Population-specific Regression Equations Research Articles

Sex estimation of frontal sinus volume from computed tomography scans in a Western Australian adult population.

With the increasing use of radiological three-dimensional imaging, different metric and morphological aspects of the frontal sinuses (FS) have been examined relative to their potential to aid human identification, including sex estimation. The aim of this study is to assess the validity of the metric analysis of the FS volume for estimating sex in a Western Australian (WA) adult population, following the Michel et al. (2015) method. The right, left and total frontal sinus volume (TFSV) from 99 computed tomography scans (47 males and 52 females) of WA individuals aged 18-40 years were three-dimensionally reconstructed using OsiriX® and their volumes acquired in mm3. Sexual dimorphism in the TFSV was tested, and the accuracy of the Michel et al. (2015) formulae was calculated. Population-specific regression equations were also produced. There was a significant difference between the mean TFSV in males and females. The classification accuracy derived from the Michel et al. (2015) formulae was 59.6%. The WA-specific logistic regression analysis yielded an accuracy of 57.2%. The low accuracy rates preclude the use of the sex estimation method in the WA population, but the volume analysis confirmed the individual variability of the frontal sinuses, which may be useful for personal identification.

Stature estimation from the scapula measurements using 3D-volume rendering technique by regression equations in the Northern Indian population.

The present study assessed the correlation between the stature and scapular measurements from both sides in order to develop population-specific regression equations to estimate the stature from measurements of the scapula in a contemporary Northern Indian population individually for the left and right sides. A total of 597 cadavers underwent postmortem multidetector computed tomography and subsequent medicolegal autopsy in our department between August 2021 and August 2022. Two hundred samples (100 males and 100 females) were randomly collected based on inclusion and exclusion criteria. Six linear anthropometric measurements of the scapula from either side were measured using the 3D volume-rendered technique by an electronic cursor. Each anthropometric measurement showed a significant difference between males and females (p < 0.05). Regression analysis was applied to match the taken measurements against stature. The accuracy to predict stature ranged from 3.99 to 4.94 cm for males and from 4.49 to 5.27 cm for females, respectively. Left-sided measurements were better predictors of stature than the right side in both genders. The results of this study indicate that scapular measurements could be useful to estimate the stature of Northern Indian individuals, particularly in scenarios of disaster victim identification lacking long bones, which are considered to be better predictors to date.

Age estimation using vertebral bone spurs; Testing the efficacy of three methods on a European population

Age-at-death estimation is an essential step in both bioarchaeological and forensic studies when human remains are found, as this can also contribute to the identification of the individual. It is critical that age-at-death methods be tested verified in various populations, to obtain the most accurate estimation, making research into new age-at-death methods also imperative. Since osteophyte formation on the vertebral column increases with age, this can be used as a possible method of age-at-death estimation. Snodgrass (2004), Watanabe and Terazawa (2006) and Praneatpolgrang et al. (2019) have tested this method before and have provided promising results. We test the efficacy of Snodgrass (2004), Watanabe and Terazawa (2006), and Praneatpolgrang et al. (2019) on a 19th-century archivally recorded Dutch population. A total of 88 individuals, 40 males, and 48 females were scored for the degree of osteophyte formation on the vertebral column. In addition to testing the three methods above, population-specific regression equations were developed and tested. Accuracy percentages for estimating the age-at-death based on the mean osteophyte score of the entire vertebral column were obtained for all three methods (73.86%, 76.14%, and 72.73%, respectively). In this study, a general pattern of osteophyte formation could be established, which is useful for estimating the age at death. We therefore recommend that this method can be used, cautiously as a means of age-at-death estimation.

Age estimation from pulp tooth area ratio of mandibular canine using an orthopantomogram: A cross-sectional study

Background: Age estimation of living adult individuals can be accomplished with limited methods. Radiographic dental methods based on secondary dentin deposition have been described as one of them. In the present study, the relationship between chronological age and the ratio of pulp to tooth area using available panoramic images of mandibular canine by Kvaal’s technique was carried out for the age estimation in the study population. Materials and Methods: 24 orthopantomogram images (OPG) of mandibular canines between 16-56 years were collected from the archives and pulp tooth area ratios were measured. Age was estimated using the regression equation obtained. Results: It was observed that variables M’, ‘L’, and ‘r’ correlated highly with age and were included in the regression model. Statistical analysis indicated that the regression equation with selected variables explained 94.4% of the total variance. There was no significant difference between chronological and estimated age (p&gt;0.05) signifying that the derived formula is appropriate for all the selected age groups. Conclusion: The derived population-specific regression equation can be potentially used for the estimation of the chronological age of the study population.

Estimation of length of femur from its distal segment

Introduction: The stature of an individual, one of the key elements of identification, can be calculated from the length of long bones in the body, of which the femur has the highest correlation with stature. Many a times, forensic anthropologists have to identify unknown dead bodies from fragments of bones that are available. Studies have proven that the total length of a bone can be estimated from fragments using population-specific regression equations. In the present study, the objective was to estimate the total length of the femur (TFL), in an Indian population, from measurements of its distal segment, using regression equations. Material and Methods: One hundred and twenty-one intact adult femurs were studied. The TFL and four variables from its distal segment were measured. Linear regression analysis was performed, and regression equations were derived to calculate the TFL from each of the variables. Results: The mean TFL was 41.9 ± 3.4 cm. All the four parameters of the distal segment showed a significant positive correlation with the total femoral length (P < 0.001), and of these, the width measured between the two epicondyles showed the maximum correlation. Multivariate and univariate regression equations were derived to estimate the TFL from these variables. Discussion and Conclusion: The TFL can be reliably calculated from the measurements of the distal fragments. These measurements can be used by forensic anthropologists for the estimation of the stature of an unknown individual.

Estimation of Muscle Mass in the Integrated Assessment of Patients on Hemodialysis.

Assessment of muscle mass (MM) or its proxies, lean tissue mass (LTM) or fat-free mass (FFM), is an integral part of the diagnosis of protein-energy wasting (PEW) and sarcopenia in patients on hemodialysis (HD). Both sarcopenia and PEW are related to a loss of functionality and also increased morbidity and mortality in this patient population. However, loss of MM is a part of a wider spectrum, including inflammation and fluid overload. As both sarcopenia and PEW are amendable to treatment, estimation of MM regularly is therefore of major clinical relevance. Whereas, computer-assisted tomography (CT) or dual-energy X-ray absorptiometry (DXA) is considered a reference method, it is unsuitable as a method for routine clinical monitoring. In this review, different bedside methods to estimate MM or its proxies in patients on HD will be discussed, with emphasis on biochemical methods, simplified creatinine index (SCI), bioimpedance spectroscopy (BIS), and muscle ultrasound (US). Body composition parameters of all methods are related to the outcome and appear relevant in clinical practice. The US is the only parameter by which muscle dimensions are measured. BIS and SCI are also dependent on either theoretical assumptions or the use of population-specific regression equations. Potential caveats of the methods are that SCI can be influenced by residual renal function, BIS can be influenced by fluid overload, although the latter may be circumvented by the use of a three-compartment model, and that muscle US reflects regional and not whole body MM. In conclusion, both SCI and BIS as well as muscle US are all valuable methods that can be applied for bedside nutritional assessment in patients on HD and appear suitable for routine follow-up. The choice for either method depends on local preferences. However, estimation of MM or its proxies should always be part of a multidimensional assessment of the patient followed by a personalized treatment strategy.

Prediction of Stature in Males of Tamil Population from Measurements of Percutaneous Tibial Length

Forensic experts are often in confrontation with the challenging task of determination of stature along withrace, age etc. for the purpose of establishing the identity of the deceased individual in those circumstanceswhere only skeletal remains, mutilated or dismembered body parts, extremely decomposed body parts etc.are provided by investigating authorities. In the current study, a genuine attempt has been made to arriveat the population specific regression equation for stature prediction from the percutaneous length of Tibia.The subjects chosen for this study include 120 adult males belonging to Tamil population falling withinthe age range of 21 to 30 years. Stature and percutaneous lengths of right and left Tibia from each subjectwere precisely recorded following standard protocols using appropriate instruments and analysis of thedata collected was done applying Pearson correlation through SPSS software version 26 to arrive at theregression equations for stature assessment based on percutaneous right and left Tibial lengths respectively.By comparing the regression formulae obtained from the present study with those derived from variouspopulation specific studies done on Indian population, our regression equations found to be distinctive toTamil population and therefore can be authentically applied for calculation of stature of deceased frompercutaneous Tibial length in males of Tamil population whenever skeletal remains are available.

Estimation of stature from percutaneous length of ulna in rural government medicalcollege and hospital in Marathwada region of central Maharashtra

Establishing the identity of person is one of important procedure in Forensic investigation. In disasters settings, establishing the biological identity of an unknown body is quite challenging because of several extrinsic and intrinsic factors. For the forensic investigators and medico legal personals, it becomes difficult when a disaster occurs at when mixed populations are present at that time. The biological factor like the putrefaction, advanced decomposition, mutilated and commingled body parts or dismembered body parts makes individual identity difficult. Stature is one of the important components. India is multiethnic country, the populations of one geographic region varies in terms of our biological and cultural identity with other geographic. Due to the unavailability of population specific regression equations there is a need of develop population specific regressions equations so that it will help the medico legal fraternity while dealing with the unknown body. In the present study an effort has been made to study correlation between stature and percutaneous length of ulna using appropriate statistical methods. The present cross-sectional study consisted of 240 medical students (male-110, female-130) between the age group of 19–23 year at SRTR Government Medical College, Ambajogai, Dist. Beed, Maharashtra, India. We measured stature and percutaneous length of ulna of study subjects with the help of stadiometer and sliding vernier caliper. The mean length of right ulna (cm) in males was 25.98 ± 1.24 and 22.01 ± 1.33 in females. The mean length of left ulna (cm) in males was 25.63 ± 1.28 and in females was 21.84 ± 1.72. The Standard error for male and female was 4.21 and 4.56 respectively. The correlation coefficient (r) for male and female was 0.62 and 0.69 respectively. Intercept for males was 89.35 and for females it was 110.44.The linear regression equation for males was found to be Y = 3.11 X + 89.35 and for females it was Y = 2.40 X + 110.44, where X: percutaneous ulnar length (cm) and Y: Stature (cm). Stature and percutaneous length of ulna of both the hands shows positive strong correlation so that forensic experts can estimate the stature with the help of percutaneous length of ulna. Since sample size is small, we can't generalize it to larger population. More extensive studies have to be undertaken in future.

Age estimation in Western Chinese adults by pulp–tooth volume ratios using cone-beam computed tomography

ABSTRACT The aim of this study was to develop population-specific regression equations for age estimation by investigating the correlation between chronological age and pulp–tooth volume ratios in three types of anterior teeth using cone-beam computed tomography (CBCT) in the Western Chinese population. Three hundred and ninety-two CBCT images of 207 female and 185 male individuals, aged between 16 to 76 years were evaluated. Mimics software was used to calculate the pulp–tooth volume ratios (PTVR) from CBCT images. Regression analysis was conducted with chronological age as a dependent variable and PTVR as an independent variable to establish a mathematical model for age estimation. The mean absolute error (MAE) was calculated to evaluate the accuracy of the regression model using an independent validation sample. Among the three types of anterior teeth, the left maxillary lateral incisor provides the most accurate age prediction for males (MAE = 6.804), and the left maxillary central incisor gave the most accurate results for females (MAE = 6.104). The statistical analysis also found gender differences exist in the PTVR for three types of anterior teeth. This study revealed that gender and tooth type specific equations are recommended when using the PTVR for age estimation.

Assessment of validity and reliability of Kvaal's method for age estimation among a population sample - A retrospective study.

The present research was carried out with an aim to estimate and correlate chronological age and estimated age by Kvaal's Method in North Indian population using digital panoramic radiography. Further, the study was an attempt to evaluate the reliability of Kvaal's method for age estimation and to arrive at a population-specific regression equation. One hundred digital orthopantomograms of participants aged between 20 and 70 years of age were selected. The evaluation of 6 teeth according to Kvaal's method was carried out using measure tool of Sidexis Software (provided by the manufacturer). Correlation coefficient was carried out between chronological age and estimated age and further regression analysis was carried out for obtaining a population specific regression equation. It was observed that coefficient of determination (R2) is highest (0.223) for mandibular canine which indicates that age can be better estimated with this particular tooth. It was observed that large variations between the chronological and estimated age were not found. Also, Kvaal's formula proved accurate for estimating age using all the six selected teeth. Thus, it was concluded that mandibular canine would be the better tooth for age estimation, followed by maxillary second premolar and maxillary three teeth taken together.

The Estimation of Stature from the Tarsals: Enhancing the Disaster Victim Identification Process in Thailand Using the Calcaneus and the Talus

The impact of climate change is estimated to be particularly severe in Thailand, where climate change events are predicted to increase in both frequency and severity, resulting in a higher number of deaths in the region. Therefore, there is an urgent need for population-specific methodologies for the identification of unknown human remains in Thailand. The current study focuses on the calcaneus and the talus to establish an accurate method of living stature estimation for a contemporary Thai sample. Paired calcanei and tali of 233 skeletonized individuals, ranging from 19 to 96 years of age, were studied from the Chiang Mai skeletal collection. Nine measurements were collected from each calcaneus, and one measurement was collected from each talus. Sexes were pooled; all measurements of the calcaneus and the talus exhibit sexual dimorphism. Regression equations of the calcaneus and the talus, generated from other samples, were found to be inaccurate predictors of stature when applied to the contemporary Thai sample. Therefore, population-specific regression equations are recommended. The results of the current study will contribute to estimating living stature of unknown contemporary Thai individuals and will assist in cases such as natural disasters where more accurate predictors of living stature, such as long bones, are unavailable.

A Model for Stature Prediction from Percutaneous Ulnar Length in Adult Males of Tamil Population

The objective of this study was to derive a linear regression formula for determination of stature from right and left ulnar length in males belonging to Tamil population. The subjects consisted of 112 adult Tamil males in the age group of 21 to 30 years. With the help of digital sliding caliper, length of each side ulna was measured between tip of olecranon process and tip of styloid process and for stature, using the stadiometer, the subject was asked to stand barefooted in anatomical position and distance from heel to vertex measured. The data thus collected was statistically analyzed with SPSS software (version 23) and a population specific regression equation for stature pertaining to length of right and left ulna derived respectively and statistically compared with that of other Indian populations and found to be unique for this study population group and therefore, this will be a tool of much significance for anthropologists, forensic experts and archaeologists when dealing with mutilated forearm remains from deceased Tamil males where necessity of stature estimation for identification arises.

Estimation of stature and sex by foot length measurements using linear regression and discriminant function analysis, respectively: A study in central india population

Background and Aim In forensic investigations establishing the identity of a person is a vital step. Stature and sex are important attributes of personal identity. In cases of mass disasters, generally isolated body parts and extremities are recovered as remains and are utilized to ascertain identity of an individual with personal attributes like gender, stature. The present study was conducted to ascertain if the foot length can be reliably used in estimation of stature and gender, and to establish population-specific regression equation and discriminant function analysis in population of Central India.Methods One hundred subjects (50 males and 50 females) between the age group of 20 and 40 years, who are residents of Central India for two generations, were studied. Foot length, of both right and left sides, was recorded for each individual and stature was measured with the help of a stadiometer. Data were subjected to statistical analysis.Results Statistical analysis of the data of the study population showed statistically highly significant differences (p < 0.001) between males and females. Statistically highly significant positive correlation was observed between stature and foot length in males and females. Linear regression equations for stature estimation were derived separately for males and females. The discriminant function analysis, utilizing foot length correctly, classified 78 to 85.1% of cases for respective gender.Conclusion The statistically significant positive correlation between the foot length and stature and accuracy of sex classification by discriminant function analysis indicate the reliability of foot length in predicting stature and gender of an individual.

Assessing the reliability of FTIR spectroscopy measurements and validity of bioelectrical impedance analysis as a surrogate measure of body composition among children and adolescents aged 8\u201319\xa0years attending schools in Kampala, Uganda

BackgroundAccurate measurement of body composition in children and adolescents is important as the quantities of fat and fat-free mass have implications for health risk. The objectives of the present study were: to determine the reliability of Fourier Transform Infrared spectroscopy (FTIR) measurements and; compare the Fat Mass (FM), Fat Free Mass (FFM) and body fat percentage (%BF) values determined by bioelectrical impedance analysis (BIA) to those determined by deuterium dilution method (DDM) to identify correlations and agreement between the two methods.MethodsA cross-sectional study was conducted among 203 children and adolescents aged 8–19 years attending schools in Kampala city, Uganda. Pearson product-moment correlation at 5% significance level was considered for assessing correlations. Bland Altman analysis was used to examine the agreement between of FTIR measurements and between estimates by DDM and BIA.. Reliability of measurements was determined by Cronbach’s alpha.ResultsThere was good agreement between the in vivo D2O saliva enrichment measurements at 3 and 4 h among the studied age groups based on Bland-Altman plots. Cronbach’s alpha revealed that measurements of D2O saliva enrichment had very good reliability. For children and young adolescents, DDM and BIA gave similar estimates of FFM, FM, and %BF. Among older adolescents, BIA significantly over-estimated FFM and significantly under-estimated FM and %BF compared to estimates by DDM. The correlation between FFM, FM and %BF estimates by DDM and BIA was high and significant among young and older adolescents and for FFM among children.ConclusionsReliability of the FTIR spectroscopy measurements was very good among the studied population. BIA is suitable for assessing body composition among children (8–9 years) and young adolescents (10–14 years) but not among older adolescents (15–19 years) in Uganda. The body composition measurements of older adolescents determined by DDM can be predicted using those provided by BIA using population-specific regression equations.

Stature estimation equations for South Asian skeletons based on DXA scans of contemporary adults.

Stature estimation from the skeleton is a classic anthropological problem, and recent years have seen the proliferation of population-specific regression equations. Many rely on the anatomical reconstruction of stature from archaeological skeletons to derive regression equations based on long bone lengths, but this requires a collection with very good preservation. In some regions, for example, South Asia, typical environmental conditions preclude the sufficient preservation of skeletal remains. Large-scale epidemiological studies that include medical imaging of the skeleton by techniques such as dual-energy X-ray absorptiometry (DXA) offer new potential datasets for developing such equations. We derived estimation equations based on known height and bone lengths measured from DXA scans from the Andhra Pradesh Children and Parents Study (Hyderabad, India). Given debates on the most appropriate regression model to use, multiple methods were compared, and the performance of the equations was tested on a published skeletal dataset of individuals with known stature. The equations have standard errors of estimates and prediction errors similar to those derived using anatomical reconstruction or from cadaveric datasets. As measured by the number of significant differences between true and estimated stature, and the prediction errors, the new equations perform as well as, and generally better than, published equations commonly used on South Asian skeletons or based on Indian cadaveric datasets. This study demonstrates the utility of DXA scans as a data source for developing stature estimation equations and offer a new set of equations for use with South Asian datasets.

Estimation of stature from foot outline 3(D) anthropometry among Kagay-Anons in philippines

Foot impression is a form of evidence and can be prove to be as specific as fingerprint. Foot impression/foot outline (3D) is used for stature estimation and to include or exclude the suspects. The present study was aimed to estimate stature from foot outline measurements among Kagay-anons in Philippines. The study sample consists of consented 200 males and 200 females and recorded footprint and stature measurements and data were analysed statistically. The study developed population specific regression equations to estimate stature from foot outline (3D) measurements suitable to Kagay-anon population in Philippines for the use in crime scene investigation.

Applicability of Demirjian’s Method and Modified Cameriere’s Methods for Dental Age Assessment in Children

Tooth development is extensively used for age estimation as a part of forensic science. The purpose of this study was to evaluate the reliability of Demirjian's, Cameriere's and modified Cameriere's population-specific regression equation methods in the dental age estimation of West Godavari children. The study included orthopantomograms (OPG) of 60 children of West Godavari district with age group between 9 to 14 years on whom all the three methods were used for age estimation. The OPG were traced with the help of a tracing paper and lead pencil and the appropriate dimensions were measured. Age estimation was done based on canine calcification stage as per Demirjian's method and measurements of the seven permanent left mandibular teeth using Cameriere's formula and modified population-specific regression equation obtained for the South Indian population from Cameriere's formula. The resultant data were subjected to statistical analysis by student's paired t-test. The estimated age was closer to the chronological age when the modified Cameriere's population-specific regression equation was used (p=0.68); whereas, the difference was more in Demirjian's method (p=0.008) followed by Cameriere's method (p<0.001). The method using modified Cameriere's population-specific regression equation exhibited a least significant difference in chronological and dental age assessment in children of West Godavari district as compared to the other two methods.

Stature Estimation from Foot Outline Measurements in Adult Lun Bawang Ethnics of East Malaysia by Regression Analysis

Stature estimation from foot impression plays a vital role in forensic investigation. The present study aimed to estimate stature from bilateral foot outlines collected from 230 consented Lun Bawangs ethnics (115 males, 115 females) residing in East Malaysia, Borneo Island and to generate population-specific regression equations. Ten outline length measurements were taken viz. five from left and five from right foot. The results show significant positive correlation between height and foot outline lengths. The correlation coefficient (R) in pooled sample (0.858–0.879) is found to be comparatively higher than those of individual male (0.693–0.754), and female foot outlines (0.712–0.792). Linear regression analysis presents smaller error of estimate. Thus, population specific regression equations were derived for stature estimation from foot outlines lengths among Lun Bawangs population of East Malaysia even when sex remains unknown.

Estimation of Stature from Footprint Length from Adult Bengali Polulation

Stature reconstruction is important as it provides a forensic anthropological estimate of the height of a person in the living state-playing a vital role in identification of individual. The present study was conducted in the department of Forensic and State Medicine Burdwan Medical College. The aim was to derive population specific regression equation for adult Bengali population of Burdwan district.100 healthy volunteers (53 male and 47 females) were studied after taking consent. The value of R obtained in case where all variables were used to predict stature was 0.6 and R square was 0.36. The standard error of estimate was 8.64. The regression formula derived Stature= 69.269 + 0.54×footlength1+0.83 footlength2-3.826 footlength3+7.07 footlength4-0.971 footlength5+ 1.651 DL. These equations maybe used to predict stature in cases when whole length of leg or long bones are not available for investigation (e.g. in mutilated body parts in mass disasters).

Regression Analysis for Stature Determination from Hand Anthropometry of Malaysian Malays for Forensic Investigation

During the investigation of mass disasters cases, the primary aim of any forensic investigator is to identify the individuals by analyzing the disintegrated human body organs. Stature determination has been shown as possible using the measurements of different body parts. Hand anthropometry is found to yield important predictive information about an individual’s stature and may further help in narrowing down the possible matching identities. Literature review shows that a limited number of studies have been conducted on stature estimation from hand measurements. The present investigation is aimed to derive population specific regression equations to estimate stature from hand anthropometry of Malaysian Malays, since it is improper to utilize a single equation derived from a particular population for various populations. Sri Lanka Journal of Forensic Medicine, Science & Law-December 2014-Vol.5 No.2; 8-15