Child development, physiological stress and survival expectancy in prehistoric fisher-hunter-gatherers from the Jabuticabeira II shell mound, South Coast of Brazil

In this study, we shed light on the interdependency of child growth, morbidity and life expectancy in the fisher-hunter-gatherers of the Jabuticabeira II shell mound (1214-830 cal B.C.E. - 118-413 cal C.E.) located at the South Coast of Brazil. We test the underlying causes of heterogeneity in frailty and selective mortality in a population that inhabits a plentiful environment in sedentary settlements. We reconstruct osteobiographies of 41 individuals (23 adults and 18 subadults) using 8 variables, including age-at-death, stature, non-specific stress markers (cribra orbitalia, porotic hyperostosis, periosteal reactions, periapical lesions and linear enamel hypoplasia), as well as weaning patterns based on stable isotope data to examine how stress factors module growth and survival. Our results show that shorter adult statures were linked to higher morbidity around weaning age and higher chances of dying earlier (before 35 years) than taller adult statures. In addition, short juvenile stature was related to physiological stressors and mortality. The adult "survivors" experienced recurrent periods of morbidity during childhood and adulthood, possibly associated with the high parasite load of the ecosystem and dense settlement rather than to malnourishment. An association between early-stress exposure and premature death was not demonstrated in our sample. To explain our data, we propose a new model called "intermittent stress of low lethality". According to this model, individuals are exposed to recurrent stress during the juvenile and adult stages of life, and, nevertheless survive until reproductive age or later with relative success.

Insights on patterns of developmental disturbances from the analysis of linear enamel hypoplasia in a Neolithic sample from Liguria (northwestern Italy)

OBJECTIVE

To assess developmental disturbances through the analysis of linear enamel hypoplasia (LEH) frequency and to infer environmental stress and life history within Neolithic communities from Liguria (Italy).

MATERIALS

43 unworn/minimally worn permanent anterior teeth of 13 individuals recovered from nearby caves and dated to c. 4800-4400 cal. BCE.

METHODS

LEH defects were identified with high-resolution macrophotos of dental replicas, age at LEH was calculated via perikymata counts. LEH defects matched between two or more teeth were considered as systemic disturbances. LEH frequency by age classes was analyzed via GLZ and Friedman ANOVA.

RESULTS

Number of matched defects per individual range between 2-12. The mean LEH per individual was highest in the 2.5-2.99 age category, with a significant increase relative to earlier growth stages, followed by a decline.

CONCLUSION

LEH may reflect life-history in the local ecology of Neolithic Liguria, where several individuals with osteoarticular tuberculosis have been recorded. Disease burden may have triggered developmental disturbances around the time of weaning. Age at first defect was negatively correlated with age at death and positively with the total number of defects, suggesting that early stress may have affected survivorship.

SIGNIFICANCE

The study contributes to the reconstruction of ecological pressures among Neolithic people of Liguria, and informs on environmental challenges during the Neolithic adaptive expansion.

LIMITATIONS

The visual examination of macrophotos is prone to observer error; mid-crown tends to display more visible LEH due to tooth architecture.

SUGGESTIONS FOR FURTHER RESEARCH

Apply different quantitative methods to examine severity and duration of disturbances.

Bilateral congenital radioulnar synostosis in an Early Horizon subadult burial from the site of Atalla, Peru

OBJECTIVE

This study was undertaken to identify pathological conditions within the population living at Atalla (1000-500 BCE), an important early village site and ritual center located in Huancavelica, Peru.

MATERIALS

Articulated burials (N = 3) and commingled human remains excavated during the 2015 and 2016 field seasons.

METHODS

Osteological remains were analyzed for macroscopic evidence of pathological changes.

RESULTS

A case of bilateral proximal radioulnar fusion was observed in an Early Horizon (ca. 800 BCE) subadult skeleton (Individual 1). A differential diagnosis of this pathology supports congenital radioulnar synostosis (CRUS), a rare developmental condition. Enamel hypoplasia was also identified in the same individual.

CONCLUSIONS

Burial treatment of Individual 1 does not provide any indication that CRUS was afforded an exceptional social significance.

CONTRIBUTION TO PALEOPATHOLOGY

This example of CRUS is notable as it represents the second published archaeological case of CRUS from Peru and the earliest reported case globally.

LIMITATIONS OF THIS STUDY

The osteological sample currently available from this site is limited.

SUGGESTIONS FOR FUTURE RESEARCH

Increased fieldwork in this region is recommended to further clarify the distribution and social significance of CRUS in the prehistoric Andes.

Valkyries: Was gender equality high in the Scandinavian periphery since Viking times? Evidence from enamel hypoplasia and height ratios

Scandinavian countries currently have very high values of female autonomy. Was this already the case in Viking Times? In this study, we trace the roots of gender equality in the Scandinavian periphery over the past two millennia. We evaluate and recommend a new measure of early gender equality: relative enamel hypoplasia values of males and females. This new indicator allows us to trace relative health and nutritional equality, using archaeological evidence. We find that Scandinavian women in the rural periphery already had relatively good health and nutritional values during the Viking era and the medieval period thereafter. The corresponding value is 0.8 equality advantage for Scandinavian women, whereas in the rest of Europe most values fall in a band around 1.2 ratio units. This suggests that the currently high gender equality had a precedence during the Middle Ages.

Influence of physiological stress on the presence of hypoplasia and fluctuating asymmetry in a medieval population from the village of Sypniewo

This study aims to estimate the levels of physiological stress in the medieval rural population of Sypniewo by evaluating patterns of fluctuating asymmetry (FA) and enamel hypoplasia (EH), and provide information on the influence of physiological stress during the prenatal and perinatal period on early childhood development. Stress is defined as any external or internal condition that challenges homeostasis of an organism. FA is associated with physiological stress occurring mainly during prenatal development and early childhood. The level of FA is thought to reflect the intensity of the stressor(s). EH is caused by physiological stress such as nutritional instability during the first years of life. The studied material consisted of 126 skulls from the village of Sypniewo (Poland). Cranial radiographs were taken in postero-anterior (P-A) and basal views. The images were scanned and calibrated. Measurements of the cranium were used to estimate FA. The presence of EH was assessed using standard anthropological methods The highest levels of FA were observed in the region of the cranial base. EH was observed in 29% of individuals from the rural skeletal series. There was no statistically significant correlation between FA and EH occurrence or between sex and the studied stress indicators.

Osteoarchaeological Studies of Human Systemic Stress of Early Urbanization in Late Shang at Anyang, China

Through the analysis of human skeletal remains and mortuary practice in Yinxu, this study investigates the impact of early urbanization on the commoners during the Late Shang dynasty (ca. 1250-1046 B.C.). A total of 347 individuals examined in this study represent non-elites who were recovered from two different burial contexts (formally buried in lineage cemeteries and randomly scattered in refuse pits). Frequencies of enamel hypoplasia (childhood stress), cribra orbitalia (childhood stress and frailty) and osteoperiostitis (adult stress) were examined to assess systemic stress exposure. Our results reveal that there was no significant difference in the frequency of enamel hypoplasia between two burial groups and between sexes, suggesting these urban commoners experienced similar stresses during childhood, but significantly elevated levels of cribra orbitalia and osteoperiostitis were observed in the refuse pit female cohort. Theoretically, urbanization would have resulted in increased population density in the urban centre, declining sanitary conditions, and increased risk of resource shortage. Biologically, children would be more vulnerable to such physiological disturbance; as a result, high percentages of enamel hypoplasia (80.9% overall) and cribra orbitalia (30.3% overall) are observed in Yin commoners. Adults continued to suffer from stress, resulting in high frequencies of osteoperiostitis (40.0% total adults); in particular, in the refuse pit females who may also reflect a compound impact of gender inequality. Our data show that the non-elite urban population in the capital city of Late Shang Dynasty had experienced extensive stress exposure due to early urbanization with further social stratification only worsening the situation, and eventually contributing to collapse of the Shang Dynasty.

Forensic odontological examination of a 1500 year-old human remain in ancient Korea (Gaya)

Forensic odontological examination was performed on one of the 1500-year old human remains of ancient Korea (Gaya) excavated from a burial site at Songhyeon-dong, Changnyeong, South Korea in April, 2008. The main purpose of the examination was to age estimate the remains and record any dental characteristics to aid full-body reconstruction and life history data collection. Oral and radiographic examinations and metric data collection were conducted. During the oral examination, the following observations were made: dental caries, semi-circular abrasion on the maxillary right lateral incisor and enamel hypoplasia on the left and right canines and first premolars in the mandible. The metric data was similar to that of average metric data of modern Koreans. Age estimation was initially conducted using the degree of dental attrition with methods of Takei and Yun, and was estimated to be approximately 40 years. However, it was observed in the radiographic examination, that the maxillary right second molar, together with the mandibular left and right second and third molars had incompletely developed root apices. The age estimation was then performed using the developmental status of the lower second and third molars. The age was estimated to be approximately 16 years using Lee's method which was consistent with the estimation using forensic anthropology. This case study highlights that the degree of attrition should not be used as a sole indicator for age estimation.

Health status among prehistoric Eskimos from Point Hope, Alaska

Using the protocol outlined in The Backbone of History: Health and Nutrition in the Western Hemisphere (BBH) (Steckel and Rose. 2002a. The backbone of history: health and nutrition in the Western Hemisphere. Cambridge: Cambridge University Press), this project compares the Mark I Health Index (MIHI) scores of the Ipiutak (n = 76; 100BCE-500CE) and Tigara (n = 298; 1200-1700CE), two samples of North American Arctic Eskimos excavated from Point Hope, Alaska. Macroscopic examination of skeletal remains for evidence of anemia, linear enamel hypoplasias (LEH), infection, trauma, dental health, and degenerative joint disease (DJD) was conducted to assess differences in health status resulting from a major economic shift at Point Hope. These data demonstrate that despite differences in settlement pattern, economic system, and dietary composition, the MIHI scores for the Ipiutak (82.1) and Tigara (84.6) are essentially equal. However, their component scores differ considerably. The Ipiutak component scores are suggestive of increased prevalence of chronic metabolic and biomechanical stresses, represented by high prevalence of nonspecific infection and high frequencies of DJD in the hip/knee, thoracic vertebrae, and wrists. The Tigara experienced more acute stress, evidenced by higher prevalence of LEH and trauma. Comparison of overall health index scores with those published in BBH shows the MIHI score for the Ipiutak and Tigara falling just above the average for sites in the Western Hemisphere, adding support to the argument that the human capacity for cultural amelioration of environmental hardships is quite significant.

Oral and physiological paleohealth in cold adapted peoples: Northeast Asia, Hokkaido

This paper examines variables useful in reconstructing oral (caries, antemortem tooth loss, alveolar defects) and physiological (cribra orbitalia, linear enamel hypoplasia) well-being in two bioarchaeological assemblages from Hokkaido, Japan: Okhotsk (n = 37 individuals) and Jomon (n = 60). Findings are compared and contrasted with each other, with published series from Honshu Japan, and samples from climatically near-equivalent Alaska. It was found that more meaningful comparisons of Hokkaido paleohealth could be made with Alaskan material, rather than the more southerly Jomon. Results were ambiguous with respect to physiological well-being. Low levels of LEH in the cold-adapted samples suggest operating in arctic and subarctic environments with marine-based subsistence regimes is not physiologically expensive. However, the relatively high levels of cribra orbitalia in Hokkaido, relative to Alaska, suggest the picture is not straightforward: the reasons for elevated cribra orbitalia in Hokkaido are unclear. The subarctic and arctic samples formed three broadly similar groupings in terms of oral health profiles: (1) Aleuts and Eskimo; (2) Ipiutak and Tigara; (3) Hokkaido Jomon, Okhotsk, and Kodiak Island. Differences between these groupings could be explained with a combination of sample demographics and subsistence orientations. The extremely high frequency of caries in one sample, caribou hunting Ipiutak, may have been influenced by factors such as low levels of dietary magnesium and potentially cariogenic foodstuffs, such as preparations of caribou stomach contents. It was concluded that oral health profiles are potentially sensitive to differences in subsistence strategies among cold-adapted hunter-gatherers, although they lack predictive value.

Dental indicators of health and stress in early Egyptian and Nubian agriculturalists: A difficult transition and gradual recovery

Although agriculture is now the globally predominant mode of food production, studies of the skeletal remains of early agriculturalists have indicated high levels of physiological stress and poor health relative to hunter-gatherers in similar environments. Previous studies identifying this trend in different regions prompt further research of the causes and effects of subsistence transitions in human societies. Here, 242 dentitions from five ancient Egyptian and Nubian populations are examined: 38 individuals from Jebel Sahaba (Upper Paleolithic), 56 from Badari (Predynastic), 54 from Naqada (Predynastic), 47 from Tarkhan (Dynastic), and 47 from Kerma (Dynastic). These populations span the early period of agricultural intensification along the Nile valley. Skeletal remains were scored for the presence of linear enamel hypoplasia (LEH) of the dentition, an established indicator of physiological stress and growth interruption. The prevalence of LEH was highest in the "proto-agricultural" (pastoralist) Badari population, with a gradual decline throughout the late Predynastic and early Dynastic periods of state formation. This suggests that the period surrounding the emergence of early agriculture in the Nile valley was associated with high stress and poor health, but that the health of agriculturalists improved substantially with the increasing urbanization and trade that accompanied the formation of the Egyptian state. This evidence for poor health among proto- and early agriculturalists in the Nile valley supports theories that agricultural intensification occurred as a response to ecological or demographic pressure rather than simply as an innovation over an existing stable subsistence strategy.

Dietary variation and stress among prehistoric Jomon foragers from Japan

Current archaeological evidence indicates that greater dietary reliance on marine resources is recorded among the eastern Jomon, while plant dependence prevailed in western/inland Japan. The hypothesis that the dietary choices of the western/inland Jomon will be associated with greater systemic stress is tested by comparing carious tooth and enamel hypoplasia frequencies between the eastern and western/inland Jomon. Demographic collapse coincides with climate change during the Middle to Late Jomon period, suggesting dwindling resource availability. It is hypothesized that this change was associated with greater systemic stress and/or dietary change among the Middle to Late Jomon. This hypothesis is tested by comparing enamel hypoplasia and carious tooth frequencies between Middle to Late and Late to Final Jomon foragers. Enamel hypoplasia was significantly more prevalent among the western/inland Jomon. Such findings are consistent with archaeological studies that argue for greater plant consumption and stresses associated with seasonal resource depletion among the western/inland Jomon. Approximately equivalent enamel hypoplasia frequencies between Middle to Late and Late to Final Jomon foragers argues against a demographic collapse in association with diminished nutritional returns. Significant differences in carious tooth frequencies are, however, observed between Middle to Late and Late to Final Jomon foragers. These results suggest a subsistence shift during the Middle to Late Jomon period, perhaps in response to a changed climate. The overall patterns of stress documented by this study indicate wide-spread environmentally directed biological variation among the prehistoric Jomon.

Gross enamel hypoplasia in molars from subadults in a 16th-18th century London graveyard

Dental Enamel Hypoplasia has long been used as a common nonspecific stress indicator in teeth from archaeological samples. Most researchers report relatively minor linear and pitted hypoplastic defects on tooth crown surfaces. In this work we report a high prevalence and early age of onset of extensive enamel defects in deciduous and permanent molars in the subadults from the post-medieval cemetery of Broadgate, east central London. Analysis of the dentition of all 45 subadults from the cemetery, using both macroscopic and microscopic methods, reveals disturbed cusp patterns and pitted, abnormal and arrested enamel formation. Forty-one individuals from this group (93.2%) showed some evidence of enamel hypoplasia, 28 of them showing moderate or extensive lesions of molars, deciduous or permanent (63.6% of the sample). Scanning Electron Microscope images reveal many molars with grossly deformed cuspal architecture, multiple extra cusps and large areas of exposed Tomes' process pits, where the ameloblasts have abruptly ceased matrix production, well before normal completion. This indented, rough and poorly mineralized surface facilitates both bacterial adhesion and tooth wear, and when such teeth erupt fully into the mouth they are likely to wear and decay rapidly. We suggest that this complex combination of pitted and plane-form lesions, combined with disruption of cusp pattern and the formation of multiple small cusps, should henceforth be identified as "Cuspal Enamel Hypoplasia."

Health of infants in an Imperial Roman skeletal sample: Perspective from dental microstructure

This study examines general health in the first year of life of a population of 127 subadults from the Imperial Roman necropolis of Isola Sacra (2nd-3rd century ACE). Health status was determined by analyzing 274 deciduous teeth from these children for Wilson bands (also known as accentuated striae), microscopic defects caused by a disruption to normal enamel development arising from some generalized external stressor. While macroscopic enamel defects, or hypoplasias, have long been used as proxies of general population health, we believe that this is the first population-wide study of microscopic defects in deciduous teeth. We used microstructural markers of enamel to attach very precise chronologies to Wilson band formation that allowed us to calculate maximum prevalence (MAP) and smoothed maximum prevalence (SMAP) distributions to portray what we believe to be a realistic risk profile for a past population of children. There appear to be two periods of high prevalence, the first beginning around age 2 months and continuing through month 5, and the second higher period beginning around month 6 and continuing through month 9. These results are discussed in light of historical records of Roman childhood rearing practices.

Dental remains from the Grotte du Renne at Arcy-sur-Cure (Yonne)

Human remains associated with the earliest Upper Paleolithic industries are sparse. What is preserved is often fragmentary, making it difficult to accurately assign them to a particular species. For some time it has been generally accepted that Neandertals were responsible for the Châtelperronian and anatomically modern humans for the early Aurignacian industries. However, the recent re-dating of several of the more-complete modern human fossils associated with the early Aurignacian (e.g., Vogelherd) has led some to question the identity of the makers and the context of these early Upper Paleolithic industries. The Grotte du Renne at Arcy-sur-Cure, France has yielded many hominin remains, from Mousterian, Châtelperronian, Aurignacian, and Gravettian layers. Previously, a child's temporal bone from the Châtelperronian Layer Xb was recognized as belonging to a Neandertal; however, most of the teeth from Châtelperronian layers VIII-X remain unpublished. We describe the dental remains from the Châtelperronian layers, place them in a comparative (Mousterian Neandertal and Upper Paleolithic modern human) context, and evaluate their taxonomic status. The teeth (n = 29) represent a minimum of six individuals aged from birth to adult. The permanent dental sample (n = 15) from the Châtelperronian layers of Arcy-sur-Cure exhibits traits (e.g., lower molar mid-trigonid crest) that occur more frequently in Neandertals than in Upper Paleolithic modern humans. Furthermore, several teeth show trait combinations, including Cusp 6/mid-trigonid crest/anterior fovea in the lower second molar, that are rare or absent in Upper Paleolithic modern humans. The deciduous teeth (n = 14) significantly increase the sample of known deciduous hominin teeth and are more similar to Mousterian Neandertals from Europe and Asia than to Upper Paleolithic modern humans. Thus, the preponderance of dental evidence from the Grotte du Renne strongly supports that Neandertals were responsible for the Châtelperronian industry at Arcy-sur-Cure.

Hypoplastic enamel defects and environmental stress in a homogeneous Romano-British population

This study investigated hypoplastic enamel defects in a well-defined sample of Romano-Britons from the 3rd to the 5th century AD and compared the findings with a modern British sample investigated by the same authors. All 178 excavated skulls with intact dentitions were examined for hypoplastic defects using the Federation Dentaire International (FDI) Developmental Defects of Enamel Index criteria. Histopathological and microradiographic sections were prepared of 5 teeth. Hypoplastic defects were found in the teeth of 37% of skulls, with 25% having 4 or more teeth affected. The teeth most frequently involved were canines. Of the defects, 75% were horizontal grooves, 12.7% were pitting, and 7.1% were areas of missing enamel. The location of defects was 82% buccal, 16.5% lingual, and 1.2% occlusal. The reproducibility of diagnosis was 84%. Microscopic and microradiographic investigations showed areas of hypomineralization of enamel and wide zones of interglobular dentine related to the hypoplastic grooves. There was higher frequency, different morphology, and greater severity of hypoplastic enamel defects compared with the modern British sample. The defects may be related to repeated environmental stresses between the ages of 2 and 6 yr. Identified environmental stresses in these Romano-Britons, including high lead ingestion, poor nutrition, and recurrent infections, may be important etiological factors for the enamel defects.

[Life in imperial Rome: new data from recent excavations in Suburbium]

One of the goals of the anthropological research of the Anthropological Service of the Archaeological Superintendence of Rome is to reconstruct the hygienic-environmental living conditions of the ancient populations in Imperial Age. We considered some not specific pointers of stress in four necropolis, that are excavated in the last years in the Suburbium. In particular Harris's lines, porotic hyperostosis and enamel hypoplasia are been considered. Two shape of research have been lead: (a) an analysis of the frequencies of the three factors on the data from a single necropolis and (b) a comparison between enamel hypoplasia and porotic hyperostosis. The distributions of such alterations indicates the presence of light stresses.

Early childhood stress and adult age mortality—A study of dental enamel hypoplasia in the medieval Danish village of Tirup

This study explores how linear enamel hypoplasia (LEH) affects mortality in the village of Tirup (A.D. 1150-1350), Denmark. Data consist of information on 583 skeletons aged 1 year or more. Three partly overlapping subsamples were defined. (1) 104 skeletons of young children aged 1-6 years and 120 skeletons of adults giving information on LEH. (2) 458 skeletons aged 6 years or more. (3) 109 adult skeletons (aged 20 years or more) that provided transition analysis age estimates, sex assessments, and LEH information. Of the 109 skeletons in Subsample 3, 60 had no and 49 had at least one LEH. In Subsample 1, it was found that the case fatality rate for episodes potentially leading to LEH dropped from over 0.5 in 1-year olds to around 0.1 in 3-5-year olds. Only models with heterogeneity of frailty could describe late childhood and adolescent mortality. Further, it was shown that only a model with continuously varying frailty preserved heterogeneity to adulthood. Among young adult females and males in all adult ages, people with LEH experienced a higher mortality than people without it. Among males, the mortality rate ratio (MRR) was 2.28. The analyses indicate that the MRR gives an unbiased estimate for the extra risk of dying for adult males with LEH. The values of the case fatality rates for young children might be slightly biased upward because of a higher than average number of older children and adolescents dying with LEH.

Health of the non-elites at Tombos: Nutritional and disease stress in New Kingdom Nubia

During the New Kingdom period, Egypt succeeded in occupying most of Nubia. Colonial towns were built, which served as centers of government and redistribution. This paper uses a bioarchaeological approach to address the effects of this cultural contact on non-elites. Skeletal remains from the site of Tombos (N = 100), a cemetery in Upper Nubia dating to this important time, are analyzed, in addition to 1,082 individuals from contemporaneous Egyptian and Nubian sites, in order to shed light on the social, political, and economic processes at play and to determine how the people at Tombos were affected during this transitional period. In many ways, the Tombos population appears to have been affected by similar stressors as the other populations under study. However, a few small differences in the subadult frequencies of pathological lesions, especially remodeling rates, are significant in the overall picture of health at Tombos. These analyses suggest that, although the people of Tombos may have been integrated into the Egyptian colonial network, the additional resources they may have obtained could not protect them from nutritional and disease stress. A lower childhood survival through bouts of ill health at Tombos is suggested. While status may have played a role in the differences seen in the comparative populations, it is likely that parasites and/or other infections led to childhood illness and death.

Linear enamel hypoplasias as indicators of systemic physiological stress: evidence from two known age-at-death and sex populations from postmedieval London

Enamel hypoplasias are useful indicators of systemic growth disturbances during childhood, and are routinely used to investigate patterns of morbidity and mortality in past populations. This study examined the pattern of linear enamel hypoplasias in two different burial populations from 18th and 19th Century church crypts in London. Linear enamel hypoplasias on the permanent dentitions of individuals from the crypt of Christ Church, Spitalfields, were compared to enamel defects on the teeth of individuals from St. Bride's. The method used involves the identification of enamel defects at a microscopic level, and systemic perturbations are detected by matching hypoplasias among different tooth classes within each individual. The pattern of linear enamel hypoplasias was contrasted between individuals from the burial sites of Spitalfields and St. Bride's, between males and females, and between those aged less than 20 years of age and those aged over 20 years at death. Six different parameters were examined: frequency of linear enamel hypoplasias, interval between defects, duration of hypoplasias, age at first occurrence of hypoplasia, age at last occurrence of hypoplasia, and the percentage of enamel formation time taken up by growth disturbances. All individuals in the study displayed linear enamel hypoplasias, with up to 33% of total visible enamel formation time affected by growth disruptions. Multiple regression analysis indicated a number of significant differences in the pattern of enamel hypoplasias. Individuals from Spitalfields had shorter intervals between defects and greater percentages of enamel formation time affected by growth disturbances than did individuals from St. Bride's. Females had greater numbers of linear enamel hypoplasias, shorter intervals between defects, and greater percentages of enamel formation time affected by growth disturbances than males. There were also differences in the pattern of enamel hypoplasias and age at death in this study. Individuals who died younger in life had an earlier age at first occurrence of enamel hypoplasia than those who survived to an older age. The pattern of enamel hypoplasias detected in this study was influenced by tooth crown geometry and tooth wear such that most defects were found in the midcrown and cervical regions of the teeth, and greater numbers of defects were identified on the anterior teeth. Differences in sensitivity of the parameters used for the detection of enamel hypoplasias were found in this study. The percentage of visible enamel formation time affected by growth disturbances was the parameter that identified the greatest number of significant differences among the subgroups examined.

Linear enamel hypoplasia and historical change in a central Australian community

BACKGROUND

The current study extends the use of linear enamel hypoplasia (LEH) to examine the historical changes in living conditions encountered by Aboriginal people at Yuendumu who were born between 1890 and 1960. LEH provides health information beyond written records and gives information beyond written records and gives insight into the relationship between individual health and living conditions during initial and ongoing contact with Europeans.

MATERIALS AND METHODS

The dental casts of 446 people, collected as part of the University of Adelaide longitudinal study of growth and development, were recorded for the presence of hypoplastic defects. Defects were recorded according to the Development Defects of the Enamel (DDE) standards and assigned to developmental units based on their crown position.

RESULTS

The frequency of LEH on the permanent dentitions increased five-fold from the 1890-1929 birth cohort to the 1955-1960 cohort. LEH also affected earlier developing enamel units. Deciduous defects did not show a strong temporal trend but overall prevalence was comparable to other disadvantaged groups.

CONCLUSION

The changes in permanent LEH frequency and age distribution correspond to altered living conditions with the worst hypoplasia recorded after settlement of Aboriginal people at Yuendumu. Prior to that period LEH was comparable to precontact Australian populations indicating that resettlement had a dramatic impact on childhood morbidity.

Invisible impacts but long-term consequences: Hypoplasia and contact in central Australia

The dental casts taken of Aboriginal people resident at Yuendumu, Central Australia, between 1950-1970 preserve a unique historical record of defects of the dental enamel (DDEs) among people born from 1890-1960 (n = 377). These data are used, in comparison with precontact data, to trace the chronological changes in childhood development that occurred among Aboriginal people from the point of initial engagement with white settlers to a period of overwhelming government control. The results demonstrate very little change in the frequency of DDE from the precontact period to 1929 but increases after that time, particularly after the forcible settlement of people on a government establishment at Yuendumu in 1946. Apart from the absolute increase in frequency, it is also clear that population variation decreased markedly, with growing numbers of children experiencing multiple defects in early childhood (ca. 0.8-1.5 years of age). The results also indicate that an early onset of DDE constituted a risk for further episodes. These changes in DDE correspond to periods of increasingly intense contact between Aboriginal people and Europeans and with changes to government policy aimed at assimilating the indigenous population. Such policies had marked costs for childhood development. The lack, however, of a visible marker of initial contact demonstrates the importance of the intensity of and motives behind interactions between indigenous and colonial populations in determining the health consequences of colonial encounters.

Leprosy and mortality in the Medieval Danish village of Tirup

Leprosy was a well-recognized and dreaded disease in Denmark in the Middle Ages (AD 1000-1536). A large fraction of the population was affected by leprosy in the 13th century. This paper analyzes the correlation between signs of leprosy and risk of dying in the small Danish village of Tirup (AD 1150-1350). Seven different dichotomous osteological lesions indicative of leprosy are analyzed, and it is possible to score at least one of these conditions on 135 skeletons of adult or adolescent people (aged 14 or more). Scores were transformed to a statistic, lambda, indicating the likelihood that the person to whom the skeleton belonged suffered from leprosy. The analyses indicate that the prevalence of leprosy among adult people in Tirup was 26% (95% confidence interval, 17-35%). The lambda statistic indicates that people who died with signs of leprosy did not differ in the distribution of age at death from those who did not have such signs. Skeletons showing dental enamel hypoplasia were less likely to come from skeletons with high lambda-values. The association between lambda and dental enamel hypoplasia indicates a relationship between stress in early childhood (ages 1-6 years) and subsequent development of signs of leprosy.

Exploring the relationship between hypoplasia and odontometric asymmetry in Isola Sacra, an imperial roman necropolis

Anthropological studies reporting odontometric asymmetry values or dental enamel hypoplasia frequencies use these markers as a record of physiological perturbations occurring during dental development. While both markers indirectly suggest the amount of relative stress a population might have experienced, a relationship between the two has been explored only recently in the literature. In this study, we address the possibility of such a relationship in two ways. First, Kendall's tau B correlations test the degree of relationship on the level of the individual between hypoplasia presence/absence (P/A) and severity of hypoplasia appearance (PS) data for the anterior dentition and directional (DA) and fluctuating asymmetry (FA) data for concurrently developing molars pairs. Second, an F-test explores between-group (ranked hypoplastic individuals and non-hypoplastic individuals) variance about the mean, expecting the hypoplastic individuals to be more variable. The sample consists of 72 individuals from the Isola Sacra necropolis, which is associated with Portus, the port city of ancient Rome. Results indicated only a very weak predictive relationship between some variables and few significant differences in variation. However, variance follows trends in published literature. Possible explanations for the lack of interaction on the level of the individual include both etiological and genetic susceptibility factors that are significant in and of themselves as they suggest a more complex reading of the hard tissue evidence for stress in archaeological populations.

Enamel hypoplasias and physiological stress in the Sima de los Huesos Middle Pleistocene hominins

This study presents an analysis of linear enamel hypoplasias (LEH) and plane-form defects (PFD) in the hominine dental sample from the Sima de los Huesos (SH) Middle Pleistocene site in Atapuerca (Spain). The SH sample comprises 475 teeth, 467 permanent and 8 deciduous, belonging to a minimum of 28 individuals. The method for recording PFD and LEH is discussed, as well as the definition of LEH. The prevalence of LEH and PFD in SH permanent dentition (unilateral total count) is 4.6% (13/280). Only one deciduous tooth (lower dc) showed an enamel disruption. Prevalence by individual ranges from 18.7-30%. The most likely explanation for the relatively low LEH and PFD prevalence in the SH sample suggests that the SH population exhibited a low level of developmental stress. The age at occurrence of LEH and PFD was determined by counting the number of perikymata between each lesion and the cervix of the tooth. Assuming a periodicity of nine days for the incremental lines, the majority of LEH in the SH sample occurred during the third year of life and may be related to the metabolic stress associated with weaning.

Prevalence and the duration of linear enamel hypoplasia: a comparative study of Neandertals and Inuit foragers

As a dental indicator of generalized physiological stress, enamel hypoplasia has been the subject of several Neandertal studies. While previous studies generally have found high frequencies of enamel hypoplasia in Neandertals, the significance of this finding varies with frequencies of enamel hypoplasia in comparative samples. The present investigation was undertaken to ascertain if the enamel hypoplasia evidence in Neandertals suggests a high level of physiological stress relative to a modern human foraging group, represented here by an archaeological sample of Inuit from Point Hope, Alaska. Unlike previous studies, this study focused specifically on linear enamel hypoplasia (LEH), emphasizing systemic over localized causes of this defect by considering LEH to be present in an individual only if LEH defects occur on two anterior teeth with overlapping crown formation periods. Moreover, this study is the first to evaluate the average growth disruption duration represented by these defects in Neandertals and a comparative foraging group. In the prevalence analysis, 7/18 Neandertal individuals (from Krapina and southern France) and 21/56 Neandertal anterior teeth were affected by LEH, or 38.9% and 37.5% respectively. These values do not differ significantly from those of the Inuit sample in which 8/21, or 38.1% of individuals, and 32/111, or 28.8% of anterior teeth were affected. For the growth disruption duration analysis, 22 defects representing separate episodes of growth disruption in Neandertals were compared with 22 defects in the Inuit group using three indicators of duration: the number of perikymata (growth increments) in the occlusal walls of LEH defects, the total number of perikymata within them, and defect width. Only one indicator, the total number of perikymata within defects, differed significantly between the Inuit and Neandertal groups (an average of 13.4 vs. 7.3 perikymata), suggesting that if there is any difference between them, the Inuit defects may actually represent longer growth disruptions than the Neandertal defects. Thus, while stress indicators other than linear enamel hypoplasia may eventually show that Neandertal populations were more stressed than those of modern foragers, the evidence from linear enamel hypoplasia does not lend support to this idea.

[Cribra orbitalia, dentin hypoplasia and life expectancy of 20-year-old persons as social and sex specific stress indicators in correlation with the health status of an early medieval population]

The aim of this study is based on the analysis of diachronically social and sexual specific considerations on the life situation of the early medieval population of Schleitheim, Kanton Schaffhausen, Switzerland. Cribra orbitalia and the linear enamel hypoplasia of the teeth are considered as stressors. This study is based on the life expectancy of the 20 years old, as the life expectancy gives information on the health condition of a social group or an entire population. The considered indicators show the same tendencies in three of the four social groups (women social group A and group B/C, men of the social group A). The female and male population of the social group A show a steady decrease in the indicator from the 5th century to come to its lowest level in the 7th century. The same parameters indicate a continuous increase in stress for the female population of the group B/C. Only one of the three indicators, the Cribra orbitalia, shows a positive tendency in the male population of the social group B/C from the 6th century to the following period, while hypoplasia and the life expectancy on the other hand indicate a negative tendency. The results show equal tendencies in the three independent indicators concerning three of the four social groups. This proves the high reliability of the indicators. These results are astonishing in two ways. First of all, the tendencies show that the originally better life situation of women of the higher ranking social group decreases in the following periods, whereas the women of the lower social group show an inverse development. This female population of low life situation in the 5th century shows an increase in life qualities in the following periods. Remarkable, too, is the fact, that the female population of both social groups shows a lower level of stress than the corresponding male population. This fact is astonishing, as we would expect inverse results in a patriarchal society. This may point to a well known fact: Women show a higher vitality than the male population.

Enamel hypoplasia in a pliocene hominid from Chad

Abel is the first Australopithecine known west of the East African Rift Valley. The fossil finds include a perisymphyseal fragment of an adult mandible with well-preserved crowns of the right I2-P4 and the left C-P4. Abel's dentition displays many enamel defects, which are described in detail for each tooth. Pitting affected every tooth, while larger, shallow depressions were observed on the canines alone. From two to four pit bands occurred on the different teeth, each resulting from a separate hypoplastic episode. In modern humans, a large number of causes, both environmental and genetic, have been suggested for such enamel defects. It seems probable that Abel's pathology was systemic. However, the occurrence of a number of bands and the variable intensity of the attacks make it difficult to say whether there was a single, repetitive cause or different etiologies. Possible causes discussed here include recurrent fevers and seasonal nutritional deficiencies.

Brief communication: diachronic investigation of linear enamel hypoplasia in prehistoric skeletal samples from Trentino, Italy

Linear enamel hypoplasia was scored on Neolithic, Copper Age, and Early Bronze Age samples from the Trentino region, Italy, in order to compare the extent of growth disruption in different biocultural subsistence systems (foragers with little agriculture, to agriculturists and agropastoralists). The Early Bronze Age sample shows a higher frequency of enamel defects and an earlier chronological onset than the early Neolithic sample. The higher frequency of defects in the Bronze Age sample could be linked to less diversified nutrition and, because of increased sedentism, a higher risk of disease.

Temporal trends in demographic profiles and stress levels in medieval (6th-13th century) population samples from continental Croatia

AIM

To analyze and compare the demographic profiles and disease frequencies of early (6th-9th century) and late (10th-13th century) medieval skeletal series from continental Croatia.

METHODS

Age and sex distributions in three early (n=277) and six late (n=175) medieval skeletal series were compared. All skeletons were analyzed for the presence of dental enamel hypoplasia, periostitis, trauma, and presence of Schmorl s depressions in vertebral bodies.

RESULTS

Data collected from the skeletal series suggested significantly higher stress in the late medieval period. This stress may have affected mortality, as evidenced by significantly higher subadult mortality and shorter adult average life span. Men in the late medieval series, in particular, seem to have been under greater stress. They exhibited significantly higher mortality in the 21-25 years age category, and significantly higher frequencies of periosteal lesions, cranial and postcranial trauma, and Schmorl s depressions.

CONCLUSION

The frequencies of all skeletal indicators of stress increased significantly during the late medieval period. This was accompanied by a significant increase in subadult mortality and shortening of the average life span of adult men and women.

[Classification of a 300,000-year-old dental crown of the upper loamy deposit of the Bad Canstatter travertine zone]

Hominid dental remains were recovered in association with fossil bones and artifacts during systematic excavations in a loamy deposit located between the two travertine zones T4 and T5 at Stuttgart-Bad Cannstatt, Southwest Germany. Direct dating of a hominid tooth crown with thermoluminescence resulted in a date of 300 kya, which is in agreement with the Holstein Interglacial floral and faunal composition of this layer. The specimen is a lower left canine with hypoplastic morphology. This interpretation is supported by thorough assessment of its overall morphology, comparative metric evaluation, and by scanning electron microscopy analyses of the enamel prisms. Additional microstructural comparison of these dental remains with a tooth from the same site, but derived from a Cervidae specimen supported the distinct differences between both teeth. Here we discuss both the classification and significance of the specimen's evolutionary position as well as compare this specimen with stomatologic results from previous palaeopathological research.

A detailed study of enamel hypoplasia in a post-medieval adolescent of known age and sex

Developmental disturbances that affect the secretion of enamel matrix can cause defective enamel structure. Linear hypoplasia is one type of enamel defect and manifests itself as a furrow that runs around the circumference of the tooth. Such defects range in size from the microscopic to those that are several millimetres wide. Enamel defects have been widely used by anthropologists for the investigation of growth disruptions in past populations, as they provide a permanent record of disturbances during much of a child's developmental period. This is a detailed case study of enamel growth disruptions in a 15-year-old female from the 18th and 19th century crypt of Christ Church, Spitalfields. The method used relates linear enamel hypoplasia to the incremental structures in the enamel surface, the perikymata, in order to investigate the timing of growth disturbances. Linear enamel hypoplasia was defined here as a greater than expected spacing between neighbouring pairs of perikymata. In addition, this study used recently published histological data on the precise timing of tooth development to establish chronologies for growth disruptions. Defects were matched in at least two teeth with overlapping developmental schedules to ensure that systemic disturbances, as opposed to localised traumas, were identified. Thirteen enamel defects were matched between five different teeth from the same individual from Spitalfields. Most linear enamel hypoplasias were evident on the anterior dentition. Using an 8-day average perikymata periodicity, the age at first defect in this individual was calculated as 1.5 years and the last growth disruption occurred when she was 4.6 years of age. The distribution of the defects was examined to identify any seasonal pattern in the occurrence of the growth disturbances.

Epidemiology of enamel hypoplasia in deciduous teeth: explaining variation in prevalence in western India

This study is based on seven samples of school children (n = 516) from rural (five groups) and urban (two groups) settings in western Maharashtra, India. Height and weight were recorded for each subject. Intra-oral observation of the labial surface of maxillary and mandibular anterior teeth was conducted with a low power (3x) illuminated hand lens. Presence of enamel hypoplasia was recorded on a dental chart by drawing the size and location of the defect on the affected tooth. Data analysis was conducted in two stages: 1) Enamel hypoplasia (EH) prevalence was analyzed by percentage of teeth and by percentage of individuals affected for the composite sample and independently for each study group and 2) an assessment of the relationship between anthropometric variables (height and weight), socio-economic status (SES), and localized hypoplasia of primary canines (LHPC; Skinner, 1986) was evaluated using multiple linear regression analysis. EH was observed less often in deciduous incisors (0.2% in di(2) to 2.5% in di(2)) than in deciduous canines (dc). Mandibular dc were affected with the greatest frequency (23.1%, tooth count). The overall individual count prevalence of dc hypoplasia (LHPC) is 26.2% (134/511) for all village samples and sexes combined. Difference in LHPC frequency by sex is non-significant, with males (24.7%, 70/284) and females (28.2%, 64/227) exhibiting nearly equal values. Significant inter-group variation in LHPC prevalence was documented among the seven groups, and the range of LHPC prevalence the among living groups exceeds variability in LHPC among four prehistoric Chalcolithic skeletal series of the Deccan Plateau. Multiple regression analysis revealed no significant relationship between height-for-age or weight-for-age in four school samples (two urban/two rural), but a significant association between stature and LHPC was found for three rural endogamous groups. Children with LHPC were significantly shorter by 1.5 cm than children who lacked the defect after controlling for differences in age. While the association between low birth weight and EH is strong and well documented clinically, the association between childhood stature and LHPC is more variable across groups and may reflect inter-group variation in the duration and intensity of environmental stress.

Diachronic patterns of dental hypoplasias and vault porosities during the predynastic in the Naqada region, Upper Egypt

The diachronic pattern of the frequencies of linear enamel hypoplasias and porotic hyperostosis was studied in temporally separated samples of adult predynastic Egyptian remains from the Naqada region, Upper Egypt. The samples covered a period of increasing population density and social complexity as well as decreasing Nile flooding in Egypt. First and second molars were evaluated for hypoplasias in material from the Naqada I, II, and III periods; sample sizes were 13, 30, and 25, respectively, for the first molar, and 11, 28, and 24 for the second molar. Cranial vaults were examined for porotic hyperostosis using several approaches; sample sizes were 26, 66, and 51 for Naqada I, II and III, respectively. Linear regression showed a decreasing trend for several variables: for the individual frequency of first molar hypoplasias (rho = 0.025), the vault porosity score, which indicates the severity of the lesions (rho < 0.001), and the extent score, which indicates the number of superior vault bones having porosities (rho < 0.001). Logistic regression showed a temporal decline in the percentage of crania per sample having any vault porosities and only higher grade lesions (rho < 0.012 and rho < 0.003, respectively). Lesions of the second molar showed no directional trend. The results contrast with the common observation that these skeletal markers usually increase in contexts of increasing population density and social complexity.

Body proportions in a medieval village population: effects of early childhood episodes of ill health

The purpose of this paper is to widen the observational basis for analysing growth patterns. To reach this aim measurements taken on skeletons from a small Danish village, Tirup, are analysed in relation to evidence for ill health in early childhood (age 1-6 years, inclusive). Enamel hypoplasia is taken as the indicator of health problems in this age range. It is found that episodes of ill health in childhood played no part in the formation of adult size. In order to analyse size independent aspects of adult morphology shape related variables like residual height and principal component scores were analysed. It is found that the episodes of ill health leading to hypoplasia did indeed change the score on some size independent linear combinations of the raw measurements. It is concluded that the kind of stress in childhood leading to enamel hypoplasia probably modified the relationship between long bone lengths and stature. It appears that the association between vertebral body breadth measurements and living height is--at least in part--brought about by episodes of ill health in early childhood.

Subadult stress, morbidity, and longevity in Latte Period populations on Guam, Mariana Islands

The frequency and age distribution of linear enamel hypoplasia (LEH) in the dentition of 293 individuals from Latte Period sites (AD 800-1521) on Guam, Mariana Islands, are examined in this study. Individuals dying as subadults (before age 16) and as young adults (ages 16-21) have more frequent LEHs than those who survived to middle or late adulthood, documenting a relationship between LEH-causing stress events and reduced life expectancy. The age distributions of cribra orbitalia and skeletal infection in children who died by age 10 exhibit striking similarities to the etiological age patterns of LEH in children, and those with skeletal infection have more frequent hypoplasias than children without infection. The comorbidity of systemic stress and infection in children, and their impact on life expectancy, are interpreted in the biocultural context of high population density in the large coastal villages of the late prehistoric period in the Marianas.

Intertooth patterns of hypoplasia expression: implications for childhood health in the classic Maya collapse

Enamel hypoplasias, which record interacting stresses of nutrition and illness during the period of tooth formation, are a key tool in the study of childhood health in prehistory. But interpretation of the age of peak morbidity is complicated by differences in susceptibility to stress both between tooth positions and within a single tooth. Here, hypoplasias are used to evaluate the prevailing ecological model for the collapse of Classic Period Lowland Maya civilization, circa AD 900. Hypoplasias were recorded in the full dentition of 160 adult skeletons from six archaeological sites in the Pasion River region of Guatemala. Instead of constructing a composite scale of stress experience, teeth are considered separately by position in the analysis. No statistical differences are found in the proportion of teeth affected by hypoplasia between "Early," Late Classic, and Terminal Classic Periods for anterior teeth considered to be most susceptible to stress, indicating stability in the overall stress loads affecting children of the three chronological periods. However, hypoplasia trends in posterior teeth may imply a change in the ontogenetic-timing of more severe stress episodes during the final occupation and perhaps herald a shift in child-care practices. These results provide little support for the ecological model of collapse but do call to attention the potential of posterior teeth to reveal subtle changes in childhood morbidity when consideredindividually.

Environmental causes of enamel defects

A large number of causes of enamel defects, both environmental and genetic, have been described. However, many of these are derived from case histories and studies of individual conditions. What is needed now is a systematic investigation of the problem. The first requirement in exploring the aetiology further is the standardization of both the clinical diagnosis and the descriptive terminology. This has been provided by the Fédération Dentaire Internationale Developmental Defects of Enamel Index. Comparing studies using standardized methods, including this index, has highlighted areas for closer investigation. The total prevalence of enamel defects in a population needs to be established as a baseline for studies on aetiology. Sixty-eight per cent of 1518 school children in London have enamel defects in the permanent dentition, with 10.5% having 10 or more teeth affected and 14.6% having hypoplasia, i.e. missing enamel. These findings are in contrast to the 37% with hypoplasia found in a group of third to fifth century Romano-Britons from Dorset, England, suggesting further consideration of possible environmental and genetic differences between the two populations. An overall long-term study of dental development in low birth weight children has shown significantly more (P < 0.001) enamel defects related to major health problems during the neonatal period. By using standardized, reproducible criteria in prevalence studies to gain an overview of the problem and then studying specific groups or conditions, it is possible to identify general and specific factors in the aetiology of enamel defects and investigate further the varying role of genetic and environmental effects.

Frequency and chronological distribution of linear enamel hypoplasia in a North American colonial skeletal sample

A skeletal sample of 44 individuals born and raised in early 18th century frontier settlements of Northeastern United States is examined for the frequency and chronological distribution of linear enamel hypoplasia (LEH) on the maxillary and mandibular incisors and canines. The prevalence of LEH ranged from 31% on the I2 to 66% on the mandibular C and the mean number of defects ranged from .59 on the I2 to 1.08 on the mandibular C. These frequencies were generally lower than those reported for two later samples; the Monroe County Poorhouse sample and the Hammon-Todd sample. Individuals in these latter two samples were derived from the lowest socioeconomic stratum of their respective populations. Frequency differences are explained within the context of the changing availability of resources that resulted from the rise of industrialization, urbanization, and wage labor which took place during the 18th and 19th centuries. The frequency of LEH was low prior to 1.5 years of age and may result from attrition and/or decreased susceptibility in the relevant area of the crown or from low morbidity or high mortality. Peak frequencies are observed in all age categories ranging from 2.5 to 3.0 years up to 4.0 to 4.5 years and are too late to result from weaning. Instead, they may reflect the susceptibility of nonimmune children to diseases that were common in colonial North America. As the majority of these diseases were not fatal, most victims who survived may have had one or more LEHs as visible proof of their earlier encounter(s).

Hypoplastic area method for analyzing dental enamel hypoplasia

Most analyses of dental enamel hypoplasia compare frequencies of disturbed tooth types, which do not account for variability in the area of affected enamel. An alternate methodology, hypoplastic area, is presented here that accounts for this variability by combining acute and continuous enamel hypoplasia into an interval-level variable. The method compares samples based on individuals, by multiple tooth type variables, or by a single value rather than by tooth types. Use of the hypoplastic area method is illustrated by analyzing human skeletal dentitions in three archaeological samples: Meroitic Nubians from Semna South, Sudan; Anasazi from Navajo Reservoir, New Mexico; and Mogollon from Grasshopper Pueblo, Arizona. Both univariate and multivariate statistical tests are employed to assess variation in defects between individuals and samples. By incorporating measurements of continuous defects, the hypoplastic area method provides information beyond that of frequency data in comparing levels of stress. Flexibility of the method is also discussed.

Frequency and chronological distribution of dental enamel hypoplasia in enslaved African Americans: a test of the weaning hypothesis

The dentition of 27 enslaved African Americans from archaeological sites in Maryland and Virginia were examined. All 17 males and 7 of the 10 females in this study exhibited enamel hypoplastic defects indicative of systemic nutritional and disease stresses interfering with amelogenesis. Estimates of the ages of occurrence of these defects show that most occur between 1.5 and 4.5 years of age, 0.5-3.75 years later than historically documented weaning age (9-12 months of age) in similar plantation populations. Comparisons are made with studies of dental enamel hypoplasia in contemporaneous enslaved and free African American populations, including our data on 75 individuals from the First African Baptist Church cemetery in Philadelphia. These populations were highly stressed. While there appears to be a modest effect of early weaning stress, no direct relationship of peak frequencies to weaning age can be shown. These data raise questions about the attribution of peak hypoplasia frequencies to age at weaning or "post-weaning" stresses in previous paleopathological studies. High hypoplasia frequencies during the middle years of enamel development are more likely the result of a combination of 1) multiple environmental stresses, 2) differences in hypoplastic susceptibility in enamel, and 3) random factors.

Enamel hypoplasia and age at weaning in 19th-century Florence, Italy

A sample representing a population of the Florence district of middle 19th century was studied to determine the age of occurrence of enamel hypoplasias. The age interval most affected was that between 1.5 and 3.5 years. Historical sources on weaning habits of 19th-century Italian populations indicate a weaning period between 12 and 18 months. This is in agreement with the data on enamel defects, showing that children of post-weaning age are more subject to stress. Wide "grooves", with prolonged duration, are concentrated between 2 and 2.5 years, whereas "lines" occur primarily between 2.5 and 3 years. We suggest that this distribution could reflect the gradual introduction of dietary supplements until weaning is complete.

Enamel hypoplasias in a 19th century population from northern Italy

In a sample from northern Italy of the second half of the 19th century hypoplasias in maxillary and mandibular anterior teeth was examined. The maxillary canine is the most frequently affected tooth. Frequencies of hypoplasias show slightly lower figures than other 19th century skeletal populations. The age interval most affected was between 2 and 4 years and suggests an association with stress at weaning and immediately thereafter.

Mechanical surface analysis of bone: a case study of cut marks and enamel hypoplasia on a Neolithic cranium from Sweden

A method for measuring, recording, and studying fine surface irregularities in three dimensions is presented. The method, which involves recording the movements of a diamond-tipped stylus as it scans the surface being studied, is demonstrated on a Neolithic cranium from Sweden. The cranium emanates from a pile dwelling dated to about 3000 B.C. Its frontal bone exhibits distinct cut marks indicative of scalping, and the teeth show signs of enamel hypoplasia. The surface topography of the putative cut marks and hypoplastic enamel were investigated using the stylus method. Measurements of enamel hypoplasia were also carried out for comparison on a front tooth from the lower jaw, and the cut mark study was compared with scanning electron micrographs. The results of this case study demonstrate that the stylus method can obtain high-resolution measurements of fine surface details directly on the original bone without preparation of or damage to the specimen.

Patterns of enamel hypoplasia in two medieval populations from Nubia's Batn el Hajar

Analysis of enamel hypoplasia frequencies for two medieval populations representing the earliest and latest Christian periods of ancient Nubia reveals important diachronic shifts in childhood stress. The mean frequency for hypoplastic bands among the early Christians is 4.2, while the late Christian sample has a mean frequency of 3.7. In addition, the earlier Christians show a prolongation of hypoplastic occurrences through childhood corresponding to a prolonged period of intensified childhood mortality. The modal time interval between hypoplastic occurrences is also shorter for the early Christian children. A comparison of hypoplasia frequencies by sex also reveals a pattern of considerable interest. Females show both lower frequencies of hypoplasias as well as a delay in onset. The diachronic differences are consistent with other indications from paleopathology and paleodemography that childhood stress decreased in later Christian times. The sex differences suggest that during the infancy and early childhood females were more resilient than their male counterparts.