Age Estimation Of Individuals Research Articles

Age estimation using postmortem computed tomography-based Hounsfield unit values of the palate and mandibular condyle and the Eichner classification

Age estimation is important in forensic investigations of unidentified human remains. This study assessed the correlation between age and Hounsfield unit (HU) values of the palate and mandibular condyle based on postmortem computed tomography (CT) and analyzed the influence of occlusal support in developing an age estimation method for Japanese individuals, including older adults.The sample consisted of a training dataset (357 cadavers) and a validation dataset (300 cadavers) that underwent postmortem CT.Three measurements were selected: the respective HU values of the palate and mandibular condyle and the Eichner classification. The correlation coefficients between age and HU values were also evaluated. Multiple stepwise regression analysis was performed to evaluate the significance of four parameters (sex, respective HU values of the palate and mandibular condyle, and the Eichner classification) for age estimation and to determine the best age estimation formula. In the validation tests, inaccuracy and bias were calculated for the groups aged ≥65 or <65 years.Significant correlations between age and HU values of the palate and mandibular condyle were observed, regardless of sex. In multiple stepwise regression analysis, all variables except sex were significantly correlated with age. The age estimation formula from the regression analysis was useful, and the validation test exhibited high accuracy, especially in older adults.The HU values of the palate and mandibular condyle and the Eichner classification are useful for age estimation in Japanese individuals.

Comparing a common clavicle maturation-based age estimation method to ordinary regression analyses with quadratic and sex-specific interaction terms in adolescents

Established methods of age estimation are based on correlating defined maturation stages of bony structures with tables representing the observed range of biological ages in the majority of cases. In this retrospective monocentric study in southwestern Germany, common age estimation methodology was assessed in n = 198 subjects at the age of 25 or younger by analyzing the influence of age, quadratic age, biological sex and age-sex interaction on the ossification stages of the medial epiphysis fugue. Three readers (ICC ≥ 0.81 for left/right side) evaluated routine care computed tomography images of the clavicle with a slice thickness of 1 mm. By using least square regression analyses, to determine the real biological age a quadratic function was determined corrected for the age estimated by established methods and sex (R2 = 0.6 each side), reducing the mean absolute error and root mean squared error in the age estimation of women (2.57 and 3.19) and men (2.57 and 3.47) to 1.54 and 1.82 for women, and 1.54 and 2.25 for men. In women, the medial clavicle epiphysis seem to fuse faster, which was particularly observable from approximately 18 years of age. Before that age, the estimation method was relatively close to the ideal correlation between assessed and real age. To conclude, the presented new method enables more precise age estimation in individuals and facilitates the determination and quantification of additional variables, quantifying their influence on the maturation of the medial clavicle epiphysis based on the established ossification stages.

Accuracy of portable ultrasound for obstetric biometry.

We assessed the accuracy of two portable ultrasound machines (PUM) in obtaining fetal biometry and estimating gestational age. We analyzed data from the Fetal Age Machine Learning Initiative, an observational study of pregnant women in the United States and Zambia. Each participant underwent assessment by an experienced sonographer using both a high-specification ultrasound machine (HSUM) and a PUM (either Butterfly iQ or Clarius C3) to measure fetal biometry and calculate estimated gestational age (EGA) at each visit. Through comparison of paired PUM-HSUM scans, we estimated agreement between individual biometry measurements and aggregate gestational age estimates by reporting mean difference, along with intraclass correlation coefficient (ICC) and Bland-Altman plots, adjusting for trend. 881 participants contributed 1386 paired PUM-HSUM ultrasound studies between April and December 2021. PUM studies included 991 Butterfly and 395 Clarius. Gestational age at scan ranged from 7 to 38 weeks. Compared to HSUM, the Butterfly PUM had a mean difference of -0.20 days (95%CI±0.40) in the 1st trimester and -0.68 days (95%CI±0.68) in the 2nd/3rd trimesters. Also compared to HSUM, the Clarius PUM had a mean difference of 0.47 days (95%CI±0.64) in the 1st trimester and -1.67 days (95%CI±0.43) in the 2nd/3rd trimesters. ICCs were 0.989 or greater throughout. Increasing gestational age was associated with increasing error and absolute error. Both PUM devices demonstrated a modest trend toward underestimation of EGA at advancing gestational ages in 2nd/3rd trimester scans, compared to HSUM. Both the Butterfly iQ and Clarius C3 PUM devices were highly accurate in performing fetal biometry in a diverse population from the US and Zambia. This article is protected by copyright. All rights reserved.

Refining age at legal-size estimation in the Newfoundland &amp; Labrador populations of the snow crab Chionoecetes opilio (Fabricius, 1788) (Decapoda: Brachyura: Oregoniidae)

Abstract Current knowledge of age at legal size in Newfoundland &amp; Labrador (NL) and other snow-crab stocks is incomplete due to historic estimations not accounting for skip-molting growth delays. Previous work has shown skip-molting incidence to occasionally be very high in males, both in NL and some other major snow-crab stocks. This warrants research to better understand impacts of skip-molting on snow-crab age and growth dynamics, which are central to population assessment and resource management. We simulated the impact of skip-molting on growth dynamics of snow crabs from three regions around NL by coupling a nineteen year time series of molt-type probabilities derived from field trawl surveys to historical data on age-at-instar based on cohort analysis of wild populations that do not consider skip-molting in making age estimations. Trawl surveys and simulations showed that skip-molting is a prominent feature in NL snow crabs, with up to four skip-molts being a reasonable maximum possible estimate for males in portions of the NL snow-crab stock. A complementary analysis examining the ability to age snow crabs using gastric mill band counts showed overall strong agreement with published growth trajectories that were modified to include skip-molting as well as reasonable average age approximations for most crabs, but unexpectedly high variability in age estimates for individuals of a same instar stage and unexpectedly low age estimates for younger crabs. Our study leads to a refinement of age at legal size for NL snow crab from the current nine-year estimate to a range of 9–13 years. Although this range is deemed to capture virtually every crab reaching legal size in NL snow-crab populations, ages higher than 11 years to fishery recruitment (2 skip-molts) are relatively infrequent.

Validation of a deep learning algorithm for bone age estimation among patients in the city of São Paulo, Brazil.

To validate a deep learning (DL) model for bone age estimation in individuals in the city of São Paulo, comparing it with the Greulich and Pyle method. This was a cross-sectional study of hand and wrist radiographs obtained for the determination of bone age. The manual analysis was performed by an experienced radiologist. The model used was based on a convolutional neural network that placed third in the 2017 Radiological Society of North America challenge. The mean absolute error (MAE) and the root-mean-square error (RMSE) were calculated for the model versus the radiologist, with comparisons by sex, race, and age. The sample comprised 714 examinations. There was a correlation between the two methods, with a coefficient of determination of 0.94. The MAE of the predictions was 7.68 months, and the RMSE was 10.27 months. There were no statistically significant differences between sexes or among races (p > 0.05). The algorithm overestimated bone age in younger individuals (p = 0.001). Our DL algorithm demonstrated potential for estimating bone age in individuals in the city of São Paulo, regardless of sex and race. However, improvements are needed, particularly in relation to its use in younger patients.

New evidence of early Holocene naturalistic rock art in Jinsha River valley, southwestern China

More than 70 rock painting sites have been discovered in the Jinsha River valley in northwestern Yunnan Province of southwestern China. These sites are dominated by naturalistic animal paintings and display certain similarities with the oldest hunting–gathering rock art discovered across the world. The Baiyunwan rock shelter is representative of the corpus of the Jinsha rock-art sites, comprising 15 identifiable naturalistic animal paintings in addition to several unidentifiable paintings. However, to date, the age estimation of these precious rock paintings lacks precision. Thus, this study performed U-series dating of carbonate samples (in total, 32 subsamples) to constrain the minimum and maximum ages of the Baiyunwan rock paintings. The U-series ages were corrected with a site-specific value of the initial 230Th/232Th ratio determined by isochron analyses, and the age reliability was evaluated by stratified dating analyses. Moreover, we used Bayesian age modeling to combine the individual age estimates and considered previously published data. The age range of the Baiyunwan rock paintings was determined as 7.09–8.93 ka, with a probability of 95 %. This age estimate corresponds to the late painting phase documented at Wanrendong Cave (∼8.37–8.70 ka), located within the same region, and provides new evidence for early Holocene naturalistic rock paintings in the Jinsha River valley, Yunnan, southwestern China.

Age estimation in infant and prenatal individuals through the metric development of the pars petrosa and squamosal portion of the temporal bone.

This study proposes an assessment of the accuracy of the Fazekas and Kósa and Nagaoka methods by measuring the squamosal and petrous portions of the temporal bone, whose application in the Mediterranean population is not recommended. Therefore, our proposal is a new formula to estimate the age of skeletal remains from individuals at 5 months gestational age to 1.5 postnatal years with the temporal bone. The proposed equation was calculated on a Mediterranean sample identified from the cemetery of San José, Granada (n = 109). The mathematical model used is the exponential regression of the estimated age for each measure and sex, and both in combination, using an inverse calibration and cross-validation model. In addition, the estimation errors and the percentage of individuals within a 95% confidence interval were calculated. The lateral development of the skull, especially the growth of the length of the petrous portion, showed the greatest accuracy, while its counterpart, the width of the pars petrosa, showed the lowest accuracy, so its use is discouraged. The positive results from this paper should be useful in both forensic and bioarchaeological contexts.

Age estimation by evaluation of obliteration of the palatine sutures: a scoping review.

The age estimation (AE) of human remains is a challenging task since it is dependent on the state in which these remains are found. Since the macroscopic evaluation of palatal sutures has been proposed as a method for AE, the aim of this study was to review the literature on this method, considering that the cases of edentulous elderly are among the greatest challenges in anthropological and forensic contexts. A scoping review was performed using a specific search strategy in PubMed, Web of Science, SciELO, LILACS, and Google Scholar. The search identified 13 articles, among which the USA yielded the most information with 3 articles. Only 1 study was identified in Latin America (Peru). There was great diversity regarding the origin of samples, and the studies were carried out on both historical and modern populations. Only 6 articles exceeded the average sample size (168.08) and 4 articles studied samples of fewer than 100 individuals. Although 6 different methods were identified, Mann et al.'s revised method was the most used. The selection of appropriate methods for AE depends on what skeletal elements are present and the general age of the specimens. Although evaluation of the obliteration of the palatal sutures has been found to be simple and promising for AE in individuals over 60years of age, this method has been reported to have less precision than other more complex methods, which makes the use of a combination of methods necessary to increase the level of confidence and the percentage of success. Further research could resolve this weakness, and methodological refinement (perhaps the digitization and automation of processes, or the application of Bayesian methodology) could provide the necessary solidity to comply with international standards in the forensic scenario.

Age estimation from alveolar bone loss, re-evaluation of Ruquet's method.

There are many dental age estimation methods,but all the methodsdo notcorrespond, especially for aging methods for adults and mature individuals, to the reality of theforensicfield,whichfavors simple, effective, andeasy-to-usemethods. Ruquet (2015) developed a method based on alveolar bone loss that predicts age for individuals between 25 and 60years old and is even more accurate for those 25-40years old. This study re-evaluated Ruquet's alveolar bone loss method using three-dimensional imaging of individuals whose age and sex were known, without taking into account their medical conditions. Digital measurements, from the cemento-enamel junction (CEJ) to the alveolar bone crest (ABC), were performed on the mesial and distal surfaces of teeth on 243 patients, independent of the tridimensional imaging test. With these measurements, two alveolar bone loss averages (ABL) were calculated, one with all the teeth present on the arches and another with only Ramfjörd's teeth. Bone loss showed a significant correlation with age (p < 0.001). The age estimation with all teeth and with only Ramfjörd's teeth showed a statistically significant difference, and age estimation was more accurate when all teeth were used. The assessment of alveolar resorption appears to be an interesting tool for age estimation in adult individuals. However, the method still lacks precision, and the mean absolute errors (MAEs) obtained by age group were all greater than 5years, except for the age group 35-39years old, for the age estimation with all teeth. Further studies should explore this existing correlation between alveolar bone loss and age and refine this method to make it more accurate.

Age estimation of Russian individuals by teeth using the London Atlas

Knowing an individual's age is necessary for several situations, both in the living and the deceased. The London Atlas uses dental development and eruption to estimate age. Testing the method in different populations is necessary to assess its performance. This study aimed to assess the performance of the London Atlas method in a Russian sample using panoramic radiographs. A sample of 703 panoramic radiographs of Russian individuals (n = 405 females, 57.61% and n = 298 males, 42.39%) with ages between 8 and 23 years were analyzed. The results showed overestimation in individuals from 8 to 14 years and underestimation from 15 to 23 years. The mean difference between estimated and chronological ages did not exceed 0.7 years among individuals with ages below 19 years. The difference increased to over three years in individuals from 20 to 23 years. Statistically significant differences were found between females and males between 17 and 18 years (p&lt;0.05). The London Atlas is suitable for Russian children and adolescents aged between 8 and 19 years; however, it showed unsatisfactory results for application in individuals over 20 years.

Analysis of the Development Trend in Forensic Odontology Based on CiteSpace.

To realize the dynamic visualization of forensic odontology based on the bibliometrics methods, and capture the research hotspots and identify the future development trend. Literature articles published from January 1995 to December 2020 were searched according to specific subject words in the core data set of Web of Science. The visualization analysis of publishing country, institution, discipline, author, co-cited journal and keywords was performed by CiteSpace 5.7.R5W software. The annual analysis of publications showed an upward trend of forensic odontology research literature year by year, with the number of annual publications more than 110 in the last five years. Developed countries were the main source of contributions and the average centrality was greater than 0.2. The research of forensic odontology involved multiple disciplines, including stomatology, biology, computer science and medical imaging, with a distinct interdisciplinary feature. A total of 115 nodes were obtained by keyword cluster analysis. The principal line of forensic odontology mainly included individual identification and age estimation and the emergence of hotspots was closely related to new technologies. Population-based odontology investigation, improvement of traditional dental age estimation method and dental age estimation based on new technology were popular research in forensic odontology. Developing countries urgently need to increase the focus on related research. It may be an important direction for the development of forensic odontology to establish and enrich the regional dental database, develop new odontology identification technology combined with frontier and high-end technology, and develop the identification program based on advanced information technology.

Age Estimation in Sportspersons From the Epiphyseal Fusion Around Wrist, Elbow, and Pelvic Joints.

Background Age estimation of an individual is an integral part of medicolegal work. Out of many scenarios for which age estimation is performed, competitive sports is the one emerging field where experts are consulted for providing accurate age of the athlete. Owing to the chances of deliberately increasing (padding) or decreasing (shaving) the age of the athlete for his own advantage, accurate age estimation is crucial. The Sports Authority of India (SAI) mandates age verification from experts prior to participation in sports events in various age group categories. One of the widely used methods of age estimation in athletes is the radiological examination of the ossification centers of bones. Methodology The study was performed on 134athletes (72 males and 62 females) with an age range of 12-18 years old with due permission from the Sports Authority of India (SAI) for this study. These participants compete at state, national, and international levels in squash, handball, swimming, cricket, and judo in under-14, under-16, and under-19 age categories. X-rays of the wrists, elbows, and pelvis were analyzed using the Schmeling five-stage method for the fusion of ossification centers. Results A greater degree of correlation between the fusion stages of all regions of interest and chronological age was observed in males than in females. The highest correlation in both sexes is observed between the fusion score of the head of the radius and the age (R = 0.814 for malesand R = 0.647 for females). The lowest correlation for both males and females is seen between the fusion score of the lateral epicondyle of the humerus and age (R = 0.754 for males and R = 0.441 for females). Multiple linear regression models showed a standard error of estimate (SEE) of 1.093 years for the elbow joint, 1.147 years for the wrist joint, 1.039 years for the pelvis joint, and 1.030 years for all three joints. Conclusion Regression models generated for estimating the age of sportspersons from the ossification centers of the elbow, wrist, and pelvis in the present study can be applied for the age estimation of individuals aged between 12 and 18 years. Future population-specific studies on the age estimation of sportspersons with greater sample sizes are necessary to validate the findings of the present study.

Age estimation in the harbour seal (Phoca vitulina) based on the closure of skull sutures and synchondroses.

Age estimation of individuals is an important tool for the management of marine mammals and is mostly done by microscopic analysis of growth layer groups (GLGs) in teeth (cementum and dentin) and bone. The present study evaluated the use of sutural and synchondrosal closure in the skull of the harbour seal (Phoca vitulina) as a potential non-destructive alternative for age estimation. For that, we scored the ectocranial closure of 12 selected sutures and synchondroses in a sample of 303 Eastern Atlantic harbour seals (P.v.vitulina; 138 males, 165 females), for which data on age at death were available, based on determined gross-morphological criteria in individuals younger than 1 year and cement layer analysis in canines in older individuals. A strong positive relationship between the sum of closure level scores (SCS) and age (males: r=0.8797, females: r=0.8825) was recorded, which was stronger than that for the relationship between age and condylobasal length (CBL, males: r=0.7085, females: 0.7086) (all p-values <0.0001). In adult individuals (≥5 years), CBL was higher in males than females (p < 0.0001), while SCS did not significantly differ between the two sexes (p=0.148). Our findings show that the analysis of sutural/synchondrosal closure is a valid alternative for age estimation in harbour seals, thereby confirming results of previous studies on other pinniped species.

Age‐at‐death estimation in archaeological samples: Differences in population means resulting from different aging methods can be predicted from the mean ages of method‐specific reference samples

AbstractAge mimicry is a well‐known phenomenon in the application of osteological age‐estimation methods. Age mimicry refers to the fact that predicting age‐at‐death from a specific trait (age indicator) based on the relation observed in a specific reference sample implies that age estimates to some degree reflect the age structure of the reference sample. In particular, the estimated population mean in a target population in which an age‐estimation method is applied is shifted towards the mean in the method‐specific reference sample. Consequently, differences in population means between different age‐estimation methods in the same target population may be due to differences in mean age of the reference samples used to develop the age‐estimation methods. We aim at quantifying the expected magnitude for such differences. Fifteen different traditional age‐estimation methods were applied to a sample of 675 adult individuals from the early medieval cemetery of Mannheim‐Seckenheim. The relation of the observed estimated population age means and the mean age in the reference samples was analyzed by linear regression. We find that up to 80% of the variation in the estimated population age means can be explained by the variation of the mean age in the reference samples. Furthermore, differences in the magnitude of 3 to 4 years in the mean age between two reference samples can imply a 1‐year difference in estimated target population age means. Because large differences in mean age between reference samples used to develop different age‐estimation methods are common, some care is needed in interpreting differences between individual age estimates or population mean age estimates in cases where different age‐estimation techniques are used.

Luminescence chronology for identifying depositional sequences in an uplifted coast since the Middle Pleistocene, eastern Japan

Feldspar post-infrared infrared stimulated luminescence (pIRIR) dating is an advantageous trapped-charge dating method concerning late Quaternary sedimentary records for its direct applicability to clastic sediments and wide time coverage. Its application to depositional sequences in various coastal settings potentially improve our understanding of long-term sea-level changes and regional tectonics that the sequences record. The Kanto coastal plain, eastern Japan is situated in a unique tectonic setting near the triple junction of plate boundaries and characterized by extensive development of the Last Interglacial raised marine terrace in contrast to the longer-term subsidence trend. In this article, we document the application of feldspar pIRIR dating to a 35-m-long sediment core collected from the marine terrace in the northeastern Kanto plain and examine how effective its chronology is for identifying depositional sequences related to the relative sea-level fluctuations since the Middle Pleistocene. The sediment core shows a succession of seven facies units, A to G, in ascending order, representing the shallow marine to shelf (units A to C), fluvial to brackish salt marsh (unit D), beach to shoreface (unit E), fluvial to aeolian (unit F), and loess (unit G) sedimentation. According to pre-tests, pIRIR at 225°C after prior infrared stimulated luminescence at 50°C (pIRIR225) was chosen as an optimal signal for dating. pIRIR225 is characterized by modest anomalous fading with an average g2days-value of 1.8%/decade. Fading-corrected pIRIR225 ages are consistent with the stratigraphy. Units A and B are dated as Marine Oxygen Isotope Stage (MIS) 7 and units C to F as MIS 5. However, uncertainties of individual age estimates do not allow further chronological correlation. Instead, using sea-level changes inferred from characteristic facies transitions as additional constraints, units C to F can be correlated to sub-stages in MIS 5. Unit E represents coastal progradation during the MIS 5c sea-level highstand, which refines the date of the marine terrace around the core site as MIS 5c and revises up the rate of the tectonic uplift accordingly. Our results exemplify a successful application of feldspar pIRIR dating for identifying depositional sequences formed in relations to 100-kyr glacial cycles, in which, with additional information of the sedimentary facies, higher-frequency sequences may be defined.

Sex identification and age estimation of bobcats and implications for management

AbstractPredictions obtained from wildlife population models may be prone to influences associated with the quality of the data available for parameterization. We assessed accuracy of furtaker‐assigned sex of bobcats (Lynx rufus; n = 123) harvested during 2017–2018 across the western USA by comparing those data to genetically assigned sex, the latter of which we assumed was 100% accurate. We also compared the precision of individual age estimates obtained through cementum annuli analysis (CAA) of the canines and incisors of harvested bobcats (n = 151), where true age was unknown. Because cementum‐line deposition may vary across populations and by sex, we hypothesized that environmental factors may affect precision of age estimates obtained via CAA. Sex of bobcats as reported by furtakers was accurate 82% of the time, and the direction of sex‐assignment error was approximately equivalent. Canine teeth were more precise than incisors for estimating age, age estimates for male bobcats may be more precise than for females, and precision of age estimates may decrease with age. However, use of incisors corrected with known rates of error may be preferred in some instances, such as studies that require live capture and tooth extraction or where assignment to age class is sufficient. In addition, we found that sex, median age, and mean elevation may influence precision of age estimates, whereas mean precipitation and geographic location (latitude, longitude) were uninformative. Knowledge of different types of errors associated with sex identification and age estimation may be integrated into population modeling efforts based on management objectives.

Tooth Cementum Thickness as a Method of Age Estimation in the Forensic Context

Simple SummaryIn a forensic context, it may be necessary to estimate the age at death of an individual from his or her skeletal remains. The age at death constitutes an essential identification parameter, along with sex, ancestry, stature, and a few other biological characteristics that can help to trace the biological profile of the deceased. Although there is an extensive number of works in the literature on this topic, traditional anthropological methods encounter considerable difficulty in estimating the age of an adult based on skeletal remains. This difficulty increases with aging mainly due to the overlapping of pathological processes. In this study, we tested the reliability of a relatively simple histological methodology to estimate an individual′s age based on tooth roots cementum and developed new equations from individuals with known age and sex. In conclusion, our results confirm the importance of teeth in the estimation of age, suggesting that the proposed method may be effective, especially for younger individuals.Estimating age at death is a key element in the process of human identification of skeletal remains. The interest in dental cementum stems from its increase in thickness throughout life and, at the same time, from the fact it should not be affected by remodeling processes. Since the age assessment is particularly difficult in adults when using traditional anthropological methods on the skeleton, we tested a dental method based on maximum cementum thickness and developed new regression equations. We microscopically analyzed the histological sections of dental roots from a sample of 108 permanent teeth with known age and sex. Age at the time of dental extraction was in the range of 18–84 years. Our findings show that there were no differences in thickness between sexes, dental arch, and mono- and pluriradicular teeth. Separate regression equations were developed for individuals in the whole age range and individuals under 45 years. The equations were then tested on a hold-out sample from the same Mediterranean population demonstrating higher reliability for the equation developed for those under 45. Conversely, due to the increased error in age estimation in individuals over 45, this method should be used with caution in the forensic context when skeletal remains presumably belong to elderly individuals.

Age-at-Death Estimation of Fetuses and Infants in Forensic Anthropology: A New "Coupling" Method to Detect Biases Due to Altered Growth Trajectories.

Simple SummaryIn forensic anthropology, estimating the age-at-death of young juvenile skeletons is crucial as a direct determinant of legal issues in many countries. Most methods published for this purpose are based on either maturation or growth processes (two essential components of development) and focus on “normal” (i.e., nonpathological) growth. However, when the osseous remains available for study are from an individual that experienced an altered growth process, age estimation may be biased, and accounting for this would be helpful for potentially avoiding inaccuracies in estimation. In this research, we developed a method based on the combined evaluation of both maturation and growth. Maturation is evaluated by the conformation of the pars basilaris, a bone at the skull base that provides an indirect estimate of brain maturation, while growth is assessed using femoral biometry. The method was tested on two medical validation samples of normal and pathological individuals. The results show that it was possible to identify “uncoupling” between maturation and growth in 22.8% of the pathological individuals. Highlighting potential uncoupling is therefore an essential step in assessing the confidence of an age estimate, and its presence should lead experts to be cautious in their conclusions in court.The coupling between maturation and growth in the age estimation of young individuals with altered growth processes was analyzed in this study, whereby the age was determined using a geometric morphometrics method. A medical sample comprising 223 fetuses and infants was used to establish the method. The pars basilaris shapes, quantified by elliptic Fourier analysis, were grouped into consensus stages to characterize the maturation process along increasing age groups. Each pars basilaris maturation stage was “coupled” to biometry by defining an associated femur length range. The method was tested on a validation sample of 42 normal individuals and a pathological sample of 114 individuals whose pathologies were medically assessed. Couplings were present in 90.48% of the normal sample and 77.19% of the pathological sample. The method was able to detect “uncoupling” (i.e., possibly altered growth) in more than 22.8% of samples, even if there was no visible traces of pathology on bones in most cases. In conclusion, experts should be warned that living conditions may cause alterations in the development of young individuals in terms of uncoupling, and that the age-at-death estimation based on long bone biometry could be biased. In a forensic context, when age has been estimated in cases where uncoupling is present, experts should be careful to take potential inaccuracies into account when forming their conclusions.

Age estimation by evaluation of osteophytes in thoracic and lumbar vertebrae using postmortem CT images in a modern Japanese population.

Estimation of age at death is important in forensic investigations of unknown remains. There have been several reports on applying the degree of osteophyte formation-an age-related change in the vertebral body-for age estimation; however, this method is not yet established. This study investigated a method for age estimation of modern Japanese individuals using osteophytes measured on CT images. The sample included 250 cadavers (125 males) aged 20-95years. The degree of osteophyte formation was evaluated as score O (0-5 points), and the degree of fusion of the osteophytes between the upper and lower vertebrae was evaluated as score B (0-2 points). Age estimation equations were developed using regression analyses with seven variables, determined by scores O and B, and the equation with the smallest standard error of estimate (SEE) was obtained when the number of vertebrae with score O ≥ 2 was used as the explanatory variable. Age estimation with SEE of about 10years was possible even when partial vertebrae with a high degree of osteophyte formation were used, showing its potential for practical application. The cutoff value for age estimation was established using the receiver operating characteristic curve analysis, wherein good results were obtained for all variables (area under the curve ≥ 0.8). The combination of the estimation equation and the cutoff value can narrow the range of age estimates.

Ageing European lobsters (Homarus gammarus) using DNA methylation of evolutionarily conserved ribosomal DNA.

Crustaceans are notoriously difficult to age because of their indeterminate growth and the moulting of their exoskeleton throughout life. The poor knowledge of population age structure in crustaceans therefore hampers accurate assessment of population dynamics and consequently sustainable fisheries management. Quantification of DNA methylation of the evolutionarily conserved ribosomal DNA (rDNA) may allow for age prediction across diverse species. However, the rDNA epigenetic clock remains to be tested in crustaceans, despite its potential to inform both ecological and evolutionary understanding, as well as conservation and management practices. Here, patterns of rDNA methylation with age were measured across 5154 bp of rDNA corresponding to 355 quality‐filtered loci in the economically important European lobster (Homarus gammarus). Across 0‐ to 51‐month‐old lobsters (n = 155), there was a significant linear relationship between age and percentage rDNA methylation in claw tissue at 60% of quality‐filtered loci (n = 214). An Elastic Net regression model using 46 loci allowed for the accurate and precise age estimation of individuals (R 2 = 0.98; standard deviation = 1.6 months). Applying this ageing model to antennal DNA from wild lobsters of unknown age (n = 38) resulted in predicted ages that are concordant with estimates of minimum size at age in the wild (mean estimated age = 40.1 months; range 32.8–55.7 months). Overall, the rDNA epigenetic clock shows potential as a novel, nonlethal ageing technique for European lobsters. However, further validation is required across a wider range of known‐age individuals and tissue types before the model can be used in fisheries management.