Quantifying cortical bone in fragmentary archeological second metacarpals.

OBJECTIVES: Skeletal variation in cortical bone thickness is an indicator of bone quality and health in archeological populations. Second metacarpal radiogrammetry, which measures cortical thickness at the shaft midpoint, is traditionally used to evaluate bone loss in bioarcheological and some clinical contexts. However fragmentary elements are regularly omitted because the midpoint cannot be determined. This methodological limitation reduces sample sizes and biases them against individuals prone to fracture, such as older individuals with low bone mass. This study introduces a new technique for measuring cortical bone in second metacarpals, the "Region of Interest" (ROI) method, which quantifies bone in archeological remains with less-than-ideal preservation while accounting for cortical heterogeneity. MATERIALS AND METHODS: The ROI method was adapted from digital X-ray radiogrammetry (DXR), a clinical method used to estimate bone mineral density, and tested using second metacarpals from Middenbeemster, Netherlands, a 19th century known age and sex skeletal collection. The ROI method quantifies cortical bone area within a 1.9 cm-long, mid-diaphyseal region, standardized for body size differences using total area (CAIROI ). CAIROI values were compared to traditional radiogrammetric cortical indices (CI) to assess the method's ability to identify age-related bone loss. RESULTS: CAIROI values have high intra- and interobserver replicability and are strongly and significantly correlated with CI values for both males (r[n = 39] = 0.906, p = 0.000) and females (r[n = 58] = 0.925, p = 0.000). CONCLUSION: The ROI method complements traditional radiogrammetry analyses and provides a reliable way to quantify cortical bone in incomplete second metacarpals, thereby maximizing sample sizes, allowing patterns in bone acquisition and loss to be more comprehensively depicted in archeological assemblages.

A new approach to recording nasal fracture in skeletonized individuals.

OBJECTIVE: This work describes a new method for recording nasal fracture in skeletonized individuals, suitable for use in biocultural studies of violence and fracture in past societies. METHODS: The method consists in recording the 'side of fracture', 'side of deviation', 'type of fracture', 'other facial fractures', and stage of 'bone remodeling'. RESULTS: A lateral impact force to the facial area is typical of interpersonal violence. This may result in a unilateral nasal fracture and/or a laterally deviated nose. Given the predominance of right-handedness in human populations, side of fracture and, especially, side of deviation, may be useful indices of interpersonal violence. As regards fracture type, although a distal fracture of the nasal bones is the most common type, their comminution may be associated with higher impact forces. The presence of other facial fractures may also be an indicator of high-energy impacts. CONCLUSIONS: Different patterns of nasal trauma may be consistent with different etiologies. SIGNIFICANCE: The method is focused at improving our ability to distinguish the direction and type of impact that caused the injury and, in particular, whether, at a population or sub-group level, such injuries are likely to be predominantly due to violence or to other causes. LIMITATIONS: Well healed fractures of the nasal bones or injury to the septum may be difficult to identify. Also, it is not possible to confirm if nasal and other facial fractures are temporally concurrent. SUGGESTIONS FOR FURTHER RESEARCH: To test this method using skeletal collections with known trauma history or 3D prints of modern nasal injuries of known etiologies.

Effects of age and body proportions on stature estimation.

OBJECTIVES: Two issues involved in mathematical estimation of stature from long bone lengths are explored: the use of different age points for estimating maximum adult stature, and the effects of linear body proportions on stature estimation errors. Both issues were raised by a recent analysis of stature in the British Medieval Wharram Percy sample. MATERIALS AND METHODS: A large (n > 500) sample of European skeletal remains with anatomically estimated statures is used to test associations between relative lower limb length and errors in stature estimation using previously published equations for European samples. Two cadaveric samples of known ages (Terry and Bass Collections) are used to identify the most appropriate age point to employ in a linear equation with an age term for estimation of maximum adult anatomical stature. RESULTS: Relative lower limb length is positively correlated with errors in stature estimation from lower limb bone lengths. Underestimation of stature in the Wharram Percy sample by the European equations is largely attributable to the relatively short lower limbs of this sample compared to Europeans in general. Two methods for assessing and adjusting for relative lower limb length variation are presented. Maximum adult stature is best estimated using an age point of 30 years when a linear age term is employed. DISCUSSION: Body proportions may vary even within relatively closely related populations, so should be assessed and compared to those of reference samples whenever possible when applying mathematical stature equations.

Analysis of patterning in the occurrence of skeletal lesions used as indicators of vitamin D deficiency in subadult and adult skeletal remains.

Paleopathological investigations of conditions linked to vitamin D deficiency have increased in the last twenty years, and a suite of skeletal lesions has been established to aid in the diagnosis of vitamin D deficiency disease in subadults and adults. This paper analyzes the occurrence of these lesions in a large skeletal series comprising 3541 Roman period individuals (1st-6th century AD). Sixteen lesions reported in rickets in subadults, and 13 associated with residual rickets and osteomalacia in adults, were analyzed. Among subadults, there were clear associations among post-cranial lesions. Porotic cranial changes were associated with each other, but not with post-cranial lesions. A range of conditions could have produced the cranial lesions. There was a general paucity of correlations between indicators found in adults, and the difficulty in recording bending deformities was clear. Pseudofractures appear to provide a useful means of investigating osteomalacia in adults. In general, a simple algorithmic approach using presence or absence of lesions is unlikely to provide an adequate means of diagnosing vitamin D deficiency in paleopathology. Knowledge and consideration of the underlying physiological mechanisms involved in lesion formation, combined with individual judgement, will be required to differentially diagnose cases.

Ancient genomes reveal a high diversity of Mycobacterium leprae in medieval Europe.

Studying ancient DNA allows us to retrace the evolutionary history of human pathogens, such as Mycobacterium leprae, the main causative agent of leprosy. Leprosy is one of the oldest recorded and most stigmatizing diseases in human history. The disease was prevalent in Europe until the 16th century and is still endemic in many countries with over 200,000 new cases reported annually. Previous worldwide studies on modern and European medieval M. leprae genomes revealed that they cluster into several distinct branches of which two were present in medieval Northwestern Europe. In this study, we analyzed 10 new medieval M. leprae genomes including the so far oldest M. leprae genome from one of the earliest known cases of leprosy in the United Kingdom-a skeleton from the Great Chesterford cemetery with a calibrated age of 415-545 C.E. This dataset provides a genetic time transect of M. leprae diversity in Europe over the past 1500 years. We find M. leprae strains from four distinct branches to be present in the Early Medieval Period, and strains from three different branches were detected within a single cemetery from the High Medieval Period. Altogether these findings suggest a higher genetic diversity of M. leprae strains in medieval Europe at various time points than previously assumed. The resulting more complex picture of the past phylogeography of leprosy in Europe impacts current phylogeographical models of M. leprae dissemination. It suggests alternative models for the past spread of leprosy such as a wide spread prevalence of strains from different branches in Eurasia already in Antiquity or maybe even an origin in Western Eurasia. Furthermore, these results highlight how studying ancient M. leprae strains improves understanding the history of leprosy worldwide.

How should we diagnose disease in palaeopathology? Some epistemological considerations.

This paper analyses some of the epistemological frameworks that underpin diagnosis in palaeopathology. Currently, the dominant approach is comparative: relationships between skeletal lesions and disease in a reference group in which there is independent evidence of the diseases present in individuals are used to identify disease in unknown archaeological skeletons on the basis of the lesions present. This is essentially a reference sample - target sample approach, analogous to that used to develop methodology in other areas of biological anthropology (e.g. age estimation in palaeodemography). As well as considerable strengths, this approach also has significant weaknesses. Many of these arise from the nature of the reference material (mainly pathology museum and other skeletal collections, and published collations of medical imaging data) used to develop diagnostic criteria. There may also be a tendency toward over-emphasis on pattern-matching between reference and target material, and an under-emphasis on developing our understanding of the biology of bone lesions. Despite its shortcomings, the comparative approach is likely to remain the foundation of most palaeopathological work, but we should increasingly augment it with other diagnostic approaches, especially those grounded in the pathophysiology of bony responses to disease.

A test of a skeletal ageing method based on resorption of the alveolar crest following tooth loss using a skeletal population of documented age at death.

OBJECTIVES: Resorption of the alveolar process occurs following tooth loss, and appears to continue for a prolonged period. Previous study (Mays, ) with a known-age collection of human remains suggested the potential of this phenomenon for age estimation in remains of adults who have lost one or more molar teeth. This article tests this ageing technique on another known age group, and attempts to evaluate the impact of some extraneous factors on the method. MATERIALS AND METHODS: The study group comprises adult skeletons (N = 110) of documented age at death from 18th to 19th century London. It examines the relationship between a previously described standardized measure of posterior corpus height (SPCH) in mandibles showing loss of one or more molars. The potential influence of a general tendency to form or lose bone (identified by the presence of ossification into the anterior longitudinal ligament of the spine and cortical thickness at the metacarpal) and (for females) parity are also investigated. RESULTS: Negative age correlation was found for SPCH in females but not in males. In females, the age-association was weaker, and the rate of loss slower, than in a previously studied 19th century European population. None of the other factors investigated showed a relationship with SPCH. DISCUSSION: As with other bony age indicators, the relationship between SPCH and age varies in different populations. Further work is needed to evaluate the extraneous factors that affect the relationship with age.

Bone-formers and bone-losers in an archaeological population.

OBJECTIVES: Recent biomedical research suggests that, in modern human populations, individuals may vary in their inherent tendency toward bone formation at skeletal and extra-skeletal locations. However, the nature of this phenomenon is incompletely understood, and the extent to which it might apply to past populations is unclear. It is hypothesized that if there is inter-individual variation in some overall tendency toward bone formation in skeletal and extra-skeletal sites then there should be a positive relationship between ligamentous ossification and thickness of cortical bone. This work is a test of this hypothesis in an archaeological population. MATERIALS AND METHODS: The study material comprises adult skeletons (N = 137 individuals) of documented age at death from 18th to 19th century London. It examines the relationship between bone deposition in the anterior longitudinal ligament (ALL) in the thoracic spine and cortical index (CI) at the metacarpal measured by radiogrammetry. RESULTS: Controlling for the potential confounders age, sex, skeletal completeness, occupation (males) and parity (females), there was a positive association between ossification into the ALL and CI. This reflects lesser medullary cavity width in those showing ALL ossification. DISCUSSION: Ligamentous ossification in the axial skeleton and peripheral cortical bone status are linked, individuals with ALL ossification showing lesser resorption of cortical bone at the endosteal surface. This is consistent with the idea of inter-individual variation in some general bone-forming/bone-losing tendency in this 200 year old study population, but there was no evidence of a link between ALL ossification and increased skeletal subperiosteal bone deposition.

The effect of factors other than age upon skeletal age indicators in the adult.

CONTEXT: Estimation of adult age from skeletal remains is problematic due to the weak and variable relationship between age indicators and age. OBJECTIVES: To assess the proportion of variation in age indicators that is associated with factors other than age and to attempt to identify what those factors might be. METHODS: The paper focuses on frequently used adult bony age markers. A literature search (principally using Web of Science) is conducted to assess the proportion of variation in age indicators associated with factors other than age. The biology of these age markers is discussed, as are factors other than age that might affect their expression. RESULTS: Typically, ∼60% of variation in bony age indicators is associated with factors other than age. Factors including inherent metabolic propensity to form bone in soft tissue, vitamin D status, hormonal and reproductive factors, energy balance, biomechanical variables and genetic factors may be responsible for this variation, but empirical studies are few. CONCLUSION: Most variation in adult skeletal age markers is due to factors other than age; dry bone study of historic documented skeletal collections and high resolution CT scanning in modern cadavers or living individuals is needed to identify these factors.

Osteological, biomolecular and geochemical examination of an early anglo-saxon case of lepromatous leprosy.

We have examined a 5th to 6th century inhumation from Great Chesterford, Essex, UK. The incomplete remains are those of a young male, aged around 21-35 years at death. The remains show osteological evidence of lepromatous leprosy (LL) and this was confirmed by lipid biomarker analysis and ancient DNA (aDNA) analysis, which provided evidence for both multi-copy and single copy loci from the Mycobacterium leprae genome. Genotyping showed the strain belonged to the 3I lineage, but the Great Chesterford isolate appeared to be ancestral to 3I strains found in later medieval cases in southern Britain and also continental Europe. While a number of contemporaneous cases exist, at present, this case of leprosy is the earliest radiocarbon dated case in Britain confirmed by both aDNA and lipid biomarkers. Importantly, Strontium and Oxygen isotope analysis suggest that the individual is likely to have originated from outside Britain. This potentially sheds light on the origins of the strain in Britain and its subsequent spread to other parts of the world, including the Americas where the 3I lineage of M. leprae is still found in some southern states of America.

Age-associated reduction in cortical bone in males, trends from the third century AD to the present day.

Osteoporosis is increasingly recognised as a health threat in the ageing male. Risk factors for osteoporosis appear to have increased through time. This study investigates the hypothesis that lifestyle changes (e.g. increasing sedentism, tobacco use) over the past 1,800 years have resulted in greater age-related reduction in cortical bone in males in more recent compared with earlier times in England. Skeletons (N = 215) from three English archaeological sites dating from the third to nineteenth century AD, together with comparison with a modern reference population, are used to investigate this hypothesis. Metacarpal cortical thickness is used as a measure of cortical bone status. Results of this cross-sectional study do not support the above hypothesis but instead suggest that patterns of age-related reduction in cortical bone in males have remained stable over an 1,800 year period.

Oxygen isotope analysis of human bone phosphate evidences weaning age in archaeological populations.

Here we report bone phosphate oxygen (δ(18)Op) values from perinates/neonates and infants (<3.5 years; n = 32); children (4-12 years; n = 12); unsexed juveniles (16-18 years; n = 2); and adult bones (n = 17) from Wharram Percy, North Yorkshire, England, in order to explore the potential of this method to investigate patterns of past breastfeeding and weaning. In prior studies, δ(15)N and δ(13)C analyses of bone collagen have been utilized to explore weaning age in this large and well-studied assemblage, rendering this material highly appropriate for the testing and development of this alternative method targeting the inorganic phase of bone. Data produced reveal (18)O-enrichment in the youngest perinatal/neonatal and infant samples, and an association between age and bone δ(18)Op (and previously-published δ(15)N values), with high values in both these isotope systems likely due to breastfeeding. After the age of 2-3 years, δ(18)Op values are lower, and all children between the ages of 4 and 12, along with the vast majority of sub-adults and adults sampled (aged 16 to >50 years), have δ(18)Op values consistent with the consumption of local modern drinking water. The implications of this study for the reconstruction of weaning practices in archaeological populations are discussed, including variations observed with bone δ(15)Ncoll and δ(18)Op co-analysis and the influence of culturally-modified drinking water and seasonality. The use of this method to explore human mobility and palaeoclimatic conditions are also discussed with reference to the data presented.

Resorption of mandibular alveolar bone following loss of molar teeth and its relationship to age at death in a human skeletal population.

Estimating adult age at death in skeletal remains is problematic, particularly in older adults. Molar wear is arguably the most reliable ageing technique for palaeopopulations, but many older adult skeletons have lost their molar teeth ante mortem, precluding its application. Resorption of the alveolar process occurs following tooth loss, and this appears to continue for a prolonged period. The current work investigates the relationship of this process to individual age in a nineteenth century AD European archaeological skeletal series of known age at death (N = 92 individuals), and discusses its potential as an age indicator. Mandibular corpus height was measured at the different molar positions. In females, reduction of corpus height with age was found at molar positions showing ante mortem loss. In both sexes, a relationship was found between age and a simple composite measure of corpus height in the molar region in those showing ante mortem loss of one or more mandibular molars. The correlation was stronger in females (r = -0.74) than in males (r = -0.49), appeared approximately linear, and continued into the ninth decade, the oldest age group in the study material. The results suggest that investigation of height of the posterior part of the mandibular corpus as a skeletal age indicator for individuals that have lost one or more molar teeth is merited in other palaeopopulations.

A test of a recently devised method of estimating skeletal age at death using features of the adult acetabulum.

Estimation of age at death from adult skeletal remains is highly problematic, due in great part to interpopulation variability in skeletal age changes. Thorough testing of aging methods is therefore of key importance. A method recently devised by Calce (Am J Phys Anthropol 148 (2012): 11-23) for placing adult skeletons into three broad age at death classes (17-39, 40-64, 65+ years) on the basis of acetabular morphology is tested on a collection of 18-19th century AD skeletons (N = 185) of documented age at death from London. Results showed that 45% were correctly assigned to age class using this method. This compares with 81% reported by Calce on 20th century North American material. This indicates significant interpopulation differences in the relationship between the Calce acetabular variables and age, even between populations of European ancestry. Until the sources of this variation are better understood, caution should be used before applying this method to estimate age in unknown skeletons.

Loss of molar occlusion and mandibular morphology in adults in an ancient human population consuming a coarse diet.

The purpose of the study is to investigate the link between number of molar teeth retained in occlusion and mandibular morphology in adults in an ancient, high dental wear human population. The study material comprises skeletons from Mediaeval Wharram Percy, England (N = 50 female, 69 male adults). It was hypothesized that adults retaining fewer occluding molars would show reduction in mandibular dimensions, particularly in the ascending ramus and gonial regions where the main muscles of mastication have their insertions. Molar occlusal status is assessed using the concept of functional units. Mandibular morphology is assessed using a suite of ten linear measurements plus the mandibular angle. Results show no evidence for any association between number of molars retained in occlusion and mandibular angle. There was an association between mandibular size and number of molars retained in occlusion, with smaller mandibular dimensions in those retaining fewer occluding molars. Some measurements were affected more than others so that there was also some shape alteration. Alteration of mandibular dimensions was more clearly demonstrable in females than in males. Only in females could significant reduction in the ascending ramus and gonial regions be demonstrated. Reasons for the apparent difference in response to loss of molar occlusion between male and female mandibles are unclear, but sex differences in bony metabolism mediated by hormonal factors may be implicated. Results suggest that care should be exercised when including mandibles from individuals showing loss of molar occlusion in morphological studies.

Nasal septal deviation in a mediaeval population.

In modern populations, there is evidence that nasal septal deviation (NSD) may be associated with maxillary sinusitis, and that those with NSD may differ in craniofacial morphology from those without or with less severe NSD. Whether these associations hold true for earlier populations has yet to be investigated. The current work is a step toward remedying this. The study group comes from a mediaeval English archaeological site. NSD was quantified using image analysis. Maxillary sinusitis was identified from new bone formation in the antrum. Cranial morphology was assessed using standard craniometric measurements. The results provided no evidence for a relationship between NSD and maxillary sinus disease. NSD was associated with reduced measures of upper facial height, suggesting decoupling of growth in vertical height of the nasal septum and the bony structures surrounding it.

Archaeological skeletons support a northwest European origin for Paget's disease of bone.

The strong genetic component in the etiology of Paget's disease of bone (PDB), together with marked geographic variation in its prevalence, with high frequencies in British populations, has led some to suggest that the disease originated in Britain and spread around the world in recent times by the migration and admixture of British populations. This study aims to investigate this hypothesis by studying the world geographic distribution of PDB cases identified in ancient skeletons excavated from archaeological sites. The methodology is a review of PDB cases described in the literature. There were 109 cases that met modern diagnostic criteria. All came from Western Europe, 94% from England. These data support the hypothesis that PDB originated in this geographic region.

Lumbar vertebral morphology and isthmic spondylolysis in a British medieval population.

The British medieval population from Wharram Percy, England, has a greater prevalence of isthmic spondylolysis (11.9% of skeletons, 8.5% at the L5 level) than in modern populations (3%-6%). This may in part be due to differences in activity patterns between groups. However, Ward and Latimer (Spine 30 [2005] 1808-1814) proposed that the likelihood of developing and maintaining spondylolytic defects is also influenced by a lack of sufficient increase in mediolateral separation between articular processes in the lowest lumbar segments, given the human lumbar lordosis. Here, we demonstrate that spondylolytic individuals from Wharram Percy tend to have a less pronounced difference between mediolateral facet joint spacing of adjacent segments in the lowest lumbar region than do unaffected individuals, as seen in modern clinical and skeletal populations. These comparisons suggest that regardless of lifestyle, insufficient mediolateral increase in facet spacing predisposes people to spondylolytic defects, and so interfacet spacing patterns may have predictive utility in a clinical context. We also compare the Wharram Percy sample to a modern sample from the Hamann Todd collection with a typically modern prevalence rate. Data do not support the hypothesis that the Wharram Percy individuals had a less pronounced interfacet increase than the Hamann Todd, although they do have narrower lumbar facet spacing at the lowest three levels. Further investigation of anatomical variation underlying population-specific prevalence rates needs to be conducted.

Comparative genomic and phylogeographic analysis of Mycobacterium leprae.

Reductive evolution and massive pseudogene formation have shaped the 3.31-Mb genome of Mycobacterium leprae, an unculturable obligate pathogen that causes leprosy in humans. The complete genome sequence of M. leprae strain Br4923 from Brazil was obtained by conventional methods (6x coverage), and Illumina resequencing technology was used to obtain the sequences of strains Thai53 (38x coverage) and NHDP63 (46x coverage) from Thailand and the United States, respectively. Whole-genome comparisons with the previously sequenced TN strain from India revealed that the four strains share 99.995% sequence identity and differ only in 215 polymorphic sites, mainly SNPs, and by 5 pseudogenes. Sixteen interrelated SNP subtypes were defined by genotyping both extant and extinct strains of M. leprae from around the world. The 16 SNP subtypes showed a strong geographical association that reflects the migration patterns of early humans and trade routes, with the Silk Road linking Europe to China having contributed to the spread of leprosy.