Abdel Omran’s 1971 theory of epidemiological transition is an attempt to account for the extraordinary advances in health care made in industrialized countries since the 18th century. According to Omran, all societies experience three "ages" in the process of modernization: the "age of pestilence and famine", during which mortality is high and fluctuating, with an average life expectancy under 30 years; the "age of receding pandemics", during with life expectancy rises considerably, from under 30 to over 503; and the "age of degenerative and man-made diseases", during which the pace of the mortality decrease slackens, while the disappearance of infectious diseases increases the visibility of degenerative diseases, while man-made diseases become more and more frequent. At the time Abdel Omran was developing his theory of epidemiologic transition, the most competent specialists, along with United Nations experts, saw life expectancies as generally converging towards a maximum age, the most advanced countries seeming very close to it. According to the United Nations World Population Prospects, the point of convergence was 75 years (United Nations, 1975).. And as things now stand in the most advanced countries, the increase in life expectancy has slowed down since the 1960s and in some countries has even halted, in particular as concerns men.
The "cardiovascular revolution" of the 1970s launched a new period of progress. However, Jay Olshansky and Brian Ault (1986), followed by Richard Rogers and Robert Hackenberg (1987), without criticizing the basic premises of the theory of epidemiologic transition, introduced the idea of a "fourth stage"4 during which the maximum point of convergence of life expectancies would seem to increase thanks to achievements in the treatment of cardiovascular diseases. Jay Olshansky et al. (1990) set this new maximum at 85 years, the same as that chosen by the United Nations at the end of the 1980s for all countries (United Nations, 1989).
Today, the 85-year threshold is strongly criticized by many authors who believe that such a limit cannot be determined (Barbi et al, 1999; Vaupel, 2001; Carey and Judge, 2001). However, our aim in this article is not to discuss this aspect of the epidemiologic transition, but to study the numerous exceptions observed since the 1960s in the general trend of increasing life expectancy. Not only have many countries (in particular Eastern European countries) lacked the means to experience the "cardiovascular revolution", but a number of others, especially in Africa, have not yet completed the second phase of the epidemiologic transition and are now hard hit by the arrival of new epidemics such as AIDS, or by the reemergence of older diseases.
After a brief overview of the first "disruption" of the 1960s, which put an end in the advanced countries of the North to the convergence observed in previous decades, and of the second failure which affected countries of the South, in particular due to the AIDS epidemic, we will see that the fact that Africa has lagged behind the North can be interpreted as a failure to complete the second phase of the epidemiologic transition; in the third part of this article, we will examine the reasons why Eastern Europe has failed to enter the fourth phase.