Did the 1917–21 economic depression accelerate the epidemiological transition? Milk prices, summer peak of mortality, and food-and-water causes of death in Madrid, Spain

This article aims to answer a provocative question: would higher prices, particularly that of milk, be beneficial for the survival of children under 2 years old? Using a database of more than 230,000 births, matched to deaths, we test this hypothesis in the context of a large Mediterranean city, Madrid, in the years 1915–1926. During this period an inflationary crisis spread from 1917 to 1921. We compare child survival, the impact of milk price fluctuations, and the summer mortality peak, controlling for socio-spatial segregation and considering all-cause mortality and mortality due to food- and water-borne illnesses, before, during and after the economic depression. A positive association between increases in the milk price and better chances of survival is statistically robust, but only observed during depression. Several explanations are discussed.