Reconstruction of paleodemographic characteristics from skeletal age at death distributions: Perspectives from Hitotsubashi, Japan

Abstract

This is a demographic exploration of the city of Edo, which reveals the changes that accompanied its urbanization and analyzes the skeletal remains of 207 individuals from a specific site in Tokyo (Hitotsubashi), using several paleodemographic approaches. A comparison of the three methods employed herein suggests that the Bayesian and maximum likelihood estimation techniques provide more plausible mortality patterns than the direct method of age estimation because the direct method of age estimation relies on published age intervals for the auricular surface and that would account for the underestimation of old people relative to the other two methods. Analyses using these new approaches indicate a short life span tendency for the people of Hitotsubashi. Although we cannot rule out methodological problems of adult-age estimation, one plausible interpretation of that life expectancy is an inadequate food supply and a poor public health situation. This study suggests that, in Tokugawa Japan, urbanization might have imposed health risks, increasing the risk of mortality. Analysis of demographic data from Hitotsubashi has refined our understanding on the impact of urbanization on the Edo period, and presents new perspectives on paleodemography in Japan.

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

“…The mortality profiles obtained from the SKT 871 series suggested a peak of deaths at the fetal stage, Nagaoka and Hirata (2007). the number of deaths decreasing with age, and a lack of adult individuals.…”

“…Table 10 compares the age structure of SKT 871 with that of Hitotsubashi, which is a contemporary archeological site located in Tokyo (1657-1683 AD) (Nagaoka and Hirata, 2007). It represented townsmen, based on the fact that the largest proportion of the graves contained wooden coffins (hayaoke) that were often used for the lower social classes (Nagaoka and Hirata, 2007).…”

“…Table 10 compares the age structure of SKT 871 with that of Hitotsubashi, which is a contemporary archeological site located in Tokyo (1657-1683 AD) (Nagaoka and Hirata, 2007). It represented townsmen, based on the fact that the largest proportion of the graves contained wooden coffins (hayaoke) that were often used for the lower social classes (Nagaoka and Hirata, 2007). Most of the SKT 871 cases were fetal individuals and the number of deaths monotonously decreased with age from the fetal stage, while the Hitotsubashi showed a peak of deaths at 1 year of age with an apparent underrepresentation of fetuses.…”

“…The proportion of deaths under the age of 5 years exhibits wide variations depending on the site: 8.8% for S'Illot des Poros, Spain (Alesan et al, 1999); 11.6% for Loisy-en Brie, France (Bocquet-Appel and Bacro, 1997); 13.8% for the Natufian period, Israel (Eshed et al, 2004); 16.4% for the Neolithic period, Israel (Eshed et al, 2004); 18.3% for Yuigahamaminami, Japan (Nagaoka et al, 2006); 29.7% for Carlston Annis, USA (Mensforth, 1990); 30.7% for Libben, USA (Lovejoy et al, 1977); and 35.9% for Hitotsubashi, Japan (Nagaoka and Hirata, 2007). The proportion of deaths under the age of 5 years in archeological samples is often smaller than that in model life tables and historical demographic documents.…”

Did the Jomon people have a short lifespan? Evidence from the adult age-at-death estimation based on the auricular surface of the ilium

“…The method of Lovejoy et al (1985) has been one of the most widely used criteria of adult age estimation (e.g. Ubelaker, 1989;Murray and Murray, 1991;Saunders et al, 1992;Bedford et al, 1993;White and Folkens, 2000;Osborne et al, 2004;Schmitt, 2004;Nagaoka et al, 2006;Nagaoka and Hirata, 2007). The original method of Lovejoy et al (1985) estimates the age of individuals older than 20 years and divides these into the age groups 20-24, 25-29, 30-34, 35-39, 40-44, 45-49, 50-59, and 60 + corresponding to the eight modal stages.…”