Assessing weaning stress - Relations between enamel hypoplasia, δ18O and δ13C values in human teeth obtained from early modern cemeteries in Wroclaw, Poland.

OBJECTIVES: The aim of this paper is to assess linear enamel hypoplasia (LEH) on canines of adults from early modern Wroclaw cemeteries to compare δ13C and δ18O values in enamel formed before, during and after LEH formation, and to attempt to find a link between the selected indicators of the weaning process. MATERIAL AND METHODS: 15 permanent canines with visible LEH were selected for analysis. Age at LEH formation was estimated using the Reid and Dean method. The perikymata count was used to estimate the duration of LEH formation. Incremental stable oxygen and carbon isotopes analysis was performed on tooth enamel to infer stress related to weaning and dietary patterns. Kruskal-Wallis ANOVA, Mann-Whitney U test and Spearman correlation were used in statistical inference. RESULTS: The average age of LEH formation was 3.14 years, with an average duration of 111 days. Stable carbon isotope values consistently increase in 73% of the individuals sampled. The values of δ18O do not show a dominant pattern. The average value of δ13C increases over the time of enamel formation. The δ13C values collected below LEH were negatively correlated with δ18O values and the duration of LEH termination. CONCLUSIONS: Marking of carbon and oxygen isotopes indicates different stages of weaning. Advancements in diet change (determined by higher δ13C) corresponds with faster recovery after physiological stress episode. There is no evidence for different breastfeeding models between distinct parishes in early modern Wroclaw.

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.

Childhood health as reflected in adult urban and rural samples from medieval Denmark.

This study examines the evidence of three skeletal markers relating to childhood health that leave permanent observable changes in the adult skeleton. Two are well known to paleopathology, namely Harris lines (HL) and linear enamel hypoplasia (LEH). The third skeletal marker is less commonly used; the permanent changes in the temporal bones, induced by chronic or recurrent infectious middle ear disease (IMED) in childhood. A total of 291 adult skeletons from an urban (n = 109) and a rural (n = 182) cemetery, from the Danish medieval period (1050-1536 CE) were included. The markers were examined for their co-occurrence, and differences between the two samples. No statistically significant difference for the three skeletal markers between the two samples was found. A trend was nevertheless apparent, with greater frequencies for all three skeletal markers for the urban population. A statistically significant relationship was found only between IMED and HL. This positive relation was very low (rɸ = 0.307, 0.275) and may be considered non-existent. The lack of co-occurrence is interpreted as if an individual was exposed to conditions that could cause the osteological expression of all three markers this could be a life-threatening health condition, during developing years.

Stress, sex, and plague: Patterns of developmental stress and survival in pre- and post-Black Death London.

OBJECTIVES: Previous research revealed declines in survivorship in London before the Black Death (c. 1346-1353), and improvements in survivorship following the epidemic. These trends indicate that there were declines in general levels of health before the Black Death and improvements thereof afterwards. This study expands on previous research by examining whether changes in survivorship were consistent between the sexes, and how patterns of developmental stress markers changed before and after the Black Death. MATERIALS AND METHODS: This study uses samples from London cemeteries dated to one of three periods: Early Pre-Black Death (1000-1200 AD, n = 255), Late Pre-Black Death (1200-1250 AD, n = 247), or Post-Black Death (1350-1540 AD n = 329). Temporal trends in survivorship are assessed via Kaplan-Meier survival analysis, and trends in tibial length (as a proxy for stature) and linear enamel hypoplasia (LEH) are assessed using t-tests and Chi-square tests, respectively. RESULTS: Survivorship for both sexes decreased before the Black Death and increased afterwards. For males, LEH frequencies increased and stature decreased before the epidemic, and LEH declined and stature increased after the Black Death. For females, the only significant change with respect to developmental stress markers was a decrease in stature after the Black Death. CONCLUSIONS: These results might reflect variation between the sexes in sensitivity to stressors, the effects of nutrition on pubertal timing, disproportionate access to dietary resources for males in the aftermath of the Black Death, the disproportionate deaths of frail individuals during the epidemic, or some combination of these factors.

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.

Dental investigation of mummies from the Capuchin Catacombs of Palermo (circa 18th-19th century CE).

Within the framework of the Sicily Mummy Project, the orofacial complex of a significant sample of individuals (n=111) from the Capuchin Catacombs of Palermo, Italy, was inspected. The heads and dentitions of the mummies were documented and the recorded findings described: the state of preservation of skeletal and soft tissues; dental pathologies such as carious lesions and alveolar bone loss; enamel hypoplasia; and ante- and post-mortem tooth loss. Despite limitations in data collection, the oral health of these mummies was assessed and the frequencies of pathologies were compared to those of similar populations. From their position within the corridors of the Catacombs, sex and social status of the mummies were also inferred, allowing the dental pathologies to be specified in the social and historical context. Most interestingly, the rate of oral health problems did not differ between the groups of the members of the Capuchin Order and the laymen of the city of Palermo, despite their different lifestyles.

Analysis of human dentition from Early Bronze Age: 4000-year-old puzzle.

This paper presents the first ever paleodontological investigation of human remains from an archeological site in Central Europe dating from the Early Bronze Age and attributed to the Strzyzow Culture. It corroborates the knowledge gained from archeological, anthropological and genetical investigations. Our study aimed to assess dental status, dental morphology and dental pathologies as well as tooth wear and enamel hypoplasia based on visual inspection and stereomicroscopic investigation. The research was supported by CBCT imaging to obtain digital images and 3D reconstructions as well as 2D radiographs essential for dental age estimation. All of the 191 teeth discovered showed morphological similarity, with adult teeth showing similar color, shape and size. A maxillary molar presenting with a unique root morphology and a mandibular molar with a rare occlusal surface were found. Both permanent and deciduous dentition presented significant tooth wear. A few specimens displayed signs of dental caries, periapical pathology and antemortem tooth loss. Three individuals exhibited linear enamel hypoplasia. CBCT provided high-quality 2D images useful for dental age estimation by non-destructive methods. Estimated dental age correlated with the age estimated by other anthropological methods. In one case, this was crucial because of insufficient material for anthropological analysis. The presented studies have proved that besides the skeleton, teeth can be used as a fundamental tool in assessing the overall health and living conditions of paleopopulations. It would seem that there is potential for considerable development to be made in the research and investigation of paleodontological material using CBCT.

Disturbances and noise: Defining furrow-form enamel hypoplasia.

OBJECTIVES: The investigation of the record of growth locked in dental enamel provides a unique opportunity to build a comprehensive picture of growth disruption episodes during childhood. This study presents a new methodological basis for the analysis of enamel growth disruptions (enamel hypoplasia) using incremental microstructures of enamel. METHODS: A three-dimensional technique based upon use of an Alicona 3D Infinite Focus imaging microscope and software is used to record developmental features in the enamel of human permanent mandibular lateral incisors of one individual from the Neolithic site of Çatalhöyük (Turkey). Using this new technique, perikymata are measured down the longitudinal axis of the crown from the incisal margin to the cervix and perikyma spacing profiles are constructed with this new technique. A mathematical basis for the detection of spacing anomalies, which serve as indicators of enamel hypoplasia is presented based upon these profiles. RESULTS: Three clearly delineated defects were identified visually, then matched and confirmed metrically using the enamel surface and perikyma spacing profiles. DISCUSSION: Human growth has often been used as an indicator of health in past societies because of developmental sensitivity to fluctuations in nutritional status and disease load. Hence, standardization of furrow-form defect identification is of crucial importance for reducing the amount of current subjectivity in the determination of a threshold for the identification of defects among individuals of past populations. The method presented here, which is based on microscopic images of the tooth crown as well as recorded measurements of incremental structures, represents a combined visual-metric approach using LOWESS residuals, and as such provides a substantial advancement to previous methods. It is therefore recommended that additional studies be carried out with this methodology to determine whether this method improves the reliability of enamel defect identification among individuals recovered from bioarchaeological contexts.

Dental enamel defects in German medieval and early-modern-age populations.

SUMMARY: Aim of this study was to investigate the frequency and type of developmental defects of enamel (DDE) in a medieval and an early-modern-age population from Thuringia, Germany. Sixty-six skeletons subdivided into 31 single burials (12th/13th c.) and 35 individuals buried in groups (15th/16th c.) were examined. DDE were classified on 1,246 teeth according to the DDE index. Molar-incisor-hypomineralisation (MIH), a special type of DDE, was recorded according to the European Academy of Paediatric Dentistry (EAPD) criteria. DDE was found in 89.4% of the individuals (single burials 90.3% and group burials 88.6%). Hypoplastic pits were the most frequent defect in primary teeth and linear enamel hypoplasia (LEH) in permanent teeth. 13 individuals (24.1%) showed at least one hypomineralised permanent tooth, 12.2% had MIH on at least one first permanent molar and 10.0% in permanent incisors. Second primary molars were affected in 8.0% of the children and juveniles. No individual suffered from affected molars and incisors in combination. Endogenous factors like nutritional deficiencies and health problems in early childhood could have been aetiological reasons of DDE and MIH. The frequency of DDE and MIH might have been masked by extended carious lesions, dental wear and ante-mortem tooth loss.

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.

The long-term impact of developmental stress. Evidence from later medieval and post-medieval London (AD1117-1853).

OBJECTIVES: Episodes of ill-health in childhood can predispose affected individuals to further periods of illness and early adult mortality. This study uses nonspecific indicators of stress to examine how growth disruptions during infancy/early childhood, and late childhood/early adolescence affected adult longevity in later medieval and post-medieval London. MATERIALS AND METHODS: Hazards analysis was used to evaluate the effect of linear enamel hypoplasia (LEH) and the size of the anteroposterior (AP) and transverse (TR) diameters of the vertebral neural canal (VNC) on adult age-at-death. This was applied to skeletal samples from later medieval (n = 461) and post-medieval (n = 480) London. RESULTS: Growth disruptions during infancy/early childhood (LEH and AP VNC diameters) were not associated with longevity, or with impaired growth at later stages of development (TR VNC diameters). Growth disruptions during late childhood/early adolescence (TR VNC diameters) were associated with a significantly increased risk of adult mortality. DISCUSSION: Macroscopic hypoplasia represent short periods of stress during infancy/early childhood which did not disrupt future investments in growth or cause long-term damage to health. Small TR diameters represent chronic stress during late childhood/early adolescence which resulted in greater susceptibility to infections and increased risk of mortality. These interactions were influenced by sex and socioeconomic status, suggesting that socioeconomic circumstances in both childhood and adult life could influence exposure and resistance to stressors.

Plasticity and constraint in response to early-life stressors among late/final Jomon period foragers from Japan: evidence for life history trade-offs from incremental microstructures of enamel.

This study evaluates two hypotheses that address how Late/Final Jomon period people responded to early-life stress using linear enamel hypoplasia (LEH) and incremental microstructures of enamel. The first hypothesis predicts that Jomon people who experienced early-life stressors had greater physiological competence in responding to future stress events (predictive adaptive response). The second hypothesis predicts that Jomon people traded-off in future growth and maintenance when early investment in growth and survival was required (plasticity/constraint). High resolution tooth impressions were collected from intact, anterior teeth and studied under an engineer's measuring microscope. LEH were identified based on accentuated perikymata and depressions in the enamel surface profile. Age of formation for each LEH was estimated by summing counts of perikymata and constants associated with crown initiation and cuspal enamel formation times. The relationship between age-at-first-defect formation, number of LEH, periodicity between LEH, and mortality was evaluated using multiple regression and hazards analysis. A significant, positive relationship was found between age-at-death relative to age-at-first-defect formation and a significant, negative relationship was found between number of LEH relative to age-at-first-defect formation. Individuals with earlier forming defects were at a significantly greater risk of forming defects at later stages of development and dying at younger ages. These results suggest that Late/Final Jomon period foragers responded to early-life stressors in a manner consistent with the plasticity/constraint hypothesis of human life history. Late/Final Jomon period individuals were able to survive early-life stressors, but this investment weakened responses to future stress events and exacerbated mortality schedules.

Age of linear enamel hypoplasia formation based on Massler and colleagues' and Reid and Dean's standards in a Polish sample dated to 13th-18th century CE.

In the study of enamel hypoplasia formation ages basically two standards of dental development are being applied. According to some authors, different methods produce different results, thus it is critical to decide which method to use. This study focuses on the comparison of three methods for estimating ages of linear enamel hypoplasia (LEH) formation. The skeletal material derives from three burial grounds localized on the territory of Poland, dated to 13th-18th c. CE. In total 642 teeth of 77 individuals were qualified for the study. The position of LEHs on the crown surface was measured and then converted to age at formation using the regression equations proposed by Goodman and Rose, Goodman and Song, and the data provided by Reid and Dean. There were 51.9% of individuals and 17.9% of teeth affected by LEH. The lowest age estimates were provided by the Goodman and Rose's method then higher by the Goodman and Song's method and the highest using the Reid and Dean's data. The age ranges and peaks of LEH provided by the three methods differed more for the maxillary than for the mandibular teeth. Crown formation ages supplied by Reid and Dean account for intra- and inter-tooth as well as inter-population variation in the timing of tooth development and also for variation in crown heights. This approach undoubtedly increases reliability of the results. Thus, it seems advisable to use the Reid and Dean's standard when calculating ages of enamel hypoplasia formation.

Missing defects? A comparison of microscopic and macroscopic approaches to identifying linear enamel hypoplasia.

Linear enamel hypoplasia (LEH), the presence of linear defects of dental enamel formed during periods of growth disruption, is frequently analyzed in physical anthropology as evidence for childhood health in the past. However, a wide variety of methods for identifying and interpreting these defects in archaeological remains exists, preventing easy cross-comparison of results from disparate studies. This article compares a standard approach to identifying LEH using the naked eye to the evidence of growth disruption observed microscopically from the enamel surface. This comparison demonstrates that what is interpreted as evidence of growth disruption microscopically is not uniformly identified with the naked eye, and provides a reference for the level of consistency between the number and timing of defects identified using microscopic versus macroscopic approaches. This is done for different tooth types using a large sample of unworn permanent teeth drawn from several post-medieval London burial assemblages. The resulting schematic diagrams showing where macroscopic methods achieve more or less similar results to microscopic methods are presented here and clearly demonstrate that "naked-eye" methods of identifying growth disruptions do not identify LEH as often as microscopic methods in areas where perikymata are more densely packed.

No significant difference in the levels of dental fluctuating asymmetry between hypoplastic and non-hypoplastic skeletal groups from the Joseon Dynasty (mid 15th-early 20th century), South Korea.

OBJECTIVES: As part of efforts to explore the relationship between linear enamel hypoplasia (LEH) and dental fluctuating asymmetry (DFA), DFA levels were compared between a hypoplastic group and a non-hypoplastic group. Since both LEH and DFA are pathological indicators of environmental stress which are represented by teeth, it was hypothesized that the hypoplastic group would exhibit higher levels of DFA than the non-hypoplastic group. DESIGN: Total of 136 sets of Korean skeletal remains from the Joseon Dynasty (mid 15th-early 20th century, South Korea) were used. To test the hypothesis, DFA levels of both groups were compared by two-way ANOVA after examining some issues related to FA research such as measurement error, type of asymmetry, and size dependence. RESULT: Contrary to the anticipations of many relavant studies, the hypothesis of this study was not supported (F=3.469, p=0.063). That is, the DFA levels of the two groups did not differ significantly, which implies that LEH and DFA do not occur concordantly. CONCLUSION: As to the reason for the result of the present study, it was speculated that (1) different kinds and/or degrees of stressors may influence the occurrence of LEH and DFA, or (2) traditional measuring methods used for DFA research may not reflect true DFA levels. Based on this study, it is recommended that both LEH and DFA should be utilized and reported independently in future research on the environmental stress and nutritional status of human populations.