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

Estimation of age at onset of linear enamel hypoplasia. New calculation tool, description and comparison of current methods

Enamel Hypoplasia (EH) is known to be a useful indicator for wide range of detrimental factors in early childhood in past populations, such as nutritional disturbances, mechanical trauma, disease, metabolic, and/or genetic disorders. EH may be divided into three categories: pits, grooves, and lines, where the last two are referred to as "Linear Enamel Hypoplasia" (LEH). The regularity of enamel formation allows retrospective determination of the age of LEH formation. The current article reviews and compares the best-known methods used to estimate age at LEH formation and provides a new computational tool. Growth curves for canines and incisors were developed based on tooth growth tables by previous authors. Optimal models were selected using the Akaike Information Criterion. A Microsoft Excel spreadsheet was created to calculate age at LEH formation using the most common methods. All method results were compared with an archaeological sample (44 teeth of 18 individuals from an early modern cemetery from Wrocław, Poland) and a theoretical model. The results of the methods were compared pairwise with Bland-Altman plots. The current article provides a quick and easy-to-use tool for analyzing LEH chronology and comparing the results of different methods. As shown by the Bland-Altman plots, most methods provide approximately consistent results for LEHs formed at around 2-3 years of age. However, LEHs formed particularly early or late are more prone to discrepancies between different methods. Comparison of the age at LEH formation obtained by different methods should be done carefully - and the new LEH calculation tool with optimized equations provided in this publication can facilitate this process.

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.

Cranial deformation and genetic diversity in three adolescent male individuals from the Great Migration Period from Osijek, eastern Croatia

Three individuals dating to the Great Migration Period (5^th century CE) were discovered in a pit at the Hermanov vinograd site in Osijek, Croatia. We were inspired to study these individuals based on their unusual burial context as well as the identification of two different types of artificial cranial deformation in two of the individuals. We combine bioarchaeological analysis with radiographic imaging, stable isotopes analysis, and ancient DNA to analyze their dietary patterns, molecular sex, and genetic affinities in the context of the archaeological data and their bioarchaeological attributes. While all three individuals were adolescent males with skeletal evidence of severe malnutrition and similar diets, the most striking observation is that they had major differences in their genetic ancestry. Results of the genetic analyses of the nuclear ancient DNA data for these individuals indicate that the individual without artificial cranial deformation shows broadly West Eurasian associated-ancestry, the individual with tabular oblique-type has East Asian ancestry and the third individual with circular erect-type has Near Eastern associated-ancestry. Based on these results, we speculate that artificial cranial deformation type may have been a visual indicator membership in a specific cultural group, and that these groups were interacting intimately on the Pannonian Plain during the Migration Period.

Growth and health status of children and adolescents in medieval Central Europe

Subadult growth and health have been analyzed in three cemetery samples from medieval Poland, including two early-urban sites: Cedynia dated to the 10t-14th centuries AD, and Ostrów Lednicki dated to the 13th-15th centuries AD, and a rural site Słaboszewo dated to the 14th-17th centuries AD. The nutritional status was not expected to have substantially differed among the settlements, due to the culturally induced undiversified diet of children, and predominant share of medium-to-low status individuals. However, city life and village life were supposed to differ in factors correlated with the spread of infections, and as such it was expected to find significant differences in respiratory health among early-urban and rural dwellers.The prevalences of diet-dependent diseases, scurvy and rickets, were found to be statistically indistinguishable among the three studied populations, while higher frequency of skeletal signs of poor respiratory health was observed in early-urban Cedynia than rural Słaboszewo. Slightly lower prevalences of skeletal stress indicators were found for the rural than the early-urban site. Skeletal growth profiles and the dynamics of long bone growth were found to be remarkably similar for the early-urban samples (Cedynia and Ostrów Lednicki), with the rural subadults having the shortest diaphyseal lengths, and lower growth dynamics.It can be concluded that adverse factors associated with the urban settlement were more detrimental to respiratory health than those in the village. A variety of factors are potentially responsible for this pattern, including population density, building structure, quality of air and water, sanitation, and occupation. Perhaps, the key factor in response to environmental and socio-cultural constraints was the stability of living conditions in the village, which allowed the inhabitants to develop sufficient adaptive mechanisms. In contrast, the history of strongholds such as Cedynia was changeable due to political situation, military threats and migrations of people.