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101-466: The program's goal was to inspire high-school students to do epidemiology research, and to inspire students to explore the broad field of public health. Such research could involve many different topics, including disease, social networking, methods of health education, sports injuries, obesity, stress, and sleeping patterns. The program offered up to 120 scholarships each year, for a total award amount of $ 456,000 . All entrants submitted their paper to

202-670: A Special Issue in Social Science and Medicine to explore the various methodological ways in which syndemics can be understood, interpreted, and evaluated through history. For instance, historical syndemics may be evaluated using archival data that is incomplete but provides a novel way of thinking about disease biography. This is exemplified by Dylann Atcher Proctor's historical work on gastrointestinal distress in Gabon using historical archives that had never yet been evaluated on their own or synergistically. Ethnographic data provides

303-422: A confluence of factors (such as climate change or social inequality) that produces multiple health conditions that afflict some populations and not others. Syndemics are not like pandemics (where the same social forces produce clustered conditions equally around the world); instead, syndemics reflect population-level trends within certain states, regions, cities, or towns. A syndemic or synergistic epidemic

404-437: A causal association does not exist in general. Conversely, it can be (and is in some circumstances) taken by US courts, in an individual case, to justify an inference that a causal association does exist, based upon a balance of probability . The subdiscipline of forensic epidemiology is directed at the investigation of specific causation of disease or injury in individuals or groups of individuals in instances in which causation

505-496: A dangerous synergy that wreaks cardiovascular havoc far beyond what's caused by the diesel or cholesterol alone." Experimentation revealed that the two mechanisms worked in tandem to stimulate genes that promote cell inflammation, a primary risk for hardening and blockage of blood vessels ( atherosclerosis ) and, as narrowed arteries collect cholesterol deposits and trigger blood clots, for heart attacks and strokes as well. A Note on Mathematical Models A mathematical model

606-506: A deeper understanding of how and why larger social forces produce disease clusters and interactions and are crucial for understanding "why" syndemics occur. Ethnographic insights have served as the bedrock of syndemic thinking since Merrill Singer's pioneering intellectual and practical work with the concept beginning in the 1990s. His first article based on ethnographic thinking about the SAVA Syndemic came from real time observations as

707-612: A failure ... Thus followed epidemics of measles, grippe [influenza], and whooping cough Pertussis , in rapid succession and with terrible fatal results..." Similarly, the Handbook of American Indians notes, "The least hopeful conditions in this respect prevail among the Dakota [Sioux] and other tribes of the colder northern regions, where pulmonary tuberculosis and scrofula are very common... Other more common diseases, are various forms of, bronchitis ...pneumonia, pleurisy , and measles in

808-513: A focus on scholarship for deepening the application of what has largely served as theory to understand why and how social and health conditions cluster together, interact, and are driven by shared forces, from climate (such as escalation of heat, rain, drought, and events) to poverty (such as food insecurity, poor housing, lack of safety, and limited work opportunities). In 2022, Alexander Tsai (an epidemiologist), Emily Mendenhall (a medical anthropologist), and Timothy Newfield (a historian) teamed up on

909-820: A full list of winners, see the YES website. Teach Epidemiology website Epidemiology Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and determinants of health and disease conditions in a defined population . It is a cornerstone of public health , and shapes policy decisions and evidence-based practice by identifying risk factors for disease and targets for preventive healthcare . Epidemiologists help with study design, collection, and statistical analysis of data, amend interpretation and dissemination of results (including peer review and occasional systematic review ). Epidemiology has helped develop methodology used in clinical research , public health studies, and, to

1010-498: A health system responds to current population health issues but also how a health system can be managed to better respond to future potential population health issues. Examples of organizations that use population-based health management that leverage the work and results of epidemiological practice include Canadian Strategy for Cancer Control, Health Canada Tobacco Control Programs, Rick Hansen Foundation, Canadian Tobacco Control Research Initiative. Each of these organizations uses

1111-521: A lesser extent, basic research in the biological sciences. Major areas of epidemiological study include disease causation, transmission , outbreak investigation, disease surveillance , environmental epidemiology , forensic epidemiology , occupational epidemiology , screening , biomonitoring , and comparisons of treatment effects such as in clinical trials . Epidemiologists rely on other scientific disciplines like biology to better understand disease processes, statistics to make efficient use of

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1212-787: A population (endemic). The term "epidemiology" appears to have first been used to describe the study of epidemics in 1802 by the Spanish physician Joaquín de Villalba  [ es ] in Epidemiología Española . Epidemiologists also study the interaction of diseases in a population, a condition known as a syndemic . The term epidemiology is now widely applied to cover the description and causation of not only epidemic, infectious disease, but of disease in general, including related conditions. Some examples of topics examined through epidemiology include as high blood pressure, mental illness and obesity . Therefore, this epidemiology

1313-520: A population-based health management framework called Life at Risk that combines epidemiological quantitative analysis with demographics, health agency operational research and economics to perform: Applied epidemiology is the practice of using epidemiological methods to protect or improve the health of a population. Applied field epidemiology can include investigating communicable and non-communicable disease outbreaks, mortality and morbidity rates, and nutritional status, among other indicators of health, with

1414-422: A prospective study, and confounders are more easily controlled for. However, they are more costly, and there is a greater chance of losing subjects to follow-up based on the long time period over which the cohort is followed. Cohort studies also are limited by the same equation for number of cases as for cohort studies, but, if the base incidence rate in the study population is very low, the number of cases required

1515-402: A random sample from the original population at risk. This has as a consequence that the control group can contain people with the disease under study when the disease has a high attack rate in a population. A major drawback for case control studies is that, in order to be considered to be statistically significant, the minimum number of cases required at the 95% confidence interval is related to

1616-522: A result of the floral changes produced by global warming, an escalation is occurring in global rates of allergies and asthma . Allergic diseases constitute the sixth leading cause of chronic illness in the United States, impacting 17 percent of the population. Asthma affects about 8 percent of the U.S. population, with rising tendency, especially in low income, ethnic minority neighborhoods in cities. In 1980 asthma affected only about three percent of

1717-656: A synergistic role in asthma development. Exposure to a combination of microscopic diesel fuel particles among people with high blood cholesterol (i.e., low-density lipoprotein , LDL or "bad cholesterol") increases the risk for both heart attack and stroke above levels found among those exposed to only one of these health risks. According to André Nel , Chief of Nanomedicine at the David Geffen School of Medicine at UCLA , "When you add one plus one, it normally totals two... But we found that adding diesel particles to cholesterol fats equals three. Their combination creates

1818-445: A unique disease process different from any other individual ("the unique disease principle"), considering uniqueness of the exposome (a totality of endogenous and exogenous / environmental exposures) and its unique influence on molecular pathologic process in each individual. Studies to examine the relationship between an exposure and molecular pathologic signature of disease (particularly cancer ) became increasingly common throughout

1919-480: Is 25 percent higher than in white people. Increases in asthma rates have occurred despite improvements in air quality produced by the passage and enforcement of clean air legislation, such as the U.S. Clean Air Act of 1963 and the Clean Air Act of 1990. Existing legislation and regulation have not kept pace with changing climatic conditions and their health consequences. Compounding the problem of air quality

2020-438: Is a synergistic epidemic. The term was developed by Merrill Singer in the mid-1990s, culminating in a 2009 textbook. Disease concentration, disease interaction, and their underlying social forces are the core concepts. Disease co-occurrence, with or without interactions, is known as comorbidity and coinfection . The difference between "comorbid" and "syndemic" is per Mustanski et al. "comorbidity research tends to focus on

2121-399: Is a core component, that is unified with management science to provide efficient and effective health care and health guidance to a population. This task requires the forward-looking ability of modern risk management approaches that transform health risk factors, incidence, prevalence and mortality statistics (derived from epidemiological analysis) into management metrics that not only guide how

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2222-592: Is a need for the development of an eco-syndemic understanding of the ways in which global warming contributes to the spread of diseases and new disease interactions. There is a need for a better understanding of how public health systems and communities can best respond to and limit the health consequences of syndemics. Systems are needed to monitor the emergence of syndemics and to allow early medical and public health responses to lessen their impact. Systematic ethno-epidemiological surveillance with populations subject to multiple social stressors must be one component of such

2323-446: Is a need to better understand processes of interaction between specific diseases with each other and with health-related factors like malnutrition, structural violence, discrimination, stigmatization, and toxic environmental exposure that reflect oppressive social relationships. There is a need to identify all of the ways, directly and indirectly, that diseases can interact and have, as a result, enhanced impact on human health. Third there

2424-529: Is a simplified representation using mathematical language to describe natural, mechanical or social system dynamics. Epidemiological modelers unite several types of information and analytic capacity, including: 1) mathematical equations and computational algorithms; 2) computer technology; 3) epidemiological knowledge about infectious disease dynamics , including information about specific pathogens and disease vectors ; and 4) research data on social conditions and human behavior. Mathematical modelling in epidemiology

2525-557: Is also exemplified in Mac Marshall's book Drinking Smoke. The largest body of methodological scholarship has emerged around the utility of epidemiological data. Epidemiological data provides opportunities to investigate the synergistic ways in which diseases emerge and interact with social and health conditions. This latter method has been the focus of contention, particularly in dialogue between Alexander Tsai and Ronald Stall. Early epidemiological studies, for example, evaluated

2626-428: Is based upon how the pattern of the disease causes change in the function of human beings. The Greek physician Hippocrates , taught by Democritus, was known as the father of medicine , sought a logic to sickness; he is the first person known to have examined the relationships between the occurrence of disease and environmental influences. Hippocrates believed sickness of the human body to be caused by an imbalance of

2727-414: Is beneficial, not deleterious. Syndemic theory seeks to draw attention to and provide a framework for the analysis of adverse disease interactions, including their causes and consequences for human life and well-being. Although the majority of this research has focused on HIV, an emerging body of work on syndemics has expanded to other co-occurring conditions. Methods for evaluating syndemics have been

2828-479: Is beyond the domain of the science of epidemiology. Epidemiology has its limits at the point where an inference is made that the relationship between an agent and a disease is causal (general causation) and where the magnitude of excess risk attributed to the agent has been determined; that is, epidemiology addresses whether an agent can cause disease, not whether an agent did cause a specific plaintiff's disease. In United States law, epidemiology alone cannot prove that

2929-483: Is disputed or is unclear, for presentation in legal settings. Epidemiological practice and the results of epidemiological analysis make a significant contribution to emerging population-based health management frameworks. Population-based health management encompasses the ability to: Modern population-based health management is complex, requiring a multiple set of skills (medical, political, technological, mathematical, etc.) of which epidemiological practice and analysis

3030-537: Is famous for his investigations into the causes of the 19th-century cholera epidemics, and is also known as the father of (modern) Epidemiology. He began with noticing the significantly higher death rates in two areas supplied by Southwark Company. His identification of the Broad Street pump as the cause of the Soho epidemic is considered the classic example of epidemiology. Snow used chlorine in an attempt to clean

3131-623: Is generally understood to be the aggregation of two or more concurrent or sequential epidemics or disease clusters in a population with biological interactions, which exacerbate the prognosis and burden of disease . The term was developed by Merrill Singer in the early 1990s to call attention to the synergistic nature of the health and social problems facing the poor and underserved. Syndemics develop under health disparity , caused by poverty , stress, climate, or structural violence and are studied by epidemiologists and medical anthropologists concerned with public health, community health and

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3232-499: Is in the term inference . Correlation, or at least association between two variables, is a necessary but not sufficient criterion for the inference that one variable causes the other. Epidemiologists use gathered data and a broad range of biomedical and psychosocial theories in an iterative way to generate or expand theory, to test hypotheses, and to make educated, informed assertions about which relationships are causal, and about exactly how they are causal. Epidemiologists emphasize that

3333-418: Is increasing recognition that a wide range of modern data sources, many not originating from healthcare or epidemiology, can be used for epidemiological study. Such digital epidemiology can include data from internet searching, mobile phone records and retail sales of drugs. Epidemiologists employ a range of study designs from the observational to experimental and generally categorized as descriptive (involving

3434-525: Is now being applied to syndemics. For example, modelling to quantify the syndemic effects of malaria and HIV in sub-Saharan Africa based on research in Kisumu, Kenya researchers found that 5% of HIV infections (or 8,500 cases of HIV since 1980) in Kisumu are the result of the higher HIV infectiousness of malaria-infected HIV patients. Additionally, their model attributed 10% of adult malaria episodes (or almost one million excess malaria infections since 1980) to

3535-408: Is possible if medical treatment or medical research creates conditions that increase the likelihood that two or more diseases come together in a population. For example, if gene splicing unites two pathogenic agents and the resulting novel organism infects a population. One study suggests the possibility of iatriogenic syndemics. During a randomized, double-blind clinical trial testing the efficacy of

3636-404: Is reduced by  1 ⁄ 2 . Although epidemiology is sometimes viewed as a collection of statistical tools used to elucidate the associations of exposures to health outcomes, a deeper understanding of this science is that of discovering causal relationships. " Correlation does not imply causation " is a common theme for much of the epidemiological literature. For epidemiologists, the key

3737-453: Is the fact that air-borne pollens have been found to attach themselves to diesel particles from truck or other vehicular exhaust floating in the air, resulting in heightened rates of asthma in areas where busy roads bisect densely populated areas, most notably in poorer inner-city areas. For every elevation of 10 μg/m3 in particulate matter concentration in the air a six percent increase in cardiopulmonary deaths occurs according to research by

3838-521: Is typically determined using DNA from peripheral blood leukocytes. Since the 2000s, genome-wide association studies (GWAS) have been commonly performed to identify genetic risk factors for many diseases and health conditions. While most molecular epidemiology studies are still using conventional disease diagnosis and classification systems, it is increasingly recognized that disease progression represents inherently heterogeneous processes differing from person to person. Conceptually, each individual has

3939-439: Is used to describe the intersection of Host , Agent , and Environment in analyzing an outbreak. Case-series may refer to the qualitative study of the experience of a single patient, or small group of patients with a similar diagnosis, or to a statistical factor with the potential to produce illness with periods when they are unexposed. The former type of study is purely descriptive and cannot be used to make inferences about

4040-704: The Sioux were dependent as a food source were gone. At the same time, after the U.S. military's defeat at the Battle of the Little Bighorn in 1876, there was a concerted effort to beat the Sioux into total submission. Thus, in 1872, Secretary of the Interior Columbus Delano stated: "as they become convinced that they can no longer rely upon the supply of game for their support, they will return to

4141-520: The nosological issues of boundaries and overlap of diagnoses, while syndemic research focuses on communities experiencing co-occurring epidemics that additively increase negative health consequences." It is possible for two afflictions to be comorbid, but not syndemic i.e., the disorders are not epidemic in the studied population, or their co-occurrence does not cause an interaction that then contributes to worsened health. Two or more diseases can be comorbid without interactions, or interaction occurs but it

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4242-476: The " one cause – one effect " understanding is a simplistic mis-belief. Most outcomes, whether disease or death, are caused by a chain or web consisting of many component causes. Causes can be distinguished as necessary, sufficient or probabilistic conditions. If a necessary condition can be identified and controlled (e.g., antibodies to a disease agent, energy in an injury), the harmful outcome can be avoided (Robertson, 2015). One tool regularly used to conceptualize

4343-459: The "who, what, where and when of health-related state occurrence". However, analytical observations deal more with the 'how' of a health-related event. Experimental epidemiology contains three case types: randomized controlled trials (often used for a new medicine or drug testing), field trials (conducted on those at a high risk of contracting a disease), and community trials (research on social originating diseases). The term 'epidemiologic triad'

4444-436: The 1957 pandemic is estimated to have been around two million globally, with approximately 70,000 deaths in the United States. A little over a decade later, the comparatively mild Hong Kong influenza pandemic erupted due to the spread of a virus strain (H3N2) that genetically was related to the more deadly form seen in 1957. The pandemic was responsible for about one million deaths around the world, almost 34,000 of which were in

4545-515: The 2000s. However, the use of molecular pathology in epidemiology posed unique challenges, including lack of research guidelines and standardized statistical methodologies, and paucity of interdisciplinary experts and training programs. Furthermore, the concept of disease heterogeneity appears to conflict with the long-standing premise in epidemiology that individuals with the same disease name have similar etiologies and disease processes. To resolve these issues and advance population health science in

4646-504: The 2010s. By 2012, it was recognized that many pathogens' evolution is rapid enough to be highly relevant to epidemiology, and that therefore much could be gained from an interdisciplinary approach to infectious disease integrating epidemiology and molecular evolution to "inform control strategies, or even patient treatment." Modern epidemiological studies can use advanced statistics and machine learning to create predictive models as well as to define treatment effects. There

4747-561: The AIDS epidemic that unfolded in tandem with substance use amidst structural violence in urban America throughout the 1990s and early 2000s. Singer demonstrated how it was impossible to think about one condition without contextualizing the broader social, structural, and health contexts in which people lived. Discussion of ethnographic methods were detailed in Emily Mendenhall's books Syndemic Suffering and Rethinking Diabetes and

4848-655: The American Cancer Society. Exhaust from the burning of diesel fuel is a complex mixture of vapors, gases, and fine particles, including over 40 known pollutants like nitrogen oxide and known or suspected carcinogenic substances such as benzene, arsenic, and formaldehyde. Exposure to diesel exhaust irritates the eyes, nose, throat and lungs, causing coughs, headaches, light-headedness and nausea, while causing people with allergies to be more susceptible allergy triggers like dust or pollen. Many particles in disease fuel are so tiny they are able to penetrate deep into

4949-574: The Native Americans had not encountered before and had not built-up immunity to. An example of a syndemic from the 19th century can be found on the reservations on which Native Americans were confined with the closing of the U.S. frontier. It is estimated that in 1860 there were well over 10 million bison living on the American Plains . By the early 1880s, the last of the great herds of bison upon which Plains Indian peoples like

5050-560: The OR, a RR greater than 1 shows association, where the conclusion can be read "those with the exposure were more likely to develop the disease." Prospective studies have many benefits over case control studies. The RR is a more powerful effect measure than the OR, as the OR is just an estimation of the RR, since true incidence cannot be calculated in a case control study where subjects are selected based on disease status. Temporality can be established in

5151-467: The Sioux confronted infectious disease from contact with whites. knowledge about the epidemiology of the Sioux from this period is limited, James Mooney , an anthropologist and representative of the Bureau of Indian Affairs sent to investigate a possible Sioux rebellion, described the health situation on the reservation in 1896: "In 1888 their cattle had been diminished by disease. In 1889, their crops were

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5252-489: The U.S. population according to the U.S. CDC. Asthma among children has been increasing at an even faster pace than among adults, with the percentage of children with asthma going up from 3.6 percent in 1980 to 9 percent in 2005. Among ethnic minority populations, like Puerto Ricans the rate of asthma is 125 percent higher than non-Hispanic white people and 80 percent higher than non-Hispanic black people. The asthma prevalence among American Indians, Alaska Natives and black people

5353-476: The United States. In both of these pandemics, death may not have been due only to the primary viral infection, but also to secondary bacterial infections among influenza patients; in short, they were caused by a viral/bacterial syndemic (but see Chatterjee 2007). The worst of the 20th-century influenza pandemics was the 1918 pandemic , where between 20 and 40 percent of the world's population became ill and between 40 and 100 million people died. More people died of

5454-465: The WHO's 14 epidemiological sub-regions around the world with findings on a range of health intervention costs and effects. First, there is a need for studies that examine the processes by which syndemics emerge, the specific sets of health and social conditions that foster multiple epidemics in a population and how syndemics function to produce specific kinds of health outcomes in populations. Second, there

5555-484: The appearance of the first symptom. It was not uncommon for people who appeared to be quite healthy in the morning to have died by sunset. Among those who survived the first several days, however, many died of secondary bacterial pneumonia. It has been argued that countless numbers of those who expired quickly from the disease were co-infected with tuberculosis, which would explain the notable plummet in TB cases after 1918. As

5656-407: The assessment of data covering time, place, and person), analytic (aiming to further examine known associations or hypothesized relationships), and experimental (a term often equated with clinical or community trials of treatments and other interventions). In observational studies, nature is allowed to "take its course", as epidemiologists observe from the sidelines. Conversely, in experimental studies,

5757-552: The big water [to Europe in 1886], because the Wasichus [whites] did not give us all the food they promised in the Black Hills treaty... But it was worse when I came back [1889]. My people looked pitiful... We could not eat lies and there was nothing we could do." Under extremely stressful conditions, with inadequate diets, and as victims of overt racism on the part of the registration agents appointed to oversee Indian reserves,

5858-414: The case control study. However, the point estimate generated is the relative risk (RR), which is the probability of disease for a person in the exposed group, P e  =  A  / ( A  +  B ) over the probability of disease for a person in the unexposed group, P u  =  C  / ( C  +  D ), i.e. RR  =  P e  /  P u . As with

5959-429: The causation of the disease. Case-control studies are usually faster and more cost-effective than cohort studies but are sensitive to bias (such as recall bias and selection bias ). The main challenge is to identify the appropriate control group; the distribution of exposure among the control group should be representative of the distribution in the population that gave rise to the cases. This can be achieved by drawing

6060-427: The cause-and-effect hypothesis and none can be required sine qua non ." Epidemiological studies can only go to prove that an agent could have caused, but not that it did cause, an effect in any particular case: Epidemiology is concerned with the incidence of disease in populations and does not address the question of the cause of an individual's disease. This question, sometimes referred to as specific causation,

6161-445: The data and draw appropriate conclusions, social sciences to better understand proximate and distal causes, and engineering for exposure assessment . Epidemiology , literally meaning "the study of what is upon the people", is derived from Greek epi  'upon, among' demos  'people, district' and logos  'study, word, discourse', suggesting that it applies only to human populations. However,

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6262-497: The disease to the cases in the series. A prospective study would involve following the case series over time to evaluate the disease's natural history. The latter type, more formally described as self-controlled case-series studies, divide individual patient follow-up time into exposed and unexposed periods and use fixed-effects Poisson regression processes to compare the incidence rate of a given outcome between exposed and unexposed periods. This technique has been extensively used in

6363-494: The effects of social conditions on health. The concept was translated from anthropology to a larger audience in 2017, with the publication of a Series on Syndemics in The Lancet , led by Emily Mendenhall. The syndemic approach departs from the biomedical approach to diseases to diagnostically isolate, study, and treat diseases as distinct entities separate from other diseases and independent of social contexts. A syndemic

6464-612: The epidemiologist is the one in control of all of the factors entering a certain case study. Epidemiological studies are aimed, where possible, at revealing unbiased relationships between exposures such as alcohol or smoking, biological agents , stress , or chemicals to mortality or morbidity . The identification of causal relationships between these exposures and outcomes is an important aspect of epidemiology. Modern epidemiologists use informatics and infodemiology as tools. Observational studies have two components, descriptive and analytical. Descriptive observations pertain to

6565-771: The era of molecular precision medicine , "molecular pathology" and "epidemiology" was integrated to create a new interdisciplinary field of " molecular pathological epidemiology " (MPE), defined as "epidemiology of molecular pathology and heterogeneity of disease". In MPE, investigators analyze the relationships between (A) environmental, dietary, lifestyle and genetic factors; (B) alterations in cellular or extracellular molecules; and (C) evolution and progression of disease. A better understanding of heterogeneity of disease pathogenesis will further contribute to elucidate etiologies of disease. The MPE approach can be applied to not only neoplastic diseases but also non-neoplastic diseases. The concept and paradigm of MPE have become widespread in

6666-442: The expectation among federal representatives that the Sioux would become farmers on individually held plots of land. The Sioux found themselves confined on a series of small reservations where they were treated as a conquered people. Moreover, the government reneged on its promises, food was insufficient and of low quality. Black Elk , a noted Sioux folk healer, told his biographer: "There was hunger among my people before I went across

6767-571: The field and advanced methods to study cancer, a disease with patterns and mode of occurrences that could not be suitably studied with the methods developed for epidemics of infectious diseases. Geography pathology eventually combined with infectious disease epidemiology to make the field that is epidemiology today. Another breakthrough was the 1954 publication of the results of a British Doctors Study , led by Richard Doll and Austin Bradford Hill , which lent very strong statistical support to

6868-405: The four humors (black bile, yellow bile, blood, and phlegm). The cure to the sickness was to remove or add the humor in question to balance the body. This belief led to the application of bloodletting and dieting in medicine. He coined the terms endemic (for diseases usually found in some places but not in others) and epidemic (for diseases that are seen at some times but not others). In

6969-458: The general population of patients with that disease. These types of studies, in which an astute clinician identifies an unusual feature of a disease or a patient's history, may lead to a formulation of a new hypothesis. Using the data from the series, analytic studies could be done to investigate possible causal factors. These can include case-control studies or prospective studies. A case-control study would involve matching comparable controls without

7070-473: The greater susceptibility of HIV infected individuals to malaria. Their model also suggests that HIV has contributed to the wider geographic spread of malaria in Africa, a process previously thought to be the consequence primarily of global warming. Modelling offers an enormously useful tool for anticipating future syndemics, including eco-syndemic, based on information about the spread of various diseases across

7171-889: The health and well-being of populations residing in a specific nation, region, city, or town. A particularly useful model based on the Soweto Syndemics study was published in Nature Human Behavior. In particular, spatial models for thinking through syndemic clusters, such as using GIS, are an emerging area of interest in syndemics research. Diseases regularly interact and this interaction influences disease course, expression, severity, transmission, and diffusion. Interaction among diseases may be both indirect (changes caused by one disease that facilitate another through an intermediary) and direct (diseases act in direct tandem). The term iatrogenesis refers to adverse effects on health caused by medical treatment. This

7272-536: The higher rate of HIV infection among individuals in the vaccinated was because the vaccine lowered defenses against HIV. Various syndemics though not always labeled as such have been described in the literature, including: Contact between Native Americans and Europeans during the Columbian Exchange led to lethal syndemics within the Native American population due to diseases introduced which

7373-575: The link between tobacco smoking and lung cancer . In the late 20th century, with the advancement of biomedical sciences, a number of molecular markers in blood, other biospecimens and environment were identified as predictors of development or risk of a certain disease. Epidemiology research to examine the relationship between these biomarkers analyzed at the molecular level and disease was broadly named " molecular epidemiology ". Specifically, " genetic epidemiology " has been used for epidemiology of germline genetic variation and disease. Genetic variation

7474-522: The lungs when inhaled. Importantly, diesel fuel particles appear to have even greater immunologic effects in the presence of environmental allergens than they do alone. "This immunologic evidence may help explain the epidemiologic studies indicating that children living along major trucking thoroughfares are at increased risk for asthmatic and allergic symptoms and are more likely to have respiratory dysfunction." according to Robert Pandya and co-workers. The damaging effects of diesel fuel pollution go beyond

7575-403: The main etiological work that brought forward the concept. His concepts were still being considered in analysing SARS outbreak by WHO in 2004 in the context of traditional Chinese medicine. Another pioneer, Thomas Sydenham (1624–1689), was the first to distinguish the fevers of Londoners in the later 1600s. His theories on cures of fevers met with much resistance from traditional physicians at

7676-496: The massacre at Wounded Knee in 1890 and the murder of their leader Sitting Bull . While the official mortality rate on the reservation was between one and two percent, the death rate was probably closer to 10 percent. There were three influenza pandemics during the 20th century that caused widespread illness, mortality, social disruption, and significant economic losses. These occurred in 1918, 1957, and 1968. In each case, mortality rates were determined primarily by five factors:

7777-448: The middle of the 16th century, a doctor from Verona named Girolamo Fracastoro was the first to propose a theory that the very small, unseeable, particles that cause disease were alive. They were considered to be able to spread by air, multiply by themselves and to be destroyable by fire. In this way he refuted Galen 's miasma theory (poison gas in sick people). In 1543 he wrote a book De contagione et contagiosis morbis , in which he

7878-414: The more reliable source of subsistence [i.e., farming]." As a result, they were forced to give up their struggle for an independent existence on their own lands and take up reservation life at the mercy of government authority. Treaties that were signed with the Sioux in 1868 and 1876 stipulated that they would be provided with government annuities and provisions in payment for sections of their land and with

7979-506: The multicausality associated with disease is the causal pie model . In 1965, Austin Bradford Hill proposed a series of considerations to help assess evidence of causation, which have come to be commonly known as the " Bradford Hill criteria ". In contrast to the explicit intentions of their author, Hill's considerations are now sometimes taught as a checklist to be implemented for assessing causality. Hill himself said "None of my nine viewpoints can bring indisputable evidence for or against

8080-585: The number of people who became infected, the virulence of the virus causing the pandemic, the speed of global spread, the underlying features and vulnerabilities of the most affected populations, and the effectiveness and timeliness of the prevention and treatment measures that were implemented. The 1957 pandemic was caused by the Asian influenza virus (known as the H2N2 strain), a novel influenza variety to which humans had not yet developed immunities. The death toll of

8181-417: The odds of exposure in the cases (A/C) to the odds of exposure in the controls (B/D), i.e. OR = (AD/BC). If the OR is significantly greater than 1, then the conclusion is "those with the disease are more likely to have been exposed", whereas if it is close to 1 then the exposure and disease are not likely associated. If the OR is far less than one, then this suggests that the exposure is a protective factor in

8282-498: The odds ratio by the equation: where N is the ratio of cases to controls. As the odds ratio approaches 1, the number of cases required for statistical significance grows towards infinity; rendering case-control studies all but useless for low odds ratios. For instance, for an odds ratio of 1.5 and cases = controls, the table shown above would look like this: For an odds ratio of 1.1: Cohort studies select subjects based on their exposure status. The study subjects should be at risk of

8383-414: The outcome under investigation at the beginning of the cohort study; this usually means that they should be disease free when the cohort study starts. The cohort is followed through time to assess their later outcome status. An example of a cohort study would be the investigation of a cohort of smokers and non-smokers over time to estimate the incidence of lung cancer. The same 2×2 table is constructed as with

8484-419: The pandemic impacted mobilized national armies. Half of U.S. soldiers who died in the "Great War," for example, were victims of influenza. It is estimated that almost 3 ⁄ 4 of a million Americans died during the pandemic. In part, the death toll during the pandemic was caused by viral pneumonia characterized by extensive bleeding in the lungs resulting in suffocation. Many victims died within 48 hours of

8585-402: The planet and the consequent co-infections and disease interactions that will result. PopMod is a longitudinal population tool developed in 2003 that models distinct and possibly interacting diseases. Unlike other life-table population models, PopMod is designed to not assume the statistical independence of the diseases of interest. The PopMod has several intended purposes, including describing

8686-400: The prevailing Miasma Theory of the time, a model of disease in which poor air quality was blamed for illness. This was used to rationalize high rates of infection in impoverished areas instead of addressing the underlying issues of poor nutrition and sanitation, and was proven false by his work. Other pioneers include Danish physician Peter Anton Schleisner , who in 1849 related his work on

8787-640: The prevention of the epidemic of neonatal tetanus on the Vestmanna Islands in Iceland . Another important pioneer was Hungarian physician Ignaz Semmelweis , who in 1847 brought down infant mortality at a Vienna hospital by instituting a disinfection procedure. His findings were published in 1850, but his work was ill-received by his colleagues, who discontinued the procedure. Disinfection did not become widely practiced until British surgeon Joseph Lister 'discovered' antiseptics in 1865 in light of

8888-401: The program no later than the beginning of February. Of all submissions: At the regional finals level, the 60 finalists were judged by a presentation to a group of judges, as well as a question and answer session. Of all the regional finalists, The National Finalists then presented again to a national panel in the same format as before. Awards for the national finalists were as follows. For

8989-475: The prototype HIV vaccine called V520 there appeared to be an increased risk for HIV infection among the vaccinated participants. Notably, participants immune to the common cold virus adenovirus type 5 had a higher risk of HIV infection. The vaccine was created using a replication-defective version of Ad5 as a carrier, or delivery vector, for three synthetically produced HIV genes. On November 6, 2007, Merck & Co. announced that research had been stopped suspecting

9090-469: The purpose of communicating the results to those who can implement appropriate policies or disease control measures. Syndemic Syndemics is the evaluation of how social and health conditions arise, in what ways they interact, and what upstream drivers may produce their interactions. The word is a blend of "synergy" and "epidemics". The idea of syndemics is that no disease exists in isolation and that often population health can be understood through

9191-402: The same population that gave rise to the cases. The case-control study looks back through time at potential exposures that both groups (cases and controls) may have encountered. A 2×2 table is constructed, displaying exposed cases (A), exposed controls (B), unexposed cases (C) and unexposed controls (D). The statistic generated to measure association is the odds ratio (OR), which is the ratio of

9292-526: The so-called Spanish flu (caused by the H1N1 viral strain) pandemic in the single year of 1918 than during all four-years of the Black Death . The pandemic had devastating effects as disease spread along trade and shipping routes and other corridors of human movement until it had circled the globe. In India, the mortality rate reached 50 per 1,000 population. Arriving during the closing phase of World War I,

9393-456: The study of adverse reactions to vaccination and has been shown in some circumstances to provide statistical power comparable to that available in cohort studies. Case-control studies select subjects based on their disease status. It is a retrospective study. A group of individuals that are disease positive (the "case" group) is compared with a group of disease negative individuals (the "control" group). The control group should ideally come from

9494-439: The term is widely used in studies of zoological populations (veterinary epidemiology), although the term " epizoology " is available, and it has also been applied to studies of plant populations (botanical or plant disease epidemiology ). The distinction between "epidemic" and "endemic" was first drawn by Hippocrates , to distinguish between diseases that are "visited upon" a population (epidemic) from those that "reside within"

9595-541: The time evolution of population health for standard demographic purposes (such as estimating healthy life expectancy in a population), and providing a standard measure of effectiveness for health interventions and cost-effectiveness analysis. PopMod is used as one of the standard tools of the World Health Organization's ( WHO ) CHOICE (Choosing Interventions that are Cost-Effective) program, an initiative designed to provide national health policymakers in

9696-716: The time. He was not able to find the initial cause of the smallpox fever he researched and treated. John Graunt , a haberdasher and amateur statistician, published Natural and Political Observations ... upon the Bills of Mortality in 1662. In it, he analysed the mortality rolls in London before the Great Plague , presented one of the first life tables , and reported time trends for many diseases, new and old. He provided statistical evidence for many theories on disease, and also refuted some widespread ideas on them. John Snow

9797-413: The water and removed the handle; this ended the outbreak. This has been perceived as a major event in the history of public health and regarded as the founding event of the science of epidemiology, having helped shape public health policies around the world. However, Snow's research and preventive measures to avoid further outbreaks were not fully accepted or put into practice until after his death due to

9898-419: The ways in which social and health conditions co-occurred. Tsai argued that instead, there is a deeper need to interrogate how conditions syngistically interact to cause more adverse health conditions that the conditions would produce on their own. This has led to a slough of emergent research interrogating mathematical models that can take seriously how health conditions may cluster together and interact to affect

9999-637: The work of Louis Pasteur . In the early 20th century, mathematical methods were introduced into epidemiology by Ronald Ross , Janet Lane-Claypon , Anderson Gray McKendrick , and others. In a parallel development during the 1920s, German-Swiss pathologist Max Askanazy and others founded the International Society for Geographical Pathology to systematically investigate the geographical pathology of cancer and other non-infectious diseases across populations in different regions. After World War II, Richard Doll and other non-pathologists joined

10100-481: The young. Whooping cough is also met with." Indian children were removed to white boarding schools and diagnosed with a wide range of diseases, including tuberculosis, trachoma, measles, smallpox, whooping cough, influenza, and pneumonia. The Sioux were victims of a syndemic of interacting infectious diseases including the 1889–1890 flu pandemic , inadequate diet, and stressful and extremely disheartening life conditions, including outright brutalization with events like

10201-668: Was the first to promote personal and environmental hygiene to prevent disease. The development of a sufficiently powerful microscope by Antonie van Leeuwenhoek in 1675 provided visual evidence of living particles consistent with a germ theory of disease . During the Ming dynasty , Wu Youke (1582–1652) developed the idea that some diseases were caused by transmissible agents, which he called Li Qi (戾气 or pestilential factors) when he observed various epidemics rage around him between 1641 and 1644. His book Wen Yi Lun (瘟疫论, Treatise on Pestilence/Treatise of Epidemic Diseases) can be regarded as

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