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Study Question: What are the best practices for undertaking epidemiologic and phenotypic studies in polycystic ovary syndrome (PCOS)?Summary Answer: Best practices for the undertaking of epidemiologic and phenotypic studies in PCOS are outlined.What Is Known Already: Currently methodologies used for studies of PCOS epidemiology and phenotypes vary widely, and the comparability of studies is low, reducing the ability to harmonize studies.Study Design, Size, Duration: The Androgen Excess and PCOS (AE-PCOS) Society established a Task Force to draft a research resource for epidemiologic and phenotypic studies in PCOS, with the aim of providing guidelines on study design and execution, insights into the limitations and alternatives and protocols to be used, taking into consideration a global perspective.Participants/materials, Setting, Methods: A targeted review of the literature was carried out as necessary.Main Results and the Role Of Chance: High level recommendations include the following: (i) Before initiating the study, a number of critical factors should be addressed including selecting the population and diagnostic criteria (which should ideally align with the recommendations of the International Guidelines), the type of observational study to be undertaken and the primary and secondary endpoint(s) of the study.(ii) To assess the 'natural' or true phenotype and epidemiology of PCOS, the least medically biased, broadest and most generalizable population, and the broadest definition of PCOS, should be used.(iii) Four PCOS phenotypes (Phenotypes A through D), based on the presence or absence of three general features (oligo-anovulation, hyperandrogenism and polycystic ovarian morphology), should be ascertained.(iv) In epidemiologic and phenotypic studies, the detection of PCOS rests on the accuracy and sensitivity of the methods used for assessing the individual features of the disorder, and how 'normal' is defined.(v) Although an assessment algorithm that minimizes the use of certain measures (e.g. androgen levels and/or ovarian ultrasonography) can be devised, when possible it is preferable to uniformly assess all subjects for all parameters of interest.(vi) The inclusion of subjects in epidemiologic studies who do not appear to have PCOS (i.e. 'non-PCOS') will provide the necessary cohort to establish population-specific normative ranges for the various features of PCOS. (vii) Epidemiologic studies of PCOS in unselected populations will yield relatively limited numbers of PCOS subjects available for genetic study; alternatively, large population-based epidemiologic studies of PCOS will potentially generate large numbers of unaffected individuals that may serve as genetic controls. (viii) Epidemiologic studies of PCOS will benefit from a clear governance structure and should begin by informing, educating and engaging both the formal and informal leaders of the populations targeted for study. (ix) In designing their study investigators should, in advance, establish statistical power and recognize, manage and account for inherent biases. (x) Subjects suspected of having PCOS but who do not/cannot complete their evaluation (i.e. have 'possible PCOS') can be included by imputation, assigning them a 'diagnostic weight' based on those subjects of similar clinical phenotype that have completed the study. (xi) In obtaining, storing and retrieving subject data, subjects should be assessed consecutively using a uniform data collection form; providing as complete and in depth data as possible. (xii) Maintenance of both paper and electronic medical records should focus on ensuring data quality, accuracy and institutional ethical compliance, and familiarity with country-dependent laws, including biobanking-specific laws, tissue laws and research laws. (xiii) In obtaining and biobanking study samples, these should be ideally collected at the time of the first assessment. (xiv) Access to stored data sets should ideally be granted to other bona fide researchers conducting research in the public interest. (xv) SOPs detailing the exact method of each of the activities for handling the data and the samples are necessary to ensure that all methods are performed uniformly. (xvi) Epidemiologic studies of PCOS must be resourced adequately.Limitations, Reasons For Caution: As with all reports involving expert interpretation of experiential and published data, inherent individual biases are possible. This risk is minimized in the present study by including experts from varying fields of study, aligning with recent international evidence-based guidelines and obtaining consensus approval of the recommendations from the Task Force and the board of the AE-PCOS.Wider Implications Of the Findings: These guidelines should encourage investigators worldwide to undertake much needed epidemiologic studies of PCOS, increasing the validity, integrity and comparability of the data.Study Funding/competing Interest(s): The study received no funding. R.A. serves as consultant for Medtronic, Spruce Biosciences and Ansh Labs; has received research funding from Ferring Pharmaceuticals; and is on the advisory board of Martin Imaging; R.L. has received research funding from MSD Pharmaceuticals; J.L. has received fees and/or grant support from the Dutch Heart Association, The Netherlands Organisation for Health Research and Development (ZonMw), Ferring Pharmaceuticals, Danone, Euroscreen/Ogeda and Titus Health Care; H.T. receives grant funding from the National Health and Medical Research Council; K.K., L.M.-P., S.S.M. and B.O.Y. have no potential conflicts of interest.Trial Registration Number: N/A. [ABSTRACT FROM AUTHOR]

Much has been written about the measurement of socio-economic position (SEP) in high-income countries (HIC). Less has been written for an epidemiology, health systems and public health audience about the measurement of SEP in low- and middle-income countries (LMIC). The social stratification processes in many LMIC—and therefore the appropriate measurement tools—differ considerably from those in HIC. Many measures of SEP have been utilized in epidemiological studies; the aspects of SEP captured by these measures and the pathways through which they may affect health are likely to be slightly different but overlapping. No single measure of SEP will be ideal for all studies and contexts; the strengths and limitations of a given indicator are likely to vary according to the specific research question. Understanding the general properties of different indicators, however, is essential for all those involved in the design or interpretation of epidemiological studies. In this article, we describe the measures of SEP used in LMIC. We concentrate on measures of individual or household-level SEP rather than area-based or ecological measures such as gross domestic product. We describe each indicator in terms of its theoretical basis, interpretation, measurement, strengths and limitations. We also provide brief comparisons between LMIC and HIC for each measure. [ABSTRACT FROM AUTHOR]

The article encourages the submission of papers focusing on measurement tools to help health scientists to make informed decisions in the field of epidemiology. The authors first provide insights into the measurement of body size and composition in order to develop measurement tools that can be used in different perspectives and to gain understanding about the impact of using these tools on epidemiology. They explain the method of epidemiological measurement used by the periodical.

Dried blood spots (DBS) on filter paper have been used in human medicine since the 1960s, predominantly for screening in-borne metabolic disorders and more recently, for toxicology. Despite its 50-year existence, this technology has not been adopted by veterinarians for routine diagnoses and research. We have validated a novel DBS analytical procedure for the routine measurement of toxic heavy metals using 50 µL of whole blood on a single DBS by inductively coupled plasma mass spectrometry (ICP-MS). Targeted heavy metals are arsenic, cadmium, mercury, lead, selenium and thallium. The limits of quantitation (LOQ) on DBS are: arsenic 1.7 µg/L, cadmium 4.0 µg/L, mercury 13.7 µg/L, lead 13.3 µg/L, selenium 6.3 µg/L and thallium 1.5 µg/L. These LOQs suffice for routine diagnoses of heavy metal intoxication in domesticated and wildlife species as well as for basic, applied and epidemiological studies. The technique is ideal for population studies involving investigations of wildlife exposure to heavy metals and other environmental pollutants. The small blood volume involved (50 µL) makes it feasible to study small animals (birds, reptiles, amphibians and small mammals) that were previously excluded, or difficult to study due to the relatively large sample volumes required by current gold standard blood collection techniques. [ABSTRACT FROM AUTHOR]

The article comments on the paper about relation between correlation and causation by Charles Spearman. According to the author, the human mind played a key role in linking correlation with causation deterministically. She adds that correlation demonstrates its ability to quantify the strength of a causal relationship despite the absence of evidence of its effectivity. She also asserts the key role of correlation in scientific discovery and innovation.

This paper discusses the use of biomarkers in clinical practice and biomedical research. Biomarkers are measurable characteristics that can be used to indicate the presence or absence of a disease or to track the progression of a disease. They can also be used to predict how a patient will respond to a particular treatment. Biomarkers have enriched clinical practice and disease prognosis by providing measurable characteristics that indicate biological processes. They offer valuable insights into disease susceptibility, progression, and treatment response, aiding drug development and personalized medicine. However, developing and implementing biomarkers come with challenges that must be addressed. Rigorous testing, standardization of assays, and consideration of ethical factors are crucial in ensuring the reliability and validity of biomarkers. Reliability is vital in biomarker research. It ensures accurate measurements by preventing biases and facilitating robust correlations with outcomes. Conversely, validation examines which and how many biomarkers correspond to theoretical constructs and external criteria, establishing their predictive value. Multiple biomarkers are sometimes necessary to represent the complex relationship between exposure and disease outcomes accurately. Susceptibility factors are pivotal in disease states' complex interaction among genetic and environmental factors. Gaining a comprehensive understanding of these factors is essential for effectively interpreting biomarker data and maximizing their clinical usefulness. Using well-validated biomarkers can improve diagnoses, more effective treatment evaluations, and enhanced disease prediction. This, in turn, will contribute to better patient outcomes and drive progress in medicine. [ABSTRACT FROM AUTHOR]

The author comments on "Smoking and lung cancer: Recent evidence and a discussion of some principles," by J. Cornfield, W. Haenszel and colleagues, published in the 1959 issue and reprinted in the 2009 issue. He discusses the significance of the study for those interested in the history of a major issue in non-infectious disease epidemiology. He also notes the potential causal interpretation of the researchers' data and the introduction of statistical models to represent causal processes.

This paper provides an overview of approaches to the allocation of scarce vaccine doses during a pandemic. Price and non-price methods are outlined to determine whom to prioritize. It is argued that depending on viral and vaccine properties, it may be superior to use epidemiological criteria than health risk criteria for prioritization. The paper concludes by noting that the key trade-offs between health risk and epidemiological properties have received too little study to systematically inform allocation during a public health emergency. Moreover, the evaluation criteria for vaccines themselves need to be adjusted to take potential short-term scarcity into account. [ABSTRACT FROM AUTHOR]

In this commentary, I reflect on the paper "Poverty and Health: Prospective Evidence From the Alameda County Study" by Haan et al. (Am J Epidemiol. 1987;125(6):989-998), which together with supporting work ushered in a surge of epidemiologic interest in the impact of social contexts on health. I discuss why the paper was influential and how the premise of this type of work influenced theories and methods in epidemiology. The paper is placed in the broader context of the nature of evidence in epidemiology and the ultimate purpose of epidemiologic inquiry. [ABSTRACT FROM AUTHOR]

The article reviews volume 160 of the "American Journal of Epidemiology."

Background The term 'long COVID' describes ongoing symptoms and conditions experienced by people infected with SARS-CoV-2. This paper illustrates how a public health approach was used to influence and inform the development of post-COVID services across two Integrated Care Systems (ICSs). Methods A literature review was conducted between October and December 2020 to identify prevalence estimates for long COVID. The prevalence estimates were applied to locally available data on the susceptible population to estimate the number of people with long COVID. They were also used to develop a dashboard to predict fluctuations in the number of people experiencing persistent symptoms over time. Results A substantial number of people in each ICS may have experienced persistent symptoms or complications as a result of COVID-19. In Lancashire and South Cumbria, it is estimated that 33 000 people may have experienced post-COVID-19 syndrome since the beginning of the pandemic, which will include respiratory or cardiovascular complications. Conclusions The findings have been valuable in informing early service developments, engaging with managers and clinicians, and supporting applications for funding at a local level. Continued attention to emergent evidence on this topic will be vital in refining estimates and supporting service planning in the longer term. [ABSTRACT FROM AUTHOR]

Contemporary searches for new risk factors frequently involve genome-wide explorations of very large numbers of candidate risk variants. Given that diseases can often be classified into subtypes that possess evidence of etiologic heterogeneity, the question arises as to whether or not a search for new risk factors would be improved by looking separately within subtypes. Etiologic risk heterogeneity inevitably increases the signal in at least one of the subtypes, but this advantage may be offset by smaller sample sizes and the increased chances of false discovery. In this article, the authors show that only a relatively modest degree of etiologic heterogeneity is necessary for the subtyping strategies to have improved statistical power. In practice, effective exploitation of etiologic heterogeneity requires strong evidence that the subtypes selected are likely to exhibit substantial heterogeneity. Further, defining the subtypes that demonstrate the most heterogeneous profiles is important for optimizing the search for new risk factors. The concepts are illustrated by using data from a breast cancer study in which results are available separately for estrogen receptor-positive (ER+) and -negative (ER−) tumors. [ABSTRACT FROM AUTHOR]

Background. Disparity between patient report and physician perception of pain from radiotracer injection for sentinel node biopsy is thought to center on the severity of the intervention, ethnic composition of population queried, and socioeconomic factors. Objective. The objectives of this study were, first, to explore agreement between physicians' and their breast cancer patients' pain assessment during subareolar radionucleotide injection; and second, to evaluate potential ethnic differences in ratings. Methods. A trial was conducted, from January 2006 to April 2009, where 140 breast cancer patients were randomly assigned to standard topical lidocaine-4% cream and 99mTc-sulfur colloid injection, or to one of three other groups: placebo cream and 99mTc-sulfur colloid injection containing NaHCO3, 1% lidocaine, or NaHCO3 + 1% lidocaine. Providers and patients completed numeric pain scales (0-10) immediately after injection. Results. Patients and providers rated pain similarly over the entire cohort (median, 3 vs 2, P = 0.15). Patients rated pain statistically significantly higher than physicians in the standard (6 vs 5, P = 0.045) and placebo + NaHCO3 (5 vs 4, P = 0.032) groups. No significant difference in scores existed between all African Americans and their physicians (3 vs 4, P = 0.27). Conclusion. Patient-physician pain assessment congruence over the less painful injections and their statistically similar scores with the more painful methods suggests the importance of utilizing the least painful method possible. Providers tended to underestimate patients with the highest pain ratings-those in the greatest analgesic need. Lack of statistical difference between African American and physician scores may reflect the equal-access-to-care over the entire patient cohort, supporting the conclusion that socioeconomic factors may lie at the heart of previously reported discrepancies. [ABSTRACT FROM AUTHOR]

Comments on research papers on investigating clusters of diseases, published in the volume 164, 2001 edition of the periodical 'Journal of the Royal Statistical Society.' Ecological investigation of the incidence of cancer; Germ warfare simulation experiments; Reasons and methodologies of investigating disease clusters.

Comments on research papers on the specific aspects of the location of clusters of disease, published in the volume 164, 2001 edition of the periodical 'Journal of the Royal Statistical Society.' Statistical methods for the detection of space-time clusters of point events; Study of spatial variations in disease rates; Geographical disease surveillance.

The article discusses reports published in volumes 161 and 162 of the "American Journal of Epidemiology." Information on the countries of origin of contributions to the two volumes are presented, along with the type and subject area of contributions, and the number of weeks from receipt to publication. In summary, volumes 161 and 162 received scholarly contributions from several continents, but the bulk of contributions emanated from the U.S., as has been the case in prior volumes. The leading topic of the journal remains chronic noninfectious diseases.

A letter to the editor is presented in response to the article "Please Read the Following Paper and Write This Way" in a 2005 issue.

Background The European Renal Association (ERA) Registry collects data on kidney replacement therapy (KRT) in patients with ESKD. This paper is a summary of the ERA Registry Annual Report 2020, also including comparisons among primary renal disease (PRD) groups. Methods Data were collected from 52 national and regional registries from 34 European countries and countries bordering the Mediterranean Sea: 35 registries from 18 countries providing individual level data and 17 registries from 17 countries providing aggregated data. Using this data, KRT incidence and prevalence, kidney transplantation rates, expected remaining lifetimes and survival probabilities were calculated. Results A general population of 654.9 million people was covered by the ERA Registry in 2020. The overall incidence of KRT was 128 per million population (p.m.p.). In incident KRT patients, 54% were older than 65 years, 63% were men and the most common PRD was diabetes mellitus (21%). Regarding initial treatment modality in incident patients, 85% received haemodialysis (HD), 11% received peritoneal dialysis (PD) and 4% received a pre-emptive kidney transplant. On 31 December 2020, the prevalence of KRT was 931 p.m.p. In prevalent patients, 45% were older than 65 years, 60% were men and glomerulonephritis was the most common PRD (18%). Of these patients, 58% were on HD, 5% on PD and 37% were living with a kidney transplant. The overall kidney transplantation rate in 2020 was 28 p.m.p. with a majority of kidney grafts from deceased donors (71%). The unadjusted 5-year survival, based on incident dialysis patient from 2011–15, was 41.8%. For patients having received a deceased donor transplant, the unadjusted 5-year survival probability was 86.2% and for patients having received a living donor transplant it was 94.4%. When comparing data by PRD group, differences were found regarding the distribution of age groups, sex and treatment modality received. [ABSTRACT FROM AUTHOR]

Published in 1999, McMichael's "Prisoners of the Proximate: Loosening the Constraints on Epidemiology in an Age of Change" (Am J Epidemiol. 1999;149(10):887-897) outlined an exciting vision for epidemiology as the field that that can help us better understand the drivers of population health so that we may intervene, paving the way for healthier populations. McMichael's paper remains today what it was when it was first published: clear, thoughtful, provocative, and usefully prescriptive in its call to action. McMichael identified 4 constraints facing epidemiology. The field has risen to this challenge and addressed some of these constraints. I discuss how successful (or not) we have been in addressing each of these 4 challenges. [ABSTRACT FROM AUTHOR]

In the 1980s debate intensified over whether there was a protective effect of high-density lipoprotein cholesterol (HDL-C) or an adverse effect of triglycerides on coronary heart disease (CHD) risk. In a 1991 paper reprinted in the IJE we suggested that the high degree of correlation between the two, together with plausible levels of measurement error, made it unlikely that conventional epidemiological approaches could contribute to causal understanding. The consensus that HDL-C was protective, popularly reified in the notion of 'good cholesterol', strengthened over subsequent years. Reviewing the biostatistical and epidemiological literature from before and after 1991 we suggest that within the observational epidemiology pantheon only Mendelian randomization studies-that began to appear at the same time as the initial negative randomized controlled trials-made a meaningful contribution. It is sobering to realize that many issues that appear suitable targets for epidemiological investigation are simply refractory to conventional approaches. The discipline should surely revisit this and other high-profile cases of consequential epidemiological failure-such as that with respect to vitamin E supplementation and CHD risk-rather than pass them over in silence. [ABSTRACT FROM AUTHOR]

The author reflects on the radical changes that occurred in scientific publishing. Topics covered include the use of the bibliographic impact factor (BIF) in determining the quality and relevance of scientific journals, the benefits of reading the "American Journal of Epidemiology (AJE)," and the use of the journal h-index as an alternative to BIF. It also discusses how the journal h-index is used, and the difference between the journal h-index and BIF.

The article comments on the paper "The Proof and Measurement of Association Between Two Things," by C. Spearman. The author explains Spearman's correlation coefficient and its application to data rankings and epidemiological studies of chance, bias, and confounding. It highlights the attenuation errors, some formulas for correction and the early versions of the Spearman-Brown equation. It also provides insights into over-interpretation of equal correlation coefficients and their unrealistic precision.

John Cassel's 1976 paper "The Contribution of the Social Environment to Host Resistance" (Am J Epidemiol. 1976;104(2):107-123) is widely regarded as a classic in epidemiology. He makes the compelling argument that the quality of a person's social relationships, that is, the degree to which her relationships are more stressful than supportive (or vice versa) influences her susceptibility to disease independent of genetic endowment, diet, physical activity, etc. Cassel's provocative thesis was anchored in a cogent synthesis of findings from animal experiments and observational studies on diverse human populations. Beginning in the late 1970s, the paper stimulated an explosion of epidemiologic research on social support and human health. Beyond advancing epidemiologic theory, Cassel showed how findings from various epidemiologic study designs could be marshalled to build a persuasive causal argument that impaired social bonds increase the risk of premature disease and death. The paper also foreshadowed core ideas of later theoretical constructs, such as weathering and allostatic load, regarding the power of chronic environmental stressors to accelerate biological aging across multiple organ systems. Cassel's assessment of the research and practice implications of his conclusions has remarkable contemporary resonance for the field of epidemiology. [ABSTRACT FROM AUTHOR]

In his 1976 paper "Estimability and Estimation in Case-Referent Studies" (Am J Epidemiol. 1976;103(2):226-235), Miettinen weaved together a patchwork of new ideas into a coherent view of case-control studies. His article spurred theoretical development in epidemiologic methods and became a platform for teaching about some key concepts in epidemiologic study design. [ABSTRACT FROM AUTHOR]

Background: it is believed that the prevalence of back pain decreases around the middle of the sixth decade. However, back pain is still among the most commonly reported symptoms in the elderly and ostcoarthritis, disc degeneration, osteoporosis and spinal stenosis all increase with age. In light of this, it is difficult to understand why the prevalence of back pain would decrease with increasing age. Objective: this stud), aimed at summarising the scientific evidence on the trends of hack pain prevalence with age. Methods: population-based studies reporting the prevalence of back pain, including people aged 65 years and over, were systematically retrieved from several bibliographic databases. These were read and assessed by two reviewers, and papers retained ('good quality studies') were aggregated according to specific criteria. Results: good quality studies showed a large heterogeneity as to their methods and prevalence figures. No specific patterns were detected by country nor outcome measure, however, most studies that considered severe forms of back pain found an increase of prevalence with increasing age. The curvilinear association between age and back pain prevalence that is widely mentioned in the literature was found only for benign and mixed problems. Conclusions: the evidence concerning the association of back pain prevalence with age is more sparse than currently believed and this association seems to be modified by the severity of the problem. This knowledge could have important public health implications, as the proportion of older people will increase considerably in the coming years in most industrialised societies. [ABSTRACT FROM AUTHOR]

Context Pheochromocytomas and paragangliomas (PPGLs) are known to be rare. However, there is scant literature reporting their epidemiology, particularly whether the diagnosis of PPGL has increased with advances in medical imaging and biochemical and genetic testing. Objective The primary objective of this systematic review was to determine the annual incidence of PPGLs and change over time. Design A systematic review was performed. Medline, Embase, PubMed, and Web of Science Core Collection databases were searched to identify studies reporting PPGL incidence. Studies were eligible for inclusion from the database's inception until August 30, 2021. Results A total of 6109 manuscripts were identified; 2282 duplicates were excluded, and a further 3815 papers were excluded after abstract and/or full text review. Twelve studies were included in the final review. The incidence of PPGL ranged from 0.04 to 0.95 cases per 100 000 per year. Incidence increased over time, from approximately 0.2/100,000 individuals in studies performed before 2000, to approximately 0.6/100,000 in studies undertaken after 2010. The mode of diagnosis changed over the same time period, with more patients diagnosed from incidental imaging findings, and fewer at autopsy or from symptoms. Conclusion The annual incidence of PPGL has increased over time. Much of this increase is likely from incidental identification of tumors on imaging. However, the epidemiology of PPGL remains understudied, in particular, in associations with altitude, ethnicity, and genetics. To improve early detection and management guidelines, these gaps should be addressed. [ABSTRACT FROM AUTHOR]

The ongoing global pandemic has sharply increased the amount of data available to researchers in epidemiology and public health. Unfortunately, few existing analysis tools are capable of exploiting all of the information contained in a pandemic-scale data set, resulting in missed opportunities for improved surveillance and contact tracing. In this paper, we develop the variational Bayesian skyline (VBSKY), a method for fitting Bayesian phylodynamic models to very large pathogen genetic data sets. By combining recent advances in phylodynamic modeling, scalable Bayesian inference and differentiable programming, along with a few tailored heuristics, VBSKY is capable of analyzing thousands of genomes in a few minutes, providing accurate estimates of epidemiologically relevant quantities such as the effective reproduction number and overall sampling effort through time. We illustrate the utility of our method by performing a rapid analysis of a large number of SARS-CoV-2 genomes, and demonstrate that the resulting estimates closely track those derived from alternative sources of public health data. [ABSTRACT FROM AUTHOR]

Simulation methods are a powerful set of tools that can allow researchers to better characterize phenomena from the real world. As such, the ability to simulate data represents a critical set of skills that epidemiologists should use to better understand epidemiologic concepts and ensure that they have the tools to continue to self-teach even when their formal instruction ends. Simulation methods are not always taught in epidemiology methods courses, whereas causal directed acyclic graphs (DAGs) often are. Therefore, this paper details an approach to building simulations from DAGs and provides examples and code for learning to perform simulations. We recommend using very simple DAGs to learn the procedures and code necessary to set up a simulation that builds on key concepts frequently of interest to epidemiologists (e.g. mediation, confounding bias, M bias). We believe that following this approach will allow epidemiologists to gain confidence with a critical skill set that may in turn have a positive impact on how they conduct future epidemiologic studies. [ABSTRACT FROM AUTHOR]

The article focuses on the epidemiological fundamentals discussed in the 1956 paper "Smoking and lung cancer: Recent evidence and a discussion of some questions," by Jerome Cornfield and colleagues. It notes the paper's account of how causal interference could be applied to observational data on smoking and lung cancer. The paper's meta-analysis of 14 case-control studies of smoking and lung cancer and its inclusion of the case-control study done by Schairer and Schöniger in Germany in the early 1940s are also cited.

In this commentary, I review the insights that have been gained using Rothman's sufficient cause model (Am J Epidemiol. 1976;104(6):587-592). Discussion pertains to the relations of the model to similar conceptualizations in other fields of study, the advances and extensions that have been made to the model since the paper's publication, and its relation to questions of actual causation, along with questions concerning the use of the model in the future of epidemiology. [ABSTRACT FROM AUTHOR]

BACKGROUND: More than 20 years ago, it was hypothesized that exposure to prenatal and early postnatal environmental xenobiotics with the potential to disrupt endogenous hormone signaling might be on the causal path to cryptorchidism, hypospadias, low sperm count and testicular cancer. Several consensus statements and narrative reviews in recent years have divided the scientific community and have elicited a call for systematic transparent reviews. We aimed to fill this gap in knowledge in the field of male reproductive disorders. OBJECTIVE AND RATIONALE: The aim of this study was to systematically synthesize published data on the risk of cryptorchidism, hypospadias, low sperm counts and testicular cancer following in utero or infant exposure to chemicals that have been included on the European Commission's list of Category 1 endocrine disrupting chemicals defined as having documented adverse effects due to endocrine disruption in at least one intact organism. SEARCH METHODS: A systematic literature search for original peer reviewed papers was performed in the databases PubMed and Embase to identify epidemiological studies reporting associations between the outcomes of interest and exposures documented by biochemical analyses of biospecimens including maternal blood or urine, placenta or fat tissue as well as amnion fluid, cord blood or breast milk; this was followed by meta-analysis of quantitative data. OUTCOMES: The literature search resulted in 1314 references among which we identified 33 papers(28 study populations) fulfilling the eligibility criteria. These provided 85 risk estimates of links between persistent organic pollutants and rapidly metabolized compounds (phthalates and Bisphenol A) and male reproductive disorders. The overall odds ratio (OR) across all exposures and outcomes was 1.11 (95% CI 0.91-1.35). When assessing four specific chemical subgroups with sufficient data for meta-analysis for all outcomes, we found that exposure to one of the four compounds, p,p'-DDE, was related to an elevated risk: OR 1.35 (95% CI 1.04-1.74). The data did not indicate that this increased risk was driven by any specific disorder. WIDER IMPLICATIONS: The current epidemiological evidence is compatible with a small increased risk of male reproductive disorders following prenatal and postnatal exposure to some persistent environmental chemicals classified as endocrine disruptors but the evidence is limited. Future epidemiological studies may change the weight of the evidence in either direction. No evidence of distortion due to publication bias was found, but exposure-response relationships are not evident. There are insufficient data on rapidly metabolized endocrine disruptors and on specific exposure-outcome relations. A particular data gap is evident with respect to delayed effects on semen quality and testicular cancer. Although high quality epidemiological studies are still sparse, future systematic and transparent reviews may provide pieces of evidence contributing to the narrative and weight of the evidence assessments in the field. [ABSTRACT FROM AUTHOR]

Multilevel genome typing (MGT) enables the genomic characterization of bacterial isolates and the relationships among them. The MGT system describes an isolate using multiple multilocus sequence typing (MLST) schemes, referred to as levels. Thus, for a new isolate, sequence types (STs) assigned at multiple precisely defined levels can be used to type isolates at multiple resolutions. The MGT designation for isolates is stable, and the assignment is faster than the existing approaches. MGT's utility has been demonstrated in multiple species. This paper presents a publicly accessible web service called MGTdb, which enables the assignment of MGT STs to isolates, along with their storage, retrieval and analysis. The MGTdb web service enables upload of genome data as sequence reads or alleles, which are processed and assigned MGT identifiers. Additionally, any newly sequenced isolates deposited in the National Center for Biotechnology Information's Sequence Read Archive are also regularly retrieved (currently daily), processed, assigned MGT identifiers and made publicly available in MGTdb. Interactive visualization tools are presented to assist analysis, along with capabilities to download publicly available isolates and assignments for use with external software. MGTdb is currently available for Salmonella enterica serovars Typhimurium and Enteritidis and Vibrio cholerae. We demonstrate the usability of MGTdb through three case studies — to study the long-term national surveillance of S. Typhimurium, the local epidemiology and outbreaks of S. Typhimurium, and the global epidemiology of V. cholerae. Thus, MGTdb enables epidemiological and microbiological investigations at multiple levels of resolution for all publicly available isolates of these pathogens. Database URL : https://mgtdb.unsw.edu.au [ABSTRACT FROM AUTHOR]

Buccal cells provide a convenient source of DNA for epidemiologic studies. Mouthwash rinses yield a higher quality and quantity of DNA than cytobrushes but are not practical for collection from infants. Although cytobrushes yield sufficient DNA for most genotyping analyses, human leukocyte antigen (HLA) analysis can require 1,000-fold more DNA. In Iowa City, Iowa, in 2002, the authors tested two cytobrush collection methods to optimize total DNA yield and purity for HLA genotyping in mothers and infants: 1) brushing the left and right inner cheeks (standard method) and 2) brushing the upper and lower “gutters”, that is, the space between the gums and the inner lips/cheeks along the front and sides of the mouth (test method). Storage and mailing experiments were performed to define conditions for optimizing DNA yield and purity. Mothers’ gutter samples yielded significantly higher total amounts of DNA (mean yield = 15.0 µg/two brushes) than cheek samples (mean yield = 7.6 µg/two brushes) (paired t test: p < 0.001), while DNA yields from cheek and gutter collections from infants were equivalent. Cytobrushes stored and/or mailed in paper envelopes yielded significantly more and higher-purity DNA than brushes in plastic bags or tubes. Cytobrush sampling of the mouth’s gutter areas can enhance DNA yield in mothers but not in young infants. DNA yields can be further optimized by controlling mailing and storage conditions. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) is a major global health threat that affects millions of people each year. Funding agencies worldwide and the global research community have expended considerable capital and effort tracking the evolution and spread of AMR by isolating and sequencing bacterial strains and performing antimicrobial susceptibility testing (AST). For the last several years, we have been capturing these efforts by curating data from the literature and data resources and building a set of assembled bacterial genome sequences that are paired with laboratory-derived AST data. This collection currently contains AST data for over 67 000 genomes encompassing approximately 40 genera and over 100 species. In this paper, we describe the characteristics of this collection, highlighting areas where sampling is comparatively deep or shallow, and showing areas where attention is needed from the research community to improve sampling and tracking efforts. In addition to using the data to track the evolution and spread of AMR, it also serves as a useful starting point for building machine learning models for predicting AMR phenotypes. We demonstrate this by describing two machine learning models that are built from the entire dataset to show where the predictive power is comparatively high or low. This AMR metadata collection is freely available and maintained on the Bacterial and Viral Bioinformatics Center (BV-BRC) FTP site ftp://ftp.bvbrc.org/RELEASE_NOTES/PATRIC_genomes_AMR.txt. [ABSTRACT FROM AUTHOR]

Objectives Takayasu arteritis (TAK) is a rare autoimmune rheumatic disease causing large-vessel vasculitis. Onset is typically between the ages of 20 and 30 years. It is associated with substantial morbidity and mortality, notably due to its effects on the cardiovascular system. It has a poorly understood global epidemiology. Our objective was to systematically review the available evidence in order to calculate the incidence rate of TAK. Methods Three databases (MEDLINE, PubMed and Embase) were searched in November 2019 and the results were screened by two reviewers. A random effects meta-analysis was then conducted in R to calculate the overall incidence rate. Heterogeneity was assessed using I2. The quality of the studies was assessed using an adapted Newcastle–Ottawa scale. Further subgroup analyses were performed by quality, sex, research setting and geographical location. Publication bias was assessed using a Begg's funnel plot. Results The incidence rate for TAK was 1.11 per million person-years (95% CI 0.70–1.76). The heterogeneity in the data was extremely high in all analyses, which suggests that there was considerable variation in incidence rates across the different populations studied. TAK was found to be more common in women (incidence rate 2.01 per million person-years, 95% CI 1.39–2.90). Conclusions TAK is an extremely rare disease. It affects women more commonly than men. There is considerable variation in the incidence rate between populations. We suggest that future research should focus on discrete populations in order to better identify genetic and environmental risk factors. [ABSTRACT FROM AUTHOR]

Objective The representation of women among authors of peer reviewed scientific papers is gradually increasing. The aims of this study were to examine the trend of the proportion of women among authors in the field of rheumatology during the last two decades. Methods Articles published in journals ranked in the top quartile of the field of rheumatology in the years 2002–2019 were analysed. The authorship positions of all authors, country of the article's source and manuscript type were retrieved by specifically designed software. Results Overall, 153 856 author names were included in the final analysis. Of them, 55 608 (36.1%) were women. There was a significant rise in the percentage of women authors over time (r  = 0.979, P  <0.001) from 30.9% in 2002 to 41.2% in 2018, with a slight decline to 39.8% in 2019. There were significantly fewer women in the senior author positions compared with the first author positions (24.3% in senior position vs 40.9% as first author, P  <0.001). Conclusion The proportion of women among authors of rheumatology articles has increased over the years, both in general and as a first or senior author; however, their proportion is still <50% and there is still a gap between the proportion of women among first authors and the proportion of women among senior authors. [ABSTRACT FROM AUTHOR]

Background The objective of this paper was to examine temporal changes of infective endocarditis (IE) incidence and epidemiology in North America. Methods A systematic review was conducted at Mayo Clinic, Rochester. Ovid EBM Reviews, Ovid Embase, Ovid Medline, Scopus, and Web of Science were searched for studies published between January 1, 2000, and May 31, 2020. Four referees independently reviewed all studies, and those that reported a population-based incidence of IE in patients aged 18 years and older in North America were included. Results Of 8588 articles screened, 14 were included. Overall, IE incidence remained largely unchanged throughout the study period, except for 2 studies that demonstrated a rise in incidence after 2014. Five studies reported temporal trends of injection drug use (IDU) prevalence among IE patients with a notable increase in prevalence observed. Staphylococcus aureus was the most common pathogen in 7 of 9 studies that included microbiologic findings. In-patient mortality ranged from 3.7% to 14.4%, while the percentage of patients who underwent surgery ranged from 6.4% to 16.0%. Conclusions The overall incidence of IE has remained stable among the 14 population-based investigations in North America identified in our systematic review. Standardization of study design for future population-based investigations has been highlighted for use in subsequent systematic reviews of IE. [ABSTRACT FROM AUTHOR]

The paper by Jardine et al. reporting results from the South African Renal Registry describes a 2-fold success. First, even in a limited-resource environment, survival of patients on renal replacement therapy (RRT) is favourable. Secondly, this information is available because a few years ago, South African nephrologists started a renal registry. These successes cannot conceal, however, that numerous patients are not offered RRT. Robust health information systems make it possible to define chronic kidney disease and end-stage kidney disease (ESKD) burdens, guide resource allocation, inform service planning and enable policy. Registries can highlight inequitable RRT access and help support advocacy in favour of additional resources for ESKD care. [ABSTRACT FROM AUTHOR]

The author reflects on the Ninth Symposium on Inhaled Particles with the previous eight volumes of the proceedings. He asserts the whole idea of the symposium provides an interesting picture of the development of the subject which is inhaled particles. He also comments that the Inhaled Particle and Vapors II provides higher proportion on biological mechanisms but loosely classified as epidemiology. He added that the Ninth Symposium may even surpass the 'quintessence of dust'.

Background: The function of the gestational sac (GS) and the placenta in the closely related processes of embryogenesis and teratogenicity in the first trimester has been minimally described. The prevailing assumption is that direct teratogenic effects are mediated by the critical extraembryonic organ, the placenta, which either blocks or transfers exposures to the foetus. Placental transfer is a dominant mechanism, but there are other paradigms by which the placenta can mediate teratogenic effects. Knowledge of these paradigms and first trimester human developmental biology can be useful to the epidemiologist in the conduct of biomarker-based studies of both maternal and child health.Objective and Rationale: Our aim is to provide a causal framework for modelling the teratogenic effects of first trimester exposures on child health outcomes mediated by the GS and placenta using biomarker data collected in the first trimester. We initially present first trimester human developmental biology for the sake of informing and strengthening epidemiologic approaches. We then propose analytic approaches of modelling placental mechanisms by way of causal diagrams using classical non-embryolethal teratogens (diethylstilboestrol [DES], folic acid deficiency and cytomegalovirus [CMV]) as illustrative examples. We extend this framework to two chronic exposures of particular current interest, phthalates and maternal adiposity.Search Methods: Information on teratogens was identified by a non-systematic, narrative review. For each teratogen, we included papers that answered the five following questions: (i) why were these exposures declared teratogens? (ii) is there a consensus on biologic mechanism? (iii) is there reported evidence of a placental mechanism? (iv) can we construct a theoretical model of a placental mechanism? and (v) can this knowledge inform future work on measurement and modelling of placental-foetal teratogenesis? We prioritized literature specific to human development, the organogenesis window in the first trimester and non-embryolethal mechanisms.Outcomes: As a result of our review of the literature on five exposures considered harmful in the first trimester, we developed four analytic strategies to address first trimester placental mechanisms in birth cohort studies: placental transfer and direct effects on the foetus (DES and maternal adiposity), indirect effects through targeted placental molecular pathways (DES and phthalates), pre-placental effects through disruptions in embryonic and extraembryonic tissue layer differentiation (folic acid deficiency), and multi-step mechanisms that involve maternal, placental and foetal immune function and inflammation (DES and CMV).Wider Implications: The significance of this review is to offer a causal approach to classify the large number of potentially harmful exposures in pregnancy when the exposure occurs in the first trimester. Our review will facilitate future research by advancing knowledge of the first trimester mechanisms necessary for researchers to effectively associate environmental exposures with child health outcomes. [ABSTRACT FROM AUTHOR]

The article discusses various papers published in the Practice of Epidemiology section of this journal, including one by Brookhart et al. on the use of propensity scores in simulation studies, one by Benowitz et al. on the National Health and Nutrition Examination Survey and one by Stuart et al. on the application of multiple imputation to account for missing data.