Rickets in a non-industrialised Iberian population: A case study in Vitoria-Gasteiz (Basque Country, Spain) between the 12th and 18th centuries

Abstract

The study of rickets in skeletal remains has traditionally focused on industrialisation's potential impact on human health, as reported in most of the studies from northern Europe. However, research on the medieval period is scarce, with rickets being considered a rare disease. Here we analyse rickets in a large non-adult sample (N = 355) recovered from Santa María Church (Vitoria-Gasteiz, Spain), dating from the 12th-18th centuries. Macroscopic features related to rickets have been found in 26 individuals (7.3%), with the highest prevalence corresponding to infants aged under 18 months. These results suggest that this is the most vulnerable stage in an infant's life, which may be related to weaning, a critical period of particular vulnerability to metabolic and/or nutritional-related conditions. Moreover, cases of rickets from Santa María Church have been analysed diachronically, considering the historical context of Vitoria-Gasteiz during the Middle and Modern Ages. These results suggest that rickets cannot be considered a rare disease during the medieval period among Vitoria-Gasteiz population, although its prevalence has been uneven (12th-13th centuries – 3.4%/14th-15th centuries – 9.6%) because of diverse adverse events that unfolded locally, probably involving crop failures and food shortages in the city. This study has revealed that the prevalence of rickets in Vitoria-Gasteiz during the Middle and Modern Ages can be broadly explained by the interaction of several cultural and socioeconomic factors, which probably limited sunlight exposure and the consumption of food with a high content of vitamin D, calcium and phosphorus. Given the above, Santa María could be considered a benchmark for the study of rickets in a non-industrialised urban environment in southern Europe between the 12th and 18th centuries.