Industrial and Post-Industrial Civilization
The most characteristic change in disease ecology relating to the Industrial Revolution and postIndustrial society is an almost complete exchange of the diseases of importance. Although medicine has claimed credit for the eradication of infectious diseases, it has been convincingly demonstrated that every major infectious disease of earlier times was already sharply in decline when medical cure became available, with only very few exceptions.
Tuberculosis is an excellent example. The tuberculosis epidemic in England and Wales can be seen to have become very significant in the eighteenth century. It peaked around 1810 and then began to decline (Lovell 1957). Effective antibiotic therapy was well over a century away. T. McKeown (1976) has shown that the introduction of antibiotic therapy lies in the asymptotic portion of the curve of incidence.The impact of the Industrial Revolution is difficult to overestimate. It produced profound changes in a nation’s gross national product, patterns of raw material usage and consumption, and real incomes that in turn led to improved living standards. All of these helped to permit explosive population growth (Wrigley 1962). For example, the population of England and Wales was under 10 million in 1800, but in 1990 is approaching 50 million; world population took until 1830 to reach one billion and had quadrupled by 1975 (McKeown 1988). Yet another unique feature of the Industrial Revolution is that explosive population growth, which the exponential increase in wealth probably could have supported for a long time, was replaced in Europe by a demography of indolent growth. This change seems to have been a directly voluntary effect. Contraception - however primitive the means - became the rule rather than the exception. Although the explosive growth begun in Europe during the Industrial Revolution continues, it does so primarily in the Third World, where agricultural progress and decreases in infant mortality allow impoverished populations to expand continuously.
Europe avoided this fate, and proceeded with a relatively stable population. Decreases in infant mortality caused average life expectancy to double, and more sanitary living conditions coupled with abundant food added still more years to the average life-span. Medicine played a major role in decreasing infant mortality, once the germ theory of disease had been accepted and infants were delivered under conditions conducive to their survival. But at the other end of the life spectrum, medicine has not contributed much. The diseases of modern societies are not primarily infectious. Atherosclerosis, interestingly enough the commonest radiographic finding when the royal mummies of ancient Egypt were X-rayed, has come to the fore as the most significant cause of adult mortality. Myocardial infarctions, fatal arrhythmias, and cerebrovascular accidents, respectively, are some of the major causes of death in modem society. This is a strikingly postIndustrial phenomenon. As late as the end of the nineteenth century, upper-class Englishmen ate a diet as rich in fats and cholesterol as the world has known. Obesity was the rule, not the exception. Yet myocardial infarction was almost unknown. For all the pretensions of modem medicine, the ecology of disease is still wrapped in mystery, particularly when it comes to the appearance and disappearance of individual diseases.
Cancer, certainly known for as long as there have been medical writings, but a rare cause of death in antiquity, has also become one of the commonest causes of death in modem society. Genetics plays some role. Some carcinogens have been convincingly identified, such as tobacco and asbestos. Yet the incidence of some cancers continues to rise, whereas the incidence of a commoner cancer of early industrial times (and still common today in parts of the Orient), namely adenocarcinoma of the stomach, is in decline. Diet is assumed to play a major role, but it is sobering to recall that diet has historically been implicated whenever it was unclear why a disease behaved as it did.
If we examine the length of the disease history of Europe, it is striking that patterns of disease experience, once identifiable, did not change significantly until the Industrial Revolution. In these terms, it is probably appropriate to divide history into post- Neolithic and post-industrial only. In any case it is clear that the Industrial Revolution changed the disease ecology of Europe almost totally. Medicine has perfected the cure of the diseases that were in the process of disappearing anyway, but has grappled with only very limited success with the diseases of the new age (McKeown 1988). It remains for future historians to determine whether or not humans will be able to alter the disease ecology they have produced by industrialization.
Stephen R. EU