Response: on economic growth, business fluctuations, and health progress.

Demographic research on preindustrial societies has documented links between harvest yields, grain prices, real wages, and changes in mortality, but mortality hikes as a result of agricultural failures or grain price inflation become more muted as the level of development increases. 1–5 During the early industrialization period in the 19th century, decades of rapid economic growth coincided with stagnating or even increasing mortality in the United States and Britain. 6,7 During the Second World War, deaths from coronary disease declined in Norway and other German-occupied countries as fats and calories were drastically cut in the diet. Then, in 1945, pre-war levels returned both in diet and coronary deaths. 8 It also appears that the blockage of Confederate cotton exports at the start of the US civil war and the subsequent work stoppage improved both adult and infant health in the textile districts of England. Adults were no longer exposed to exhausting work and fumes in the factories, and infants could be breastfed by their mothers, who no longer gave them the Godfried’s cordial, a ‘baby syrup’ made with opiates. 9 Though opiate syrups sold as medicines have been considered a major contributor to deaths of children,3 years old in 19th century England, 10 the health hazards of the early industrialization period have been generally attributed to overcrowding and lack of sanitary conditions in cities, as well as working conditions that packed workers (including children), animals, fumes, and water in mines and factories for working days of 12 and even more hours. 7,11,12 These examples of health declines during periods of prosperity and health improvements during periods of economic hardship show how the relationship between affluence and health is not a univocal one. 13 Two recent major pandemics—nicotine addiction and obesity—are unequivocally associated with increased purchasing power of multitudes who consume marketed commodities that are harmful to health. Most researchers studying the secular decline of mortality would accept ‘some kind’ of link between demographic transition—in which death rates drop because of the decline in infectious disease mortality—and various factors associated with social and economic advancement in the past two centuries, including increasing levels of education; the abolition of slavery; significant reductions in discrimination by gender, ethnic, or religious issues; rising availability ofmaterial resources; urbanization; and improvement in physical infrastructure. But there is no consensus on which particular aspect is the major cause of the mortality decline. 14–21 Early in the 20th century, the secular drop in mortality was attributed to advances in medical technology, improvements in the standard of life or in urban sanitation, and, even, to changes in the virulence of germs. But Dubos questioned these ideas 8,22 andMcKeown 17,18