Cementum annulation and age determination in Homo sapiens. I. Tooth variability and observer error

In order to test the feasibility of cementum annulations to estimate age in humans, observer error and tooth variability in cementum ring counts were evaluated in a sample of 42 mandibular canine and first premolar pairs. Additionally, two sectioning techniques were evaluated. Demineralized thin sections (7 micron) stained with hematoxylin are the preferred technique since their age related variance is greater than 75% for all tooth types examined. In contrast, less than 50% of the total variance was accounted for among individuals when mineralized sections (80 micron) stained with alizarin red were used. Intertooth variability in ring counts of demineralized sections was large between canines and premolars (43%). Premolars provide counts with lower interobserver error and are the preferred tooth. In an expanded sample (N = 51) of demineralized premolars, intraobserver and interobserver error accounted for 2% and 5% of the total variance, respectively. Evaluation of several experimental designs showed that increasing the number of slides per tooth has the greatest effect on reducing variance followed by increasing the number of observers. Increasing the number of observations has little effect. Cementum ring counts are measurable to a highly repeatable extent and provide a level of repeatability greater than that reported for the pubic symphysis and auricular surface aging techniques.     

Evaluating precision of cementum annuli analysis for aging mule deer from southern California

We evaluated the precision of age estimates produced by cementum annuli analysis (CAA) of blind-duplicate specimens taken from 994 southern mule deer (Odocoileus hemionus) collected over 15 years. We found that the mean annual proportion of unreliably aged incisor pairs was greater for females (0.48, SD = 0.13) than for males (0.22, SD = 0.07). Most of the 308 unreliably aged tooth pairs disagreed by only 1 year. Sex, precipitation, and certainty codes assigned by Matson's Lab to the age estimates were the best predictors for agreement of estimated ages within incisor pairs. Our estimated overall age error rate of CAA (17%) was >2 times as large as estimated error rates from Montana and South Dakota, but less than half of error rates estimated for Mississippi and south Texas. Knowing the error rate of age estimates from a specific deer population allows wildlife managers to perform tasks requiring specific age class information such as monitoring the harvest rate of older female deer in a hunted population or performing population reconstruction. © 2011 The Wildlife Society.     

Technical note: Applicability of tooth cementum annulation to an archaeological population

The use of tooth cementum annulations for age determination has been deemed promising, exhibiting high correlations with chronological age. Despite its apparent potential, to date, the tooth cementum annulations method has been used rarely for estimating ages in archaeological populations. Here we examine the readability of cementum annulations and the consistency of age estimates using a sample of 116 adults from the Iron Gates Gorge Mesolithic/Neolithic series. Our examination of the method pointed to several sources of error that call into question the use of this method for estimating the chronological ages of archaeologically derived dental samples. The poor performance of the method in our analysis might be explained by taphonomic influences, including the effect of chemical and biological agents on dental microstructures. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.     

Age estimation and growth layer patterns in teeth of crabeater seals: A comparison of techniques

Age estimation of marine mammals provides important information about ecological and life history parameters. Counting growth layer groups (GLGs) in the dentine and cementum of teeth is the most common technique for age estimation in pinnipeds. In this study, we used acid-etched canines (n = 38) and decalcified stained postcanine sections (n = 40) to calibrate readings in mummified crabeater seals (Lobodon carcinophaga). A subsample of this group received a prior cleaning treatment of boiling the teeth with hydrogen peroxide (H₂O₂). Ages ranged from 0 to 31 years. Dentine from canines and cementum from postcanines showed higher estimated ages (maximum 31 years) than dentine from postcanines (maximum 24 years), mainly in those teeth that did not receive prior treatment. Boiling with H₂O₂ has shown to affect cementum structure and, thus, results in underestimated ages, but dentine did not seem to be affected. The results presented here showed that ages can be estimated for the crabeater seal regardless of which tooth/tissue or method is used, at least for seals <13 years old. However, nontreated, stained thin sections of postcanine teeth are recommended because more reliable age estimations in older crabeater seals are obtained.     

Tooth cementum annulation for age estimation: results from a large known-age validation study

Recent research indicates that tooth-cementum annulations (TCA) may be used more reliably than other morphological or histological traits of the adult skeleton to estimate age. Until now, however, confidence intervals for age estimated by this method have not been available for paleodemographic and forensic applications. The present study addresses this problem. Based on a large known-age sample, age estimates by TCA were conducted in a blind study involving 363 teeth. Tooth-root cross sections were made using a refined preparation technique. Improved digital graphic procedures and enhancement strategies were used to produce digital images with a specially adapted software package. This resulted in high concordance between the TCA age estimates and chronological age. Assessment of the method's accuracy, as expressed by 95% confidence intervals, showed that error bounds for age estimates do not exceed 2.5 years. Sex differences, intraindividual correlations, and the effects of periodontal disease were studied. None of these indicators had a quantitative effect on the number of TCA bands when the proposed methodological standard was followed. We conclude that the TCA technique is a reliable method for estimating a subject's age from cementum annulations.     

Incremental lines of dental cementum in biological age estimation

The aim of this study is to evaluate the use of counting incremental lines of dental root cementum for biological age determination, and to compare it with alternative methods. Two samples were taken: 51 teeth from 49 individuals of known age obtained at the Stomatological Clinic, Vilnius University, as well as the canine teeth from the remains of 48 individuals from the mass graves of Tuskulenai in Vilnius (inhumed 1944-47). In the latter sample, the chronological age of 43 individuals was known through personal identification. Undecalcified teeth were sectioned with the Leica SP 1600 microtome diamond saw, and incremental line count as a blind test was made on sections of 35 to 100 microns thickness. Incremental line count was possible in 82-86 percent of cases. The results of three independent counts showed that intra-observer bias has no significant impact. Biological age was estimated by adding incremental line number to the average age of tooth eruption. It was found that mean absolute error was 6.46 years for the 1st sample, 6.27 years for the 2nd sample, and in some cases exceeded 10 years. For the 2nd sample, the results were compared to those of other methods such as endocranial suture ossification, pubic symphysis morphology and the "combined" method of Nemeskéri. All four methods yield a similar correlation in regard to an individual's chronological age. The highest correlation was found for the combined method, and the lowest one for public symphysis morphology. All correlations had a similar standard error. Thus our assessment is less enthusiastic than in some past studies; it is suggested that the incremental lines rather have a similar use as other methods.     

Fluoride profiles in the cementum and root dentine of human permanent anterior teeth extracted from adult residents in a naturally fluoridated and a non-fluoridated area

Objectives: To determine the effect of water fluoride concentration on the fluoride profile across the entire thickness of the cementum and root dentine of human permanent anterior teeth in adults. Subjects: Twenty-eight human permanent anterior teeth from individuals aged from 30 to over 60 years were studied. Setting: Teeth were obtained from a natural high-fluoride area (West Hartlepool, UK; 1.0–1.3 ppm F in drinking water, WHP) and the other from a non-fluoridated naturally low fluoride area (Leeds, UK; 0.1 ppm F in drinking water, LDS). Design: Cementum and root dentine were sampled using an abrasive micro-sampling technique from the cementum surface to the pulpal surface of root dentine. Results: Fluoride concentration was higher in tooth roots (the cementum and dentine) taken from the naturally fluoridated area (WHP) than from the non-fluoridated area (LDS). Age and average fluoride concentration showed a positive correlation in WHP dentine, middle region of the root (r = 0.78, P < 0.001) and in the apical region of the root (r = 0.67, P < 0.05). WHP cementum had the strongest fluoride concentration correlation with age in the cervical region of the root (r = 0.67, P < 0.01). An analysis of variance (ANOVA) showed that the area (water fluoride content), age and number of years lived in the area combined with total age were significant. Conclusions : The fluoride content of cementum and root dentine in adult residents is related to fluoride content in drinking water.     

Basics in paleodemography: a comparison of age indicators applied to the early medieval skeletal sample of Lauchheim

Recent advances in the methods of skeletal age estimation have rekindled interest in their applicability to paleodemography. The current study contributes to the discussion by applying several long established as well as recently developed or refined aging methods to a subsample of 121 adult skeletons from the early medieval cemetery of Lauchheim. The skeletal remains were analyzed by 13 independent observers using a variety of aging techniques (complex method and other multimethod approaches, Transition Analysis, cranial suture closure, auricular surface method, osteon density method, tooth root translucency measurement, and tooth cementum annulation counting). The age ranges and mean age estimations were compared and results indicate that all methods showed smaller age ranges for the younger individuals, but broader age ranges for the older age groups.     

Age estimation of the White rhinoceros (Ceratotherium simum)

Age estimation criteria for the southern White rhinoceros ( Ceratotherium simum simum ) are presented both for free-ranging live animals and for cranial material. These are based on: (i) size appearance and horn development of live animals; (ii) stages of tooth eruption; (iii) tooth wear classes; (iv) attrition in height of the first molar tooth; (v) counts of cementum lines visible in tooth sections. Selected measurements are presented for live animals, skulls and horns.
For live animals, eight size classes are distinguished, seven of these covering immature animals up to ten years of age. Sixteen tooth wear classes are established, based on eruption and surface wear of maxillary dentition. Chronological ages were assigned from individually known animals followed in the field, and from skulls from animals for which exact records of age were available, or which could be assigned to an age category from appearance at death. Cementum line counts corresponded approximately with age in years, despite difficulties in interpreting lines. Some variability was observed, possibly related to nutritional conditions.
The maximum cementum line count obtained indicates a longevity of at least 40 years. Full body weight and socio-sexual maturity are attained by males between 10 and 15 years of age, while females first give birth between six and eight years of age. Sequences and times of tooth eruption are similar to those reported for the Black rhinoceros ( Diceros bicornis ).
Comparative cranial and body measurements are presented for the northern subspecies ( Ceratotherium simum cottoni ).     

Mountain reedbuck Redunca fulorufula growth and age determination using dentition

Lower jaws and measurements were obtained from 473 mountain reedbuck Redunca fulvorufula culled on two reserves in the north-eastern karoo of South Africa. All mandibles were allocated to subjective age classes that were based on tooth-eruption and tooth-wear. In a sample of 69 jaws. the molar and premolar cementum annuli were counted by examining bisected whole teeth under reflected light. One light line appeared to have been deposited per year, and a usable relationship between tooth-wear category and cementum line count was obtained. although indistinct and paired lines often confused the picture. Good correlations were also obtained between the number of cementum lines and the crown height of the first molar (r²= 0.68) and the second molar (r²= 0.77). Actual ages of immatures were estimated by comparing peaks in the distribution in the different age classes with the age since expected mean birth date in different culls. The age of transition to adult dentition (pL 30 months) was determined from two females that were earmarked when young and shot two years later. Von Bertalanffy (1957) growth curves were fitted to measurements of body mass, jaw length and horn length in males to aid field identification of immatures. Asymptotic body mass was reached at 30 months in females and 40 months in males, and asymptotic jaw length was reached at 30 months in both sexes. Horns in males only reached full length at about five years.     

Cementum annulations,age estimation,and demographic dynamics in Mid-Holocene foragers of North India

One of the principal problems facing palaeodemography is age estimation in adult skeletons and the centrist tendency that affects many age estimation methods by artificially increasing the proportion of individuals in the 30–45-year age category. Several recent publications have indicated that cementum annulations are significantly correlated with known age of extraction or death. This study addresses the question of how demographic dynamics are altered for an archaeological sample when cementum-based age estimates are used as opposed to those obtained via conventional macroscopic methods. Age pyramids were constructed and demographic profiles were compared for the early Holocene skeletal population from Damdama (India). The results demonstrate that the use of cementum annulations for age estimation in only a subset of the skeletal sample has a significant impact on the demographic profile with regard to specific parameters such as mean age at death and life expectancy at birth. This confirms the importance of using cementum annulations to refine age estimates in archaeological samples, which, when combined with a fertility-centred approach to demography, can provide new insights into population dynamics in the past.     

Nightmare frequency as a function of age, gender, and September 11, 2001: Findings from an Internet questionnaire.

Retrospective estimates of nightmare frequency for a sample of 23,990 respondents to an Internet questionnaire (female: N = 19,367, mean age = 24.9 ± 10.14 years; male: N = 4,623; mean age = 25.5 ± 10.81) were evaluated as a function of age, gender, and pre- versus post-September 11, 2001. Female respondents reported more frequent monthly nightmares (4.44 ± 6.71) than did male respondents (3.39 ± 6.07), and this result was seen for all age strata younger than 60. Also, for female respondents, nightmare frequency increased from ages 10-19 to 20-39 then decreased monotonically to ages 50-59. For male respondents, nightmare frequency was stable from ages 10-19 to 30-39 then decreased to ages 50-59. An increase in nightmare frequency was observed post-September 11 only for male respondents-particularly for 10- to 29-year-olds. This increase was sustained 2 years later. These effects were maintained when dream recall was held constant. Results replicate, in a single sample, previously published gender and age effects and provide new evidence that the nightmares of males may be differentially sensitive to traumatic events for which victims and/or perpetrators are primarily male. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Oral health status in elders from South Brazil: a population-based study

doi: 10.1111/j.1741‐2358.2011.00617.x Oral health status in elders from South Brazil: a population‐based study Objective: To assess the oral health status of community‐dwelling adults aged 60 years and older from southern Brazil and to determine demographics, socioeconomic, behavioural and dental risk indicators. Materials and methods: This cross‐sectional study used a multistage, probability sampling method to draw a representative sample of the metropolitan area of Porto Alegre, Brazil. A subsample of 217 subjects was included in this analysis. Oral mucosal lesions, dental caries, tooth loss and periodontal status (full‐mouth, six sites per tooth exam) were assessed by calibrated examiners. Results: Prevalence of edentulism was 39.5%, and mean tooth loss was 20.2 (SE = 0.6). Older individuals [Odds Ratio (OR) = 2.2], women (OR = 2.3), white people (OR = 5.9), individuals of lower socioeconomic status (OR = 5.6) and smokers (OR = 3.5) had higher likelihood of being edentulous. Approximately 36% of dentate individuals had caries and/or restoration affecting, in average, 5.0 teeth. Periodontitis affected 79% of subjects, and it was associated with older age (OR = 4.0), men (OR = 3.4) and large amounts of supragingival plaque (OR = 3.0). Conclusion: Poor oral health was observed in this elderly population from South Brazil. Sociodemographic disparities accounted for most of the burden of disease and treatment needs.     

A new non-exercise-based Vo2max prediction equation for aerobically trained men

The purposes of the present study were to (a) modify previously published Vo(2)max equations using the constant error (CE = mean difference between actual and predicted Vo(2)max) values from Malek et al. (28); (b) cross-validate the modified equations to determine their accuracy for estimating Vo(2)max in aerobically trained men; (c) derive a new non- exercise-based equation for estimating Vo(2)max in aerobically trained men if the modified equations are not found to be accurate; and (d) cross-validate the new Vo(2)max equation using the predicted residual sum of squares (PRESS) statistic and an independent sample of aerobically trained men. One hundred and fifty-two aerobically trained men (Vo(2)max mean +/- SD = 4,154 +/- 629 ml.min(-1)) performed a maximal incremental test on a cycle ergometer to determine actual Vo(2)max. An aerobically trained man was defined as someone who had participated in continuous aerobic exercise 3 or more sessions per week for a minimum of 1 hour per session for at least the past 18 months. Nine previously published Vo(2)max equations were modified for use with aerobically trained men. The predicted Vo(2)max values from the 9 modified equations were compared to actual Vo(2)max by examining the CE, standard error of estimate (SEE), validity coefficient (r), and total error (TE). Cross-validation of the modified non-exercise-based equations on a random subsample of 50 subjects resulted in a %TE > or = 13% of the mean of actual Vo(2)max. Therefore, the following non-exercise-based Vo(2)max equation was derived from a random subsample of 112 subjects: Vo(2)max (ml.min(-1)) = 27.387(weight in kg) + 26.634(height in cm) - 27.572(age in years) + 26.161(h.wk(-1) of training) + 114.904(intensity of training using the Borg 6-20 scale) + 506.752(natural log of years of training) - 4,609.791 (R = 0.82, R(2) adjusted = 0.65, and SEE = 378 ml.min(-1)). Cross-validation of this equation on the remaining sample of 40 subjects resulted in a %TE of 10%. Therefore, the non-exercise-based equation derived in the present study is recommended for estimating Vo(2)max in aerobically trained men.     

Peak vertical jump power estimations in youths and young adults

The purpose of this study was to develop and validate a regression equation to estimate peak power (PP) using a large sample of athletic youths and young adults. Anthropometric and vertical jump ground reaction forces were collected from 460 male volunteers (age: 12-24 years). Of these 460 volunteers, a stratified random sample of 45 subjects representing 3 different age groups (12-15 years [n = 15], 16-18 years [n = 15], and 19-24 years [n = 15]) was selected as a validation sample. Data from the remaining 415 subjects were used to develop a new equation ("Novel") to estimate PP using age, body mass (BM), and vertical jump height (VJH) via backward stepwise regression. Independently, age (r = 0.57), BM (r = 0.83), and VJ (r = 0.65) were significantly (p < 0.05) correlated with PP. However, age did not significantly (p = 0.53) contribute to the final prediction equation (Novel): PP (watts) = 63.6 × VJH (centimeters) + 42.7 × BM (kilograms) - 1,846.5 (r = 0.96; standard error of the estimate = 250.7 W). For each age group, there were no differences between actual PP (overall group mean ± SD: 3,244 ± 991 W) and PP estimated using Novel (3,253 ± 1,037 W). Conversely, other previously published equations produced PP estimates that were significantly different than actual PP. The large sample size used in this study (n = 415) likely explains the greater accuracy of the reported Novel equation compared with previously developed equations (n = 17-161). Although this Novel equation can accurately estimate PP values for a group of subjects, between-subject comparisons estimating PP using Novel or any other previously published equations should be interpreted with caution because of large intersubject error (± >600 W) associated with predictions.     

African elephant age determination from teeth: validation from known individuals

We assess tooth‐based age criteria for African elephants developed by Laws in relation to known‐aged individuals in the Amboseli elephant population. Laws’s technique remains a robust and useful mechanism for age determination, although we suggest revisions to the oldest age categories. Blind age assignment to jaws of unknown sex using the Laws criteria resulted in misclassification of M4 and M5; measures overlapped too much to differentiate these teeth by sex. Sexes could be reliably distinguished after age 30 or XIX in tooth category by two measures: mandible thickness and width of the ascending ramus, but individuals of the same known age differed in tooth wear and progression rates. Such variation needs to be incorporated in the error assigned to tooth age categories. Ages at death of found jaws (n = 266) were similar to results of survival analysis from all demographic data (n = 2455), excluding calves whose jaws decompose because of weathering and scavengers. Jaw‐based models of age at death need correction for the inability to detect this early mortality, which artificially extends mean longevity by up to 6 years.     

Power output estimation in vertical jump performed by young male soccer players

The purpose of the study was (a) to assess the accuracy of the regression equations available in the literature to estimate the actual peak power (PPac) of the countermovement jump (CMJ) executed by young male soccer players, (b) to develop new regression equations from this population, and (c) to verify whether regression equations obtained from age-based subgroups could increase the accuracy of the estimation (PPes) of PPac. In all, 117 young players (age: 13.6 ± 2.4 years) were enrolled in the study. Each subject performed 5 CMJs on a force platform. The new regression equations were obtained from the entire experimental sample (G1) and 3 age-based subsamples (G2 = prepubertal, G3 = peripubertal, G4 = postpubertal) using 2 different approaches: the best jump and the mean values achieved by each subject. All the equations in the literature underestimated the peak power (p < 0.00005) in all the groups. The approach based on the mean values was more accurate (adjusted R = 0.925, SEE = 302.9 W) than the one based on the best jump (adjusted R = 0.892; SEE = 360.8 W). Moreover, calculating the regression equations from the 3 age-based subsamples, SEE resulted improved (15.5% in G2, 5.6% in G3 and 0.9% in G4). Regression equations must be derived from homogeneous populations, in terms of gender, sports practice, and age. The approach based on the mean values for each subject was more accurate than the approach used in the literature up to now. In practical applications, regression equation estimates cannot be used to assess the performance of a single subject, because errors may exceed 50%, whereas they may be useful for group comparisons.     

Identification and validity of accelerometer cut-points for toddlers

The purpose of this study was to derive ActiGraph cut-points for sedentary (SED), light-intensity physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) in toddlers and evaluate their validity in an independent sample. The predictive validity of established preschool cut-points were also evaluated and compared. Twenty-two toddlers (mean age = 2.1 years ± 0.4 years) wore an ActiGraph accelerometer during a videotaped 20-min play period. Videos were subsequently coded for physical activity (PA) intensity using the modified Children's Activity Rating Scale (CARS). Receiver operating characteristic (ROC) curve analyses were conducted to determine cut-points. Predictive validity was assessed in an independent sample of 18 toddlers (mean age = 2.3 ± 0.4 years). From the ROC curve analyses, the 15-s count ranges corresponding to SED, LPA, and MVPA were 0-48, 49-418, and >418 counts/15 s, respectively. Classification accuracy was fair for the SED threshold (ROC-AUC = 0.74, 95% confidence interval = 0.71-0.76) and excellent for MVPA threshold (ROC-AUC = 0.90, 95% confidence interval = 0.88-0.92). In the cross-validation sample, the toddler cut-point and established preschool cut-points significantly overestimated time spent in SED and underestimated time in spent in LPA. For MVPA, mean differences between observed and predicted values for the toddler and Pate cut-points were not significantly different from zero. In summary, the ActiGraph accelerometer can provide useful group-level estimates of MVPA in toddlers. The results support the use of the Pate cut-point of 420 counts/15 s for MVPA.     

Brief communication: Estimates of some demographic parameters in a neolithic rock-cut chamber (approximately 2000 BC) using iterative techniques for aging and demographic estimators

Two new techniques—one anthropological, which estimates the mean age at death for adult skeletons, the other demographic, which gives main survivorship curve parameters—are used on a sample of skeletons (N ≅ 170) discovered in a Neolithic rock-cut chamber (Loisy-en-Brie, France). The iterative technique for aging used a stochastic sampled F matrix derived from the trabecular involution of the femoral head observed in the reference collection of Coimbra (Portugal; N = 421). The results, obtained from techniques and data, independent of each other, are strongly consistent. Overall, they give a life expectancy at birth of about 25–28 years and the probability of death at 1 and 5 years, respectively, of about .271-.249 and .429-.380. Am J Phys Anthropol 102:569–575, 1997. © 1997 Wiley-Liss, Inc.     

Heterogeneity of genetic control of blood pressure in ethnically different populations.

We review the literature on statistical genetic analyses of blood pressure in samples from various ethnic backgrounds using different statistical methods and packages. We then provide the results of a complex segregation analysis performed on familial data on systolic and diastolic blood pressure in 2 ethnically different populations, Chuvashans and Turkmenians. Two types of major gene models were tested in the segregation analysis: Model type 1 tests for a Mendelian mode of transmission and estimates genotype-specific averages regardless of age and sex effect, and model type 2 estimates age and sex effects on each of 3 genotypes within the putative major genotype. In both total samples, by both types of segregation analysis, familial aggregation of both systolic and diastolic blood pressure was inconsistent with the Mendelian mode of inheritance. In the next step of analysis the pedigrees in both samples were sorted into 2 groups on the basis of 2 likelihoods as obtained under Mendelian and nontransmission models for each entire sample. This procedure resulted in the appearance of 2 subsamples (large and small) in each ethnic sample. The segregation analysis that was carried out then on the larger subsample provided consistent evidence to support the major gene effect on systolic and diastolic blood pressure in 2 ethnic groups. Interestingly, model type 2 showed that in both ethnically different large subsamples, for each sex the genotype predisposing to a larger mean value of systolic (or diastolic) blood pressure also displayed the highest rate of blood pressure increase with age. We discuss in detail possible sources of heterogeneity in familial transmission of blood pressure observed in our 2 samples, and we suggest a method to improve the analysis of heterogeneity for trait inheritance.