Point: Reconciling Epidemiology's Aspirations and Capabilities

Interpreting the results of epidemiologic studies calls for objectivity and rigorous scrutiny, acknowledging the limitations that temper the applicability of the findings to public health action. Current trends have posed new challenges to balancing goals of scientific objectivity and validity with public health applications. The ongoing tension between epidemiology's aspirations and capability has several sources: the need to overpromise in research proposals, compromising methodological rigor because of public health importance, defending findings in the face of hostile critics, and appealing to core constituencies who have specific expectations from the research.

Epidemiology and reporting characteristics of preclinical systematic reviews

In an effort to better utilize published evidence obtained from animal experiments, systematic reviews of preclinical studies are increasingly more common-along with the methods and tools to appraise them (e.g., SYstematic Review Center for Laboratory animal Experimentation [SYRCLE's] risk of bias tool). We performed a cross-sectional study of a sample of recent preclinical systematic reviews (2015-2018) and examined a range of epidemiological characteristics and used a 46-item checklist to assess reporting details. We identified 442 reviews published across 43 countries in 23 different disease domains that used 26 animal species. Reporting of key details to ensure transparency and reproducibility was inconsistent across reviews and within article sections. Items were most completely reported in the title, introduction, and results sections of the reviews, while least reported in the methods and discussion sections. Less than half of reviews reported that a risk of bias assessment for internal and external validity was undertaken, and none reported methods for evaluating construct validity. Our results demonstrate that a considerable number of preclinical systematic reviews investigating diverse topics have been conducted; however, their quality of reporting is inconsistent. Our study provides the justification and evidence to inform the development of guidelines for conducting and reporting preclinical systematic reviews.

Interpreting SARS-CoV-2 seroprevalence, deaths, and fatality rate - Making a case for standardized reporting to improve communication

The SARS-CoV-2 virus has spread across the world, testing each nation's ability to understand the state of the pandemic in their country and control it. As we looked into the epidemiological data to uncover the impact of the COVID-19 pandemic, we discovered that critical metadata is missing which is meant to give context to epidemiological parameters. In this review, we identify key metadata for the COVID-19 fatality rate after a thorough analysis of mathematical models, serology-informed studies and determinants of causes of death for the COVID-19 pandemic. In doing so, we find reasons to establish a set of standard-based guidelines to record and report the data from epidemiological studies. Additionally, we discuss why standardizing nomenclature is be a necessary component of these guidelines to improve communication and reproducibility. The goal of establishing these guidelines is to facilitate the interpretation of COVID-19 epidemiological findings and data by the general public, health officials, policymakers and fellow researchers. Our suggestions may not address all aspects of this issue; rather, they are meant to be the foundation for which experts can establish and encourage future guidelines throughout the appropriate communities.

Perspectives on the Future of Epidemiology: A Framework for Training

Over the past century, the field of epidemiology has evolved and adapted to changing public health needs. Challenges include newly emerging public health concerns across broad and diverse content areas, new methods, and vast data sources. We recognize the need to engage and educate the next generation of epidemiologists and prepare them to tackle these issues of the 21st century. In this commentary, we suggest a skeleton framework upon which departments of epidemiology should build their curriculum. We propose domains that include applied epidemiology, biological and social determinants of health, communication, creativity and ability to collaborate and lead, statistical methods, and study design. We believe all students should gain skills across these domains to tackle the challenges posed to us. The aim is to train smart thinkers, not technicians, to embrace challenges and move the expanding field of epidemiology forward.

Lessons Learned From an Epidemiologist-Led Countywide Community Assessment for Public Health Emergency Response (CASPER) in Oregon

CONTEXT

Conducting a large-scale Community Assessment for Public Health Emergency Response (CASPER) in a geographically and linguistically diverse county presents significant methodological challenges that require advance planning.

PROGRAM

The Centers for Disease Control and Prevention (CDC) has adapted methodology and provided a toolkit for a rapid needs assessment after a disaster. The assessment provides representative data of the sampling frame to help guide effective distribution of resources.

IMPLEMENTATION

This article describes methodological considerations and lessons learned from a CASPER exercise conducted by Washington County Public Health in June 2016 to assess community emergency preparedness. The CDC's CASPER toolkit provides detailed guidance for exercises in urban areas where city blocks are well defined with many single family homes. Converting the exercise to include rural areas with challenging geographical terrain, including accessing homes without public roads, required considerable adjustments in planning. Adequate preparations for vulnerable populations with English linguistic barriers required additional significant resources. Lessons learned are presented from the first countywide CASPER exercise in Oregon.

EVALUATION

Approximately 61% of interviews were completed, and 85% of volunteers reported they would participate in another CASPER exercise. Results from the emergency preparedness survey will be presented elsewhere.

DISCUSSION

This experience indicates the most important considerations for conducting a CASPER exercise are oversampling clusters, overrecruiting volunteers, anticipating the actual cost of staff time, and ensuring timely language services are available during the event.

[A Perspective on the OECD Report "Health at a Glance 2019"]

N/a.

The Changing Science of HIV Epidemiology in the United States

In 1984, a large prospective study of the natural history of human immunodeficiency virus (HIV) infection, the Multicenter AIDS Cohort Study (MACS), was established; 10 years later, the Women's Interagency HIV Study (WIHS) was launched. Motivated by the merger and redesign of these long-standing HIV cohort studies in 2019, we review ways in which HIV epidemiology in the United States has transformed over the lives of these studies and how this evolution has influenced planning for enrollment and follow-up. We highlight changes that have occurred in the 3 major domains that are central to epidemiologic science: changes to key populations at highest risk for HIV, refinements in measurement and shifts in the outcomes of interest, and a new era in the tools and approaches that epidemiologists use to synthesize evidence from measurements made on populations. By embracing foundational principles with modern methods, the epidemiologic approach of analyzing the causes and distributions of diseases in contemporaneous populations will continue to advance HIV science over the next decade.

Epidemiologic Characteristics of Multimorbidity and Sociodemographic Factors Associated With Multimorbidity in a Rapidly Aging Asian Country

IMPORTANCE

Multimorbidity is a growing health care problem in aging societies and is strongly associated with epidemiologic characteristics and sociodemographic factors. Knowledge of these associations is important for the design of effective preventive and management strategies.

OBJECTIVES

To determine the association between multimorbidity and sociodemographic factors (age, socioeconomic status [SES], sex, and race/ethnicity) and the association between mental health diseases and physical diseases, as well as their implications for the types and costs of health care use.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cross-sectional study used deidentified Singapore Eastern Regional Health System data collected between January 1, 2012, and December 31, 2016. Patients who were alive as of January 1, 2016, and residing in the Regional Health System region in 2016 (N = 1 181 024) were included. Patients who had no year of birth records (n = 573), were born in 2017 (n = 93), or died before January 1, 2016 (n = 47 322), were excluded.

MAIN OUTCOMES AND MEASURES

Multimorbidity, age, sex, SES, mental health, race/ethnicity, and health care use.

RESULTS

In the study population of 1 181 024 individuals, the mean (SD) age was 39.6 (22.1) years, 51.2% were women, 70.1% were Chinese, 7.1% were Indian, 13.5% were Malayan, and 9.3% were other races/ethnicities. Multimorbidity, present in 26.2% of the population, was more prevalent in female (26.8%; 95% CI, 26.7%-26.9%) than in male (25.6%; 95% CI, 25.5%-25.7%) patients and among patients with low SES (41.6%) than those with high SES (20.1%). Mental health diseases were significantly more prevalent among individuals with low SES (5.2%; 95% CI, 5.1%-5.2%) than high SES (2.1%; 95% CI, 2.0%-2.1%; P < .001). The 3 most prevalent disease combinations were chronic kidney disease and hypertension, chronic kidney disease and lipid disorders, and hypertension and lipid disorders. Although chronic kidney disease, hypertension, lipid disorders, and type 1 and/or type 2 diabetes-related diseases had a low cost per capita, the large number of patients with these conditions caused the overall proportion of the cost incurred by health care use to be more than twice that incurred in other diseases.

CONCLUSIONS AND RELEVANCE

These findings emphasize the association between multimorbidity and sociodemographic factors such as increasing age, lower SES, female sex, and increasing number of mental disorders. Health care policies need to take sociodemographic factors into account when tackling multimorbidity in a population.

Reproductive control by others: means, perpetrators and effects

BACKGROUND

Reproductive control of women by others comprises a wide range of behaviours, from persuasion to pressure such as emotional blackmail, societal or family expectations, through to threats of or actual physical violence. It is defined as behaviours that interfere with women's reproductive autonomy as well as any actions that pressurise or coerce a woman into initiating or terminating a pregnancy METHOD: Narrative review based on a search of medical and social science literature.

RESULTS

Reproductive control by others includes control or coercion over decisions about becoming pregnant and also about continuing or terminating a pregnancy. It can be carried out by intimate partners, the wider family, or as part of criminal behaviour. One form is contraceptive sabotage, which invalidates the consent given to sex. Contraceptive sabotage includes the newly-described behaviour of 'stealthing': the covert removal of a condom during sex. Reproductive control by others is separate from intimate partner violence but there are similarities and the phenomena overlap. Reproductive control by others is reported by as many as one quarter of women attending sexual and reproductive healthcare services. Those treating such women should be familiar with the concept and how to ameliorate its effects. Screening questions for its detection have been developed as well as interventions to reduce its risk.

CONCLUSIONS

Reproductive control by others is common and those working in women's health should be familiar with the concept and with screening tools used to detect it.

What is epidemiology? Changing definitions of epidemiology 1978-2017

CONTEXT

Epidemiology is a discipline which has evolved with the changes taking place in society and the emergence of new diseases and new discipline related to epidemiology. With these evolutions, it is important to understand epidemiology and to analyse the evolution of content of definitions of epidemiology.

OBJECTIVES

The main objective of this paper was to identify new definitions of epidemiology available since 1978. Secondary objectives were to analyse the content of these definitions, to compare them with those used by Lilienfeld and to determine whether changes have taken place over the last forty years.

METHODS

A review of grey literature and published literature was conducted to find the definitions of epidemiology written between 1978 and 2017.

RESULTS

102 definitions of epidemiology were retained. They helped to highlight 20 terms and concepts related to epidemiology. Most of them were already used in the definitions used by Lilienfeld. Five terms were present in more than 50% of definitions from the period 1978 to 2017: "population", "study", "disease", "health" and "distribution". Several developments have occurred: strengthening of the terms "control" and "health" already used, the concept of "disease" was less frequently encountered whereas the concepts "infectious diseases", "mass phenomenon" are no longer used in definitions from 1978 to 2017.

CONCLUSION

This evolution of content of definition of epidemiology is absent from books on epidemiology. A thematic analysis of definitions of epidemiology could be conducted in order to improve our understanding of changes observed.

Population Neuroscience: Dementia Epidemiology Serving Precision Medicine and Population Health

Over recent decades, epidemiology has made significant contributions to our understanding of dementia, translating scientific discoveries into population health. Here, we propose reframing dementia epidemiology as "population neuroscience," blending techniques and models from contemporary neuroscience with those of epidemiology and biostatistics. On the basis of emerging evidence and newer paradigms and methods, population neuroscience will minimize the bias typical of traditional clinical research, identify the relatively homogenous subgroups that comprise the general population, and investigate broader and denser phenotypes of dementia and cognitive impairment. Long-term follow-up of sufficiently large study cohorts will allow the identification of cohort effects and critical windows of exposure. Molecular epidemiology and omics will allow us to unravel the key distinctions within and among subgroups and better understand individuals' risk profiles. Interventional epidemiology will allow us to identify the different subgroups that respond to different treatment/prevention strategies. These strategies will inform precision medicine. In addition, insights into interactions between disease biology, personal and environmental factors, and social determinants of health will allow us to measure and track disease in communities and improve population health. By placing neuroscience within a real-world context, population neuroscience can fulfill its potential to serve both precision medicine and population health.

Emerging Role of Epidemiologic Literacy

Background:

The ability to understand and apply epidemiology methods is a growing part of pharmacy practice, pharmacy accreditation standards, and evidence-based practice.

Objective:

TO examine the trends in epidemiology-related terminology used in the literature over the past 20 years.

Methods:

The frequency of the use of epidemiology-related terminology in 3 representative pharmacy Journals, 2 representative medical journals, and 1 public health journal from January through December 1984, 1994, and 2004 was recorded. The 3 pharmacy journals were the American Journal of Health-System Pharmacy (formerly American Journal of Hospital Pharmacy), The Annals of Pharmacotherapy (formerly Drug Intelligence and Clinical Pharmacy), and Pharmacotherapy. The 2 medical journals were the New England Journal of Medicine and The Journal of the American Medical Association (JAMA), and the public health journal was the American Journal of Public Health. The number of times an epidemiology-related term was used was summed for each year and each journal.

Results:

For all the journals examined in this study combined, the proportion of epidemiologic terms used in the literature has increased over the past 20 years. In 1984, of the total articles published in the 6 journals, 7.02% contained epidemiologic terms increasing to 12.27% and 15.46% in 1994 and 2004, respectively. The most dramatic differences in the 20-year comparisons were noted for Pharmacotherapy (0 to 17.75%) and JAMA (7.32 to 26.72%).

Conclusions:

The increase in the use of epidemiology-related terms has implications for both curricular planning in schools and colleges of pharmacy, as well as for continuing education programs and effective interprofessional communication.

Sometimes Scientists Get the Flu. Wrong…!

In an international research environment, accurate communication is vital. However, the scientific literature does not always utilise consistent terminology and the misuse of some expressions in epidemiology is rife. We encourage the correct terms to be used appropriately to avoid confusion between scientists, policy makers, and members of the public.

Population attributable fraction: planning of diseases prevention actions in Brazil

Epidemiology is the study of occurrence, distribution and determinants of health-related events, including the application of that knowledge to the prevention and control of health problems. However, epidemiological studies, in most cases, have limited their research questions to determinants of health outcomes. Research related to the application of knowledge for prevention and control of diseases have been neglected. In this comment, we present a description of how population attributable fraction estimates can provide important elements for planning of prevention and control of diseases in Brazil. RESUMO Epidemiologia é o estudo da ocorrência, distribuição e determinantes de eventos relacionados à saúde da população, incluindo a aplicação desse conhecimento para a prevenção e o controle dos problemas de saúde. Entretanto, estudos epidemiológicos, na maioria das vezes, têm limitado suas perguntas de pesquisa aos fatores determinantes de desfechos em saúde. Pesquisas relacionadas à aplicação do conhecimento para ações de prevenção e controle de doenças têm sido negligenciadas. Nesse comentário, apresentamos uma descrição de como as estimativas de fração atribuível populacional podem fornecer importantes elementos para planejamento de ações de prevenção e controle de doenças no Brasil.

Challenges of Epidemiologists of Developing Countries in the 21st Century

There are many published articles which cover current and future challenges of epidemiology. However, up until now, most of them are written by developed world epidemiologists. Therefore, despite a common use of assumptions, they did not have the opportunity to discuss the different range of practical tasks and priorities away from developed countries. The topics covered are; facing poverty, non-democratic government that has links to developed countries, man-made and natural disasters, handling low-quality data and accessing it, and finally improving contribution to the world epidemiological knowledge for the 21st century.

Public Health and Epidemiology Informatics: Recent Research and Trends in the United States

OBJECTIVES

To survey advances in public health and epidemiology informatics over the past three years.

METHODS

We conducted a review of English-language research works conducted in the domain of public health informatics (PHI), and published in MEDLINE between January 2012 and December 2014, where information and communication technology (ICT) was a primary subject, or a main component of the study methodology. Selected articles were synthesized using a thematic analysis using the Essential Services of Public Health as a typology.

RESULTS

Based on themes that emerged, we organized the advances into a model where applications that support the Essential Services are, in turn, supported by a socio-technical infrastructure that relies on government policies and ethical principles. That infrastructure, in turn, depends upon education and training of the public health workforce, development that creates novel or adapts existing infrastructure, and research that evaluates the success of the infrastructure. Finally, the persistence and growth of infrastructure depends on financial sustainability.

CONCLUSIONS

Public health informatics is a field that is growing in breadth, depth, and complexity. Several Essential Services have benefited from informatics, notably, "Monitor Health," "Diagnose & Investigate," and "Evaluate." Yet many Essential Services still have not yet benefited from advances such as maturing electronic health record systems, interoperability amongst health information systems, analytics for population health management, use of social media among consumers, and educational certification in clinical informatics. There is much work to be done to further advance the science of PHI as well as its impact on public health practice.

Mapping epidemiology's past to inform its future: metaknowledge analysis of epidemiologic topics in leading journals, 1974-2013

An empiric perspective on what epidemiology has studied over time might inform discussions about future directions for the discipline. We aimed to identify the main areas of epidemiologic inquiry and determine how they evolved over time in 5 high-impact epidemiologic journals. We analyzed the titles and abstracts of 20,895 articles that were published between 1974 and 2013. In 5 time periods that reflected approximately equal numbers of articles, we identified the main topics by clustering terms based on co-occurrence. Infectious disease and cardiovascular disease epidemiology were the prevailing topics over the 5 periods. Cancer epidemiology was a major topic from 1974 to 2001 but disappeared thereafter. Nutritional epidemiology gained relative importance from 1974 to 2013. Environmental epidemiology appeared during 1996-2001 and continued to be important, whereas 2 clusters related to methodology and meta-analysis in genetics appeared during 2008-2013. Several areas of epidemiology, including injury or psychiatric epidemiology, did not make an appearance as major topics at any time. In an ancillary analysis of 6 high-impact general medicine journals, we found patterns of epidemiologic articles that were overall consistent with the findings in epidemiologic journals. This metaknowledge investigation allowed identification of the dominant topics in and conversely those that were absent from 5 major epidemiologic journals. We discuss implications for the field.

Use of the Microbiome in the Practice of Epidemiology: A Primer on -Omic Technologies

The term microbiome refers to the collective genome of the microbes living in and on our bodies, but it has colloquially come to mean the bacteria, viruses, archaea, and fungi that make up the microbiota (previously known as microflora). We can identify the microbes present in the human body (membership) and their relative abundance using genomics, characterize their genetic potential (or gene pool) using metagenomics, and describe their ongoing functions using transcriptomics, proteomics, and metabolomics. Epidemiologists can make a major contribution to this emerging field by performing well-designed, well-conducted, and appropriately powered studies and by including measures of microbiota in current and future cohort studies to characterize natural variation in microbiota composition and function, identify important confounders and effect modifiers, and generate and test hypotheses about the role of microbiota in health and disease. In this review, we provide an overview of the rapidly growing literature on the microbiome, describe which aspects of the microbiome can be measured and how, and discuss the challenges of including the microbiome as either an exposure or an outcome in epidemiologic studies.

Epidemiology's continuing contribution to public health: The power of "Then and Now"

The 47th annual meeting of the Society for Epidemiologic Research hosted 17 invited speakers charged by the Executive Committee with presenting some of the many ways that epidemiologists have improved the health of the general population. There were 9 "Then and Now" sessions that were structured to focus on how early epidemiologists overcame research hurdles and advanced health through innovative strategies. For most topics, a longstanding expert was paired with an excellent contemporary epidemiologist working in the area, and both were given the freedom to deliver an integrated story about epidemiology's temporal role in protecting and promoting public health. Epidemiologic discoveries in cardiovascular, cancer, and perinatal epidemiology were discussed on day 1, followed by discussions of accomplishments in reducing exposures that adversely impact health (nutrition, environment/occupation, and tobacco use) on day 2. Topics with relevancy for many aspects of epidemiology were presented on day 3, including infectious diseases, social forces, and causal thinking in epidemiologic research. Given the large number of outstanding senior and junior epidemiologists that attended the meeting, choosing speakers was a unique challenge. What became evident from all sessions was the passion that epidemiologists have for population health, tempered with concerns for remaining true to epidemiologic principles, the timely adoption of innovative methods, and the responsible interpretation of research findings.

Climate change, human health, and epidemiological transition

The health of populations depends on the availability of clean air, water, food, and sanitation, exposure to pathogens, toxins and environmental hazards, and numerous genetic, behavioral and social factors. For many thousands of years, human life expectancy was low, and population growth was slow. The development of technology-based civilizations facilitated what Abdel Omran called "epidemiological transition," with increasing life expectancy and rapid population growth. To a large extent, the spectacular growth of human populations during the past two centuries was made possible by the energy extracted from fossil fuels. We have now learned, however, that greenhouse gases from fossil fuel combustion are warming the planet's surface, causing changes in oceanic and atmospheric systems, and disrupting weather and hydrological patterns. Climate change poses unprecedented threats to human health by impacts on food and water security, heat waves and droughts, violent storms, infectious disease, and rising sea levels. Whether or not humanity can reduce greenhouse gas emissions quickly enough to slow climate change to a rate that will allow societies to successfully adapt is not yet known. This essay reviews the current state of relevant knowledge, and points in a few directions that those interested in human health may wish to consider.

Foreword

This MMWR Supplement presents data related to disease patterns across the United States and describes recent national trends in health status. Indicators of health status (i.e., measures of observed or calculated data on the status of a health condition) were chosen to reflect the range of health issues relevant to CDC's programs that are used across the agency to monitor health. In response to the status of these health issues, CDC works with state and local health systems across the United States on these diseases and others to save lives and protect persons.

Psychiatric epidemiology in Turkey: main advances in recent studies and future directions

OBJECTIVE

To overview and evaluate the main findings, methodological shortcomings, and time trends of the recent psychiatric epidemiology studies in Turkey, as well as to provide areas prone for development in forthcoming research.

METHOD

PubMed and Turkish Psychiatry Index were screened to identify relevant studies. Any epidemiological study from 2000 to 2012 with a general population or unique sub-population sample was included. Papers and results were classified as depression, anxiety, psychotic, dissociative, conversion, personality, alcohol and substance abuse, and trauma-related disorders, and common geriatric disorders.

RESULTS

There are various epidemiological studies on various psychiatric disorders in Turkey. However, there are main shortcomings and trends in research that subsequently stagnate current psychiatric epidemiological research. First, epidemiological studies were mainly conducted for academic purposes, not for addressing epidemiological issues or issues of health policy. Second, studies mainly focused on particular fields and institutions, which led to non-systematic accumulation of epidemiological results. Third, although Turkey is a natural laboratory of social conflicts and disasters, there were few studies with a focus on probable outcomes. Fourth, high-quality epidemiological studies with disseminating results tended to decrease, even in common mental disorders such as depression. Fifth, there were very few epidemiological studies using contemporary designs such as follow-up, genetic, or biomarker data in the general-population.

CONCLUSION

Although psychiatric epidemiological studies of the last decade provide a suitable ground for future challenges, current trends in this research area has tended to stagnate, despite the potential for unique contributions. Forthcoming studies and researchers may notice novel methodological developments in epidemiology, with a growing attention on rapid urbanization, natural disasters, social conflicts, and migration.

At the crossroads of anthropology and epidemiology: current research in cultural psychiatry in the UK

Cultural psychiatry research in the UK comprises a broad range of diverse methodologies, academic disciplines, and subject areas. Methodologies range from epidemiological to anthropological/ethnographic to health services research; mixed methods research is becoming increasingly popular, as are public health and health promotional topics. After briefly outlining the history of cultural psychiatry in the UK we will discuss contemporary research. Prominent themes include: the epidemiology of schizophrenia among Africans/Afro-Caribbeans, migration and mental health, racism and mental health, cultural identity, pathways to care, explanatory models of mental illness, cultural competence, and the subjective experiences of healthcare provision among specific ethnic groups such as Bangladeshis and Pakistanis. Another strand of research that is attracting increasing academic attention focuses upon the relationship between religion, spirituality, and mental health, in particular, the phenomenology of religious experience and its mental health ramifications, as well as recent work examining the complex links between theology and psychiatry. The paper ends by appraising the contributions of British cultural psychiatrists to the discipline of cultural psychiatry and suggesting promising areas for future research.

Epidemiology in Ethiopia 200 years after John Snow's birth

The year 2013 marks exactly 200 years since John Snow, known as the father of modern epidemiology, was born. In 19th century, epidemiologists like John Snow, concentrated almost entirely upon infectious diseases of humans measuring the burden of disease, describing pattern and attempting to understand the transmission dynamics. During the second half of the 20th century; big changes occurred so that epidemiologists in the developed world started to use systematized approaches to investigate the etiologies, conditions and to evaluate interventions through different study designs. However, the situation in the developing world is not the same as the rest of the world. Even 200 years after Snow's birth, epidemiological capacity is lowest in Africa. This article attempts to describe that Ethiopia is not exceptional. In the past few decades, there have been some attempts to build capacity in the country by launching training programs in clinical epidemiology, general epidemiology and field epidemiology. However, not only few epidemiologists are trained, but, limited funding, high-teaching burdens, poor working conditions and low salaries are among important contributors for epidemiological brain drain in Ethiopia. Thus, strengthening learning opportunities and rewarding career paths are required to increase human resource capacity and retain skilled personnel in the field of epidemiology.

Six paths for the future of social epidemiology

Social epidemiology is now an accepted part of the academic intellectual landscape. However, in many ways, social epidemiology also runs the risk of losing the identity that distinguished it as a field during its emergence. In the present article, we scan the strengths of social epidemiology to imagine paths forward that will make the field distinct and useful to the understanding of population health in future. We suggest 6 paths to such a future, each emerging from promising research trends in the field in which social epidemiologists can, and should, lead in coming years. Each of these paths contributes to the formation of distinct capacities that social epidemiologists can claim and use to elaborate or fill in gaps in the already strong history of social epidemiology. They present an opportunity for the field to build on its strengths and move forward while leading in new and critical areas in population health.

[A Latin-American perspective regarding the past, present and future of epidemiology]

This article addresses three questions. Concerning the past, why was there no pre-Columbian epidemiology? What are the origins of modern epidemiology (including its South American roots)? A surrealistic title has been chosen regarding the future to emphasise the fact that making predictions is not easy. Why are complex phenomena the dark object of epidemiological desire?

[The background, development and perspectives of modern epidemiology]

Epidemiology is an ongoing discipline (i.e. still being constructed) and many of the foundations of the theory and methods now in use were mostly developed during the second half of the twentieth century, arising from what is known today as "modern epidemiology". This paper summary the history and main ideas which guided epidemiology at that time, the debates and divisions that characterized such advance and presents a "biased" point of view concerning the perspectives which could help thinking about the disciplinary development of epidemiology.

Rapid health transition in China, 1990-2010: findings from the Global Burden of Disease Study 2010

BACKGROUND

China has undergone rapid demographic and epidemiological changes in the past few decades, including striking declines in fertility and child mortality and increases in life expectancy at birth. Popular discontent with the health system has led to major reforms. To help inform these reforms, we did a comprehensive assessment of disease burden in China, how it changed between 1990 and 2010, and how China's health burden compares with other nations.

METHODS

We used results of the Global Burden of Diseases, Injuries, and Risk Factors Study 2010 (GBD 2010) for 1990 and 2010 for China and 18 other countries in the G20 to assess rates and trends in mortality, causes of death, years of life lost (YLLs), years lived with disability (YLDs), disability-adjusted life-years (DALYs), and healthy life expectancy (HALE). We present results for 231 diseases and injuries and for 67 risk factors or clusters of risk factors relevant to China. We assessed relative performance of China against G20 countries (significantly better, worse, or indistinguishable from the G20 mean) with age-standardised rates and 95% uncertainty intervals.

FINDINGS

The leading causes of death in China in 2010 were stroke (1·7 million deaths, 95% UI 1·5-1·8 million), ischaemic heart disease (948,700 deaths, 774,500-1,024,600), and chronic obstructive pulmonary disease (934,000 deaths, 846,600-1,032,300). Age-standardised YLLs in China were lower in 2010 than all emerging economies in the G20, and only slightly higher than noted in the USA. China had the lowest age-standardised YLD rate in the G20 in 2010. China also ranked tenth (95% UI eighth to tenth) for HALE and 12th (11th to 13th) for life expectancy. YLLs from neonatal causes, infectious diseases, and injuries in children declined substantially between 1990 and 2010. Mental and behavioural disorders, substance use disorders, and musculoskeletal disorders were responsible for almost half of all YLDs. The fraction of DALYs from YLDs rose from 28·1% (95% UI 24·2-32·5) in 1990 to 39·4% (34·9-43·8) in 2010. Leading causes of DALYs in 2010 were cardiovascular diseases (stroke and ischaemic heart disease), cancers (lung and liver cancer), low back pain, and depression. Dietary risk factors, high blood pressure, and tobacco exposure are the risk factors that constituted the largest number of attributable DALYs in China. Ambient air pollution ranked fourth (third to fifth; the second highest in the G20) and household air pollution ranked fifth (fourth to sixth; the third highest in the G20) in terms of the age-standardised DALY rate in 2010.

INTERPRETATION

The rapid rise of non-communicable diseases driven by urbanisation, rising incomes, and ageing poses major challenges for China's health system, as does a shift to chronic disability. Reduction of population exposures from poor diet, high blood pressure, tobacco use, cholesterol, and fasting blood glucose are public policy priorities for China, as are the control of ambient and household air pollution. These changes will require an integrated government response to improve primary care and undertake required multisectoral action to tackle key risks. Analyses of disease burden provide a useful framework to guide policy responses to the changing disease spectrum in China.

FUNDING

Bill & Melinda Gates Foundation.

How do we more effectively move epidemiology into policy action?

A major focus of the American College of Epidemiology's Policy Committee has been to review the translation of epidemiologic evidence into policy by developing case studies. This article summarizes crosscutting policy process lessons across the eight cases developed to date through two workshops held in 2009 and 2011. A framework for evidence-based public health policy has emerged to suggest that process, content, and outcomes are all needed to help move policy forward. The most readily and apparent contributions from epidemiologists are towards content and outcomes activities, and although this is apparent in all of the case studies presented, much of the 2011 workshop discussion focused on six process issues. Policy and process issues are not well incorporated into current epidemiologic training, and controversy remains over the role of the epidemiologist as an advocate for policy changes. As these case studies show, epidemiologic evidence impacts policy to address emerging public health problems, yet few epidemiologists are formally trained in the domains to support policy development. As we continue to learn from current policy efforts, we encourage the incorporation of these case studies and the emerging experience within epidemiologic training programs.

Application of dietary phenolic biomarkers in epidemiology: past, present, and future

Phenolics are a large group of plant compounds that have been associated with protective health effects against several chronic diseases due to their potential antioxidant, anti-inflammatory, and anticarcinogenic properties. Consequently, in nutritional epidemiology it is essential to make an accurate assessment of phenolic exposure to evaluate their protective activities against human diseases. Self-reported questionnaires and biomarkers are the two main methods used for estimating dietary phenolics. Despite the limitations of self-reported methods, they are still an acceptable and useful measure. Meanwhile, nutritional biomarkers provide an alternative, more accurate measure, but they are expensive, and to date there are few validated biomarkers of phenolic intake. Nowadays, new analytical techniques, using both targeted and untargeted metabolomic approaches, play an important part in the rapid increase in the understanding of phenolic bioavailability and, consequently, have provided new potential biomarkers in small trials. In the near future, these dietary biomarkers should be tested in large epidemiological studies. Furthermore, the use of two independent measures-questionnaires and biomarkers-together provides a more thorough analysis of true phenolic exposure. Indeed, the challenge in the long term is to combine the information from biomarkers and self-reported questionnaires to clarify the relationship between dietary phenolics and disease.