Epidemiologic Transition:Changes of fertility and mortality

with modernizationAbdel Omran. The Epidemiologic Transition: A Theory of

the epidemiology of population change. Milbank Quarterly. 1971;49:509-538

http://www.who.int/docstore/bulletin/pdf/2001/issue2/vol.79no.2.159-170.pdf

Lecture

Epidemiologic Transition Geographic Studies, what do they tell us?

Charles DarwinEvolution of Species

Abdel OmranEvolution of Disease

Epidemiology

Psychiatric Epidemiologists Diabetes Epidemiology Cardiovascular Epidemiology Cancer Epidemiology Infectious Disease Epidemiology

Instead at looking at individual diseases, we need to look at the

patterns of diseases

Mortality is the fundamental factor in the dynamics of

population growth and causes of death.

Mortality has no fixed upper limits. Thus if fertility approached its upper maximum, depopulation

would still occur.

During the epidemiologic transition, a long-term shift

occurs in mortality and disease patterns whereby pandemics of

infection are replaced by degenerative and man-made

diseases...

Age of Pestilence and Famine

Characterized by high mortality rates, wide swings in the mortality rate, little population growth and very

low life expectancy

Age of Receding Pandemics

Epidemics become less frequent, infectious diseases in general

become less frequent, a slow rise in degenerative diseases begin to

appear

The shifts in disease patterns in the 19th century were primarily

related to changing SES.With the 20th Century more related with disease control

activities independent of SES:e.g. Mexico, China

Epidemiologic Transition in Developing and Developed

Countries

0

10

20

30

40

50

60

70

80

1945 1960 1980 1995

Developing

Developed

35 years

14 years

40 44 48 52 56 60 64 68 72 76

Population Life Expectancy

0

20

40

60

80

100

InfectionCA

CHD

Other

Violence

Increasing Life Expectancy and Causes of Death

Epidemiologic Transition

Mor

tali

ty R

ates

Infectious Diseases

NCD

Death Rates for TB in England and Wales

0

500

1000

1500

2000

2500

3000

3500

4000

4500

1840 1855 1875 1895 1915 1935 1948 1958 1968

Death Rates for TB in England and Wales

0

500

1000

1500

2000

2500

3000

3500

4000

4500

1840 1855 1875 1895 1915 1935 1948 1958 1968

TB Bacillus Identified

Chemotherapy

BCG Vaccination

Death Rates for Measles in Children in England and Wales

0

200

400

600

800

1000

1200

1400

1850 1870 1890 1910 1930 1950 1970

Death Rates for Measles in Children in England and Wales

0

200

400

600

800

1000

1200

1400

1850 1870 1890 1910 1930 1950 1970

Immunization begun

Epidemiologic Transition

Mor

tali

ty R

ates

CA

CHDNIDDM

Trauma

Importance ofGeographic Patterns

Incidence of Stomach CAMales

0 20 40 60 80 100

Nigeria

India

US White

US NW

UK

Finland

Iceland

Columbia

Japan

Breast Cancer IncidenceFemales

0 5 10 15 20 25 30

Japan

Nigeria

Brazil

Singapore

Jamaica

Poland

UK

US NW

US Whites

CHD Death RatesMales, aged 45-54

0 500 1000 1500

Thailand

Guatamala

Japan

Egypt

Italy

Bulgaria

US

UK

Scotland

Finland

Cirrhosis Death Rates,Males, aged 45-54

0 10 20 30 40 50 60 70 80 90

UK

Scotland

Hong Kong

US

Japan

Italy

France

High Incidence of NCDs in Developing Countries

Possible Infectious Etiology

Macronodular Cirrhosis

Hepatocellular Carcinoma

Rheumatic Heart Disease

Iron deficiency anemia

Related to Nutrition Deficiency Endemic Goiter

Malnutrition Related Diabetes.

High Incidence of NCDs in Developed Countries Cardiovascular

CHD

Deep Vein Thrombosis

Respiratory

Emphysema

Lung CA

Female Genital

Endometriosis

Endometrial CA

Breast

Breast CA

Fibrocystic Disease

Male Genital

Prostrate CA

Metabolic

NIDDM

Back to Nature

Improved Physical activity A Healthier Diet, less saturated

fats, more fiber Less Stress

Transition

Nomads Farmers Urban

45 yrs

60 yrs

70 yrs

1960

Urban Rural

USA DevelopingCountries

rural urban

2006

Urban Rural

USA DevelopingCountries

ruralurban

Causes of Death

Age 15-44 Accidents

CA

CHD Age 45-54 CHD

CA

Accidents

Age 15-44 Accidents

CHD

CA

Age 45-54 CHD

CA

Accidents

Developed Developing

48

Health Transition – Developed Countries

Currently, most developed countries are in the third stage of the health transition:

– fertility rates are low

– causes of diseases and deaths have shifted from infectious to chronic diseases.

49

Health Transition – Developed Countries …

All developed countries in Europe, North America and Asia are seen as having arrived in the latter stage of the health transition in the 1970s, although there were large differences with regard to timing, particularly in the onset the decline in fertility.

In these countries, declining fertility rates and increased life expectancy have led to the ageing, or so‑called 'greying', of the population.

50

Health Transition – Developing Countries

The health situation in developing countries varies greatly from one country to another.

In most, there is still very low life expectancy; this is due largely to malnutrition and the lack of safe drinking water, which are compounded by poor healthcare facilities.

In other countries, however, particularly in Asia and Latin America, chronic diseases have now become more important than infectious diseases.

51

Health Transition – Developing Countries …

The same large variation is reflected in the demographic situation.

In countries such as China and Thailand fertility rates are very low; in others they are very high.

Due to sub‑national differences of an economic, social or ecological nature, there may also be large differences within a single country.

52

Health Transition – Developing Countries …

It is widely believed that, with increasing economic growth, developing countries will follow the same pattern of health transition as Europe and North America.

Many countries, especially the poorest, will not 'trade' infectious diseases for chronic diseases; instead, they may even suffer a 'double burden' of disease.