Bone histomorphometry of the clavicle in a forensic sample from Albania

Forensic assessment of skeletal material includes age estimation of unknown individuals. When dealing with extremely fragmented human remains that lack macro-features used in age estimation, histological assessment of the skeletal elements can be employed. Historically, microscopic methods for age assessment used by forensic anthropologists have been available since 1965. Several skeletal elements have been used for this purpose. Among them, the clavicle has garnered very little attention. The purpose of this study is to explore the validity of clavicular histomorphometry as an age marker in a modern Balkan sample. This study examined a modern clavicular autopsy sample from Albania. The sample consisted of 33 individuals of known age and cause of death. Data were collected for micro-anatomical features including osteon population density (OPD) and cortical area. Intra- and inter-observer errors were assessed through technical error of measurement (TEM) and R coefficient. A validation study was performed in order to test the accuracy of existing histological formulae. Regression analysis was run to developed age prediction models with the best models tested through cross-validation and the comparison between OPD for the Albanian sample and a European-American sample examined. Intra- and inter-observer error TEM results demonstrated values falling within the limits of acceptance. The existing histological methods did not perform accurately on the sample under study. Regression equations for Albanians produced age estimations deviating 8 and 11 years from known age. Cross-validation on the most accurate regression formula which includes OPD as a single variable demonstrated similar mean errors. Statistically significant differences were observed between the Albanian and the European-American population when the two samples were compared. The research presented is the fifth article published and the fifth population explored on clavicular microstructure. The potential of histology to estimate age on the Albanian population is shown here; however, population effect, diet and health status might be considered. Further inclusion of individuals will corroborate our preliminary findings

Estimation of Age-at-Death Using Cortical Bone Histomorphometry of the Rib and Femur: A Validation Study on a British Population

Histomorphometry constitutes a valuable tool for age estimation. Histological interpopulation variability has been shown to affect the accuracy of age estimation techniques and therefore validation studies are required to test the accuracy of the pre-existing methodologies. The present research constitutes a validation study of widely known histological methods on the sixth rib and the femoral midshaft of a 19th century British population originating from Blackburn, England. An evaluation of the histomorphometric features of eleven ribs and five femora was performed and used to test the accuracy of selected methods. Results indicated that osteon area and circularity were the only histomorphometric variables that presented significant interpopulation variability. Cho et al.’s method for the ribs and the average value produced using Kerley and Ubelaker’s method for intact osteon and percentage of lamellar bone equations for femur were considered the only reliable markers for estimating the age on the Blackburn sample. In the case of old individuals, Goliath et al.’s method provided more satisfactory results. Overall, the present study provides evidence on the applicability of the aging histomorphometric methods on a British sample and highlights the limitations of applying histomorphometric methods developed on different reference populations than the one under investigation

The use of Bayes Factor for model selection for predicting age: an example on clavicular histomorphometry

Introduction: Histomorphometry has been extensively applied for estimating age-atdeath. Although ribs have been commonly used for histological age, other bones need to be considered in order to contemplate possible bone specific remodelling rates and various recovery scenarios. Materials and Methods: Thirty-two left clavicle midshaft fragments were obtained from routine autopsies conducted at the Institute of Forensic Medicine (Albania, 2014-2015). Thin-sections of 0.5-1mm were prepared using standard protocols. Thirteen histomorphometric variables were collected using a Reflected Light Microscope and data were analysed using JASP 9.0.1. Results: Bayes factor showed that the existence of positive correlation of OPD with age is 348,050 times more likely than the lack of correlation. In addition, Mean Perimeter and Mean area are 1.047 and 1.357 times more likely to have a positive correlation with age that the alternative variables. Bayes linear regression was used to compare different predicting models. The best model includes OPD and Osteon Perimeter (R²=0.678, SEE=7.5years) which is 2.388,000 times more likely to explain age than the null model. Discussion: The Bayesian approach allowed the evaluation of the fitness of the model compared to the null model and to better explain the causative relationship of the predictors with age. This study is only the fourth worldwide performed on clavicular histomorphometry and provides unique population specific standards for age estimation of future forensic cases in Albania. The use of RLM as a new technique on forensic bone histology can be further tested and applied on a variety of skeletal elements