Sex-specific effects of environmental temperature during gestation on fluctuating asymmetry in deciduous teeth.

OBJECTIVES: External environmental heat exposure during gestation impacts the physiology of human development in utero, but evidence for these impacts has not yet been explored in dentition. We examined deciduous teeth for fluctuating asymmetry (FA), a measure of developmental instability, together with gestational environmental temperature data drawn from historical weather statistics. MATERIALS AND METHODS: We measured dental casts from the longitudinal Burlington Growth Study, representing 172 participants (ages 3-6 years) with health records. FA was calculated from crown dimensions and intercuspal distances that develop during gestation. Multiple regression separated by sex (nfemale = 81) examined the effects of mean temperatures in each trimester, controlling for birth year. RESULTS: In females, increased temperatures during the first trimester are significantly associated with an increase in FA (p = 0.03), specifically during the second and third prenatal months (p = 0.03). There is no relationship between temperature and FA for either sex in the second or third trimesters, when enamel is formed. DISCUSSION: Dental instability may be sensitive to temperature in the first trimester in females during the scaffolding of crown shape and size in the earliest stages of tooth formation. Sexual dimorphism in growth investment strategies may explain the differences in results between males and females. Using enduring dental characteristics, these results advance our understanding of the effects of temperature on fetal physiology within a discrete period.

Error and bias in race and ethnicity descriptions in medical examiner records in New Mexico: Consequences for understanding mortality among Hispanic/Latinos.

Researchers use public records from deceased individuals to identify trends in manners and causes of death. Errors in the description of race and ethnicity can affect the inferences researchers draw, adversely impacting public health policies designed to eliminate health inequity. Using the New Mexico Decedent Image Database, we examine: 1) the accuracy of death investigator descriptions of race and ethnicity by comparing their reports to those from next of kin (NOK), 2) the impact of decedent age and sex on disagreement between death investigators and NOK, and 3) the relationship between investigators' descriptions of decedent race and ethnicity and cause and manner of death from forensic pathologists (n = 1813). Results demonstrate that investigators frequently describe race and ethnicity incorrectly for Hispanic/Latino decedents, especially regarding homicide manner of death and injury and substance abuse causes of death. Inaccuracies may cause biased misperceptions of violence within specific communities and affect investigative processes.

Refined, regionally-specific data standards reveal heterogeneity in Hispanic death records.

Hispanic ethnicity can be captured with differing levels of granularity using various data standards, including those from the Office of Management and Budget, Health and Human Services and National Academy of Medicine. Previous research identified seven subgroups of Hispanics in New Mexico using open-ended interviews and information about the culture/history of the state. We examined age and manner of death to determine whether differences among subgroups are hidden by less-refined categorization. Significant differences in the mean age at death were found between some groups, including Spanish and Mexican Americans. We found an association between specific manners of death codes and subgroups. However, significance disappeared when manners of death were grouped (e.g. accident, homicide, etc.). This indicates that while certain manners of death are associated with group membership, overall types of death are not. Data descriptors for Hispanics should reflect more refined, regionally relevant groups, in order to unmask heterogeneity.

Conventional microscopy makes perikymata count and spacing data feasible for large samples.

OBJECTIVES: Current methods of quantifying defects of dental enamel (DDE) include either gross or low-level examination for linear enamel hypoplasia, histological analysis of striae of Retzius, or scanning electron microscopy (SEM) of a tooth or a tooth cast. Gross examination has been shown to miss many defects. Other methods can be destructive, require transporting samples, and are expensive. Here, we show that digital light microscopy (DLM) can be used for the analysis of DDE as indicated by widened perikymata spacing (WPS). This method takes advantage of high-power (100×) microscopy, but is non-destructive, can be implemented almost anywhere, and is inexpensive. MATERIALS AND METHODS: As proof of concept, we created photomontages of labial surfaces of five human canines from images made using DLM and SEM. We counted and measured the widths of all visible perikymata for each imaging modality and fit measurements to a negative curve representing the expected values for each tooth. We calculated residuals for each measurement. WPS were defined when R2 was in the 90th percentile, and were considered matched in DLM and SEM images when observed within the same decile of the tooth surface. RESULTS: There were more WPS detected in the images derived from DLM than from SEM. Overall, the data derived from the two imaging modalities provided similar information about the frequency and timing of stress during dental development. CONCLUSIONS: The method described here allows for DDE data acquisition as WPS from large samples, making feasible population-level studies that reflect sophisticated understanding of dental development.

Childhood dietary quality predicts adult facial fluctuating asymmetry in contemporary New Mexicans.

Fluctuating asymmetry (FA) in adults is thought to reflect specific types of developmental stress. If true, adult FA may be a proxy for developmental stress in past as well as current populations. To date, studies of the link between development and adult FA have produced ambiguous results due to insufficient measurement data for childhood environments. This study seeks to overcome this limitation using a structural equation modeling approach to evaluate the relationship between 29 measures of developmental environments and precise measures of adult FA. Sociodemographic information and 3D facial photographs were collected from 80 adult New Mexicans. Facial FA was measured from the photographs using geometric morphometric analysis of 12 facial landmarks. Each participant responded to a questionnaire addressing the developmental environment, including childhood home environment, family SES, health, and dietary quality. We used structural equation models to examine predictive relationships between latent variables constructed from questionnaire responses and adult facial FA. Childhood dietary quality was negatively associated with adult FA scores, meaning that poorer diets predict higher FA (standardized path coefficient -0.174, p = 0.039). Factors that loaded positively on the dietary quality construct were a diet quality index, the frequency of homemade meals, and the frequency of homemade breakfast, while the frequency of fast-food meals loaded negatively. No other latent variable predicted adult facial FA. We posit that the negative relationship between dietary quality and FA reflects a negative energy balance experienced during development. Insufficient nutrition results in a reduced capacity to buffer against environmental perturbations, with increased FA as evidence. Given previously established links between FA and adult health outcomes in humans, this finding also underscores the importance of dietary quality during development for ensuring health and wellbeing later in life. These results indicate that FA in facial shape may signal the relative quality of dietary conditions during development.

Developing the Minimum Dataset for the New Mexico Decedent Image Database.

BACKGROUND: A minimum dataset (MDS) can be determined ad hoc by an investigator or small team; by a metadata expert; or by using a consensus method to take advantage of the global knowledge and expertise of a large group of experts. The first method is the most commonly applied. OBJECTIVE: Here, we describe a use of the third approach using a modified Delphi method to determine the optimal MDS for a dataset of full body computed tomography scans. The scans are of decedents whose deaths were investigated at the New Mexico Office of the Medical Investigator and constitute the New Mexico Decedent Image Database (NMDID). METHODS: The authors initiated the consensus process by suggesting 50 original variables to elicit expert reactions. Experts were recruited from a variety of scientific disciplines and from around the world. Three rounds of variable selection showed high rates of consensus. RESULTS: In total, 59 variables were selected, only 52% of which the original resource authors selected. Using a snowball method, a second set of experts was recruited to validate the variables chosen in the design phase. During the validation phase, no variables were selected for deletion. CONCLUSION: NMDID is likely to remain more "future proof" than if a single metadata expert or only the original team of investigators designed the metadata.

Geographic and temporal diversity in dental morphology reflects a history of admixture, isolation, and drift in African Americans.

OBJECTIVES: While genetic studies have documented variation in admixture proportions in contemporary African Americans across the US, relatively little is known about the socio-historical roots of this variation. Our goal in this study is to use dental morphology to explore the socio-historical correlates of admixture, localized gene flow, and drift in African Americans. METHODS: Our data are ordinally-graded dental morphological traits scored in 196 Africans, 335 Europeans and European Americans, 291 pre-Spanish-contact Native Americans, and 722 African Americans. The African American data derived from contemporary and historic samples. We eliminated from analysis individuals and traits with greater than 20% missing data. We summarized the major axes of trait variation using principal component analysis (PCA), estimated biological distance, constructed multidimensional scaling (MDS) plots of the distances, and measured the correlation between geographic and biological distance. RESULTS: In the PCA, African American groups clustered between Africans and Europeans on PC 1, reflecting admixture between the groups. PC 2 separated African American samples, possibly reflecting movement, isolation, and drift. MDS analyses confirmed the existence of sizable biological distances between African American samples, especially between contemporary and past African American samples. We found no relationship between biological and geographic distances. DISCUSSION: We demonstrate that admixture and drift can be inferred from multi-variable analyses of patterns of dental morphology in admixed populations. Localized gene flow has not affected patterns of trait variation in African Americans, but long-range movement, isolation, and drift have. We connect patterns of dental trait variation to efforts to flee oppression during the Great Migration, and the repeal of anti-miscegenation laws.

Cribra orbitalia and porotic hyperostosis are associated with respiratory infections in a contemporary mortality sample from New Mexico.

OBJECTIVES: Cribra orbitalia (CO) and porotic hyperostosis (PH) are porous cranial lesions (PCLs) classically associated with iron-deficiency anemia in bioarchaeological contexts. However, recent studies indicate a need to reassess the interpretation of PCLs. This study addresses the potential health correlates of PCLs in a contemporary sample by examining relationships between the known cause of death (COD) and PCL presence/absence. METHODS: This study includes a sample of 461 juvenile individuals (6 months to 15 years of age) who underwent examination at the University of New Mexico's Office of the Medical Investigator between 2011 and 2019. The information available for each individual includes their sex, age at death, and their COD and manner of death. RESULTS: Odds ratio of having CO (OR = 3.92, p < .01) or PH (OR = 2.86, p = .02) lesions are increased in individuals with respiratory infections. Individuals with heart conditions have increased odds of having CO (OR = 3.52, p = .03) lesions, but not PH. CONCLUSION: Individuals with respiratory infection are more likely to have CO and/or PH. CO appears to have a greater range of health correlates than PH does, as indicated by the heart condition results. However, individuals with congenital heart defects are at higher risk for respiratory infections, so bony alterations in cases of heart conditions may be due to respiratory illness. Since respiratory infection remains a leading cause of mortality today, CO and PH in bioarchaeological contexts should be considered as potential indicators of respiratory infections in the past.

Early isotopic evidence for maize as a staple grain in the Americas.

Maize is a cultigen of global economic importance, but when it first became a staple grain in the Americas, was unknown and contested. Here, we report direct isotopic dietary evidence from 52 radiocarbon-dated human skeletons from two remarkably well-preserved rock-shelter contexts in the Maya Mountains of Belize spanning the past 10,000 years. Individuals dating before ~4700 calendar years before present (cal B.P.) show no clear evidence for the consumption of maize. Evidence for substantial maize consumption (~30% of total diet) appears in some individuals between 4700 and 4000 cal B.P. Isotopic evidence after 4000 cal B.P. indicates that maize became a persistently used staple grain comparable in dietary significance to later maize agriculturalists in the region (>70% of total diet). These data provide the earliest definitive evidence for maize as a staple grain in the Americas.

Extracting and Standardizing Medical Examiner Data to Improve Health.

Data from medical examiner offices are not commonly used in informatics but may contain information not in medical records. However, the vast majority of data is not standardized and is available only in large free text fields. We sought to extract information from the medical examiner database using Canary, a natural language processing tool. The text was then standardized to fit the selected normative answer list for each field. Multiple terminology and vocabulary standards from a variety of settings were utilized as data came from the medical examiner and interviews with next of kin. Thirty-seven percent of the metadata fields could be mapped directly to existing standards, twenty-five percent required a modification, and thirty-eight required creation of a standardized normative answer list. The newly formed database (New Mexico Decedent Image Database (NMDID)), will be available to researchers and educators at the beginning of 2020.

Sociocultural determinants of health and wealth in historic African Americans.

In this study, we examine the impacts of individual ancestry and socioeconomic status (SES) on health in historic African Americans through bioarchaeological means. We estimate ancestry from dental morphology and SES from the costs of coffin hardware. We include 188 adult individuals from Freedman's Cemetery in Dallas, Texas, and 2,301 individuals of African and European descent for comparison. Freedman's Cemetery functioned as the only cemetery available to freed people and their descendants between 1869 and 1907. Linear discriminant analysis (LDA) of dental morphological traits was used to estimate individual ancestry. LDA results were then used in Cox proportional hazards analysis to examine whether ancestry impacted mortality risk or SES. Ancestry was not found to impact SES. However, paralleling results from analysis of census mortality data, individuals with greater African ancestry on average have shorter lifespans and higher mortality hazards than individuals who have more European ancestry. This finding provides evidence for structural violence in this historic African American skeletal sample. The negative effects of social constructs are embodied and can be detected in skeletal samples through use of statistical methods combined with information about the cultural context in which people lived.

Standardizing Data from the Dead.

A database of full-body CT scans and associated lifestyle and health data from decedents who underwent an autopsy at the Office of the Medical Investigator (OMI) is under construction. The dataset has 68 metadata fields containing data from the OMI's database and interviews with next of kin. Some metadata fields could be mapped to existing standards, but the majority of fields required some modifications to current standards or the creation of new standards.

Informativeness of dental morphology in ancestry estimation in African Americans.

OBJECTIVES: Our objective is to assess the informativeness of dental morphology in estimating biogeographic ancestry in African Americans. MATERIALS AND METHODS: The data are 62 dental morphological traits scored as nondichotomized and dichotomized in 797 individuals, 992,601 SNPs from 271 individuals, and 645 STRs from 177 individuals. Each dataset consists of Africans, Europeans, and African Americans. For each dataset, we summed Fisher Information (FI), then used STRUCTURE to estimate ancestry. RESULTS: Total FI was highest for SNPs, followed by STRs, nondichotomized dental traits, and dichotomized dental traits. For both genetic datasets, Africans and Europeans fell into two distinctive clusters with low 90% credible regions for individual ancestry estimates. In African Americans, membership in the African cluster was 76.4% and 80.4% for SNPs and STRs, respectively. For the dental data, all Africans and Europeans had appreciable membership in both clusters and comparatively high 90% credible regions for individual ancestry estimates. Nonetheless, African Americans had consistently higher membership in the same cluster in which Africans had high membership. African American membership in this cluster was significantly higher for the nondichotomized form than for the dichotomized. DISCUSSION AND CONCLUSIONS: FI potentially provides a useful gauge of the effectiveness of dental and genetic data for ancestry estimation. The comparatively high FI of nondichotomized dental traits suggests data in this form may be better suited for studies of admixture than dichotomized data. Because of high error in individual ancestry estimates, dental morphological data may be unable to distinguish differences in ancestry among individuals within admixed populations.

Can Cephalometrics Discriminate Between the Sexes in a Diverse Juvenile Sample?

A critical component of the biological profile is sex estimation. Methods commonly used for sex estimation in adults do not work well for juveniles. Population-specific studies have used cephalometrics to estimate juvenile sex with 80-90% accuracy. Our study attempts to estimate sex in individuals less than 18 years of age using a sample of 1618 lateral cephalograms incorporating all three Angle Class occlusions as well as population diversity. For the sample as a whole, 10 skeletal cephalometrics were found to have significant differences between the sexes. Males and females classify correctly about 50% of the time. Dividing the sample by age groups and race/ethnicity improves results for older age groups and Native Americans, Hispanics, and Asian Americans. Our results indicate that cephalometrics are not useful in determining sex of unidentified juveniles when age and race are not known.

Defining the Differences in Transverse Plane Trajectories for Thoracic Pedicle Screw Insertion: Anatomic Versus Medial.

STUDY DESIGN: Comparing thoracic pedicle screw trajectories, screw lengths, and starting points by examining osteologic specimens. OBJECTIVE: Describe a medial screw trajectory (MST) compared to a screw trajectory along the anatomic pedicle angle (APA) in terms of trajectory, screw length, and starting point. SUMMARY OF BACKGROUND DATA: Although thoracic pedicle screw insertion is commonly used for posterior fusion and instrumentation, there is little data to quantify an MST that avoids the great vessels and allows for greater screw purchase. METHODS: Thirty adult female skeleton thoracic vertebral columns from the University of New Mexico Maxwell Museum of Anthropology Osteology Collection were photographed from axial and right and left lateral views from T1 to T12. Axial plane measurements included APA and MST (both measured from the midline), screw lengths, and APA/MST intersection on the superior articular facet (SAF). The MST was defined as an insertion angle through the midpoint of the pedicle isthmus intersecting the anterior midpoint of the vertebral body. The intersection of each trajectory with the SAF was measured in relation to the lateral base of the SAF, reported as a percentage of the SAF base width from the lateral SAF border. RESULTS: At every vertebral level, the APA was different from the MST for angle, screw length, and SAF intersection (p < .0001), with the largest difference at T12. The T12 differences were APA versus MST angles (-25.5°, 95% CI -22.7° to -28.4°), screw lengths (11.0 mm, 95% CI 9.2 mm to 12.9 mm), and percentage of SAF width from the lateral border of the SAF base (38.6%, 95% CI 29.1% to 48.1%). CONCLUSIONS: The MST was approximately 8° to 10° greater at T1-T10 (19° at T11 and 25° at T12) than the traditional APA insertion angle. This resulted in a much more lateral starting point on the SAF and longer screw length, greatest at T12.

Cultural interaction and biological distance in postclassic period Mexico.

Economic, political, and cultural relationships connected virtually every population throughout Mexico during Postclassic period (AD 900-1520). Much of what is known about population interaction in prehistoric Mexico is based on archaeological or ethnohistoric data. What is unclear, especially for the Postclassic period, is how these data correlate with biological population structure. We address this by assessing biological (phenotypic) distances among 28 samples based upon a comparison of dental morphology trait frequencies, which serve as a proxy for genetic variation, from 810 individuals. These distances were compared with models representing geographic and cultural relationships among the same groups. Results of Mantel and partial Mantel matrix correlation tests show that shared migration and trade are correlated with biological distances, but geographic distance is not. Trade and political interaction are also correlated with biological distance when combined in a single matrix. These results indicate that trade and political relationships affected population structure among Postclassic Mexican populations. We suggest that trade likely played a major role in shaping patterns of interaction between populations. This study also shows that the biological distance data support the migration histories described in ethnohistoric sources.

Technical note: 3D representation and analysis of enthesis morphology.

This comparison of methods for assessing the development of muscle insertion sites, or entheses, suggests that three-dimensional (3D) quantification of enthesis morphology can produce a picture of habitual muscle use patterns in a past population that is similar to one produced by ordinal scores for describing enthesis morphology. Upper limb skeletal elements (humeri, radii, and ulnae) from a sample of 24 middle-aged adult males from the Pottery Mound site in New Mexico were analyzed for both fibrous and fibrocartilaginous enthesis development with three different methods: ordinal scores, two-dimensional (2D) area measurements, and 3D surface areas. The methods were compared using tests for asymmetry and correlations among variables in each quantitative data set. 2D representations of enthesis area did not agree as closely as ordinal scores and 3D surface areas did regarding which entheses were significantly asymmetrical. There was significant correlation between 3D and 2D data, but correlation coefficients were not consistently high. Intraobserver error was also assessed for the 3D method. Cronbach's alpha values fell between 0.68 and 0.73, and error rates for all entheses fell between 10% and 15%. Marginally acceptable intraobserver error and the analytic versatility of 3D images encourage further investigation of using 3D scanning technology for quantifying enthesis development.

Estimation of ancestry using dental morphological characteristics.

The use of dental morphological characteristics to estimate the ancestry of skeletal remains commonly includes few traits, combines dental traits with other skeletal characteristics, and is nonstatistical. Here, discriminant function equations for estimating whether an unknown person was African American or European American, or Hispanic American are presented. Equations were developed from observations of 29 dental traits in 509 individuals. These equations were then applied to the original sample and a test sample (n = 40). Correct assignment rates for estimating African or European American versus Hispanic American range from 66.7 to 89.3%. Correct assignment of African Americans versus European Americans is 71.4 to 100%. Correct geographic assignment of Hispanics from South Florida or New Mexico range from 46.2 to 72.7%. Various discriminant equations using combinations of characteristics are provided. Coupled with the error estimates, these equations offer an important step in the use of dental morphology in contemporary, post-Daubert forensic science.

Using LOINC to link 10 terminology standards to one unified standard in a specialized domain.

Despite the existence of multiple standards for the coding of biomedical data and the known benefits of doing so, there remain a myriad of biomedical information domain spaces that are essentially un-coded and unstandardized. Perhaps a worse situation is when the same or similar information in a given domain is coded to a variety of different standards. Such is the case with cephalometrics - standardized measurements of angles and distances between specified landmarks on X-ray film used for orthodontic treatment planning and a variety of research applications. We describe how we unified the existing cephalometric definitions from 10 existing cephalometric standards to one unifying terminology set using an existing standard (LOINC). Using our example of an open and web-based orthodontic case file system, we describe how this work benefited our project and discuss how adopting or expanding established standards can benefit other similar projects in specialized domains.

Inter-observer agreement on subjects' race and race-informative characteristics.

Health and socioeconomic disparities tend to be experienced along racial and ethnic lines, but investigators are not sure how individuals are assigned to groups, or how consistent this process is. To address these issues, 1,919 orthodontic patient records were examined by at least two observers who estimated each individual's race and the characteristics that influenced each estimate. Agreement regarding race is high for African and European Americans, but not as high for Asian, Hispanic, and Native Americans. The indicator observers most often agreed upon as important in estimating group membership is name, especially for Asian and Hispanic Americans. The observers, who were almost all European American, most often agreed that skin color is an important indicator of race only when they also agreed the subject was European American. This suggests that in a diverse community, light skin color is associated with a particular group, while a range of darker shades can be associated with members of any other group. This research supports comparable studies showing that race estimations in medical records are likely reliable for African and European Americans, but are less so for other groups. Further, these results show that skin color is not consistently the primary indicator of an individual's race, but that other characteristics such as facial features add significant information.