Societal and ecological determinants of urban health: A case study of pre-reproductive mortality in 19th century Gibraltar

A historical based enquiry of colonial Gibraltar at the turn of the 19th century was conducted in order to assess what factors gave rise to residential variation of pre-reproductive mortality. Gibraltar's unusual configuration of a port city, garrison town, and commercial centre at the tip of the Iberian peninsula offers a unique opportunity to examine the interplay of ecology, demographic and socio-economic factors on childhood mortality. Communal living under the patio system and the sharing of essential resources were characteristic features of life on the Rock. Using the residential district as the focus of enquiry, stepwise regression results for the period 1879-1881, designated as a period of 'low ecological stress', indicated that the number of gallons of portable water per person captured a significant amount of variability in mortality. During the year 1878, a serious shortfall in rainfall was associated with lower life expectancy, a change in the seasonal pattern of mortality, and elevated rates of deaths attributable to the diarrhea complex. Under this period of 'high ecological stress', the percentage of servants in the household, a proxy for wealth/status, proved to be the single most important factor accounting for 46.6% of the variation in the death rate under 15. Analysis of mortality at the patio level revealed that residents of buildings of two household units had lower mortality than residents living in smaller or larger dwellings, particularly in the period of high ecological stress. The complex pattern of mortality at the district and patio level is explained in terms of the development of residential preferences and decentralized nature of vital resources, such as the water support system and food supply.