Influences of industrial development and urbanization on human lives in premodern Japan: Views from paleodemography.

OBJECTIVE: This study tests the hypothesis that industrial development and urbanization negatively impacted the living circumstances and health of inhabitants. MATERIALS: The materials used in this study included 881 human skeletons aged 15 years and older from the Medieval (1185-1573), Edo (1603-1867), and Meiji (1868-1912) periods. The Meiji period corresponds to the period when the industrial revolution spread in Japan. METHODS: Age at death and sex were estimated for each skeleton, and demographic profiles of the Medieval, Edo, and Meiji periods were compared. RESULTS: The rate of young deaths was higher in the Meiji period than in preceding periods, and urban inhabitants had a higher proportion of young deaths than rural inhabitants in the Edo period. CONCLUSIONS: The results suggest that industrial development and urbanization led to a decline in human health. LIMITATIONS: The results produced through Bayesian methods are likely tentative, because they vary according to the priors and reference sample. SIGNIFICANCE: Paleodemographic approaches are a useful method to elucidate the impact of industrialization and urbanization on health. SUGGESTIONS FOR FURTHER RESEARCH: Decline of health associated with industrialization should be examined combining paleopathological and paleodemographic methods.

A novel case of multiple variations in the brachial plexus with the middle trunk originating from the C7 and C8.

The brachial plexus is an important nervous structure from which all major nerves to the upper limb arise. It typically originates from the anterior rami of the C5-T1 spinal nerves. As it passes laterally, the roots are successively organized into three trunks, six divisions, and three cords. The BP is susceptible to injury during the perinatal and postnatal periods, as well as in adulthood. Its structure can show considerable variation, and there is a wealth of literature describing its variations, providing indispensable information to neurosurgeons. Here, we report a novel unilateral variant of the brachial plexus found in an adult Japanese male cadaver. In this case, the middle trunk arose from the C7 and C8 spinal nerves, and the inferior trunk continued from the T1 alone. At the interscalene triangle, the subclavian artery was situated between the C8 and T1 nerves. The posterior cord arose from the posterior divisions of the superior and middle trunks, while the root from the T1 nerve/inferior trunk was absent. The anterior division of the middle trunk gave independent roots to the musculocutaneous and median nerves, without completely establishing the lateral cord. A communicating branch arose from the musculocutaneous nerve to join the median nerve. Some branches from the roots and cords also deviated from typical configurations. This case represents a rare combination of variations in the trunks, divisions, cords, and the median nerve and offers a valuable addition to the literature regarding variations in the brachial plexus.

Societal perceptions and lived experience: Infant feeding practices in premodern Japan.

OBJECTIVES: A change in how children were treated and valued occurred in premodern Japan, as popularized ideas of an inheritance-based family system led to more careful and affectionate child-rearing practices by lower social-status groups. A number of books were written, advising that breastfeeding should last approximately 3 years. The objective of this study is to reconstruct and compare breastfeeding and weaning practices before and after the transition, to illuminate the impact of documented changes in child-rearing practices on subadults' lived experience. MATERIALS AND METHODS: Carbon and nitrogen stable isotopic data were obtained from 40 subadult skeletons excavated from the Sakai Kango Toshi 871 (SKT871) site (late 17th-19th century, Osaka, Japan). Isotopic results from SKT871 were compared with previously reported results from the Hitotsubashi site (AD 1657-1683, Tokyo, Japan). Hitotsubashi and SKT871 represent urban populations of lower status before and after the transition of societal perception of subadults. RESULTS: The most probable age at the end of weaning reconstructed in SKT871 was 1.9 years (1.4-2.7 years with a 95% credible interval) and was lower than that in Hitotsubashi (2.1-4.1 years with a 95% credible interval). DISCUSSION: The age at the end of weaning became younger after the transition of societal perception toward subadults, and this younger weaning age is inconsistent with written recommendations for the duration of weaning in premodern Japan. It is possible that an increased need for inheritors under the inheritance-based family system led to earlier weaning and shorter inter-birth intervals, but authorities recommended an ideal practice of a longer breastfeeding period.

A health crisis during the Japanese Medieval Period: A new paleodemographic perspective.

OBJECTIVE: To test the hypothesis that the "Little Ice Age" (LIA) (in Japan, ˜1440 - 1730 CE) co-occurred with unique age-at-death patterns. MATERIALS: 810 adult human skeletons from the early Medieval Period (EMP) of Japan, which are contemporaneous with the Medieval Warm Period (10th - mid 13th century AD), and the late Medieval Period (LMP) and Edo Period, which are contemporary with the LIA. METHODS: Age at death and sex was determined for each skeleton and demographic profiles of the Yayoi Period (5th century BC - 3rd century AD), EMP, LMP, and Edo site samples were compared. Paleopathological data from previously published reports were evaluated. RESULTS: The EMP had the highest mortality among young adults. Longevity increased in the samples (LMP and Edo) contemporaneous with the LIA. CONCLUSIONS: EMP early age-at-death was the result of poor community health, violent death, and frequent large-scale natural catastrophes. The LMP and Edo Period samples have an older age-at-death pattern and higher frequency of stress markers, argued to be a consequence of a colder climate. SIGNIFICANCE: This study is the first to synthesize paleodemographic and paleopathological data on a large scale to assess the possible effects of the Little Ice Age in Japan. LIMITATIONS: Varying skeletal preservation and focus on adult skeletons reduces the ability to evaluate health throughout the life span. SUGGESTIONS FOR FURTHER RESEARCH: Analysis of nonadult remains and multiple health indicators will likely shed more light on the effects of the Little Ice Age in Japan.

Bioarchaeological evidence of decapitation from Pacopampa in the northern Peruvian highlands.

Little is known about the precise date of the emergence of decapitation in a ritual context and the presence of systematic postmortem modification patterns in the ancient Central Andes. The ceremonial complex at Pacopampa in the northern Peruvian highlands provides early osteological evidence of decapitation in six individuals dating to the latter half of the Late-Final Formative Periods (500-50 BC) and to the Early Cajamarca Period (AD 200-450). Based on osteological evidence, and when taken together with archaeological settings and settlement patterns, researchers can be certain that those whose heads were disembodied were not likely to have been involved in organized battles. In addition, the similarities in the cut-mark distribution, direction, and cross-sectional morphology of each individual's remains, as well as the characteristics of selected individuals, imply that the decapitated individuals were carefully prepared using a standardized method and that those who modified the heads may have been professional decapitators. This study offers indisputable bioarchaeological evidence of ritualistic offerings of human skulls and systematic postmortem modification patterns, which is consistent with a contemporaneous iconographic motif of decapitation and extends the chronology of this practice back to the Formative Period in the northern Peruvian highlands.

Prevalence of cribra orbitalia in Pacopampa during the formative period in Peru.

Cribra orbitalia is characterized by an aggregation of small apertures in the orbital roof in response to marrow hypertrophy. This pathological change is indicative of biological stress during youth. We examined the prevalence of this lesion in Pacopampa, a ceremonial center of the formative period, located in the northern highlands of Peru. Using this evaluation of cribra orbitalia, we reconstructed aspects of the population's health and nutritional status during the formation of Andean civilization. We examined 41 orbits of 27 adult individuals (13 males, 14 females) and recorded the macroscopic presence or absence of cribra orbitalia. The presence or absence of cribra orbitalia was the same bilaterally for all 14 individuals having both orbits preserved. The pathology was present in two of the 13 males (15.4%), one of the 14 (7.1%) females, and three of 27 individuals (11.1%) for both sexes combined. There was no difference in the frequency between sexes. The prevalence of cribra orbitalia was found to be lower in Pacopampa than in the comparative data of coastal populations. It is reasonable to assume that the increase in social complexity in Pacopampa was probably unrelated to the decline in overall health of the people.

Pacopampa: Early evidence of violence at a ceremonial site in the northern Peruvian highlands.

OBJECTIVES: Pacopampa, a ceremonial complex in Peru's northern highlands, reveals early evidence of trauma in the Middle to Late Formative Period coinciding with the emergence of social stratification in the area. We examine the prevalence of trauma in human remains found at the site and present evidence of the circumstances surrounding the deaths of individuals who lived during the early stages of Andean civilization. MATERIALS AND METHODS: The materials are the remains of 104 individuals (38 non-adult and 66 adult) from the Middle to Late Formative Periods. We explored trauma macroscopically and recorded patterns based on skeletons' locations, age at death, sex, social class, and chronology. RESULTS: We detected trauma in remains over the Middle to Late Formative Periods. While the prevalence of trauma was minimal in the Middle Formative Period, skeletons from the subsequent era exhibit more severe disturbances. However, all the skeletons show signs of healing and affected individuals experienced a low degree of trauma. DISCUSSION: Given the archaeological context (the remains were recovered from sites of ceremonial practices), as well as the equal distribution of trauma among both sexes and a lack of defensive architecture, it is plausible that rituals, rather than organized warfare or raids, caused most of the exhibited trauma. Pacopampa was home to a complex society founded on ritual activity in a ceremonial center: this is indicated by the presence of ritual violence in a society that built impressively large, ceremonial architecture and developed social stratification without any political control of surplus agricultural goods.

Proteomic profiling of archaeological human bone.

Ancient protein analysis provides clues to human life and diseases from ancient times. Here, we performed shotgun proteomics of human archeological bones for the first time, using rib bones from the Hitotsubashi site (AD 1657-1683) in Tokyo, called Edo in ancient times. The output data obtained were analysed using Gene Ontology and label-free quantification. We detected leucocyte-derived proteins, possibly originating from the bone marrow of the rib. Particularly prevalent and relatively high expression of eosinophil peroxidase suggests the influence of infectious diseases. This scenario is plausible, considering the overcrowding and unhygienic living conditions of the Edo city described in the historical literature. We also observed age-dependent differences in proteome profiles, particularly for proteins involved in developmental processes. Among them, alpha-2-HS-glycoprotein demonstrated a strong negative correlation with age. These results suggest that analysis of ancient proteins could provide a useful indicator of stress, disease, starvation, obesity and other kinds of physiological and pathological information.

Prevalence of caries in deciduous teeth in early modern Japan: analyses of human skeletons from Hitotsubashi (Tokyo, Japan).

The early modern Edo period in Japan refers to the division of chronological age dated from the seventeenth to nineteenth centuries. During that period, the social structure was stratified, with warriors at the top, followed by farmers, and finally townsmen at the bottom. I aimed to examine carious lesions in deciduous teeth in the commoners from the city of Edo (now Tokyo), to compare them with those in the warriors and commoners from Kyushu, and to reveal differences in the incidence of caries across social classes and regions. I examined 843 deciduous teeth of 115 individuals from the Hitotsubashi site in Tokyo. The comparative samples were obtained from warriors and commoners whose remains were excavated from the Sougenji and Kyoumachi sites, respectively, in Kyushu [Oyamada et al. (2008) Anthropol Sci 116:9-15]. The caries frequency in the Hitotsubashi sample was 11.3 %. Carious lesions in the upper teeth were more frequent than those in the lower teeth in all age groups. The upper incisors exhibited the highest frequency of caries, while there was almost no caries in the lower incisors and canines. I also found population differences in deciduous caries among the Edo populations. Remains of teeth excavated from Hitotsubashi were found to have a mild degree of caries compared to remains of teeth excavated from Sougenji and Kyoumachi in Kyushu in terms of caries frequency and location. Thus, the influence of regional differences in diet and living circumstances was stronger than expected, and the variation observed in the frequency of deciduous caries among the Edo populations cannot be explained by social class alone.

Using the petrous part of the temporal bone to estimate fetal age at death.

Little is understood about the age-related changes in the petrous part of the temporal bone in fetal life. The purposes of this study were to examine documented skeletal remains of Japanese fetuses, to measure the length of the petrous part, and to develop diagnostic standards for fetal age-at-death estimation that could be applied to poorly preserved skeletons. The results indicated that it is possible to use a regression equation to estimate age at death directly from the length of the petrous part of the temporal bone. The application of the present method to a different population led to a fetal age-at-death estimation with an error of less than 1 month. We also used the Bayesian estimation, which yielded posterior probabilities of age, conditional on being of a particular length of the petrous part. The reference table of estimated gestational age may provide an easy-to-use indicator of the fetal age at death. In conclusion, measurement of the petrous part of the temporal bone may offer a new methodological basis for forensic and bioarchaeological diagnoses of fetuses.

Infant feeding practice in medieval Japan: stable carbon and nitrogen isotope analysis of human skeletons from Yuigahama-minami.

A longer breastfeeding duration provides various positive effects in subadult health because of abundant immunological factors and nutrients in human breast milk, and decreases the natural fertility of a population through lactational amenorrhea. In this study, we measured stable carbon and nitrogen isotope ratios in the bone collagen of three adults and 45 subadults from the Yuigahama-minami site (from 12th to 14th century) in Kamakura, the early medieval capital of Japan. Marine foods, C3 -based terrestrial foods, and freshwater fish are the primarily protein sources for adults. The changes in the nitrogen isotope ratios of subadults suggest that the relative dietary protein contribution from breast milk started to decrease from 1.1 years of age and ended at 3.8 years. The age at the end of weaning in the Yuigahama-minami population was greater than that in the typical non-industrial populations, a premodern population in the Edo period Japan, and medieval populations in the UK. Skeletons of townspeople from medieval Kamakura indicate severe nutritional stress (e.g., enamel hypoplasia and cribra orbitalia), yet this longer duration of breastfeeding did not compensate adverse effects for nutritional deficiency. The longer breastfeeding period may have been a consequence of complementary food shortage and bad health of subadults. Kamakura experienced urbanization and population increase in the early medieval period. The younger age-at-death distribution and high nutritional stresses in the Yuigahama-minami population and later weaning, which is closely associated with longer inter-birth interval for mothers, suggests that Kamakura developed and increased its population by immigration during urbanization.

Patterns of morphological variation in enamel-dentin junction and outer enamel surface of human molars.

Tooth crown patterning is governed by the growth and folding of the inner enamel epithelium (IEE) and the following enamel deposition forms outer enamel surface (OES). We hypothesized that overall dental crown shape and covariation structure are determined by processes that configurate shape at the enamel-dentine junction (EDJ), the developmental vestige of IEE. This this hypothesis was tested by comparing patterns of morphological variation between EDJ and OES in human permanent maxillary first molar (UM1) and deciduous second molar (um2). Using geometric morphometric methods, we described morphological variation and covariation between EDJ and OES, and evaluated the strength of two components of phenotypic variability, canalization and morphological integration, in addition to the relevant evolutionary flexibility, i.e. the ability to respond to selective pressure. The strength of covariation between EDJ and OES was greater in um2 than in UM1, and the way that multiple traits covary between EDJ and OES was different between these teeth. The variability analyses showed that EDJ had less shape variation and a higher level of morphological integration than OES, which indicated that canalization and morphological integration acted as developmental constraints. These tendencies were greater in UM1 than in um2. On the other hand, EDJ and OES had a comparable level of evolvability in these teeth. Amelogenesis could play a significant role in tooth shape and covariation structure, and its influence was not constant among teeth, which may be responsible for the differences in the rate and/or period of enamel formation.

Stable isotopic reconstructions of adult diets and infant feeding practices during urbanization of the city of Edo in 17th century Japan.

The urbanization of the city of Edo, the capital of premodern Japan, has been assumed to be not as a result of natural increase but that of in-migration although this assumption has never been verified. To obtain information on natural fertility in Edo, we analyzed stable carbon and nitrogen isotopes in 46 adult and 84 subadult human skeletons excavated from the Hitotsubashi site (1657-1683 AD: the early Edo period), Tokyo, Japan and reconstructed their breastfeeding period, one of the most important determinants of fertility. Adult females are significantly more depleted in (15) N by 0.7‰ than adult males, suggesting a dietary differentiation between sexes and/or the effect of pregnancy. The changes in the nitrogen isotope ratios of subadults suggest that supplementary foods were introduced around the age of 0.2 years and weaning ended around 3.1 years, which agrees with descriptions in various historical documents of the period. The duration of breastfeeding in the Hitotsubashi population was relatively longer than those in modern industrial and traditional societies and four previously reported populations in medieval and in the industrial England. As later weaning closely associates with longer inter-birth interval for mothers, our data suggest a lower natural fertility for the Hitotsubashi population. Assuming that the proportion of married people was also lower in the major cities of the earlier Edo period, our results support the assumption that Edo developed and increased its population by attracting immigrants during urbanization.

Estimation of fetal age at death from the basilar part of the occipital bone.

The purposes of this study are to examine documented fetal skeletal remains of Japanese, to measure the basilar part of the occipital bone, and to develop diagnostic standards for estimating fetal age at death which can be applied to poorly preserved skeletons. The sample is composed of 272 Japanese individuals of the early to middle twentieth century, whose ages were recorded in months from gestations of 5 to 11 months. The measurement items used here are the length, breadth, and index of the basilar part. The regression equations of gestational age in months for one or two variables were calculated. The results indicated that it is possible to use the regression equations to estimate the age at death of fetuses directly from the basilar part measurements. Another indicator for estimating age at death from the basilar part is the ratio of the width to the length, which was here expressed as the index of the basilar part. The width exceeded the length at 7 months and the basilar part changed with age from an anteriorly posteriorly long shape to a bilaterally wide one. It is concluded that the basilar part is a good indicator for estimating the fetal age at death.

A case study of a high-status human skeleton from Pacopampa in Formative Period Peru.

The Pacopampa site is located in the northern highlands of Peru and is an archaeological site belonging to the Formative Period (2500-1 BC). The excavation of the Pacopampa site yielded unusual human skeletons from the main platform of a ceremonial center of the site during the 2009 field season. The skeletal remains were associated with a pair of gold earplugs, a pair of gold earrings, and shell objects. This specimen is possibly a female aged 20-39 years. Detailed examination of the neurocranium revealed the presence of artificial cranial deformation with decreased cranial length, increased cranial breadth, and lateral bulging of the parietal bones. The estimated stature of this individual was 162 cm, which is about 15 cm higher than that of contemporary females of Pacopampa and about 20-25 cm higher than that of other Formative Period sites in northern Peru. The peculiarity of this individual, detected not only in the cultural artifacts but also in the physical features, is possible evidence for social stratification in the Formative Period.

Weapon-related traumas of human skeletons from Yuigahama Chusei Shudan Bochi, Japan.

The Yuigahama Chusei Shudan Bochi site (AD: twelfth to thirteenth centuries), located along the seashore of the southern end of Kamakura City in Japan, and has yielded a mass grave containing hundreds of human crania. The purpose of this study is to document cut marks on crania made by an edged weapon, paying specific attention to individuals who may exhibit scratch marks, and to understand the variability of weapon-related traumas in the medieval period in Japan. The observation leads to tentative findings regarding the identification and interpretation of weapon-related traumas of human skeletal remains. From macroscopic observation, the marks display the sharpness of cut surfaces which are characteristic of unhealed cut marks. Scanning electron microscopic observation of the marks also shows that they are V-shaped in cross-section, a morphological feature that is characteristic of cut marks. This study first demonstrates that the scratches on the crania have morphological features consistent with human-induced cut marks, and that the macroscopic and microscopic approaches provide important information for identifying anthropogenic cut marks on the human skeletal remains from an archaeological site in Japan.

Reliability of metric determination of sex based on long-bone circumferences: perspectives from Yuigahama-minami, Japan.

The purpose of this study is to develop new standards to determine the sex of fragmentary human skeletal remains from archaeological sites in Japan. In order to accomplish this, we measured the long-bone circumferences of Japanese skeletons from the medieval period and provided metric diagnosis of sex using discriminant function analysis. We discuss whether the osteometric approach provides the criterion for sex assessment of human skeletal remains. The materials comprised human skeletal remains from the Yuigahama-minami site, Kamakura, Japan. The sample size used in this study was 68 males and 62 females excavated from individual burial graves. The accuracy of sex classification is more than 80% for discriminant functions with only one variable and reaches 90% for those with a combination of multiple variables. The multivariate functions provide better results than the univariate functions. Another improvement in sex diagnosis which this study contributes to is that new standards enabling reliable diagnosis with small numbers of variables are developed from well-preserved parts of the skeletons. This paper provides new standards, focusing on the diaphysial circumferences of limb bones from a medieval population, and will contribute to the advancement of medieval studies of skeletal remains from archaeological sites in Japan.

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

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.

Paleodemography of a medieval population in Japan: analysis of human skeletal remains from the Yuigahama-minami site.

The purpose of this study is to obtain demographic data regarding the medieval population buried at the Yuigahama-minami site in Kamakura, Japan, and to detect a secular trend in the life expectancy of Japanese population over the last several thousand years. The Yuigahama-minami skeletal sample consists of 260 individuals, including 98 subadults (under 20 years old) and 162 adults. A Yuigahama-minami abridged life-table analysis yielded a life expectancy at birth (e0) of 24.0 years for both sexes, a life expectancy at age 15 years (e15) of 15.8 years for males, and an e15 of 18.0 years for females. The reliability of the estimated e0 was confirmed by analysis of the juvenility index. Demographic profiles comparing the Yuigahama-minami series with other skeletal series indicated that both the survivorship curve and life expectancy of the Yuigahama-minami sample are similar to those of the Mesolithic-Neolithic Jomon population, but are far lower than those of the early modern Edo population. These comparisons strongly suggest that life expectancy changed little over the thousands of years between the Mesolithic-Neolithic Jomon and medieval periods, but then improved remarkably during the few hundred years between the medieval period and early modern Edo period. The short-lived tendency of the Yuigahama-minami sample does not contradict the archaeological hypothesis of unsanitary living conditions in medieval Kamakura. This is the first investigation to address the demographic features of a medieval population in Japan, and will help refine our understanding of long-term trends in the demographic profiles of inhabitants of Japan.