Ancient Human Bone Microstructure in Medieval England: Comparisons between Two Socio-Economic Groups

Understanding the links between bone microstructure and human lifestyle is critical for clinical and anthropological research into skeletal growth and adaptation. The present study is the first to report correspondence between socio-economic status and variation in bone microstructure in ancient humans. Products of femoral cortical remodeling were assessed using histological methods in a large human medieval sample (N:450) which represented two distinct socio-economic groups. Osteonal parameters were recorded in posterior midshaft femoral sections from adult males (N:233) and females (N:217). Using univariate and multivariate statistics, intact, fragmentary, and osteon population densities, Haversian canal area and diameter, and osteon area were compared between the two groups, accounting for sex, age, and estimated femoral robusticity. The size of osteons and their Haversian canals, as well as osteon density, varied significantly between the socio-economic groups, although minor inconsistencies were observed in females. Variation in microstructure was consistent with historical textual evidence that describes differences in mechanical loading and nutrition between the two groups. Results demonstrate that aspects of ancient human lifestyle can be inferred from bone microstructure

Deciduous enamel 3D microwear texture analysis as an indicator of childhood diet in medieval Canterbury, England

This study conducted the first three dimensional microwear texture analysis of human deciduous teeth to reconstruct the physical properties of medieval childhood diet (age 1-8yrs) at St Gregory's Priory and Cemetery (11th to 16th century AD) in Canterbury, England. Occlusal texture complexity surfaces of maxillary molars from juvenile skeletons (n=44) were examined to assess dietary hardness. Anisotropy values were calculated to reconstruct dietary toughness, as well as jaw movements during chewing. Evidence of weaning was sought, and variation in the physical properties of food was assessed against age and socio-economic status. Results indicate that weaning had already commenced in the youngest children. Diet became tougher from four years of age, and harder from age six. Variation in microwear texture surfaces was related to historical textual evidence that refers to lifestyle developments for these age groups. Diet did not vary with socio-economic status, which differs to previously reported patterns for adults. We conclude, microwear texture analyses can provide a non-destructive tool for revealing subtle aspects of childhood diet in the past

Histomorphometry and cortical robusticity of the adult human femur

Recent quantitative analyses of human bone microanatomy, as well as theoretical models that propose bone micro- and gross anatomical associations, have started to reveal insights into biological links that may facilitate remodeling processes. However, relationships between bone size and the underlying cortical bone histology remain largely unexplored. The goal of this study is to determine the extent to which static indicators of bone remodeling and vascularity, measured using histomorphometric techniques, relate to femoral midshaft cortical width and robusticity. Using previously published and new quantitative data from 450 adult human male (n = 233) and female (n = 217) femora, we determine if these aspects of femoral size relate to bone microanatomy. Scaling relationships are explored and interpreted within a context of tissue form and function. Analyses revealed that the area and diameter of Haversian canals and secondary osteons, and densities of secondary osteons and osteocyte lacunae from the sub-periosteal region of the posterior midshaft femur cortex were significantly, but not consistently, associated with femoral size. Cortical width and bone robusticity were correlated with osteocyte lacunae density and scaled with positive allometry. Diameter and area of osteons and Haversian canals decreased as the width of cortex and bone robusticity increased, revealing a negative allometric relationship. These results indicate that measures of cortical bone remodeling and vascularity products link to femur size. Allometric relationships between more robust human femora with thicker cortical bone and histological products of bone remodeling correspond with principles of bone functional adaptation. Future studies may benefit from combining bone histomorphometric data with measurements of bone macrostructure

Socio-economic Determinants of Bone Health from Past to Present

Increasing epidemiology evidence amounts for social determinants of bone health underlying musculo-skeletal conditions such as osteoporosis. Amongst different facets influencing skeletal health, socio-economic status (SES) has been identified as a critical factor determining one’s access to resources, health care, education, nutrition, and physical activity. Recent conceptual and epigenetic studies assessing SES links with DNA methylation offer further support for the adverse effects of social disadvantage in early life on bone quantity and quality in adulthood. However, this evidence for socially patterned risks in bone fragility is not restricted to the contemporary society. Data exist for ancient human skeletal samples deriving from SES stratified cemeteries that also reflect bone changes consistent with lifestyles specific to social standing. Similarly to modern data, the conclusion drawn from the ancient times has been for a negative effect of low SES on bone growth and maintenance. Some contradictory results, mirroring previously reported inconsistencies in epidemiological studies, have also been reported showing that high SES can equally result in poor bone health. It becomes clear that ancient perspectives can offer a further line of support into these ongoing epidemiological and epigenetic research efforts. Taken together, a holistic approach to clinical understanding and practice of bone health is recommended, building upon ancient and modern findings to target living groups who are most at risk of developing low bone mass and compromised bone micro-architecture

Bone loss markers in the earliest Pacific Islanders

International audienceAbstract Kingdom of Tonga in Polynesia is one of the most obese nations where metabolic conditions, sedentary lifestyles, and poor quality diet are widespread. These factors can lead to poor musculoskeletal health. However, whether metabolic abnormalities such as osteoporosis occurred in archaeological populations of Tonga is unknown. We employed a microscopic investigation of femur samples to establish whether bone loss afflicted humans in this Pacific region approximately 3000 years ago. Histology, laser confocal microscopy, and synchrotron Fourier-transform infrared microspectroscopy were used to measure bone vascular canal densities, bone porosity, and carbonate and phosphate content of bone composition in eight samples extracted from adult Talasiu males and females dated to 2650 BP. Compared to males, samples from females had fewer vascular canals, lower carbonate and phosphate content, and higher bone porosity. Although both sexes showed evidence of trabecularised cortical bone, it was more widespread in females (35.5%) than males (15.8%). Our data suggest experiences of advanced bone resorption, possibly as a result of osteoporosis. This provides first evidence for microscopic bone loss in a sample of archaeological humans from a Pacific population widely afflicted by metabolic conditions today

Cartesian coordinates in two-dimensional bone histology images

Palaeohistologists who work with well-preserved hominin cortical bone can examine two-dimensional (2D) histology images for quantitative parameters of secondary osteons and Haversian canals to reconstruct past bone remodelling. Standard techniques in this space include area measurements and counts of histology components recorded from an image. The ‘point-count’ technique involves counting all the items (e.g., secondary osteons, osteocyte lacunae) of interest per image area. The open access image analysis software ImageJ/ FIJI facilitates this technique in a user-friendly way. Raw data points are captured and can be saved in a spreadsheet. Aside from the total number of counts, the software also issues Cartesian (XY) coordinates locating each counted point. These XY coordinates are typically neglected within palaeohistological approaches due their assumed irrelevance to research questions of bone remodelling significance. We provide a short evaluation of XY coordinates captured by ImageJ/FIJI from 2D bone histology images, and a protocol for a simple calculation of XY distances that follow the path of point counting. We focus on osteocyte lacunae which serve as a proxy for osteoblast-osteocyte conversion in live bone by replicating the protocol on a bone sample from a Medieval English individual. We discuss the potential of XY coordinates for reconstructing the proximity of osteocyte lacunae and related bone remodelling activity through exchange of nutrients by neighbouring cells. We recommend palaeohistologists report XY coordinate data in their results to ensure better hominin palaeobiology characterisation

Island rule and bone metabolism in fossil murines from Timor

Skeletal growth rates reconstructed from bone histology in extinct insular hippopotamids, elephants, bovids and sauropods have been used to infer dwarfism as a response to island conditions. Limited published records of osteocyte lacunae densities (Ot.Dn), a proxy for living osteocyte proliferation, have suggested a slower rate of bone metabolism in giant mammals. Here, we test whether insularity might have affected bone metabolism in a series of small to giant murine rodents from Timor. Ten adult femora were selected from a fossil assemblage dated to the Late Quaternary (~5000–18 000 years old). Femur morphometric data were used in computing phylogenetically informed body mass regressions, although the phylogenetic signal was very low (Pagel’s λ = 0.03). Estimates of body weight calculated from these femora ranged from 75 to 1188 g. Osteocyte lacunae densities from histological sections of the midshaft femur were evaluated against bone size and estimated body weight. Statistically significant (P < 0.05) and strongly negative relationships between Ot.Dn, femur size and estimated weight were found. Larger specimens were characterized by lower Ot.Dn, indicating that giant murines from Timor might have had a relatively slow pace of bone metabolic activity, consistent with predictions made by the island rule

Vitamin D status in post-medieval Northern England: Insights from dental histology and enamel peptide analysis at Coach Lane, North Shields (AD 1711–1857)

Objectives: The post-medieval period in Europe saw a dramatic increase in metabolic bone disease related to vitamin D deficiency (VDD). Recent paleopathological work has utilized interglobular dentin (IGD) as a proxy for poor vitamin D status during development, while enamel peptide analysis allows the identification of chromosomal sex in non-adult remains. Here we explore the relationship between sex, the presence of IGD, and macroscopic markers of VDD in an industrial era assemblage from Northeast England. Materials and methods: 25 individuals (9 females, 9 males, 9 unknown sex) from the cemetery site at Coach Lane, North Shields (1711–1857) were selected for paleopathological analysis, histological assessment of IGD, and enamel peptide determination of chromosomal sex. Results: Ground tooth sections from 21 individuals were of suitable quality for detection of IGD, and enamel peptide analysis confirmed the chromosomal sex of ten individuals. Sixteen individuals (76.1%) exhibited ≥1 episode of IGD. Nine of these (42.8%) exhibited >1 episode and four (19%) exhibited ≥4 episodes in regular intervals. Male sex was significantly associated with the presence of IGD (p = 0.0351; 100% males vs. 54.5% females). Females were more likely to exhibit macroscopic evidence of VDD (45.5% females vs 30% males) but this was not statistically significant. Discussion and conclusions: Periods of poor mineral metabolism during childhood appear much more prevalent at Coach Lane than macroscopic evidence suggests. Evidence of seasonal IGD episodes indicates that northern latitude played a major role in poor VD status in the Northeast of England. The significant association of IGD with male sex may be due to sex-related differences in dentinal mineralization or a higher risk of poor VD status in males aged <5 years. More work is needed to establish an evidence-based threshold for pathological levels of IGD before the presence of this feature can confidently be used as a biomarker for poor VD status

Bone deep: variation in stable isotope ratios and histomorphometric measurements of bone remodelling within adult humans

Stable carbon (?13C) and nitrogen (?15N) isotope studies of ancient human diet increasingly sample several skeletal elements within an individual. Such studies draw upon differences in bone turnover rates to reconstruct diet during different periods of time within an individual’s lifetime. Rib and femoral bone, with their respectively fast and slow remodeling rates, are the bones most often sampled to reconstruct shorter and longer term signals of diet prior to death. It is poorly understood if ?13C and ?15N vary between bone types within a single individual, or if this variation corresponds with bone turnover rate (BTR). Here, we determined ?13C and ?15N for ten different bones from ten adult human skeletons (n=5 males; n=5 females). Isotope values were compared to the rate that each bone remodeled, calculated from osteon population (OPD) density. Results reveal that isotope ratios varied within each skeleton (?13C: max= -1.58‰; ?1542 N: max= 3.05‰). Humeri, metacarpals, and ribs had the highest rate of bone remodelling; the occipital bone had the lowest. A regression analyses revealed that higher rates of bone remodeling are significantly and negatively correlated with lower ?15N. Our results suggest that the occipital bone, with its slow rate of bone renewal, may prove useful for isotopic studies that reconstruct diet over longer periods of time within an individual’s lifetime. Isotope studies that compare individual skeletal elements between populations should standardize their methodology to bones with either a slow or fast turnover rate

Enamel biorhythms of humans and great apes: the Havers-Halberg Oscillation hypothesis reconsidered

The Havers-Halberg Oscillation (HHO) hypothesis links evidence for the timing of a biorhythm retained in permanent tooth enamel (Retzius periodicity) to adult body mass and life history traits across mammals. Potentially, these links provide a way to access life history of fossil species from teeth. Recently we assessed intra-specific predictions of the HHO on human children. We reported Retzius periodicity (RP) corresponded with enamel thickness, and cusp formation time, when calculated from isolated deciduous teeth. We proposed the biorhythm might not remain constant within an individual. Here, we test our findings. RP is compared between deciduous second and permanent first molars within the maxillae of four human children. Following this, we report the first RPs for deciduous teeth from modern great apes (n = 4), and compare these with new data for permanent teeth (n = 18) from these species, as well as with previously published values. We also explore RP in teeth that retain hypoplastic defects. Results show RP changed within the maxilla of each child, from thinner to thicker enameled molars, and from one side of a hypoplastic defect to the other. When considered alongside correlations between RP and cusp formation time, these observations provide further evidence that RP is associated with enamel growth processes and does not always remain constant within an individual. RP of 5 days for great ape deciduous teeth lay below the lowermost range of those from permanent teeth of modern orangutan and gorilla, and within the lowermost range of RPs from chimpanzee permanent teeth. Our data suggest associations between RP and enamel growth processes of humans might extend to great apes. These findings provide a new framework from which to develop the HHO hypothesis, which can incorporate enamel growth along with other physiological systems. Applications of the HHO to fossil teeth should avoid transferring RP between deciduous and permanent enamel, or including hypoplastic teeth