Paleodemographic analysis of age at death for a population of Black Sea Scythians: An exploration by using Bayesian methods.

OBJECTIVES: Studies of the demography of past populations involving deterministic life tables can be criticized for ignoring the errors of estimation. Bayesian methods offer an alternative, by focusing on the uncertainty of the estimates, although their results are often sensitive to the choice of prior distributions. The aim of this study is to explore a range of Bayesian methods for estimating age at death for a population of nomadic warriors-Scythians from the Black Sea region. MATERIALS AND METHODS: In total, skeletons of 312 individuals (93 children and 219 adults) from Glinoe (Moldova), dated to the 5th-2nd century BCE, were examined. We unified the age categories corresponding to different aging methods, allowing an application of a probabilistic assessment of the age categorization. A hierarchical Bayesian multinomial-Dirichlet-Dirichlet model was applied, with a hypothetical, subjective reference population, a real reference population, and no reference. RESULTS: Stationary-population life expectancy was estimated as 27.7 years (95% CI: 25.1-30.3) for a newborn (e0 ), and 16.4 years (14.0-19.0) for 20-year-olds (e20 ), although with high uncertainty, and sensitive to the model specification. Slight differences in longevity between different social strata and between the Classical and Late chronological periods were found, although with high estimation errors. A more robust finding, confirming earlier studies, was a high probability of death in young adulthood, which could depend on Scythian lifestyle (conflicts, wars). DISCUSSION: Our study shows a way to overcome some limitations of broad age categorization by using the Bayesian approach with alternative model specifications, allowing to assess the impact of reference populations.

Insight into age-related changes of the human facial skeleton based on medieval European osteological collection.

Aging changes in the facial skeleton are concentrated mostly in orbits, maxilla and mandible. The aim of this study was to analyze metric traits of the adult viscerocranium in a medieval sample from Cedynia (Poland, Central Europe) and confront the results with literature data for modern populations. It was assumed that diet-related greater biomechanical forces generated during mastication in medieval versus modern times led to slower rate of bone resorption with age. 3D models of the facial skeleton are created for 230 individuals, categorized into young, middle and old adults, and a subgroup of edentulous middle adults is distinguished. Orbits, piriform aperture, maxilla and mandible are measured using Geomagic Studio 12 and analyzed among age categories as well as dentate and edentulous subgroups. The values of the orbital and piriform aperture measurements tend to increase with age and reached statistical significance in males (right orbit height, left orbit width, piriform aperture surface area). In females, maxillary height significantly decrease at right first premolar and first molar, together with height of the right mandibular ramus. In edentulous individuals of both sexes the orbits are wider, and maxillary and mandibular heights are lower than in dentate individuals. This study reveals similar character and direction of the aging process of the facial skeleton in medieval and modern adults, however slower rate of resorptive changes is found in the former sample, which suggests, that diet-related biomechanical forces can influence intensification of the aging processes in the facial skeleton.

Morphometry of auditory ossicles in medieval human remains from Central Europe.

Human auditory ossicles, the malleus, the incus, and the stapes, are located in the tympanic cavity in the temporal bone and through forming a chain for the sound transmission from the tympanic membrane to the cochlea, they play an important role in the hearing process. Despite their clinical, phylogenetic, and evolutionary significance, the morphometry of the human ear bones has not been examined systematically. The ear ossicles are the smallest bones of the human skeleton, attaining their final size and morphology already at birth. Initially, they have been found to exhibit minimal morphometric variation, but further studies brought the opposite results. The aim of this study was to examine the morphometric variation of human auditory ossicles recovered from medieval and postmedieval subadult skeletons from Poland, Central Europe. The analysis involved in a total of 166 ear bones. Their measurements were performed on microscopic images using CorelDraw x4, according to a protocol of Quam and Rak with modification of Flohr et al. and Wadhwa et al. Our study showed a significant metric variation in the measurements taken at areas of the greatest morphological variability of the ossicles. We found that greater linear dimensions were associated with lower values of angular measurements. These results reveal the inherent variation found in these supposed functionally constrained structures. Representation of even greater number of populations, time periods, and developmental stages are needed. Further study will expand our understanding of the global scope of variation found in ear ossicular morphology and its functional implications for paleoanthropology.

Season of birth and subsequent body size: the potential role of prenatal vitamin D.

OBJECTIVES: The relationship between season of birth and various physical and psychological outcomes was reported in many studies, although the underlying mechanism still remains unrecognized. The aim of this study was to explore the season-of-birth effect on body size in the sample of 1,148 eight-year-old Polish urban children and propose the mechanism responsible for this effect. METHODS: The children were examined three times at their birthdays and at two cross-sectional surveys. Effects of the season of birth were checked by fitting the cosine function to empirical values and by comparison between two groups born in different periods of the year. RESULTS: Data gathered at three examinations led to the same results: season-of-birth effect occurred only in boys and only in those relatively shortly breastfed and/or descended from the families of low-socioeconomic status. Specifically, the individuals born in October-April were taller (by 2-3 cm), heavier (by 2-3 kg), and fatter than those born in May-September. CONCLUSIONS: The following explanatory mechanism has been formulated: insolation in Poland is minimal in November-February (winter period), and so ultraviolet absorption and vitamin D production is then the lowest. Vitamin D regulates embryo's cellular differentiation, and its deficiency triggers permanent developmental changes. Therefore, individuals conceived in autumn (i) are at the greatest risk of early vitamin D deficiency, (ii) are born in summer, and (iii) are relatively small in their further lives. The contribution of low-socioeconomic status, short breastfeeding, and being a male to the occurrence of the season-of-birth effect is also discussed.

Osteoarthritis: A problematic disease in past human populations. A dependence between entheseal changes, body size, age, sex, and osteoarthritic changes development.

Osteoarthritis is a problematic trait in terms of etiology and interpretation in past human populations. The relationships between osteoarthritic changes (osteophytes, porosity, and eburnation) and entheseal changes, body mass, stature, bone massiveness, sex, and age on the basis of skeletal material from Lekno (Poland) are analyzed here. Entheses were the strongest contributor to the prediction of osteophyte expression and when all types of changes and all joints were taken together. Stature demonstrates a negative dependence on porosity. When each joint was analyzed separately, entheses were the strongest contributor to the prediction of arthritis expression in the wrist and hip. Age was the strongest contributor to the prediction of arthritis expression in the elbow. Body mass, stature, bone massiveness, and sex had no effect on osteoarthritic changes in any of the examined joints. The results of the present study suggest an important dependence between entheses and osteoarthritic changes. Other factors had little to no effect on differences in OA severity. These results do not dispel all doubts but enrich knowledge about the effect of etiological factors on osteoarthritic change formation. This knowledge is essential for proper, reliable interpretation of osteoarthritic changes in the context of past human biology, ecology, and behavior.

Ancient genomes suggest the eastern Pontic-Caspian steppe as the source of western Iron Age nomads.

For millennia, the Pontic-Caspian steppe was a connector between the Eurasian steppe and Europe. In this scene, multidirectional and sequential movements of different populations may have occurred, including those of the Eurasian steppe nomads. We sequenced 35 genomes (low to medium coverage) of Bronze Age individuals (Srubnaya-Alakulskaya) and Iron Age nomads (Cimmerians, Scythians, and Sarmatians) that represent four distinct cultural entities corresponding to the chronological sequence of cultural complexes in the region. Our results suggest that, despite genetic links among these peoples, no group can be considered a direct ancestor of the subsequent group. The nomadic populations were heterogeneous and carried genetic affinities with populations from several other regions including the Far East and the southern Urals. We found evidence of a stable shared genetic signature, making the eastern Pontic-Caspian steppe a likely source of western nomadic groups.

Diverse origin of mitochondrial lineages in Iron Age Black Sea Scythians.

Scythians were nomadic and semi-nomadic people that ruled the Eurasian steppe during much of the first millennium BCE. While having been extensively studied by archaeology, very little is known about their genetic identity. To fill this gap, we analyzed ancient mitochondrial DNA (mtDNA) from Scythians of the North Pontic Region (NPR) and successfully retrieved 19 whole mtDNA genomes. We have identified three potential mtDNA lineage ancestries of the NPR Scythians tracing back to hunter-gatherer and nomadic populations of east and west Eurasia as well as the Neolithic farming expansion into Europe. One third of all mt lineages in our dataset belonged to subdivisions of mt haplogroup U5. A comparison of NPR Scythian mtDNA linages with other contemporaneous Scythian groups, the Saka and the Pazyryks, reveals a common mtDNA package comprised of haplogroups H/H5, U5a, A, D/D4, and F1/F2. Of these, west Eurasian lineages show a downward cline in the west-east direction while east Eurasian haplogroups display the opposite trajectory. An overall similarity in mtDNA lineages of the NPR Scythians was found with the late Bronze Age Srubnaya population of the Northern Black Sea region which supports the archaeological hypothesis suggesting Srubnaya people as ancestors of the NPR Scythians.

Investigating kinship of Neolithic post-LBK human remains from Krusza Zamkowa, Poland using ancient DNA.

We applied an interdisciplinary approach to investigate kinship patterns and funerary practices during the middle Neolithic. Genetic studies, radiocarbon dating, and taphonomic analyses were used to examine two grave clusters from Krusza Zamkowa, Poland. To reconstruct kinship and determine biological sex, we extracted DNA from bones and teeth, analyzed mitochondrial genomes and nuclear SNPs using the HID-Ion AmpliSeq™ Identity panel generated on Illumina and Ion Torrent platforms, respectively. We further dated the material (AMS 14C) and to exclude aquatic radiocarbon reservoir effects, measures of carbon and nitrogen stable isotopes for diet reconstruction were used. We found distinct mitochondrial genomes belonging to haplogroups U5b2a1a, K1c and H3d in the first grave cluster, and excluded maternal kin patterns among the three analyzed individuals. In the second grave cluster one individual belonged to K1a4. However, we could not affiliate the second individual to a certain haplogroup due to the fragmented state of the mitochondrial genome. Although the individuals from the second grave cluster differ at position 6643, we believe that more data is needed to fully resolve this issue. We retrieved between 26 and 77 autosomal SNPs from three of the individuals. Based on kinship estimations, taking into account the allelic dropout distribution, we could not exclude first degree kin relation between the two individuals from the second grave cluster. We could, however, exclude a first degree kinship between these two individuals and an individual from the first grave cluster. Presumably, not only biological kinship, but also social relations played an important role in the funerary practice during this time period. We further conclude that the HID-Ion AmpliSeq™ Identity Panel may prove useful for first degree kin relation studies for samples with good DNA preservation, and that mitochondrial genome capture enrichment is a powerful tool for excluding direct maternal relationship in ancient individuals.

Prevalence of chronic maxillary sinusitis in children from rural and urban skeletal populations in Poland.

Maxillary sinuses of 100 subadults from Cedynia, an early-urban site (stronghold), dated to the 10th-14th centuries AD, and of 28 subadults from Slaboszewo, a rural site, dated to the 14th-17th centuries AD, were examined for bone formation indicative of chronic sinusitis in order to explore the effect of urban and rural environments on the occurrence of upper respiratory tract infections in the past. We expected a higher prevalence of sinusitis in subadults from a stronghold than from a village, because of such factors as crowding, rapid spread of infections, and pollution from workshops located in the streets. We found a statistically non-significant tendency toward a higher prevalence of the condition in Cedynia compared to Slaboszewo (18.0% and 7.1%, respectively). The majority of maxillary lesions were classified as spicules. Changes to bone morphology suggestive of sinusitis of dental origin were not found. The development of observed osseous lesions may be attributed to culturally determined risk factors such as low quality of housing, air pollution caused by smoke from the household hearth and street workshops, poor levels of hygiene, and water contamination.

Is the Relationship Between Breastfeeding and Childhood Risk of Asthma and Obesity Mediated by Infant Antibiotic Treatment?

BACKGROUND: Studies of the protective effect of breastfeeding on asthma have not brought unequivocal results, and thus this issue remains controversial. Antibiotic use, known to increase asthma risk, may be involved in this relationship. The objective of this study was to assess the influence of breastfeeding duration on obesity and asthma risk in childhood and to test a mediating role of antibiotic use in infancy. SUBJECTS AND METHODS: A cross-sectional anthropometric and questionnaire study was conducted on 1,277 schoolchildren 8 years of age. Data on weight status, asthma, breastfeeding duration, antibiotic administration in infancy, socioeconomic status, and lifestyle were analyzed. Multivariate standard and logistic regression and mediation analyses, controlling for confounders, were applied. RESULTS: Total duration of breastfeeding was negatively related to the child's body mass index (p=0.038), fat percentage (p=0.030), and obesity risk (p=0.032). Dropping the variable of antibiotic use from the model made the breastfeeding duration a significant predictor of low asthma risk (p=0.027). Antibiotic treatment mediated the relationship between breastfeeding duration and asthma risk (Sobel's z=-2.61, p=0.009). CONCLUSIONS: Our findings support protective effects of longer duration of breastfeeding against obesity and asthma. We propose a new mechanism for a relationship between breastfeeding and asthma: shorter breastfeeding compromises infant health and thereby leads to antibiotic treatment, which in turn increases the risk of asthma.

Month-of-birth effect on height and weight in Polish rural children.

This study investigated a hypothesis of dependence of child height and weight on the month of their birth. The sample comprised 1,241 subjects, 568 boys and 673 girls, age 6-20 years, from villages in Olsztyn Province, Northeast Poland. Individuals' height and weight data were standardized by sex and age to allow grouping of individuals born in the same month irrespective of their sex and age at examination. Subjects born in October to March proved to be significantly taller and heavier than those born in April to September. The magnitude of differences between the semiannual groupings equaled 13.1% of a standard deviation (SD) in height (P = 0.03) and 14.2% of SD in weight (P = 0.02). The month-of-birth effect was much stronger for children characterized by high socioeconomic status, where these differences amounted to 39.1% of SD in height (P = 0.02) and 49.4% of SD in weight (P = 0.01). There were no regular changes of the effect with age and no differences between the sexes were found. Fitted cosine functions identified the highest values of examined traits for individuals born in December with the lowest values being found in those born in June. Possible explanations of the month-of-birth effect are considered in terms of age categorizing, seasonal variety of growth rates, as well as birth-related or conception-related global, hemispheric, and local factors. This study rejects the first two possibilities and suggests this effect requires further research to be conducted in various geographical locations, climates, and cultures, on humans as well as on other species.