Abstract
The Metabolic Syndrome (MetS) is a cluster of metabolic-risk factors comprising obesity, dyslipidaemia, high blood pressure, and elevated glucose. A diagnosis of MetS increases the risk of metabolic chronic diseases, such as diabetes type 2 and cardiovascular disease. Gout (an erosive arthropathy) and DISH (diffuse idiopathic skeletal hyperostosis) are two joint conditions associated with MetS that are observable on the skeleton and offer palaeopathologists an opportunity to investigate MetS in the archaeological record. Gout and DISH are highly prevalent among Austronesian-speaking peoples in the Asia-Pacific region, with greater prevalences reported among both modern and archaeological groups. These high prevalences reveal a long history of these conditions in the region, and possibly a hereditary component underlying their manifestations. MetS is a global health condition today, but little is known about its existence in prehistory. This thesis, therefore, builds on the current understanding of gout and DISH in the Asia-Pacific by focusing regionally on the Asian mainland, where Austronesian-speaking peoples originated.
The aim of this thesis is to better understand MetS in the prehistory of the Asian mainland. Skeletal assemblages (n=321) from five archaeological sites in East Asia and Mainland Southeast Asia are examined: Con Co Ngua (pre-Neolithic, 6700-6200 BP), Khok Phanom Di (Neolithic, 4000-3500 BP), Man Bac (Neolithic, 3906-3523 BP), Xin’anzhuang (Bronze Age, 3250-3046 BP), and Non Ban Jak (Iron Age, 1700-1200 BP). Three objectives are set out to address the aim of this thesis: First, gout and DISH prevalences are determined at each of the studied sites. Second, bone size is recorded as a proxy for physiological stress influencing bone growth at different stages of the developmental life course. The reason for assessing stress is that it may have contributed to MetS development. Part of this second objective also addresses the impact of the agricultural transition on early life stress among these groups. Third, the two bodies of evidence that are collected in the first and second objectives are synthesized to test for a possible relationship between early life stress, and individuals with skeletal evidence of gout and DISH. These relationships are examined through the lens of the metabolic capacity load model proposed by Wells (2016). The aetiologies of gout and DISH are also explored from within the biocultural context of each site.
A high prevalence of gout cases (25/94, 27%) and a low prevalence of DISH cases (3/88, 3%) are found in mainland Asia as a whole. Skeletal evidence of gout or DISH are present at all five sites, indicating that MetS and/or its components existed in the prehistory of this region, and as far back as the era of pre-Neolithic hunter-gatherers (Con Co Ngua). The thesis also found that the onset of agriculture was not necessarily a detrimental event, given that early life stress influencing bone size did not increase with the shift in subsistence. Moreover, the findings of this thesis support a relationship between early life stress, and gout and DISH, though early life stress may not be a factor underlying all gout and DISH cases. A combination of stress and overnutrition, or just overnutrition, can compromise a person’s metabolic system leading to a disease state associated with the MetS.
Overall, this thesis presents a large-scale systematic investigation of gout and DISH in the Asian mainland. It investigates early life stress in the same region by relying uniformly on bone dimensions as proxies for stress exposure at different stages of the developmental life course. At the same time, it also introduces a new scoring system to diagnose for gout in the skeleton. This thesis therefore originally contributes to the current knowledge of the MetS in the prehistory of mainland Asia by investigating the prevalence of gout and DISH, and their possible aetiological factors, among different communities in the region. Furthermore, the thesis helps to set the stage for further research on metabolic chronic diseases in the past, an essential topic of research, given that MetS has evolved to becoming one of the world’s greatest health burdens today.