Ancient human dental calculus metadata collection and sampling strategies: Recommendations for best practices.

OBJECTIVES: Ancient human dental calculus is a unique, nonrenewable biological resource encapsulating key information about the diets, lifestyles, and health conditions of past individuals and populations. With compounding calls its destructive analysis, it is imperative to refine the ways in which the scientific community documents, samples, and analyzes dental calculus so as to maximize its utility to the public and scientific community. MATERIALS AND METHODS: Our research team conducted an IRB-approved survey of dental calculus researchers with diverse academic backgrounds, research foci, and analytical specializations. RESULTS: This survey reveals variation in how metadata is collected and utilized across different subdisciplines and highlights how these differences have profound implications for dental calculus research. Moreover, the survey suggests the need for more communication between those who excavate, curate, and analyze biomolecular data from dental calculus. DISCUSSION: Challenges in cross-disciplinary communication limit researchers' ability to effectively utilize samples in rigorous and reproducible ways. Specifically, the lack of standardized skeletal and dental metadata recording and contamination avoidance procedures hinder downstream anthropological applications, as well as the pursuit of broader paleodemographic and paleoepidemiological inquiries that rely on more complete information about the individuals sampled. To provide a path forward toward more ethical and standardized dental calculus sampling and documentation approaches, we review the current methods by which skeletal and dental metadata are recorded. We also describe trends in sampling and contamination-control approaches. Finally, we use that information to suggest new guidelines for ancient dental calculus documentation and sampling strategies that will improve research practices in the future.

Ancient dental calculus reveals oral microbiome shifts associated with lifestyle and disease in Great Britain.

The prevalence of chronic, non-communicable diseases has risen sharply in recent decades, especially in industrialized countries. While several studies implicate the microbiome in this trend, few have examined the evolutionary history of industrialized microbiomes. Here we sampled 235 ancient dental calculus samples from individuals living in Great Britain (∼2200 BCE to 1853 CE), including 127 well-contextualized London adults. We reconstructed their microbial history spanning the transition to industrialization. After controlling for oral geography and technical biases, we identified multiple oral microbial communities that coexisted in Britain for millennia, including a community associated with Methanobrevibacter, an anaerobic Archaea not commonly prevalent in the oral microbiome of modern industrialized societies. Calculus analysis suggests that oral hygiene contributed to oral microbiome composition, while microbial functions reflected past differences in diet, specifically in dairy and carbohydrate consumption. In London samples, Methanobrevibacter-associated microbial communities are linked with skeletal markers of systemic diseases (for example, periostitis and joint pathologies), and their disappearance is consistent with temporal shifts, including the arrival of the Second Plague Pandemic. This suggests pre-industrialized microbiomes were more diverse than previously recognized, enhancing our understanding of chronic, non-communicable disease origins in industrialized populations.

Studying ancient human oral microbiomes could yield insights into the evolutionary history of noncommunicable diseases.

Noncommunicable diseases (NCDs) have played a critical role in shaping human evolution and societies. Despite the exceptional impact of NCDs economically and socially, little is known about the prevalence or impact of these diseases in the past as most do not leave distinguishing features on the human skeleton and are not directly associated with unique pathogens. The inability to identify NCDs in antiquity precludes researchers from investigating how changes in diet, lifestyle, and environments modulate NCD risks in specific populations and from linking evolutionary processes to modern health patterns and disparities. In this review, we highlight how recent advances in ancient DNA (aDNA) sequencing and analytical methodologies may now make it possible to reconstruct NCD-related oral microbiome traits in past populations, thereby providing the first proxies for ancient NCD risk. First, we review the direct and indirect associations between modern oral microbiomes and NCDs, specifically cardiovascular disease, diabetes mellitus, rheumatoid arthritis, and Alzheimer's disease. We then discuss how oral microbiome features associated with NCDs in modern populations may be used to identify previously unstudied sources of morbidity and mortality differences in ancient groups. Finally, we conclude with an outline of the challenges and limitations of employing this approach, as well as how they might be circumvented. While significant experimental work is needed to verify that ancient oral microbiome markers are indeed associated with quantifiable health and survivorship outcomes, this new approach is a promising path forward for evolutionary health research.

Community-curated and standardised metadata of published ancient metagenomic samples with AncientMetagenomeDir.

Ancient DNA and RNA are valuable data sources for a wide range of disciplines. Within the field of ancient metagenomics, the number of published genetic datasets has risen dramatically in recent years, and tracking this data for reuse is particularly important for large-scale ecological and evolutionary studies of individual taxa and communities of both microbes and eukaryotes. AncientMetagenomeDir (archived at https://doi.org/10.5281/zenodo.3980833 ) is a collection of annotated metagenomic sample lists derived from published studies that provide basic, standardised metadata and accession numbers to allow rapid data retrieval from online repositories. These tables are community-curated and span multiple sub-disciplines to ensure adequate breadth and consensus in metadata definitions, as well as longevity of the database. Internal guidelines and automated checks facilitate compatibility with established sequence-read archives and term-ontologies, and ensure consistency and interoperability for future meta-analyses. This collection will also assist in standardising metadata reporting for future ancient metagenomic studies.

Effect of hand hygiene on infectious diseases in the office workplace: A systematic review.

BACKGROUND: Extensive data suggests that hand hygiene is a critical intervention for reducing infectious disease transmission in the clinical setting. However, it is unclear whether hand hygiene is effective at cutting down on infectious illnesses in non-clinical workplaces. The aim of this review is to assess the current literature concerning the effects of hand-washing interventions on infectious disease prevention among employees in nonclinical, office-based workplaces. METHODS: In compiling this review, PubMed, Scopus, and Business Source Premier were examined for studies published from 1960 through 2016. RESULTS: Eleven studies (eight experimental, two observational, one a simulation) were identified as eligible for inclusion. Hand-hygiene interventions at various levels of rigor were shown to reduce self-reported illness symptoms. CONCLUSIONS: Hand hygiene is thought to be more effective against gastrointestinal illness than it is against respiratory illness, but no clear consensus has been reached on this point. Minimal hand-hygiene interventions seem to be effective at reducing the incidence of employee illness. Along with reducing infections among employees, hand-hygiene programs in the workplace may provide additional benefits to employers by reducing the number of employee health insurance claims and improving employee morale. Future research should use objective measures of hand hygiene and illness, and explore economic impacts on employers more fully.