An official website of the United States government
Abstract ObjectivesPreviously developed methods in subadult body mass estimation have not been tested in populations other than European–American or African–American. This study uses a contemporary Taiwanese sample to test these methods. Through evaluating their accuracy and bias, we addressed whether the allometric relationships between body mass and skeletal traits commonly used in subadult body mass estimation are conserved among different populations. Materials and MethodsComputed tomography scans of lower limbs from individuals aged 0–17 years old of both sexes were collected from National Taiwan University Hospital along with documented body weight. Polar second moment of area, distal femoral metaphyseal breadth, and maximum superior/inferior femoral head diameter were collected either directly from the scans or from reconstructed 3D models. Estimated body mass was compared with documented body mass to assess the performance of the equations. ResultsCurrent methods provided good body mass estimates in Taiwanese individuals, with accuracy and bias similar to those reported in other validation studies. A tendency for increasing error with increasing age was observed for all methods. Reduced major axis regression showed the allometric relationships between different skeletal traits and body mass across different age categories can all be summarized using a common fitted line. A revised, maximum likelihood‐based approach was proposed for all skeletal traits. DiscussionThe results suggested that the allometric relationships between body mass and different skeletal traits are largely conserved among populations. The revised method provided improved applicability with strong underlying theoretical justifications, and potential for future improvements.
more »
« less
Estimating adult age categories in commingled skeletons with Transition Analysis 3
Abstract ObjectivesWe estimate adult age frequencies from Unar 1 and Unar 2, two late Umm an‐Nar (2400–2100 BCE) tombs in the modern‐day Emirate of Ras al‐Khaimah, United Arab Emirates. These collective tombs each contained hundreds of skeletons in commingled, fragmented, and variably cremated states. Previous studies placed the vast majority of this mortuary community in a generalized “adult” category, as have most analyses of similar tombs from this period. We sought to test how adult age estimation methods compare in identifying young, middle, and old‐age individuals in commingled assemblages. Materials and MethodsWe employed Transition Analysis 3 (TA3) and traditional age estimation methods to generate adult age frequencies for each tomb. We compared these frequencies between tomb contexts as well as by method. ResultsUnar 1 and Unar 2 had similar adult age frequencies within each method, but TA3 age frequencies included significantly more middle and older adult individuals than those generated by traditional methods. DiscussionThese results support findings of earlier iterations of transition analysis in regard to sensitivity in old adult age estimation, compared with traditional methods. Our findings indicate a potential use of TA3 in reconstructing age frequencies and mortality profiles in commingled skeletal assemblages. Increasing our understanding of everyday life in the distant past necessitates better understandings of adult age, and here, we illustrate how age estimation method choice significantly changes bioarchaeological interpretations of aging in Bronze Age Arabia. Research HighlightsAdult age estimation using TA3 revealed significantly more middle and older adults than traditional methods in two commingled tombs.Similar mean maximum likelihood point estimates by side and across skeletal elements were found between tombs.
more »
« less
- Award ID(s):
- 1852426
- PAR ID:
- 10509573
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- American Journal of Biological Anthropology
- Volume:
- 183
- Issue:
- 2
- ISSN:
- 2692-7691
- Page Range / eLocation ID:
- e24890
- Subject(s) / Keyword(s):
- age-at-death estimations, bioarchaeology, commingling, paleodemography, transition analysis
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract BACKGROUNDLimited research has explored the effect of cardiovascular risk and amyloid interplay on cognitive decline in East Asians. METHODSVascular burden was quantified using Framingham's General Cardiovascular Risk Score (FRS) in 526 Korean Brain Aging Study (KBASE) participants. Cognitive differences in groups stratified by FRS and amyloid positivity were assessed at baseline and longitudinally. RESULTSBaseline analyses revealed that amyloid‐negative (Aβ–) cognitively normal (CN) individuals with high FRS had lower cognition compared to Aβ– CN individuals with low FRS (p < 0.0001). Longitudinally, amyloid pathology predominantly drove cognitive decline, while FRS alone had negligible effects on cognition in CN and mild cognitive impairment (MCI) groups. CONCLUSIONOur findings indicate that managing vascular risk may be crucial in preserving cognition in Aβ– individuals early on and before the clinical manifestation of dementia. Within the CN and MCI groups, irrespective of FRS status, amyloid‐positive individuals had worse cognitive performance than Aβ– individuals. HighlightsVascular risk significantly affects cognition in amyloid‐negative older Koreans.Amyloid‐negative CN older adults with high vascular risk had lower baseline cognition.Amyloid pathology drives cognitive decline in CN and MCI, regardless of vascular risk.The study underscores the impact of vascular health on the AD disease spectrum.more » « less
-
Abstract INTRODUCTIONIdentification of individuals with mild cognitive impairment (MCI) who are at risk of developing Alzheimer's disease (AD) is crucial for early intervention and selection of clinical trials. METHODSWe applied natural language processing techniques along with machine learning methods to develop a method for automated prediction of progression to AD within 6 years using speech. The study design was evaluated on the neuropsychological test interviews ofn = 166 participants from the Framingham Heart Study, comprising 90 progressive MCI and 76 stable MCI cases. RESULTSOur best models, which used features generated from speech data, as well as age, sex, and education level, achieved an accuracy of 78.5% and a sensitivity of 81.1% to predict MCI‐to‐AD progression within 6 years. DISCUSSIONThe proposed method offers a fully automated procedure, providing an opportunity to develop an inexpensive, broadly accessible, and easy‐to‐administer screening tool for MCI‐to‐AD progression prediction, facilitating development of remote assessment. HighlightsVoice recordings from neuropsychological exams coupled with basic demographics can lead to strong predictive models of progression to dementia from mild cognitive impairment.The study leveraged AI methods for speech recognition and processed the resulting text using language models.The developed AI‐powered pipeline can lead to fully automated assessment that could enable remote and cost‐effective screening and prognosis for Alzehimer's disease.more » « less
-
Abstract The Arctic is rapidly warming, and tundra vegetation community composition is changing from small, prostrate shrubs to taller, erect shrubs in some locations. Across much of the Arctic, the sensitivity of shrub secondary growth, as measured by growth ring width, to climate has changed with increased warming, but it is not fully understood how shrub age contributes to shifts in climate sensitivity.We studied Siberian alder,Alnus viridisssp.fruticosa, a large nitrogen‐fixing shrub that has responded to climate warming with northward range expansion over the last 50 years. We used serial sectioning of 26 individual shrubs and 94 cross‐sections to generate a 98‐year growth ring chronology, including one 142‐year‐old, Siberian alder in Northern Alaska. We tested how secondary growth sensitivity to climate has changed over the past century (1920–2017) and how shrub age affects climate sensitivity of alder growth through time.We found that over time, alder growth as expressed by the stand chronology became more sensitive to July mean monthly air temperature. Older shrubs displayed higher sensitivity to June and July temperature than younger alders. However, during the first 30 years of growth of any shrub, temperature sensitivity did not differ among individuals. In addition, the June temperature sensitivity of growth series from individual cross‐sections depended on the age of the attached shrub.Our results suggest that age contributes to climate sensitivity, likely through modifying internal shrub carbon budgets by changing size and reducing alder's dependence on N‐fixation over time. Older, more sensitive alder may enhance C and N‐cycling while having greater recruitment potential. Linking alder age to climate sensitivity, recruitment and total N‐inputs will enable us to better predict ecosystem carbon and nitrogen cycling in a warmer Arctic. Read the freePlain Language Summaryfor this article on the Journal blog.more » « less
-
Abstract ObjectivesRecurrent famine events during the medieval period might have contributed to excess mortality during the Black Death in London, England (c. 1349–1350). Previous research using conventional methods of age estimation revealed that adult males experienced lower risks of mortality under “normal” (attritional) but not famine mortality conditions following the Black Death. However, given the biases inherent in conventional age estimation methods, this study reassesses sex differences in risks of medieval adult famine mortality using ages estimated via transition analysis, which avoids some of the limitations of conventional age estimation methods. Materials and MethodsWe apply hazards analysis (the Gompertz model of adult mortality) to ages estimated for human skeletal remains (n= 1245) from London cemeteries dated to the pre‐Black Death (c. 1000–1250 CE) and post‐Black Death (c. 1350–1540 CE) periods. ResultsThe results reveal no sex differences in risks of mortality before the Black Death but indicate that adult males faced lower risks of mortality after the Black Death during conditions of normal and famine mortality. ConclusionsThese findings largely support those of our previous research, which suggested that selective mortality during the Black Death or sex‐biased improvements in standard of living following the epidemic reduced risk of mortality for adult males in the post‐Black Death period under normal mortality conditions. However, the use of transition analysis age estimates also revealed a reduced risk of mortality for post‐Black Death adult males under famine conditions.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1002/ajpa.24890
