According to the epidemiological transition theory, the dominant pattern of causes of death due to infectious disease began to give way from approximately 1870 onwards to a pattern dominated by degenerative diseases which include various forms of cancer, cardiovascular diseases and strokes. Although the general outline of this theory is widely accepted, there are two limitations. First, the theory is based on highly aggregated data, such as national statistics. Second, the theory does not take into account socioeconomic gradients within populations. Possibly, the epidemiological transition of disease occurred at a different pace and timepoint for designated socioeconomic groups, confounded by the spatial distribution of these groups in a given city. Within this scope,_ _the socioeconomic and nutritional determinants that have driven the modernization of the health system in the Netherlands were spatially reconstructed. In the_ Amsterdam Health and Disease Database Crowdsourcing Project,_ individual-level determinants of death and disease at the city level in Amsterdam from 1854-1940 were collected and digitized for 625.563 individuals. Apart from the cause of death, the registers state age, sex, address, marital status, rental price, and occupation of each individual. With this unique data, the epidemiological transition theory can be tested with more accuracy. To what extend, was the decline in the burden of infectious disease socioeconomically and nutritionally patterned across the city? A spatial analysis of individual-level cause of death data was employed to understand diffusion mechanisms linked to the spread and variation of sociodemographic behaviors. This novel approach promises to make a breakthrough in the current academic debate on the determinants of the great leaps in life expectancy before the 1940s, thereby offering prevention strategies for countries currently undergoing the epidemiological transition of disease.