The transformation of death rates, birth rates and disease profiles around the world, over part or all of the past 150 years, reflects various radical changes in human ecology. In Western societies, this epidemiological transition had its roots in the late eighteenth century and has led to the replacement of the fluctuating ravages of infectious disease epidemics, famine and malnutrition by a more constant attrition by the noncommunicable diseases of adulthood. These are the ‘diseases of modern civilisation’. Similar changes in disease profile are now emerging in much of the rest of the world, even as the poorer segments of those populations continue to be burdened by infectious diseases and malnutrition.

Earlier chapters have shown how the gains in material conditions of living, the advent of sanitation, the introduction of vaccination, gains in education, the nascent democratic process and general social modernisation all contributed to these great changes in disease and survival. Over the past two centuries in Western; populations, infant and child mortality declined by an order of magnitude, life expectancy at birth doubled and, among adults, the average age at death increased by approximately 15 years. The later stage of this transformation, entailing the rise of noncommunicable diseases of middle and later adulthood, reflects the advent of mass markets, altered consumption patterns, changes in patterns of diet and physical activity, and the various other shifts in way of life that characterised twentieth-century Western populations.