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[...]despite the large influx of papers, our peer reviewers managed to keep pace and render 2105 decision recommendations to our editors, most within 12 days of accepting the invitation to review. "9 Articles in the journal also echoed the uproar against racism and assertions of White supremacy articulated in the massive demonstrations that followed the murder of George Floyd.10,11 From the beginning of the pandemic, our editorial strategy has been to focus on post-COVID-19 reconstruction. Because it takes three to four months from submission to publication of a research paper or analytic essay in AJPH, we could not publish time-sensitive results about the evolution of the pandemic. Alpren et al. described the control of an outbreak of HIV infection among people who inject drugs during 2015 to 2018 in two cities in northeastern Massachusetts, which resulted in a significant decline in new HIV diagnoses, but also observed that opioid use was fueling HIV transmission in Massachusetts and likely in other urban settings.17 Cicero et al. also reported that polysubstance use needed to be taken into consideration to effectively meet the treatment, prevention, and policymaking challenges ofthe opioid epidemic.18 Another significant area of public health in which the pandemic exacerbated problems is workplace health and safety. A meta-analysis by Wang et al., showing that e-cigarettes used as consumer products are not associated with increased smoking cessation but that free e-cigarettes provided as a clinical intervention are, contributes support to the FDA strategy.23 Finally, Norris et al. described the evolution of abortion access in Ohio between 2010 and 2018,24 an issue that has been exacerbated by the imperviousness ofthe previous administration to the anxiety of pregnant women infected by COVID-19.

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.

Patient: Female, 68 Final Diagnosis: Adrenal hemorrhage Symptoms: Abdominal and/or epigastric pain Medication: Rivaroxavan Clinical Procedure: — Specialty: General and Internal Medicine Objective: Rare disease Background: Adrenal hemorrhage is an uncommon and under-recognized disorder with a wide array of etiologies ranging from pregnancy to septic shock. It is one of the complications of anticoagulation therapy, including direct anticoagulant medications. Case Report: Here, we present a case of a 68-year-old female with recent right knee arthroplasty who was on rivaroxaban for deep vein thrombosis (DVT) prophylaxis presented to the emergency department (ED) for severe acute onset abdominal pain, computed tomography (CT) of abdomen and pelvis revealed possible left adrenal hemorrhage that was confirmed with magnetic resonance imaging (MRI). On repeat CT, her unilateral adrenal hemorrhage converted to a bilateral adrenal hemorrhage (BAH) and, as a result, the patient developed adrenal insufficiency. Conclusions: An undiagnosed and untreated adrenal hemorrhage can have catastrophic consequences, leading to adrenal insufficiency with potential shock and death. Therefore, it is important for clinicians to have an increased awareness and knowledge about adrenal hemorrhage.

Background In the presence of non-adherence and lost to follow up, results of an Intention to Treat (ITT) analysis may be biased as it is measuring the effect of assignment rather than the effect of treatment. Given that Marginal Structural Models (MSMs) adjust for such issues, this study examines the use of MSMs to assess the validity of ITT analyses in the presence of non-adherence and lost to follow up in an existing randomized clinical trial on asthma treatment. Methods Inverse probability weights were obtained from a pooled logistic regression assessing the probability of staying on assigned treatment (adherence) and of remaining uncensored (censored) for subjects at each visit by treatment arm. Weights were then pooled into a MSM analysis using a Poisson generalized estimating equation with an independent correlation matrix. Results Out of 488 participants, 174 (36%) did not adhere to the baseline assignment and 85 (17%) were lost to follow up by the end of the study. The adjusted relative risks (RR), and 95% confidence intervals (CI), obtained from the MSMs (theophylline vs. montelukast; RR=1.24; 95% CI: 0.83,1.84; theophylline vs. placebo: RR=1.01; 95% CI: 0.70,1.48; and montelukast vs. placebo: RR=0.83; 95% CI: 0.57,1.19) were nearly identical to that of the ITT analysis (theophylline vs. montelukast: RR=1.22; 95% CI: 0.82,1.86; theophylline vs. placebo: RR=0.99; 95% CI: 0.67,1.50; and montelukast vs. placebo: RR=0.82; 95% CI: 0.55,1.21). Conclusion Concordance between the results of ITT and MSMs indicate adherence and censoring may not invalidate ITT analysis. However, no adherence or censorship thresholds currently exist to assist researchers in determining when MSMs may be superior to ITT in the analysis of clinical trials with non-adherence or censorship issues, and therefore, MSMs should be conducted as a sensitivity analysis to the ITT approach in clinical trials.

Background: Published findings on breast cancer risk associated with different types of menopausal hormone therapy (MHT) are inconsistent, with limited information on long-term effects. We bring together the epidemiological evidence, published and unpublished, on these associations, and review the relevant randomised evidence. Methods: Principal analyses used individual participant data from all eligible prospective studies that had sought information on the type and timing of MHT use; the main analyses are of individuals with complete information on this. Studies were identified by searching many formal and informal sources regularly from Jan 1, 1992, to Jan 1, 2018. Current users were included up to 5 years (mean 1·4 years) after last-reported MHT use. Logistic regression yielded adjusted risk ratios (RRs) comparing particular groups of MHT users versus never users. Findings: During prospective follow-up, 108 647 postmenopausal women developed breast cancer at mean age 65 years (SD 7); 55 575 (51%) had used MHT. Among women with complete information, mean MHT duration was 10 years (SD 6) in current users and 7 years (SD 6) in past users, and mean age was 50 years (SD 5) at menopause and 50 years (SD 6) at starting MHT. Every MHT type, except vaginal oestrogens, was associated with excess breast cancer risks, which increased steadily with duration of use and were greater for oestrogen-progestagen than oestrogen-only preparations. Among current users, these excess risks were definite even during years 1–4 (oestrogen-progestagen RR 1·60, 95% CI 1·52–1·69; oestrogen-only RR 1·17, 1·10–1·26), and were twice as great during years 5–14 (oestrogen-progestagen RR 2·08, 2·02–2·15; oestrogen-only RR 1·33, 1·28–1·37). The oestrogen-progestagen risks during years 5–14 were greater with daily than with less frequent progestagen use (RR 2·30, 2·21–2·40 vs 1·93, 1·84–2·01; heterogeneity p Interpretation: If these associations are largely causal, then for women of average weight in developed countries, 5 years of MHT, starting at age 50 years, would increase breast cancer incidence at ages 50–69 years by about one in every 50 users of oestrogen plus daily progestagen preparations; one in every 70 users of oestrogen plus intermittent progestagen preparations; and one in every 200 users of oestrogen-only preparations. The corresponding excesses from 10 years of MHT would be about twice as great.

The crisis spurred by the pandemic of COVID-19 has revealed weaknesses in our epidemiologic methodologic corpus, which scientists are struggling to compensate. This article explores whether this phenomenon is characteristic of pandemics or not. Since the emergence of population-based sciences in the 17th century, we can observe close temporal correlations between the plague and the discovery of population thinking, cholera and population-based group comparisons, tuberculosis and the formalization of cohort studies, the 1918 Great Influenza and the creation of an academic epidemiologic counterpart to the public health service, the HIV/AIDS epidemic, and the formalization of causal inference concepts. The COVID-19 pandemic seems to have promoted the widespread understanding of population thinking both with respect to ways of flattening an epidemic curve and the societal bases of health inequities. If the latter proves true, it will support my hypothesis that pandemics did accelerate profound changes in epidemiologic methods and concepts.

Natural disasters, including this pandemic, hurricanes, flooding, fires, and earthquakes, have become the new public health normal 1 AJPH, in collaboration with the Centers for Disease Control and Prevention, has strived to make the evidence and the history available in regular issues and supplements (https://am ajph link/Emergency-Management_2017, https://am ajph link/Medical-Countermeasures_2018, https://am ajph link/ Community-Preparedness_2019) Workers in the health care, mail and delivery, food establishment and restaurant, retail, warehouse, and transportation sectors are taking huge risks to keep the economy and public health functioning, but they have been neglected-because of the gig economy, precarious jobs, endemic poverty, lack of access to care, insufficient wages and benefits, andso on-fora decade or more The evidence supporting this is overwhelming 7 The pandemic, compounded or not by natural disasters, hasn't put an end to the epidemics of opioid addiction, deaths ofdespair, mass incarceration, punitive immigration policies, vaping among youths, gun violence and other forms of violence exacerbated by the quarantine, lack of access to food locally and globally, and wide disparities in health between rural and urban regions

The author discusses the annual National Public Health Week (NPHW) held each year during the first full week of April and its mission to showcase the importance of public health in daily life and promote its strengthening. Topics include the 2019 focus on the importance of basing policymaking on scientific evidence to make it available for the public health actors and proactively advancing the health of the public.

An introduction is presented to a special section that discusses the notion of providing firearms training to U.S. school teachers, noting articles on topics including the lack of evidence to support such a policy, the workloads of teachers, and U.S. public opinion on gun control.

Background: We sought to determine whether post-traumatic stress disorder (PTSD) is a risk factor for myocardial infarction (MI) and stroke, beyond the expected effects from recognized cardiovascular risk factors and depression. Methods and Results: World Trade Center–Heart is an observational prospective cohort study of 6481 blue-collar first responders nested within the World Trade Center Health Program in New York City. Baseline measures in 2012 and 2013 included blood pressure, weight and height, and blood lipids. PTSD, depression, smoking, and dust exposure during the 2001 cleanup were self-reported. During the 4-year follow-up, outcomes were assessed through (1) interview-based incident, nonfatal MI, and stroke, validated in medical charts (n=118); and (2) hospitalizations for MI and stroke for New York city and state residents (n=180). Prevalence of PTSD was 19.9% in men and 25.9% in women, that is, at least twice that of the general population. Cumulative incidence of MI or stroke was consistently larger for men or women with PTSD across follow-up. Adjusted hazard ratios (HRs) were 2.22 (95% confidence interval [CI], 1.30–3.82) for MI and 2.51 (95% CI, 1.39–4.57) for stroke. For pooled MI and stroke, adjusted HRs were 2.35 (95% CI, 1.57–3.52) in all and 1.88 (95% CI, 1.01–3.49) in men free of depression. Using hospitalization registry data, adjusted HRs were 2.17 (95% CI, 1.41–3.32) for MI; 3.01 (95% CI, 1.84–4.93) for stroke; and for pooled MI and stroke, the adjusted HR was 2.40 (95% CI, 1.73–3.34) in all, HR was 2.44 (95% CI, 1.05–5.55) in women, and adjusted HR was 2.27 (95% CI, 1.41–3.67) in men free of depression. World Trade Center dust exposure had no effect. Conclusions: This cohort study confirms that PTSD is a risk factor for MI and stroke of similar magnitude in men and women, independent of depression.

No Abstract

Undocumented migrants, meaning migrants without a legal residency permit, come to Geneva from countries with high tuberculosis (TB) incidence. We estimate here whether being undocumented is a determinant of TB, independently of origin. Cross-sectional study including undocumented migrants in a TB screening program in 2002; results were compared to 12,904 age and frequency matched participants in a general TB screening program conducted at various workplaces in Geneva, Switzerland from 1992 to 2002. A total of 206 undocumented migrants (36% male, 64% female, mean age 37.8 years (SD 11.8), 82.5% from Latin America) participated in the TB screening program. Compared to legal residents, undocumented migrants had an adjusted OR for TB-related fibrotic signs of 1.7 (95% CI 0.8;3.7). The OR of TB-related fibrotic signs for Latin American (vs. other) origin was 2.7 (95% CI 1.6;4.7) among legal residents and 5.5 (95% CI 2.8;10.8) among undocumented migrants. Chest X-ray screening identified a higher proportion of TB-related fibrotic signs among Latin Americans, independently of their residency status.

In an attempt to reproduce the results of an inconclusive 1927 report by the British Medical Research Council on the hereditary versus social origins of rheumatic fever, Read, Ciocco, and Taussig, from Johns Hopkins University, with the support of Frost, conducted a case-control study in 1935 and 1936. Their study, which appeared in the American Journal of Hygiene in 1938, was outstanding for its clear and tidy rationale for separating hereditary from environmental causes. The authors compared the prevalence of rheumatic fever among the relatives of 33 children admitted for "incident" rheumatic fever and 33 control children admitted in a tuberculosis clinic for reasons other than rheumatic fever. Both rheumatic fever (cases) and tuberculosis (controls) were diseases of the poor. All family members of both cases and controls, including uncles, aunts, and grandparents, were eligible for interview and physical examination. The results were compatible with the presence of an "inherited predisposition" to rheumatic fever because the disease was more prevalent among the uncles, aunts, and grandparents of case patients than among those of control patients. Methodologically, the paper by Read, Ciocco, and Taussig is an important but almost completely forgotten milestone in the evolution of case-control studies and of genetic epidemiology.

Before World War II, epidemiology was a small discipline, practiced by a handful of people working mostly in the United Kingdom and in the United States. Today it is practiced by tens of thousands of people on all continents. Between 1945 and 1965, during what is known as its “classical” phase, epidemiology became recognized as a major academic discipline in medicine and public health. On the basis of a review of the historical evidence, this article examines to which extent classical epidemiology has been a golden age of an action-driven, problem-solving science, in which epidemiologists were less concerned with the sophistication of their methods than with the societal consequences of their work. It also discusses whether the paucity of methods stymied or boosted classical epidemiology's ability to convince political and financial agencies about the need to intervene in order to improve the health of the people.

Benign breast disease deserves attention because of its high prevalence, its impact on women's quality of life, and, for some histologic types, its cancerous potential. Identification of risk factors for benign breast disease could improve our understanding of its etiology and pathogenesis and help to define preventive strategies. Benign breast disease has been extensively studied, and this wealth of literature warrants periodic reevaluation. This paper both updates and extends a previous review by Ernster (1) by summarizing accumulated information on the relation of benign breast disease to smoking, methylxanthines, and diet that was not covered in that earlier review. It does not, however, include a section on the relation between benign breast disease and breast cancer, a topic recently reviewed by Bodian (2). We have also attempted to consolidate the wide range of terms used to describe the histologic manifestations of this disease.

It is often assumed, but has not been consistently observed, that some characteristics of reproductive history are specifically related to breast cancer of pre- or postmenopausal onset. To determine whether inconsistent reports may be due to differences in definition of menopause, we computed the relative odds (RO) of breast cancer for nulliparity, age at first live birth, family history of breast cancer and prior history of benign breast disease, separately in pre- and postmenopausal women, using seven different definitions of menopause. Results show that (i) relative odds of breast cancer and their confidence intervals may vary according to definitions of menopause; (ii) age-based definitions of menopause are associated with moderate differential misclassification bias between cases and controls; (iii) nulliparity, late age at first birth and family history of breast cancer seem to be specific risk factors for pre- but not postmenopausal breast cancer when cutoff for menopausal status is 10 years or more after last menses; and (iv) when information on menstrual history is not available, 50 years of age may be the best proxy for all menses-based definitions of menopause. We conclude that inconsistent findings on the effect of menopausal status in the association of breast cancer with some reproductive factors are partly due to statistical imprecision and differential misclassification bias associated with different age-based or menses-based definitions of menopause. Researchers should either test whether their conclusions hold using several definitions of menopause or give a biological rationale for the choice of a given definition of menopause.

The aim of this study was to determine the prevalence of symptoms related to constipation in urban Swiss men and to identify associated sociodemographic factors and health habits. A sample of 773 men aged between 35 and 74 years randomly selected from the Geneva population answered a questionnaire on bowel habits during a personal interview in a mobile epidemiological unit. 'Constipation' was reported by more than 6% of subjects, difficulties in stool evacuation by approximately 5% and less than three stools per week by approximately 2%. These symptoms appeared less prevalent in subjects with post-baccalaureate education (the excess prevalence of setf-reported constipation, difficulty in stool evacuation and frequent dally defecation was greater than 5%). Smokers were more likely to have a frequency of 3-7 stools per week and were less affected by frequent daily defecation. Self-reported constipation was more prevalent in subjects with a higher dietary fibre intake. No statistically significant effects of age, nationality, dietary fat or physical activity were observed. These results are consistent with national surveys in US populations. Factors related to socioeconomic status or education may be a cause of constipation in men, but they still need to be elucidated.

This study sought to determine cumulative lifetime exposure to environmental tobacco smoke (ETS) among urban women in relation to sociodemographic factors. In a population survey carried out in Geneva, Switzerland, during 1993-1995, a representative sample of 1, 883 women aged 35-74 years answered interview questions on lifetime ETS exposure. Exposed women were defined as those who had spent at least 1 hour daily in a smoky environment during 1 or more years. The prevalence of current ETS exposure was 31.0% among 1, 458 never or former smokers. Lifetime prevalence was 58.3% among 1, 061 never smokers. The home (42.1%) and the workplace (39.6% of employed women) were the most frequent sources of ETS exposure, leisure time activity being a secondary source. Throughout a lifetime, work accounted for the greatest average intensity of exposure (on average, 19 hours of exposure per week), while the longest duration of exposure (on average, 18 years) was in the home. Cumulative lifetime exposure (intensity (in hours/week) x duration) from all sources combined was 308 hours/week-years, which can correspond to 30.8 hours/week over a period of 10 years or 20.5 hours/week over a period of 15 years. Women from low socioeconomic classes had more intense and longer exposures than women from higher socioeconomic classes, mainly because of work exposure. Both the intensity and the duration of lifetime ETS exposure were greater than previously suspected. Reduction of ETS exposure in the workplace should be a public health priority. Am J Epidemiol 1998; 148: 1040-7

An introduction is presented in which the author discusses various articles in the issue which address topics such as the state of public health in the U.S., the health aspects of climate change, and the relationship between populist politics and science in America as of 2017.

An introduction is presented in which the Editor-in-Chief discusses various issues of the journal which were published in 2016, including information on stories about mass lead poisoning in Flint, Michigan, men's health, and a Zika virus crisis, as well as journal sections such as Law and Ethics.

For almost a century, epidemiologists have stratified age-specific disease rates by year of birth to better understand the distribution of a disease in a population and its evolution across time. In the present article, I review the contributions of John Brownlee, Kristian Feyer Andvord, and Wade Hampton Frost and, to accentuate the similarities of their approaches, redraw their original graphs of age-specific death rates of tuberculosis organized either by year of death or year of birth. In addition, this article reports on an apparently universally forgotten publication in the American Journal of Hygiene published in 1929, which both upsets the conventional history of the earliest reports of disease rates stratified by birth cohorts and challenges the theory that Frost discovered cohort analysis independently and gave it its name.

In 1946, the physician and statistician Joseph Berkson (1899–1982) pointed out that two diseases that are independent in the general population may become ‘spuriously associated’ in hospital-based case-control studies.1 This spurious association was later referred to, often in lively debates,2–14 as Berkson’s fallacy, Berkson’s paradox or Berkson’s bias. Some authors restricted the interpretation of Berkson’s fallacy to disease-disease associations,2,5,7,8 whereas others thought that the fallacy would also apply to exposure-disease associations in hospital-based case-control studies.10–15 In this article we use directed acyclic graphs (DAGs) to describe the structure of Berkson’s fallacy, first for disease-disease associations and then for exposure-disease associations. This permits us to understand the contentious debates and strongly differing opinions about Berkson’s fallacy, and has practical implications for study design and interpretation (see Box 1). Box 1. Practical implications of Berkson’s fallacy The fallacy that became eponymous for Berkson caused controversy from its initial formulation onwards. Some held that it biased all case-control studies in hospitals; others maintained that it was only pertinent for associations between prevalent diseases, and did not exist for exposure-disease associations. The DAG analyses in this paper show that Berkson’s fallacy can exist when studying exposure-disease associations, be it only in an ‘indirect’ form and in exceptional circumstances: when in a hospital-based case-control study persons with a prevalent diagnosis are enrolled who were hospitalized for another disease that is associated with this exposure. The DAG of the problem that Berkson originally described has the same structure of all biases due to conditioning on a collider, but cannot be endowed with a causal interpretation since it was formulated and worked out as a problem of the association of prevalent diseases. When using incident cases in hospital-based case-control studies, Berkson’s fallacy becomes highly unlikely for exposure-disease associations, unless there are many people who have developed two different new diseases more or less at the same time and are hospitalized for the other disease, i.e. the disease that is not the subject of the case-control study. When incident cases in a case-control study consist only of people who have been hospitalized for that disease, Berkson’s fallacy is not possible. It is likely that Berkson’s fallacy has had very limited, if any, impact on the findings of epidemiological studies.

The author discusses his views about the contributions that U.S. President Barack Obama, his wife Michelle Obama, and their children Malia and Sasha Obama have made to public health in America as of 2016, and it mentions Michelle Obama's mother Marian Robinson who has also resides in the U.S. White House with her daughter's family. African American families are addressed, along with the U.S. Patient Protection and Affordable Care Act. LGBTQ rights, and obesity prevention.

The article discusses events of the 1960's that influenced public health in the U.S. Topics include the Students for a Democratic Society's defense of justice and equality, the development of social medicine and collective health in Latin America, and the impact of the Biafran famine on modern emergency public health.

An introduction is presented discussing several reports from the issue on topics including public health advocacy, environmental protection, and single payer health insurance.

An introduction is presented in which the authors discuss various reports within the journal on topics including natural disaster-related preparations and rebuilding efforts, public health in the wake of Hurricanes Harvey, Irma, and Maria, and climate change.

In the summer of 1924, an outbreak of scarlet fever occurred in Flint, Michigan. Unable to trace it to the usual causes, particularly fresh milk, the Michigan Department of Health used a novel approach to disentangle the enigma: The 116 cases of scarlet fever were compared with 117 “controls” selected from neighbors of the quarantined cases and from patients at the City Health Center who had been treated for ailments unrelated to scarlet fever. The extraordinary culprit was ice cream, which had a frequent/occasional/none consumption prevalence of 60%, 34%, and 6% among the cases and 24%, 51%, and 25% among the controls, respectively. The 1925 report reads, “Detailed epidemiological investigation, by means of case histories and control histories on well persons, confirmed early suspicions and established the fact that the epidemic was spread by ice cream” (Am J Hyg. 1925;5(5):669–681). This forgotten epidemiologic study is the oldest study using the case-control design to have been resurrected thus far. The case-control study design may have been conceived simultaneously, but independently and for different purposes, in England (Janet Lane-Claypon’s 1926 report on the determinants of breast cancer) and the United States. case-control studies; disease transmission; epidemiologic methods; history of medicine; ice cream; scarlet fever

Wade Hampton Frost, who was a Professor of Epidemiology at Johns Hopkins University from 1919 to 1938, spurred the development of epidemiologic methods. His 6 publications in the American Journal of Hygiene, which later became the American Journal of Epidemiology, comprise a 1928 Cutter lecture on a theory of epidemics, a survey-based study of tonsillectomy and immunity to Corynebacterium diphtheriae (1931), 2 papers from a longitudinal study of the incidence of minor respiratory diseases (1933 and 1935), an attack rate ratio analysis of the decline of diphtheria in Baltimore (1936), and a 1936 lecture on the age, time, and cohort analysis of tuberculosis mortality. These 6 American Journal of Hygiene /American Journal of Epidemiology papers attest that Frost's personal evolution mirrored that of the emerging “early” epidemiology: The scope of epidemiology extended beyond the study of epidemics of acute infectious diseases, and rigorous comparative study designs and their associated quantitative methods came to light.

In 1906 Arthur Newsholme linked artificial feeding and fatal diarrhea in infants aged one year and younger on the basis of two independent sources of information: mortality registration and a three-year (1903–1905) census of infants from Brighton, United Kingdom. Artificial feeding was more common in the infants who had died (89.3%) than in those in the survey (22.3%). However, boldly assuming the two data sources were nested, Newsholme computed the risks of fatal diarrhea: these were 48 times greater for infants fed fresh cow’s milk and 94 times greater for those fed condensed milk than for infants who were exclusively breastfed. This mode of computing risks and risk ratios before the invention of the cohort study design was more innovative than was the usual investigation techniques of his contemporary epidemiologists. Newsholme’s conclusions were consistent with the current knowledge that breastfeeding protects against fatal diarrhea.

consisting of seven parts, 63 sections, and comprising 98 collaborators, is different from all the epidemiology textbooks available in any of the languages I can read.Briefly, the seven parts of the book cover:(1) History (of the world and of Brazil) and phi-losophy (epistemology, concept of risk);(2) Methodology (measurements of occurrence of health events and principal study designs);(3) Epidemiological data analysis (regression models, multilevel, structural, and complex ap-proaches, and meta-analyses);(4) Applications of epidemiology by levels of or-ganization (molecular, genetic, clinical, environ-mental, social, and “ethno-epidemiological”);(5) Applications of epidemiology across the live course (childhood, adolescence, adulthood, ag-ing);(6) Specific health problems (infectious, respi-ratory, and cardiovascular diseases, cancer, vio-lence, addiction, mental, oral, occupational, nu-tritional, reproductive and sexual);(7) Application of epidemiology to public health, health policy and economics, and concluding with a section entitled

George W. Comstock (1915–2007), MD, MPH, DrPH, was lecturer and then professor of epidemiology at the Johns Hopkins University School of Hygiene and Public Health from 1956 to 2007 and served as editor-in-chief of the American Journal of Epidemiology from 1979 to 1988. This interview of George W. Comstock took place in Hagerstown, Maryland, in the spring of 1990. The selection of questions and answers published here represent approximately 10% of the whole interview, which had been reviewed and hand-corrected by Dr. Comstock. He first describes how epidemiology was taught at Hopkins in the 1950s and 1960s. He then distinguishes “epidemiology per se” from a “practical epidemiology” that works closely with local health departments, and he finally expresses his wish that in the future, epidemiology would become more widely involved in policy and accepted by policy makers. Photo of George, Margaret, and Gordon Comstock taken during World War II, most likely in 1944, while Dr Comstock was serving as Medical Officer in an Escort Destroyer Division. Keywords: history, interview, policy, teaching In this first publication of the new section “Epidemiology in History,” I pay a tribute to George W. Comstock, with whom I had the privilege to work (1, 2). George passed away in 2007. He was 92 years old. His exit was suffered as a great loss by the scientific community at large, with obituaries appearing in The Washington Post (3), The New York Times (4), Lancet (5), American Review of Respiratory and Critical Care Medicine (6), and Revista de Saude Publica (Brazil) (7). The October 1, 2008, issue of the American Journal of Epidemiology was entirely dedicated to Comstock, with personal remembrances (8–11) and discussion of his contributions to the Washington County Training Center (12) and the fields of tuberculosis research (13), noninvasive imaging and hypertension (14), respiratory disease epidemiology (15), and the epidemiologic use of biological samples (16). The articles by Comstock that were republished in that memorial issue are still great readings and examples of careful studies at a time when constraints on article length were not what they are today and articles provided a thorough review and discussion of the literature. It is fortunate that in 2003, Dale Sandler had a videotaped conversation with Comstock for “Voices” in the journal Epidemiology (17). A snippet of the video is viewable online (18). Comstock was already 88 years old then, but the video nicely captures his unforgettable voice and the gentle way in which he made authoritative statements. There also exists a short movie about George Comstock (19). I happen to have interviewed George in 1990. The cover letter of his hand-edited copy of the 55-page interview is reproduced in this article. The interview was transcribed verbatim and published without alteration except for the inclusion of a few edits handwritten by Comstock on the paper copy. However, I selected questions that were different from those published by Dale Sandler in her conversation with Dr. Comstock (17). The first set deals with his reminiscence of the way epidemiology was taught when he was a student. Comstock mentions 2 exercises that have been used over very long periods of time in the Department of Epidemiology. The first was the charity luncheon problem, which, according to Comstock, “has been used with practically no break in Epi 1 since 1955.” The exercise is “Principles of epidemiology: problem 1: An outbreak of acute sore throats following a charity luncheon” from the Department of Epidemiology, The Johns Hopkins University Bloomberg School of Public Health, 2006. The exercise is based on a paper by Farber and Korff (20). The second exercise mentioned by Dr. Comstock is “Epidemiology 2A: exercise 4: methods of longitudinal study” from the Department of Epidemiology, The Johns Hopkins University School of Hygiene and Public Health, 1986–1987. It analyzes the longevity of members the Radiological Society of North America and the American Academy of Ophthalmology and Otolaryngology and is based on 4 papers by Seltzer, Sartwell, and Matanoski (21–24). Cover letter of Dr. Comstock's hand-edited copy of the 55-page interview. In a second set of questions, Comstock contrasts what he calls “epidemiology per se,” which has no direct implications for the community, with “practical epidemiology” that works closely with local health departments. In the last set of questions, Comstock expresses his wish that in the future, epidemiology would become more widely involved in policy and accepted by policy makers. Comstock spoke plainly and was not shy about defending ideas, no matter iconoclastic they sounded. For example, when asked whether the concept of interaction was taught at Hopkins at the time of his doctorate of public health in the 1950s, he answered, “I'm sure we didn't worry about that as such. Of course, you probably know I still don't.” This 23-year-old conversation with Comstock is a historical document that reflects the thinking of a classic epidemiologist who felt his role was not only to identify causes of diseases but also to apply this knowledge to improving people's health. The generation of epidemiologists to whom Comstock belongs was driven more or less by this same mission. Looking at the world through their lenses for a moment is terribly important to perceive the historical forces that shaped the epidemiology we practice today.

Between 1600 and 1700, sudden, profound, and multifarious changes occurred in philosophy, science, medicine, politics, and society. In an extremely convulsed century, these profound and convergent upheavals produced the equivalent of a cultural big bang, which opened a new domain of knowledge acquisition based on population thinking and group comparisons. In 1662, when John Graunt applied-for the first time-the new approach to the analysis of causes of death in London, he gave epidemiology a singular date of birth. This was exactly 350 years ago.

An introduction is presented in which the author discusses several articles in the issue which address the historical legacy of the Black Panther Party in relation to public health in America, and it mentions free health clinics and health activism in the U.S. in the 1960s.

Everyone in public health has heard of the first Nurses’ Health Study (NHS). This cohort of 121 700 nurses assembled in 1976 has generated a substantial part of what we know today about women’s health and the prevention of chronic diseases. A brilliant and competent team of investigators from Harvard University originated it 40 years ago and have conducted it since then, but as every epidemiologist knows, wonderful ideas do not necessarily translate into great studies. The NHS is the encounter of a wonderful idea (i.e., enrolling nurses in a large cohort study) and the historically outstanding response from nurses, who made the study theirs. Nurses joined, persisted, and used their unique and essential skills to make this cohort study an exemplar.

The author reflects on the 40th anniversary of the Nurses' Health Study (NHS) in 2016, and it mentions assessments of the health of U.S. nurses, as well as the views of several American Public Health Association (APHA) members who participated in the NHS cohort study. The NHS II and Growing Up Today Study (GUTS) research programs are examined, along with the attitudes of various mothers and daughters who were involved in the NHS. Public health history in America is also assessed.

Background. The Collaborative Group on Hormonal Factors in Breast Cancer has brought together and reanalysed about 90% of the worldwide epidemiological evidence on the relation between risk of breast cancer and use of hormone replacement therapy (HRT). Methods. Individual data on 52,705 women with breast cancer and 108,411 women without breast cancer from 51 studies in 21 countries were collected, checked, and analysed centrally. The main analyses are based on 53,865 postmenopausal women with a known age at menopause, of whom 17,830 (33%) had used HRT at some time. The median age at first use was 48 years, and 34% of ever-users had used HRT for 5 years or longer. Estimates of the relative risk of breast cancer associated with the use of HRT were obtained after stratification of all analyses by study, age at diagnosis, time since menopause, body-mass index, parity, and the age a woman was when her first child was born. Findings. Among current users of HRT or those who ceased use 1-4 years previously, the relative risk of having breast cancer diagnosed increased by a factor of 1.023 (95% CI 1.011-1.036; 2p = 0.0002) for each year of use; the relative risk was 1.35 (1.21-1.49; 2p = 0.00001) for women who had used HRT for 5 years or longer (average duration of use in this group 11 years). This increase is comparable with the effect on breast cancer of delaying menopause, since among never-users of HRT the relative risk of breast cancer increases by a factor of 1.028 (95% CI 1.021-1.034) for each year older at menopause. 5 or more years after cessation of HRT use, there was no significant excess of breast cancer overall or in relation to duration of use. These main findings did not vary between individual studies. Of the many factors examined that might affect the relation between breast cancer risk and use of HRT, only a woman's weight and body-mass index had a material effect: the increase in the relative risk of breast dancer associated with long durations of use in current and recent users was greater for women of lower than of higher weight or body-mass index. There was no marked variation in the results according to hormonal type or dose but little information was available about long durations of use of any specific preparation. Cancers diagnosed in women who had ever used HRT tended to be less advanced clinically than those diagnosed in never-users. In North America and Europe the cumulative incidence of breast cancer between the ages of 50 and 70 in never-users of HRT is about 45 per 1000 women. The cumulative excess numbers of breast cancers diagnosed between these ages per 1000 women who began use of HRT at age 50 and used it for 5, 10, and 15 years, respectively, are estimated to be 2 (95% CI 1-3), 6 (3-9), and 12 (5-20). Whether HRT affects mortality from breast cancer is not known. Interpretation. The risk of having breast cancer diagnosed is increased in women using HRT and increases with increasing duration of use. This effect is reduced after cessation of use of HRT and has largely, if not wholly, disappeared after about 5 years. These findings should be considered in the context of the benefits and other risks associated with the use of HRT.