Thoracic skeletal morphology and high-altitude hypoxia in Andean prehistory

Waist Reduction through Conversion from False to Floating Ribs

Background

Waist reduction by ultrasound-guided monocortical fracture (RibXcar), usually performed on floating ribs, may show limitations when performed on false ribs (9 and 10) because of the stress force exerted on the anterior fixation point (cartilage union to sternum). Hence, we introduced a procedure for conversion from false to floating ribs to improve the final result of the treatment of false ribs through a rib treatment scheme.

Methods

Forty-nine female patients undergoing rib surgery were recruited. Waist measurements and angular variations were compared between two groups of patients, the first (26 patients) consisting of patients who underwent RibXcar with conversion surgery (ribs 9 and 10) and the second (23 patients) consisting of patients who underwent RibXcar without conversion surgery (ribs 9 and 10).

Results

The waist measurements taken after 6 months showed a mean decrease of 8.70 cm in the group where only RibXcar was performed, whereas a statistically significant mean reduction of 17.04 cm was observed in the group where RibXcar was performed with rib conversion surgery.

Conclusions

The false-to-floating-rib conversion technique combined with RibXcar demonstrated more reduction in waist circumference and a more efficient rib angulation compared with RibXcar alone.

Comparison of Cardiorespiratory Fitness of Chinese Tibetan Adolescents with Their Han Counterparts: A Cross-Sectional Retrospective Study

Cardiorespiratory fitness (CRF) is a core element of healthy physical fitness. Foreign attention to CRF in adolescents at different altitudes is high, while less research has been conducted on Chinese adolescents. In order to compare the CRF of Chinese Tibetan adolescents with their Han counterparts born and raised at high altitude and Chinese Han adolescents at sea level. A total of 2748 participants, including Chinese Tibetan adolescents, Chinese Han adolescents born and raised at high altitudes, and Chinese Han adolescents at sea level aged 12-18 years old, were obtained using convenience sampling and random cluster sampling. The method of the 20 m shuttle run test (20 m SRT) test was used to derive VO_2max by equation. One-way ANOVA and LSD methods were conducted, and effect sizes were calculated to compare the CRF of the three types of adolescents. Regression analysis was used to analyze the relationship between altitude and VO_2max. The VO_2max scores of Chinese Tibetan adolescents and Chinese Han adolescents at sea level were higher than Chinese Han adolescents born and raised at high altitudes. For both boys and girls, the VO_2max scores of Chinese Tibetan adolescents exceeded Chinese Han adolescents at sea level after the age of 16 years old. Regression analysis showed that altitude was inversely associated with VO_2max. The pace of lung growth may distinguish Chinese Tibetan adolescents from Chinese Han adolescents born and raised at high altitudes. The results of the study suggest that we should focus on the changes in CRF in adolescents at different altitudes and should adopt different CRF interventions for adolescents at different altitudes.

Twenty-first century bioarchaeology: Taking stock and moving forward

This article presents outcomes from a Workshop entitled "Bioarchaeology: Taking Stock and Moving Forward," which was held at Arizona State University (ASU) on March 6-8, 2020. Funded by the National Science Foundation (NSF), the School of Human Evolution and Social Change (ASU), and the Center for Bioarchaeological Research (CBR, ASU), the Workshop's overall goal was to explore reasons why research proposals submitted by bioarchaeologists, both graduate students and established scholars, fared disproportionately poorly within recent NSF Anthropology Program competitions and to offer advice for increasing success. Therefore, this Workshop comprised 43 international scholars and four advanced graduate students with a history of successful grant acquisition, primarily from the United States. Ultimately, we focused on two related aims: (1) best practices for improving research designs and training and (2) evaluating topics of contemporary significance that reverberate through history and beyond as promising trajectories for bioarchaeological research. Among the former were contextual grounding, research question/hypothesis generation, statistical procedures appropriate for small samples and mixed qualitative/quantitative data, the salience of Bayesian methods, and training program content. Topical foci included ethics, social inequality, identity (including intersectionality), climate change, migration, violence, epidemic disease, adaptability/plasticity, the osteological paradox, and the developmental origins of health and disease. Given the profound changes required globally to address decolonization in the 21st century, this concern also entered many formal and informal discussions.

Body proportions and environmental adaptation in gorillas

OBJECTIVES

Limb length and trunk proportions are determined in a large, taxonomically and environmentally diverse sample of gorillas and related to variation in locomotion, climate, altitude, and diet.

MATERIALS AND METHODS

The sample includes 299 gorilla skeletons, 115 of which are infants and juveniles, distributed between western lowland (G. gorilla gorilla), low and high elevation grauer (G. beringei graueri), and Virunga mountain gorillas (G. b. beringei). Limb bone and vertebral column lengths scaled to body mass are compared between subgroups by age group.

RESULTS

All G. beringei have relatively short 3rd metapodials and manual proximal phalanges compared to G. gorilla, and this difference is apparent in infancy. All G. beringei also have shortened total limb lengths relative to either body mass or vertebral column length, although patterns of variation in individual skeletal elements are more complex, and infants do not display the same patterns as adults. Mountain gorillas have relatively long clavicles, present in infancy, and a relatively long thoracic (but not lumbosacral) vertebral column.

DISCUSSION

A variety of environmental factors likely contributed to observed patterns of morphological variation among extant gorillas. We interpret the short hand and foot bones of all G. beringei as genetic adaptations to greater terrestriality in the last common ancestor of G. beringei; variation in other limb lengths to climatic adaptation, both genetic and developmental; and the larger thorax of G. b. beringei to adaptation to reduced oxygen pressure at high altitudes, again as a product of both genetic differences and environmental influences during development.

Ribcage measurements indicate greater lung capacity in Neanderthals and Lower Pleistocene hominins compared to modern humans

Our most recent fossil relatives, the Neanderthals, had a large brain and a very heavy body compared to modern humans. This type of body requires high levels of energetic intake. While food (meat and fat consumption) is a source of energy, oxygen via respiration is also necessary for metabolism. We would therefore expect Neanderthals to have large respiratory capacities. Here we estimate the pulmonary capacities of Neanderthals, based on costal measurements and physiological data from a modern human comparative sample. The Kebara 2 male had a lung volume of about 9.04 l; Tabun C1, a female individual, a lung volume of 5.85 l; and a Neanderthal from the El Sidrón site, a lung volume of 9.03 l. These volumes are approximately 20% greater than the corresponding volumes of modern humans of the same body size and sex. These results show that the Neanderthal body was highly sensitive to energy supply.

Daniel García-Martínez et al. report Neanderthal lung volume estimates based on measurements from rib bone fossils and lung capacity data from modern humans. They estimate that Neanderthal individuals had approximately 20% higher lung capacity than modern humans, possibly due to higher energy requirements.

Eco-geographic adaptations in the human ribcage throughout a 3D geometric morphometric approach

OBJECTIVES

According to eco-geographic rules, humans from high latitude areas present larger and wider trunks than their low-latitude areas counterparts. This issue has been traditionally addressed on the pelvis but information on the thorax is largely lacking. We test whether ribcages are larger in individuals inhabiting high latitudes than in those from low latitudes and explored the correlation of rib size with latitude. We also test whether a common morphological pattern is exhibited in the thorax of different cold-adapted populations, contributing to their hypothetical widening of the trunk.

MATERIALS AND METHODS

We used 3D geometric morphometrics to quantify rib morphology of three hypothetically cold-adapted populations, viz. Greenland (11 individuals), Alaskan Inuit (8 individuals) and people from Tierra del Fuego (8 individuals), in a comparative framework with European (Spain, Portugal and Austria; 24 individuals) and African populations (South African and sub-Saharan African; 20 individuals).

RESULTS

Populations inhabiting high latitudes present longer ribs than individuals inhabiting areas closer to the equator, but a correlation (p < 0.05) between costal size and latitude is only found in ribs 7-11. Regarding shape, the only cold adapted population that was different from the non-cold-adapted populations were the Greenland Inuit, who presented ribs with less curvature and torsion.

CONCLUSIONS

Size results from the lower ribcage are consistent with the hypothesis of larger trunks in cold-adapted populations. The fact that only Greenland Inuit present a differential morphological pattern, linked to a widening of their ribcage, could be caused by differences in latitude. However, other factors such as genetic drift or specific cultural adaptations cannot be excluded and should be tested in future studies.

Nasal variation in relation to high-altitude adaptations among Tibetans and Andeans

OBJECTIVES

High-altitude (>2500 m) populations face several pressures, including hypoxia and cold-dry air, resulting in greater respiratory demand to obtain more oxygen and condition inspired air. While cardiovascular and pulmonary adaptations to high-altitude hypoxia have been extensively studied, adaptations of upper-respiratory structures, e.g., nasal cavity, remain untested. This study investigates whether nasal morphology presents adaptations to hypoxic (larger noses) and/or cold-dry (tall/narrow noses) conditions among high-altitude samples.

METHODS

CT scans of two high- and four low-altitude samples from diverse climates were collected (n = 130): high-altitude Tibetans and Peruvians; low-altitude Peruvians, Southern Chinese (temperate), Mongolian-Buriats (cold-dry), and Southeast Asians (hot-wet). Facial and nasal distances were calculated from 3D landmarks placed on digitally-modeled crania. Temperature, precipitation, and barometric pressure data were also obtained.

RESULTS

Principal components analysis and analyses of variance primarily indicate size-related differences among the cold-dry (Mongolian-Buriats) and hot-wet (Southeast Asians) adapted groups. Two-block partial least squares (PLS) analysis show weak relationships between size-standardized nasal dimensions and environmental variables. However, among PLS1 (85.90% of covariance), Tibetans display relatively larger nasal cavities related to lower temperatures and barometric pressure; regression analyses also indicate high-altitude Tibetans possess relatively larger internal nasal breadths and heights for their facial size.

CONCLUSIONS

Overall, nasal differences relate to climate among the cold-dry and hot-wet groups. Specific nasal adaptations were not identified among either Peruvian group, perhaps due to their relatively recent migration history and population structure. However, high-altitude Tibetans seem to exhibit a compromise in nasal morphology, serving in increased oxygen uptake, and air-conditioning processes.

Early Homo, plasticity and the extended evolutionary synthesis

The Modern Synthesis led to fundamental advances in understandings of human evolution. For human palaeontology, a science that works from ancestral phenotypes (i.e. the fossil record), particularly important have been perspectives used to help understand the heritable aspects of phenotypes and how fossil individuals might then be aggregated into species, and relationships among these groups understood. This focus, coupled with the fragmentary nature of the fossil record, however, means that individual phenotypic variation is often treated as unimportant 'noise', rather than as a source of insight into population adaptation and evolutionary process. The emphasis of the extended evolutionary synthesis on plasticity as a source of phenotypic novelty, and the related question of the role of such variation in long-term evolutionary trends, focuses welcome attention on non-genetic means by which novel phenotypes are generated and in so doing provides alternative approaches to interpreting the fossil record. We review evidence from contemporary human populations regarding some of the aspects of adult phenotypes preserved in the fossil record that might be most responsive to non-genetic drivers, and we consider how these perspectives lead to alternate hypotheses for interpreting the fossil record of early genus Homo. We conclude by arguing that paying closer attention to the causes and consequences of intraspecific phenotypic variation in its own right, as opposed to as noise around a species mean, may inspire a new generation of hypotheses regarding species diversity in the Early Pleistocene and the foundations for dispersal and regional diversification in Homo erectus and its descendants.

Bioarchaeological profile of stress and dental disease among ancient high altitude Himalayan communities of Nepal

OBJECTIVES

This study examines biological indicators of dental disease and nonspecific stress in human remains of three high altitude Himalayan archaeological sites to test whether shared ecological constraints led to similar bioarchaeological profiles in these markers.

METHODS

Samples (n = 170) derive from three sites in Nepal dating to two periods (400-50 BCE and c. 400-650 CE). Dental diseases (caries, antemortem tooth loss, and abscesses) were assessed by both the number of individuals and the number of elements observed, while childhood stress markers included observation of growth disruptions (enamel hypoplasia and adult femur length/stature) and cranial porosities. Statistical analysis included chi-square and Fisher's exact tests for categorical data and ANOVA and t-tests for metric data.

RESULTS

There are significant differences between the sites and sexes in frequencies of dental diseases in the adult samples. There are low frequencies of childhood stress markers overall and the femur length data show no significant differences across sites, but significant sexual dimorphism within each site. Females have reduced stature compared to contemporary Tibetan samples residing at a similar elevation.

CONCLUSIONS

Variations in dental disease frequencies between the sites may be due to local variations in microenvironment, cultural, and/or temporal differences in resource availability, food consumption and preparation, as well as the age structure of the samples. The low frequencies of markers for nonspecific stress may be indicative of the ability of these ancient Himalayan groups to successfully meet the challenges posed by the extreme conditions of high altitude living through biocultural adaptations.

Lower Prevalence of Alzheimer's Disease among Tibetans: Association with Religious and Genetic Factors

BACKGROUND

The prevalence of dementia differs among racial groups, the highest prevalence being in Latin America (8.5%) compared to sub-Saharan African regions (2-4%). The most common type of dementia is Alzheimer's disease (AD).

OBJECTIVE

To estimate the prevalence of AD in the Qinghai-Tibet plateau and to investigate the related factors.

METHODS

This was a cross-sectional, multistage cluster sampling design survey. Data was collected from May 2014 to September 2014 from 4,060 Tibetan aged >60 years. Participants underwent clinical examinations and neuropsychological evaluations. MALDI-TOF was used to test the genotypes of CLU, TFAM, TP53INP1, IGHV1-67, CR1, ApoE, and BIN1. Logistic regression models were used to ascertain the associations with AD.

RESULTS

The prevalence of AD among Tibetan individuals aged >60 years was 1.33% (95% CI: 0.98-1.69). The CLU haplotypes AA+GA (odds ratio (OR) = 4.483; 95% CI: 1.069-18.792) of rs2279590 was correlated with AD. The CLU haplotypes GG+GC (OR = 0.184; 95% CI: 0.038-0.888) of rs9331888 and kowtow (OR = 0.203; 95% CI 0.046-0.896) were negatively correlated with AD.

CONCLUSION

A low prevalence of AD was found in Tibetans from the Qinghai-Tibet plateau. Multivariate analysis might suggest that regular "mind-body" religious meditative activities may be negatively associated with AD in this population, as well as the CLU genotype at rs9331888.

Intergenerational changes in chest size and proportions in children and adolescents aged 3-18 from Kraków (Poland), within the last 70 years

OBJECTIVES

The size and proportions of the human body change continuously in response to social change and economic development. As reported by papers on intergenerational changes in chest size, this part of the human body is also influenced by environmental factors. The aim of this study was to assess changes in the dimensions and proportions of the chest of children and adolescents over a span of 70 years.

METHODS

In 2010 an anthropological study was conducted on 3878 children and adolescents aged 3-18 years living in Kraków (Poland). Data on chest dimensions (breadth, depth, circumference, chest index) were compared to data from 1938 (3719 children) and 1983 (6464 children).

RESULTS

In boys, chests became increasingly deep; in boys 18 years of age, the chest index increased by 4.8 units, unlike girls, whose chests markedly flattened. The chest index in girls 18 years of age decreased by 4.2 units. In almost all age categories these differences were statistically significant. Also, in all age categories, children studied in 2010 had a significantly bigger chest circumference than boys and girls surveyed in 1983, respectively, by averages of 3.6 cm and 3 cm.

CONCLUSIONS

The main reason for these changes may be the socio-economic transformation, which has been especially strong in recent decades. These results may have practical importance in many areas of knowledge, including medicine, nutritional science, and sports. They can also be important for informing preventive measures that should be taken in order to increase the physical activity of children and youth, especially boys.

Ontogeny of 3D rib curvature and its importance for the understanding of human thorax development

OBJECTIVES

Sagittal and axial rib orientation relative to the spine are two factors that modify rib cage morphology during ontogeny. Some studies suggest that these factors do not operate in the same way at the upper (ribs 1-5) and lower thorax (ribs 6-10) during postnatal growth, but it is unknown if the ontogenetic thoracic changes are produced by morphological changes of the ribs (intrinsic rib factors) or by external factors related to costal joints (extrinsic rib factors).

MATERIAL AND METHODS

To clarify these questions, we applied 3D geometric morphometrics of landmarks and sliding semilandmarks (N = 20/rib) to 280 individual ribs (1-10) of Homo sapiens comprising the entire human ontogeny and growth simulations were carried out.

RESULTS

PCA shows that intrinsic rib factors (rib torsion and axial rib curvature) are ontogenetic factors of variability that contribute to configuring the adult thorax shape. Moreover, growth simulations and regression slopes suggest that the upper thorax unit is comprised by ribs 1-7 and the lower unit at least by ribs 8-10.

DISCUSSION

These results suggest anatomical constraints for ontogenetic rib variation, since ribs 1-7 (true ribs) are directly linked to the sternum. Moreover, these results are supported by functional anatomy because pulmonary kinematics would influence the upper unit and diaphragmatic kinematics would influence the lower one. Our findings are relevant not only to understanding how changes at individual ribs contribute to the adult thorax morphology, but also to the development and evolution of the modern human rib cage.

Chest circumference and sitting height among children and adolescents from Lhasa, tibet compared to other high altitude populations

OBJECTIVES

The adaptation of human beings to a high altitude environment during growth has been reported in several populations but is less known for Tibetans. The objective of this study was to investigate similarities and differences of Tibetans in patterns and characteristics of physical growth and development in comparison to other high altitude populations.

METHODS

We measured the stature, weight, chest circumference and sitting height of 2,813 healthy children and adolescents aged 6- to 21-year-old living at 3,658-4,500 m in Tibet, China, and compared them with published data from other high altitude populations. Eligible participants must have been born and raised in Tibet, and both their parents' families have to be Tibetan for at least the past three generations.

RESULTS

The physical growth and development of children and adolescents in Tibet and the Andes followed similar patterns, such as delayed growth, short stature and sitting height, and large chest dimensions. Relative to stature, Tibetan sitting heights are similar to Andeans, but chest circumferences are smaller.

CONCLUSIONS

Findings from this study reinforce the conclusion that Tibetan and Andean populations have adapted differently to high altitude hypoxia. The physical features of each population may result from unique adaptation to hypoxia, as well as socio-ecological factors, such as poor nutrition.