Epidemiological Transition
How have the causes of death evolved over the centuries?
To answer this question, researcher Abdel Omran proposed a simple theoretical framework in 1971: the “epidemiological transition.” According to him, Western societies have gone through three major phases in the evolution of mortality.
... - 1750
The age of pestilence and famine
During this period, mortality was very high and was dominated by infectious diseases such as whooping cough, diphtheria, tetanus, tuberculosis, and smallpox. Death rates were highly irregular and also reflected the impact of epidemics, famines, and wars. Life expectancy at birth rarely exceeded 40 years.
1750 - 1940
The age of receding pandemics
During this phase, epidemics became less frequent, despite occasional outbreaks of cholera, smallpox, typhus, and influenza. Communicable diseases of viral, microbial, or bacterial origin declined significantly. Life expectancy at birth increased from about 40 to 60 years.
1945 - 1970
The age of degenerative and man-made diseases
During this phase, the decline in mortality slowed down. While infectious diseases had virtually disappeared as major causes of death, chronic diseases (cardiovascular diseases, cancer, diabetes, etc.) and socially related causes of death (road traffic accidents, suicides, occupational hazards, etc.) increased. Nevertheless, by around 1970, life expectancy had reached 70 years.
The evolution of life expectancy at birth and the different phases of the epidemiological/health transition.
Source: Human Mortality Database.
Since then, a new phase of mortality improvement has been identified, and the term “health transition” is now often used.
1970 - ...
The age of the cardiovascular revolution and neurodegenerative diseases
Life expectancy continues to increase, driven by two major developments:
- the significant decline of cardiovascular diseases and certain cancers as causes of death;
- the adoption of healthier lifestyles: less smoking and alcohol consumption, more physical activity, and a stronger culture of prevention.
However, this period is also characterized by the rise of age-related neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. Today, life expectancy exceeds 80 years.