Estimation of mortality profiles from non-adult human skeletons in Edo-period Japan

Abstract

Reconstruction of the mortality profiles of non-adult human skeletons from an archeological site should greatly assist the interpretation of the sanitation, health, disease, and behavior of past human populations. The purposes of this study are to examine non-adult skeletons from the Sakaikango-toshi 871 (SKT 871) site in Edo-period (17-19th centuries AD) Japan, to estimate their age-atdeath distribution, and to discuss whether paleodemographic estimates can yield appropriate mortality patterns of this sample. The use of the Bayesian method for fetal age estimation, assuming uniform priors, yielded a peak of deaths at 10 months of gestation. The age-at-death distribution obtained from the whole population further indicated the peak of deaths being at the fetal stage and the number of deaths decreasing with age. The concentration on full-term of gestation implied deaths related to birth, which is consistent with natural mortality. Another important finding of this study is that individuals aged less than 7 years accounted for about 98% of the deaths and there was no burial for adults. An explanation for the lack of adults is preferential mortuary practices, in which the very young are buried separately from adults. It is concluded that this paleodemographic study of non-adults provides us with important information on mortality profiles and mortuary practices in Edo-period Japan.

Performance analysis of deciduous morphology for detecting biological siblings

“…In archaeology, this reflects perceptions of childhood agency. Mortality profiles for archaeological hunter-gather samples corroborate a bimodal pattern with mortality peaking during the earliest years and then again at a later stage in life (Angel, 1969;Owsley and Bass, 1979;Mensforth, 1990;Nagaoka et al, 2012;Flensborg et al, 2013). However, research on living communities suggests that children are essential to understanding kin and social structure in prehistoric contexts.…”

Demographic and pathological characteristics of the medieval Japanese: new evidence from human skeletons from Kamakura, Japan

“…The contingency tables of age and Buckberry and Chamberlain's auricular surface stage for Japanese reference samples (Nagaoka et al, 2012b) were used to calculate the posterior probability of being a particular age conditional on being in a particular state of an age indicator. The prior probabilities used in the calculation are uniform ones, where an equal prior probability is assigned to each age category, because in this assumption the estimated age-at-death distribution of the target sample is independent of that of the reference one (Nagaoka et al, 2012a).…”

Variation in the prevalence of deciduous caries in early modern human skeletons from Japan

“…The age‐at‐death distribution of this entire population indicates that the peak was the foetal stage and that the number of deaths decreased with age (Nagaoka et al, ). A concentration at full gestation term implies that deaths in this sample are related to birth, consistent with natural mortality (Nagaoka et al, ).…”

“…Most studies on Japanese Edo skeletons have revealed secular trends (Nakahashi, ; Suzuki, ) and regional and socioeconomic differences (Nagaoka, ; Suzuki, ) through craniometric traits. Recent advances in bioarchaeology have involved the studies of dental caries (Oyamada et al, ), linear enamel hypoplasia (Nakayama, ), paleodemography (Nagaoka, Abe, & Shimatani, ), and stable isotope analyses (Tsutaya, Nagaoka, Sawada, Hirata, & Yoneda, , ; Yoneda et al, ) of Edo period remains. These multidisciplinary studies indicate that social classes, regions, and chronological ages played an important role in intrapopulation and interpopulation variation in these bioarchaeological markers.…”

“…It is important to explore the occurrence of intrapopulation and interpopulation variation in caries among children under such social conditions. Unfortunately, little is known about intrapopulation and interpopulation variation particularly in deciduous caries in the Edo period because children's skeletons are poorly preserved and were buried outside the burial places of adults (Nagaoka et al, 2012). In this study, however, we could access a large amount of children's remains from the Edo period.…”