Skeletal fluorosis in Italy beyond Vesuvius? Multi-analytical evidence for an environment-linked pathology from the Alps

The incidence of a disease in a given period might be underestimated due to various factors, such as its non-endemic nature, variations in the pathocenoses, difficulty in establishing its aetiology, or changes in environmental factors related to its presence and development in a specific territory. Among these, we can consider fluorosis, a bone and dental disease resulting from excessive fluoride accumulation, causing heterotopic ossification and hypoplastic defects. In Italy, skeletal fluorosis is considered endemic in the Vesuvian territory, with cases dating back to the 1st century CE. This paper presents the results of the analyses conducted on a sample of 31 individuals from the 1st century CE to the 19th century CE, likely affected by fluorosis, discovered in the church of Santa Maria Assunta in the village of Smarano (northeastern Italian Alpine region). Our investigation employed macroscopic, electron microprobe and isotopic methods to recognise skeletal changes, assess the fluoride content in the teeth and the burial soil, and acquire data on the diet of 19 of these individuals. The results of the chemical analyses, conducted on the 12 individuals who had teeth, revealed abnormal levels of fluorine, in two cases accompanied by evident skeletal and enamel alterations. The analyzed individuals allow us to enhance our understanding of the historical presence of skeletal fluorosis in Italy and represent the first probable cases of skeletal fluorosis identified outside the Vesuvian plain. Moreover, the study highlights the significance of evaluating the contemporary environmental context of individuals to acquire data for differential diagnosis. This research also demonstrates the importance of osteological studies in investigating environmental health and its history.