Possible diffuse idiopathic skeletal hyperostosis (DISH) in a 3000-year-old Pacific Island skeletal assemblage

Abstract

The Teouma skeletal assemblage represents a group of colonists from the earliest phase of the Vanuatu archipelago's prehistory. Previous examinations of the assemblage identified high levels of hyperostosis, which we investigate further here. Based on a differential diagnosis of conditions known to produce ectopic bone formation, we argue that the pattern of skeletal change is most consistent with diffuse idiopathic skeletal hyperostosis (DISH) although we acknowledge that, given the preservation of the sample, it is difficult to distinguish DISH from other causes of hyperostosis with absolute certainty. In modern and bioarchaeological studies, DISH has been associated with metabolic disease and dietary practices. Based on previous stable isotopes analyses, it is thought that the Teouma people were heavily reliant on purine-rich marine resources and terrestrial animal protein, the type of diet thought to contribute to DISH development. We therefore compared dietary stable isotope values of groups of individuals with and without evidence for DISH. No significant relationships between DISH status and carbon (δ13C) and nitrogen (δ15N) stable isotope values were observed, suggesting that individual access to particular dietary resources was not the cause of DISH in those affected from Teouma, although the dietary constraints of the colonizing context may still have played an important role in the development of this condition for individuals otherwise predisposed to the disease. Individual predisposition may have been influenced by a propensity for hyperinsulinemia or hyperuricemia, brought about by the selective pressures of the colonization process. The high prevalence of hyperostosis and DISH in this skeletal assemblage may be evidence for a prehistoric variant of metabolic disease, which is observed at a high frequency in the Pacific today.