 1900 1925 1950 1975 2000
Sources: B.R. Mitchell, European Historical Statistics 1750-1970 (1976): Council of Europe, Recent Demographic
Developments in Europe 2001 (2001) and UN Population Division, World Population Prospects, 2002
Epidemiologic transition
•
Definition: is the general shift from acute infections and deficiency
diseases characteristic of underdevelopment to chronic noncomunicable
diseases charachteristic of modernisation and advanced levels of
development (Omran AR, 1971; 1982)
•
The most evident indicators of this transition are changes in the pattern of mortality, paticularly in
cause of death, as well as changes in morbidity.
•
What are the mechanisms involved in the epidemiologic transition?
•
(1) Demographic changes : both in mortality and fertility- the so alled Demographic Transtion
described above. As more people will survive to adulthood-disease pattern of adults as well as
diseases of the elderly (in summary more noncomunicable diseases)
•
•
•
(2) Changes in risk factors
- Biological (alteration in antigenic identity; emergency of drug-resistant strains and dual infection)
- Environmental factors (exposure to environmental pollutants and overcrowding)
Models of Epidemiologic Transition
Stage 1. The Classical Epidemiologic Transition (Omran AR, 1971; 1982)
-gradual and progressive transition as modernization occurred
- typicall of Western societies (Europe, USA, NZ, AUS)
Stage 2. The Acelerated Epidemiologic Transition (Omran AR, 1971;
1982)
- faster mortality decline (Japan)
- faster pace to non-comunicable diseases
Stage 3. The delayed Epidemiological Transition
- Africa, Latin America and Asia
- Substantial decreases in mortality and high fertility
- Transition triggered mostly by public health measures and health technology
and not necessary great economic development
Criticism fr of Omran’s Epidemiologic Transition (e.g. Barret et al, 1998;
Reher DS, 2004; Hugh E, 2006)
Models of Epidemiologic Transition
(cont)
Stage 4. Age of Delayed Degenerative Diseases
Degenerative diseases remain important but advances in
medical technology lenghten the life expectancy of elderly people
with cancers and CVD.
Stage 5. Age of of Emergent and Re-Emergent Infections
Old (e.g. Tuberculosis) and New Diseases (e.g. SARS; H1N1)
Important!
- The satges of epidemiologic transition can overlap in the same
country (for instance, different socioeconomic groups may
experience the transition differently)
The Nutrion Transition
• Definition: shift in dietary and physical activity patterns
(Olshansy SJ, 1998 )
• Usualy societies converge to a pattern of diet high in
satured fat, suggar and refined foods and low in fiberassociated --- high levels of degenerative diseases!
• The Nutrition Transition is strictly linked to the
Demographic and Epidemiologic Transitions
Figure 4. Stages of Demographic-Epidemiologic and
Nutrition Transitions
The relationship between the Demographic-Epidemiologic transitions and
Social Determinants of Health
•
•
•
While the age structure of the population
and the distribution of disease change,
socially disadvantaged people and those
who are socially isolated continue to be at
increased risk (this is true for all countries,
developed or under-developed)
And when the epidemiologic and
demographic transition collide:
- Increased demand on health and health
care for the elderly
–
Middle aged adults in the work force
need flexible jobs because they may
be in need to provide care for their
elderly
–
Older workers will also need more
flexible jobs to contribute fully in the
society
–
Societies need to sort out their
policies. For instance benefits and
practices related to retirement, child
care, sick leave, part-time work,
health insurance and workers
compensation schemes
–
Countries need to redress the
general socio-economic, cultural and
environmental conditions of the
society
Thanks for Listening!