Age estimation for two Mediterranean populations: rib histomorphometry applied to forensic identification and bone remodelling research

Abstract

Numerous intrinsic and extrinsic factors influence bone remodelling rates and have shown to affect the accuracy of histological aging methods. The present study investigates the rib cortex from two Mediterranean skeletal collections exploring the development of population-specific standards for histomorphometric age-at-death estimation. Eighty-eight standard ribs from two samples, Cretans and Greek-Cypriots, were processed histologically. Thirteen raw and composite histomorphometric parameters were assessed and observer error tested. The correlation between age and the parameters and the differences between sex and population subsamples were explored through group comparisons and analysis of covariance. General linear models assessed through data fit indicators and cross-validation were generated from the total dataset, and by sex and population subsamples. Most of the histological variables showed a statistically significant correlation with age with some differences observed by sex and by sample. From the twelve models generated, the optimal model for the whole sample included osteon population density (OPD), osteon perimeter, and osteon circularity producing an error of 10.71 years. When sex and samples were separated, the best model selected included OPD and osteon perimeter producing an error of 8.07 years for Greek-Cypriots. This research demonstrates the feasibility of quantitative bone histology to estimate age, obtaining errors rates in accordance with macroscopic ageing techniques. Sex and sample population differences need further investigation and inter-population variation in remodelling rates is suggested. Moreover, this study contributes to the creation of population-specific standards for Cretans and Greek-Cypriots.

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

“…Histomorphometry is a valuable method for age estimation when the integrity of skeletal remains has been compromised. Age-estimation methods are however adapted to the demographic and histomorphometric characteristics of the population they were developed on [ 46 , 47 ], and usually produce inaccurate estimates when applied to other populations [ 8 , 27 ]. The evaluation of the histological features and the demographic characteristics of the study sample should always be considered a necessary procedure in validation studies.…”

“…These methods, however, are heavily affected by the observer’s subjective interpretation [ 5 ] and are of limited value when the skeletal elements are taphonomically altered or commingled [ 6 ]. Consequently, during the last few decades, many researchers have focused on developing new age-estimation methods based on the quantitative microscopic evaluation of cortical bone [ 5 , 7 , 8 ].…”

“…Most of the published methodologies have been limited to one reference population, producing more accurate age estimates when tested on populations closely related to the original sample [ 32 ]. The performance of validation studies is therefore necessary to assess the accuracy of the existing methods, and to identify potential factors affecting these results [ 8 ]. Both weight-bearing and non-weight-bearing bones should be evaluated to better identify the sources of intra and interpopulation variability [ 32 ].…”

The Effects of Experimental Whole-Body Burning on Histological Age-at-Death Estimation from Human Cortical Bone and Dental Cementum

“…Although there are many uses for histological analysis of bones and teeth in applied contexts broadly, microscopic analysis of bone in applied contexts most frequently focuses on analysis of bone type as well as cortical bone structures such as osteons (discrete remodeled units of cortical bone) for human vs. nonhuman differentiation [ 5 , 6 , 7 , 8 ] and age-at-death estimation [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ]. This analysis often involves the observation of the presence and/or absence of osteons as well as their number and size.…”

“…Regardless of the method, adult histological age-at-death estimation from cortical bone is based generally on two principles: (1) osteons accumulate as age increases and (2) the amount of cortical bone available for osteon creation decreases with age. Although methods for estimation of age-at-death from histological analysis differ in terms of variable inclusion, statistical approach, and sampling area, most histological age estimation of bone is conducted using cross-sectional samples of undecalcified cortical bone from either the femur [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ] or rib [ 11 , 28 , 29 , 30 , 31 , 32 , 33 ] and evaluating how much of the cross-section is populated with osteons either whole or fragmentary.…”