Epidemiology: Field of medicine concerned with the determination of causes, incidence, and characteristic behavior of disease outbreaks affecting human populations. It includes the interrelationships of host, agent, and environment as related to the distribution and control of disease.Bias (Epidemiology): Any deviation of results or inferences from the truth, or processes leading to such deviation. Bias can result from several sources: one-sided or systematic variations in measurement from the true value (systematic error); flaws in study design; deviation of inferences, interpretations, or analyses based on flawed data or data collection; etc. There is no sense of prejudice or subjectivity implied in the assessment of bias under these conditions.Molecular Epidemiology: The application of molecular biology to the answering of epidemiological questions. The examination of patterns of changes in DNA to implicate particular carcinogens and the use of molecular markers to predict which individuals are at highest risk for a disease are common examples.Selection Bias: The introduction of error due to systematic differences in the characteristics between those selected and those not selected for a given study. In sampling bias, error is the result of failure to ensure that all members of the reference population have a known chance of selection in the sample.Incidence: The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.Publication Bias: The influence of study results on the chances of publication and the tendency of investigators, reviewers, and editors to submit or accept manuscripts for publication based on the direction or strength of the study findings. Publication bias has an impact on the interpretation of clinical trials and meta-analyses. Bias can be minimized by insistence by editors on high-quality research, thorough literature reviews, acknowledgement of conflicts of interest, modification of peer review practices, etc.SEER Program: A cancer registry mandated under the National Cancer Act of 1971 to operate and maintain a population-based cancer reporting system, reporting periodically estimates of cancer incidence and mortality in the United States. The Surveillance, Epidemiology, and End Results (SEER) Program is a continuing project of the National Cancer Institute of the National Institutes of Health. Among its goals, in addition to assembling and reporting cancer statistics, are the monitoring of annual cancer incident trends and the promoting of studies designed to identify factors amenable to cancer control interventions. (From National Cancer Institute, NIH Publication No. 91-3074, October 1990)Prevalence: The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.United StatesDisease Outbreaks: Sudden increase in the incidence of a disease. The concept includes EPIDEMICS and PANDEMICS.Epidemiologic Methods: Research techniques that focus on study designs and data gathering methods in human and animal populations.Confounding Factors (Epidemiology): Factors that can cause or prevent the outcome of interest, are not intermediate variables, and are not associated with the factor(s) under investigation. They give rise to situations in which the effects of two processes are not separated, or the contribution of causal factors cannot be separated, or the measure of the effect of exposure or risk is distorted because of its association with other factors influencing the outcome of the study.Population Surveillance: Ongoing scrutiny of a population (general population, study population, target population, etc.), generally using methods distinguished by their practicability, uniformity, and frequently their rapidity, rather than by complete accuracy.Epidemiologic Research Design: The form and structure of analytic studies in epidemiologic and clinical research.Age Distribution: The frequency of different ages or age groups in a given population. The distribution may refer to either how many or what proportion of the group. The population is usually patients with a specific disease but the concept is not restricted to humans and is not restricted to medicine.Infant, Newborn: An infant during the first month after birth.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Age Factors: Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.Seasons: Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Cluster Analysis: A set of statistical methods used to group variables or observations into strongly inter-related subgroups. In epidemiology, it may be used to analyze a closely grouped series of events or cases of disease or other health-related phenomenon with well-defined distribution patterns in relation to time or place or both.Bacterial Typing Techniques: Procedures for identifying types and strains of bacteria. The most frequently employed typing systems are BACTERIOPHAGE TYPING and SEROTYPING as well as bacteriocin typing and biotyping.Cross Infection: Any infection which a patient contracts in a health-care institution.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Reproducibility of Results: The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Public Health: Branch of medicine concerned with the prevention and control of disease and disability, and the promotion of physical and mental health of the population on the international, national, state, or municipal level.Electrophoresis, Gel, Pulsed-Field: Gel electrophoresis in which the direction of the electric field is changed periodically. This technique is similar to other electrophoretic methods normally used to separate double-stranded DNA molecules ranging in size up to tens of thousands of base-pairs. However, by alternating the electric field direction one is able to separate DNA molecules up to several million base-pairs in length.DNA Fingerprinting: A technique for identifying individuals of a species that is based on the uniqueness of their DNA sequence. Uniqueness is determined by identifying which combination of allelic variations occur in the individual at a statistically relevant number of different loci. In forensic studies, RESTRICTION FRAGMENT LENGTH POLYMORPHISM of multiple, highly polymorphic VNTR LOCI or MICROSATELLITE REPEAT loci are analyzed. The number of loci used for the profile depends on the ALLELE FREQUENCY in the population.Sex Factors: Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.Cohort Studies: Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.Laboratory Personnel: Professionals, technicians, and assistants staffing LABORATORIES.Sex Distribution: The number of males and females in a given population. The distribution may refer to how many men or women or what proportion of either in the group. The population is usually patients with a specific disease but the concept is not restricted to humans and is not restricted to medicine.Serotyping: Process of determining and distinguishing species of bacteria or viruses based on antigens they share.Genetic Variation: Genotypic differences observed among individuals in a population.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Bartonella: A genus of gram-negative bacteria characteristically appearing in chains of several segmenting organisms. It occurs in man and arthropod vectors and is found only in the Andes region of South America. This genus is the etiologic agent of human bartonellosis. The genus Rochalimaea, once considered a separate genus, has recently been combined with the genus Bartonella as a result of high levels of relatedness in 16S rRNA sequence data and DNA hybridization data.Research Design: A plan for collecting and utilizing data so that desired information can be obtained with sufficient precision or so that an hypothesis can be tested properly.EuropeDNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.3-Iodobenzylguanidine: A guanidine analog with specific affinity for tissues of the sympathetic nervous system and related tumors. The radiolabeled forms are used as antineoplastic agents and radioactive imaging agents. (Merck Index, 12th ed) MIBG serves as a neuron-blocking agent which has a strong affinity for, and retention in, the adrenal medulla and also inhibits ADP-ribosyltransferase.History, 20th Century: Time period from 1901 through 2000 of the common era.Data Interpretation, Statistical: Application of statistical procedures to analyze specific observed or assumed facts from a particular study.Allethrin: Synthetic analogs of the naturally occurring insecticides cinerin, jasmolin, and pyrethrin. (From Merck Index, 11th ed)Molecular Typing: Using MOLECULAR BIOLOGY techniques, such as DNA SEQUENCE ANALYSIS; PULSED-FIELD GEL ELECTROPHORESIS; and DNA FINGERPRINTING, to identify, classify, and compare organisms and their subtypes.Anti-Bacterial Agents: Substances that reduce the growth or reproduction of BACTERIA.Polymorphism, Restriction Fragment Length: Variation occurring within a species in the presence or length of DNA fragment generated by a specific endonuclease at a specific site in the genome. Such variations are generated by mutations that create or abolish recognition sites for these enzymes or change the length of the fragment.Disease Reservoirs: Animate or inanimate sources which normally harbor disease-causing organisms and thus serve as potential sources of disease outbreaks. Reservoirs are distinguished from vectors (DISEASE VECTORS) and carriers, which are agents of disease transmission rather than continuing sources of potential disease outbreaks.Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Environmental Exposure: The exposure to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals.Causality: The relating of causes to the effects they produce. Causes are termed necessary when they must always precede an effect and sufficient when they initiate or produce an effect. Any of several factors may be associated with the potential disease causation or outcome, including predisposing factors, enabling factors, precipitating factors, reinforcing factors, and risk factors.Disease Transmission, Infectious: The transmission of infectious disease or pathogens. When transmission is within the same species, the mode can be horizontal or vertical (INFECTIOUS DISEASE TRANSMISSION, VERTICAL).Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.China: A country spanning from central Asia to the Pacific Ocean.Neoplasms: New abnormal growth of tissue. Malignant neoplasms show a greater degree of anaplasia and have the properties of invasion and metastasis, compared to benign neoplasms.BrazilFeces: Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.ItalyMolecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.IndiaMultilocus Sequence Typing: Direct nucleotide sequencing of gene fragments from multiple housekeeping genes for the purpose of phylogenetic analysis, organism identification, and typing of species, strain, serovar, or other distinguishable phylogenetic level.MinnesotaAsia: The largest of the continents. It was known to the Romans more specifically as what we know today as Asia Minor. The name comes from at least two possible sources: from the Assyrian asu (to rise) or from the Sanskrit usa (dawn), both with reference to its being the land of the rising sun, i.e., eastern as opposed to Europe, to the west. (From Webster's New Geographical Dictionary, 1988, p82 & Room, Brewer's Dictionary of Names, 1992, p34)Communicable Diseases, Emerging: Infectious diseases that are novel in their outbreak ranges (geographic and host) or transmission mode.Odds Ratio: The ratio of two odds. The exposure-odds ratio for case control data is the ratio of the odds in favor of exposure among cases to the odds in favor of exposure among noncases. The disease-odds ratio for a cohort or cross section is the ratio of the odds in favor of disease among the exposed to the odds in favor of disease among the unexposed. The prevalence-odds ratio refers to an odds ratio derived cross-sectionally from studies of prevalent cases.Cross-Sectional Studies: Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with LONGITUDINAL STUDIES which are followed over a period of time.Zoonoses: Diseases of non-human animals that may be transmitted to HUMANS or may be transmitted from humans to non-human animals.Great BritainEpidemics: Sudden outbreaks of a disease in a country or region not previously recognized in that area, or a rapid increase in the number of new cases of a previous existing endemic disease. Epidemics can also refer to outbreaks of disease in animal or plant populations.Spain: Parliamentary democracy located between France on the northeast and Portugual on the west and bordered by the Atlantic Ocean and the Mediterranean Sea.History, 21st Century: Time period from 2001 through 2100 of the common era.France: A country in western Europe bordered by the Atlantic Ocean, the English Channel, the Mediterranean Sea, and the countries of Belgium, Germany, Italy, Spain, Switzerland, the principalities of Andorra and Monaco, and by the duchy of Luxembourg. Its capital is Paris.Microbial Sensitivity Tests: Any tests that demonstrate the relative efficacy of different chemotherapeutic agents against specific microorganisms (i.e., bacteria, fungi, viruses).Meta-Analysis as Topic: A quantitative method of combining the results of independent studies (usually drawn from the published literature) and synthesizing summaries and conclusions which may be used to evaluate therapeutic effectiveness, plan new studies, etc., with application chiefly in the areas of research and medicine.Duodenal Ulcer: A PEPTIC ULCER located in the DUODENUM.Public Health Practice: The activities and endeavors of the public health services in a community on any level.Epidemiological Monitoring: Collection, analysis, and interpretation of data about the frequency, distribution, and consequences of disease or health conditions, for use in the planning, implementing, and evaluating public health programs.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Geography: The science dealing with the earth and its life, especially the description of land, sea, and air and the distribution of plant and animal life, including humanity and human industries with reference to the mutual relations of these elements. (From Webster, 3d ed)Epidemiologic Factors: Events, characteristics, or other definable entities that have the potential to bring about a change in a health condition or other defined outcome.Disease Vectors: Invertebrates or non-human vertebrates which transmit infective organisms from one host to another.Cameroon: A republic in central Africa lying east of CHAD and the CENTRAL AFRICAN REPUBLIC and west of NIGERIA. The capital is Yaounde.Gastroenteritis: INFLAMMATION of any segment of the GASTROINTESTINAL TRACT from ESOPHAGUS to RECTUM. Causes of gastroenteritis are many including genetic, infection, HYPERSENSITIVITY, drug effects, and CANCER.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.Seroepidemiologic Studies: EPIDEMIOLOGIC STUDIES based on the detection through serological testing of characteristic change in the serum level of specific ANTIBODIES. Latent subclinical infections and carrier states can thus be detected in addition to clinically overt cases.Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.Codon: A set of three nucleotides in a protein coding sequence that specifies individual amino acids or a termination signal (CODON, TERMINATOR). Most codons are universal, but some organisms do not produce the transfer RNAs (RNA, TRANSFER) complementary to all codons. These codons are referred to as unassigned codons (CODONS, NONSENSE).Models, Genetic: Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Risk: The probability that an event will occur. It encompasses a variety of measures of the probability of a generally unfavorable outcome.Hospitals: Institutions with an organized medical staff which provide medical care to patients.Questionnaires: Predetermined sets of questions used to collect data - clinical data, social status, occupational group, etc. The term is often applied to a self-completed survey instrument.European Continental Ancestry Group: Individuals whose ancestral origins are in the continent of Europe.Hospitalization: The confinement of a patient in a hospital.Logistic Models: Statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable. A common application is in epidemiology for estimating an individual's risk (probability of a disease) as a function of a given risk factor.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.EnglandDrug Resistance, Bacterial: The ability of bacteria to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).Ethnic Groups: A group of people with a common cultural heritage that sets them apart from others in a variety of social relationships.Staphylococcal Infections: Infections with bacteria of the genus STAPHYLOCOCCUS.Models, Theoretical: Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Communicable DiseasesGenetic Predisposition to Disease: A latent susceptibility to disease at the genetic level, which may be activated under certain conditions.Carrier State: The condition of harboring an infective organism without manifesting symptoms of infection. The organism must be readily transmissible to another susceptible host.Data Collection: Systematic gathering of data for a particular purpose from various sources, including questionnaires, interviews, observation, existing records, and electronic devices. The process is usually preliminary to statistical analysis of the data.Animals, Wild: Animals considered to be wild or feral or not adapted for domestic use. It does not include wild animals in zoos for which ANIMALS, ZOO is available.Databases, Factual: Extensive collections, reputedly complete, of facts and data garnered from material of a specialized subject area and made available for analysis and application. The collection can be automated by various contemporary methods for retrieval. The concept should be differentiated from DATABASES, BIBLIOGRAPHIC which is restricted to collections of bibliographic references.Topography, Medical: The systematic surveying, mapping, charting, and description of specific geographical sites, with reference to the physical features that were presumed to influence health and disease. Medical topography should be differentiated from EPIDEMIOLOGY in that the former emphasizes geography whereas the latter emphasizes disease outbreaks.Communicable Disease Control: Programs of surveillance designed to prevent the transmission of disease by any means from person to person or from animal to man.Bacteremia: The presence of viable bacteria circulating in the blood. Fever, chills, tachycardia, and tachypnea are common acute manifestations of bacteremia. The majority of cases are seen in already hospitalized patients, most of whom have underlying diseases or procedures which render their bloodstreams susceptible to invasion.Regression Analysis: Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.Continental Population Groups: Groups of individuals whose putative ancestry is from native continental populations based on similarities in physical appearance.Diarrhea: An increased liquidity or decreased consistency of FECES, such as running stool. Fecal consistency is related to the ratio of water-holding capacity of insoluble solids to total water, rather than the amount of water present. Diarrhea is not hyperdefecation or increased fecal weight.Socioeconomic Factors: Social and economic factors that characterize the individual or group within the social structure.Comorbidity: The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival.Travel: Aspects of health and disease related to travel.Australia: The smallest continent and an independent country, comprising six states and two territories. Its capital is Canberra.Urban Population: The inhabitants of a city or town, including metropolitan areas and suburban areas.Randomized Controlled Trials as Topic: Works about clinical trials that involve at least one test treatment and one control treatment, concurrent enrollment and follow-up of the test- and control-treated groups, and in which the treatments to be administered are selected by a random process, such as the use of a random-numbers table.Survival Rate: The proportion of survivors in a group, e.g., of patients, studied and followed over a period, or the proportion of persons in a specified group alive at the beginning of a time interval who survive to the end of the interval. It is often studied using life table methods.Middle East: The region of southwest Asia and northeastern Africa usually considered as extending from Libya on the west to Afghanistan on the east. (From Webster's New Geographical Dictionary, 1988)Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.North AmericaCaliciviridae Infections: Virus diseases caused by CALICIVIRIDAE. They include HEPATITIS E; VESICULAR EXANTHEMA OF SWINE; acute respiratory infections in felines, rabbit hemorrhagic disease, and some cases of gastroenteritis in humans.History, 19th Century: Time period from 1801 through 1900 of the common era.Tuberculosis: Any of the infectious diseases of man and other animals caused by species of MYCOBACTERIUM.Attention: Focusing on certain aspects of current experience to the exclusion of others. It is the act of heeding or taking notice or concentrating.Demography: Statistical interpretation and description of a population with reference to distribution, composition, or structure.HIV Infections: Includes the spectrum of human immunodeficiency virus infections that range from asymptomatic seropositivity, thru AIDS-related complex (ARC), to acquired immunodeficiency syndrome (AIDS).Chymases: A family of neutral serine proteases with CHYMOTRYPSIN-like activity. Chymases are primarily found in the SECRETORY GRANULES of MAST CELLS and are released during mast cell degranulation.Athletic Injuries: Injuries incurred during participation in competitive or non-competitive sports.Geographic Information Systems: Computer systems capable of assembling, storing, manipulating, and displaying geographically referenced information, i.e. data identified according to their locations.Canada: The largest country in North America, comprising 10 provinces and three territories. Its capital is Ottawa.Sentinel Surveillance: Monitoring of rate of occurrence of specific conditions to assess the stability or change in health levels of a population. It is also the study of disease rates in a specific cohort such as in a geographic area or population subgroup to estimate trends in a larger population. (From Last, Dictionary of Epidemiology, 2d ed)Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Confidence Intervals: A range of values for a variable of interest, e.g., a rate, constructed so that this range has a specified probability of including the true value of the variable.WalesModels, Statistical: Statistical formulations or analyses which, when applied to data and found to fit the data, are then used to verify the assumptions and parameters used in the analysis. Examples of statistical models are the linear model, binomial model, polynomial model, two-parameter model, etc.Egypt: A country in northern Africa, bordering the Mediterranean Sea, between Libya and the Gaza Strip, and the Red Sea north of Sudan, and includes the Asian Sinai Peninsula Its capital is Cairo.Insect Vectors: Insects that transmit infective organisms from one host to another or from an inanimate reservoir to an animate host.Multivariate Analysis: A set of techniques used when variation in several variables has to be studied simultaneously. In statistics, multivariate analysis is interpreted as any analytic method that allows simultaneous study of two or more dependent variables.Bayes Theorem: A theorem in probability theory named for Thomas Bayes (1702-1761). In epidemiology, it is used to obtain the probability of disease in a group of people with some characteristic on the basis of the overall rate of that disease and of the likelihood of that characteristic in healthy and diseased individuals. The most familiar application is in clinical decision analysis where it is used for estimating the probability of a particular diagnosis given the appearance of some symptoms or test result.Likelihood Functions: Functions constructed from a statistical model and a set of observed data which give the probability of that data for various values of the unknown model parameters. Those parameter values that maximize the probability are the maximum likelihood estimates of the parameters.JapanHealth Surveys: A systematic collection of factual data pertaining to health and disease in a human population within a given geographic area.Community-Acquired Infections: Any infection acquired in the community, that is, contrasted with those acquired in a health care facility (CROSS INFECTION). An infection would be classified as community-acquired if the patient had not recently been in a health care facility or been in contact with someone who had been recently in a health care facility.Survival Analysis: A class of statistical procedures for estimating the survival function (function of time, starting with a population 100% well at a given time and providing the percentage of the population still well at later times). The survival analysis is then used for making inferences about the effects of treatments, prognostic factors, exposures, and other covariates on the function.Occupational Exposure: The exposure to potentially harmful chemical, physical, or biological agents that occurs as a result of one's occupation.SingaporeMinisatellite Repeats: Tandem arrays of moderately repetitive, short (10-60 bases) DNA sequences which are found dispersed throughout the GENOME, at the ends of chromosomes (TELOMERES), and clustered near telomeres. Their degree of repetition is two to several hundred at each locus. Loci number in the thousands but each locus shows a distinctive repeat unit.Thailand: Formerly known as Siam, this is a Southeast Asian nation at the center of the Indochina peninsula. Bangkok is the capital city.Bites and StingsForecasting: The prediction or projection of the nature of future problems or existing conditions based upon the extrapolation or interpretation of existing scientific data or by the application of scientific methodology.Developing Countries: Countries in the process of change with economic growth, that is, an increase in production, per capita consumption, and income. The process of economic growth involves better utilization of natural and human resources, which results in a change in the social, political, and economic structures.Probability: The study of chance processes or the relative frequency characterizing a chance process.Rotavirus Infections: Infection with any of the rotaviruses. Specific infections include human infantile diarrhea, neonatal calf diarrhea, and epidemic diarrhea of infant mice.IsraelBreast Neoplasms: Tumors or cancer of the human BREAST.Review Literature as Topic: Published materials which provide an examination of recent or current literature. Review articles can cover a wide range of subject matter at various levels of completeness and comprehensiveness based on analyses of literature that may include research findings. The review may reflect the state of the art. It also includes reviews as a literary form.Hong Kong: The former British crown colony located off the southeast coast of China, comprised of Hong Kong Island, Kowloon Peninsula, and New Territories. The three sites were ceded to the British by the Chinese respectively in 1841, 1860, and 1898. Hong Kong reverted to China in July 1997. The name represents the Cantonese pronunciation of the Chinese xianggang, fragrant port, from xiang, perfume and gang, port or harbor, with reference to its currents sweetened by fresh water from a river west of it.Biomedical Research: Research that involves the application of the natural sciences, especially biology and physiology, to medicine.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Prejudice: A preconceived judgment made without factual basis.Cattle Diseases: Diseases of domestic cattle of the genus Bos. It includes diseases of cows, yaks, and zebus.Research: Critical and exhaustive investigation or experimentation, having for its aim the discovery of new facts and their correct interpretation, the revision of accepted conclusions, theories, or laws in the light of newly discovered facts, or the practical application of such new or revised conclusions, theories, or laws. (Webster, 3d ed)Environmental Microbiology: The study of microorganisms living in a variety of environments (air, soil, water, etc.) and their pathogenic relationship to other organisms including man.Longitudinal Studies: Studies in which variables relating to an individual or group of individuals are assessed over a period of time.TaiwanScotlandStatistics as Topic: The science and art of collecting, summarizing, and analyzing data that are subject to random variation. The term is also applied to the data themselves and to the summarization of the data.Drug Resistance, Multiple, Bacterial: The ability of bacteria to resist or to become tolerant to several structurally and functionally distinct drugs simultaneously. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).beta-Lactamases: Enzymes found in many bacteria which catalyze the hydrolysis of the amide bond in the beta-lactam ring. Well known antibiotics destroyed by these enzymes are penicillins and cephalosporins.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Emigration and Immigration: The process of leaving one's country to establish residence in a foreign country.Escherichia coli Infections: Infections with bacteria of the species ESCHERICHIA COLI.GermanyAfrican Continental Ancestry Group: Individuals whose ancestral origins are in the continent of Africa.Influenza, Human: An acute viral infection in humans involving the respiratory tract. It is marked by inflammation of the NASAL MUCOSA; the PHARYNX; and conjunctiva, and by headache and severe, often generalized, myalgia.Morbidity: The proportion of patients with a particular disease during a given year per given unit of population.Smoking: Inhaling and exhaling the smoke of burning TOBACCO.Polymorphism, Single Nucleotide: A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.Medicare: Federal program, created by Public Law 89-97, Title XVIII-Health Insurance for the Aged, a 1965 amendment to the Social Security Act, that provides health insurance benefits to persons over the age of 65 and others eligible for Social Security benefits. It consists of two separate but coordinated programs: hospital insurance (MEDICARE PART A) and supplementary medical insurance (MEDICARE PART B). (Hospital Administration Terminology, AHA, 2d ed and A Discursive Dictionary of Health Care, US House of Representatives, 1976)Environment: The external elements and conditions which surround, influence, and affect the life and development of an organism or population.Base Composition: The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.Age of Onset: The age, developmental stage, or period of life at which a disease or the initial symptoms or manifestations of a disease appear in an individual.Mass Screening: Organized periodic procedures performed on large groups of people for the purpose of detecting disease.Disease Notification: Notification or reporting by a physician or other health care provider of the occurrence of specified contagious diseases such as tuberculosis and HIV infections to designated public health agencies. The United States system of reporting notifiable diseases evolved from the Quarantine Act of 1878, which authorized the US Public Health Service to collect morbidity data on cholera, smallpox, and yellow fever; each state in the US has its own list of notifiable diseases and depends largely on reporting by the individual health care provider. (From Segen, Dictionary of Modern Medicine, 1992)Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Streptococcal Infections: Infections with bacteria of the genus STREPTOCOCCUS.Animals, Domestic: Animals which have become adapted through breeding in captivity to a life intimately associated with humans. They include animals domesticated by humans to live and breed in a tame condition on farms or ranches for economic reasons, including LIVESTOCK (specifically CATTLE; SHEEP; HORSES; etc.), POULTRY; and those raised or kept for pleasure and companionship, e.g., PETS; or specifically DOGS; CATS; etc.Intensive Care Units: Hospital units providing continuous surveillance and care to acutely ill patients.Environmental Monitoring: The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment (soil, air, and water), workplace, or in the bodies of people and animals present in that environment.Chronic Disease: Diseases which have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care. (Dictionary of Health Services Management, 2d ed)PeruAfrica South of the Sahara: All of Africa except Northern Africa (AFRICA, NORTHERN).Linear Models: Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.CaliforniaChickenpox: A highly contagious infectious disease caused by the varicella-zoster virus (HERPESVIRUS 3, HUMAN). It usually affects children, is spread by direct contact or respiratory route via droplet nuclei, and is characterized by the appearance on the skin and mucous membranes of successive crops of typical pruritic vesicular lesions that are easily broken and become scabbed. Chickenpox is relatively benign in children, but may be complicated by pneumonia and encephalitis in adults. (From Dorland, 27th ed)Candidemia: A form of invasive candidiasis where species of CANDIDA are present in the blood.
  • These questions illustrate some statistical problems and some bias encountered during clinical studies, which can lead to erroneous results. (isharonline.org)
  • in addition to the lectures on epidemiology and evidence-based medicien outlined on this page, we will also spend some time learning the R statistical computing program, the material for which can be found here . (columbia.edu)
  • Using ancestry informative markers (AIMs), we aimed to measure the African influences in Spanish populations and to explore whether these might introduce statistical bias in population-based association studies. (plos.org)
  • Recent advances in computing power, coupled with state-of-the-art statistical methods, have greatly increased the ability of analysts to control healthy worker survivor bias. (rti.org)
  • The Norwegian Large Encyclopaedia of Medicine refers to the concept of bias as: "used in statistical and empirical research when results or inferences systematically deviate from the true values. (etikkom.no)
  • We propose the use of administrative record-linkage and novel methodology to overcome non-response bias, and illustrate this using the 2003 Scottish Health Survey measures of alcohol consumption. (bmj.com)
  • This methodology offers a promising route for advancing efforts to resolve non-response bias. (bmj.com)
  • The disadvantage of the PROBIT method is that the bias of the PROBIT methodology depends upon the deviation of the true population of WHZ from the assumed normal distribution of WHZ defined by the mean and standard deviation. (biomedcentral.com)
  • The successful completion of the proposed bias analysis will assist other researchers to draw plausible inference of WTC health effects and other future disaster studies by adjusting for bias. (cdc.gov)
  • Instead of simply dismissing all ecologic studies as unreliable, it is preferable to estimate the direction and magnitude of potential biases. (nap.edu)
  • Because of the difficulties in achieving high response rates and the potential biases resulting from self-selection, understanding the reasons for non-response and the application of methods for limiting non-response is indispensible. (isciii.es)
  • The objectives of this observational study were to describe the methodological quality of neonatal randomized controlled trials and quantify the bias related to specific methodological and study-level characteristics. (mendeley.com)
  • In the context of such uncertainty, we present pragmatic recommendations that promote transparency and reproducibility in processes, address methodological advances in the risk-of-bias assessment, and can be applied consistently across review topics. (rti.org)
  • Among women, a modest change in reporting bias was observed for a small number of experiences, possibly due to changes in participation, social acceptability and methodological differences between surveys. (bmj.com)
  • The aim of this paper is to address recall bias in selective studies employing retrospective and prospective designs and present some key methodological strategies to consider in analytic research using reported data in order to avoid or minimize recall bias. (ispub.com)
  • National estimates of the use of cancer screening procedures are based primarily on self-reported results from the National Health Interview Survey (NHIS) 9 and the Behavior Risk Factor Surveillance System (BRFSS), 10 These estimates are well-known to be subject to biases such as social response bias and recall bias ( 1 , 2 ). (aacrjournals.org)
  • Toward the null bias or negative bias yields estimates closer to the null value (for example, lower and closer OR to 1), whereas away from the null bias produces the opposite, higher estimates than the true ones. (bmj.com)
  • I demonstrate the potential bias in estimates of recent transmission and the impact of risk factors for clustering by using computer simulations to reconstruct populations of tuberculosis patients and sample from them. (cdc.gov)
  • Conclusion Corrected estimates suggest non-response bias leads to an underestimation of overall alcohol consumption as well as of disparities between men living in deprived and non-deprived areas. (bmj.com)
  • Unlike immortal time bias, it is not possible, a priori, to predict the direction of this bias on the point estimates since it directly depends on the differential durations for exposure assessment in the cases and controls. (diabetesjournals.org)
  • We compared estimates for outcomes that occurred before Natsal-2 and expected these to be consistent between surveys if no change in reporting bias had occurred. (bmj.com)
  • This occurs with post hoc analysis that may lead to a publication bias when significant results are more frequently reported. (bmj.com)
  • Type I and II errors, surveillance, prescription or publication bias as well as the healthy user effect are described. (isharonline.org)
  • To render it meaningful, "bias" must be linked to another word (such as selection bias, recall bias and publication bias). (etikkom.no)
  • Among the goals of the molecular epidemiology of infectious disease are to quantify the extent of ongoing transmission of infectious agents and to identify host- and strain-specific risk factors for disease spread. (cdc.gov)
  • Molecular epidemiology makes use of the genetic diversity within strains of infectious organisms to track the transmission of these organisms in human populations. (cdc.gov)
  • BACKGROUND: Sometimes in descriptive epidemiology or in the evaluation of a health intervention policy change, proportions exposed to a risk factor or to an intervention are used as explanatory variables in log-linear regressions for disease incidence or mortality. (biomedsearch.com)
  • This hands-on course will put the concepts of intermediate epidemiology into application as the students perform a data analysis project from start to finish. (bu.edu)
  • Texts: The last time I counted, there were well over 50 introductory and intermediate epidemiology texts in print. (columbia.edu)
  • Sackett 3 and Choi 4 classified biases according to the stages of research that can occur: reading up on the field, specification and selection the study sample, execution of the experimental manoeuvre, measurement of exposures/outcomes, data analysis, results interpretation and publication. (bmj.com)
  • Biases in data interpretation, writing, and citing will not be discussed (see for a description of them by Sackett 3 and Choi 4 ). (bmj.com)
  • Bias also refers to a prejudiced or partial viewpoint that would affect someone's interpretation of a problem. (etikkom.no)
  • The final participation in the study depends on a series of factors that individually or jointly may give rise to bias in the interpretation of results with regard to the population that the study is intended to represent. (etikkom.no)
  • Lead time bias can affect interpretation of the five-year survival rate. (wikipedia.org)
  • Evidence for biased recall was presented. (unc.edu)
  • The data on heterogeneity support the previously published conclusion that differential reporting (biased recall) of this common exposure, tapwater consumption, is the likely explanation for its observed association with the risk of spontaneous abortion. (unc.edu)
  • Recall bias in a case-control study of low birth weight. (biomedsearch.com)
  • This pattern of recall errors can lead to differential misclassification of the related variable among study subjects with a subsequent distortion of measure of association in any direction from the null, depending on the magnitude and direction of the bias. (ispub.com)
  • Recall bias is a classic form of information bias 1 . (ispub.com)
  • According to Sackett's catalog of biases in analytic research, recall bias can be introduced in the data collection stage of investigation 6 . (ispub.com)
  • Recall bias of sufficient magnitude can depart the estimated measure of effect size either towards or away form the null, depending on the proportions of subjects misclassified. (ispub.com)
  • Biases can be classified by the research stage in which they occur or by the direction of change in a estimate. (bmj.com)
  • These results, which were consistent across diverse participant samples, suggest that the 5 A Day method yields both biased and imprecise measures of vegetable intake and that research to improve this measure is needed. (aacrjournals.org)
  • Topics include conceptualizing data analysis by defining an addressable research question, utilizing directed acyclic graphs (DAGs) for confounder selection, choosing appropriate exposure and outcome measurements and interpreting the results with respect to strengths, limitations, and biases. (bu.edu)
  • On completion of this course students should be familiar with the major concepts and tools of epidemiology, the study of health populations, and should be able to judge the quality of evidence in health-related research literature. (edu.au)
  • Cognitive biases are a hallmark of depression but there is scarce research on whether these biases can be directly modified by using specific cognitive training techniques. (bioportfolio.com)
  • Bias can be minimized by insistence by editors on high-quality research, thorough literature reviews, acknowledgement of conflicts of interest, modification of peer review practices, etc. (bioportfolio.com)
  • The fifith editon retains the book's simplicity and brevity, at the same time providing the reader with the core elements of epidemiology needed in health care practice and research. (ebooks.com)
  • Bias (skewness) in research may give rise to results that fail to reflect reality. (etikkom.no)
  • Unintended bias may occur at all stages of the research process, and the researcher needs to be aware of this. (etikkom.no)
  • Bias constitutes a challenge in all forms of research activities. (etikkom.no)
  • Bias" has no unambiguous or generally accepted meaning, either inside or outside the framework of research ethics. (etikkom.no)
  • In research there are many types of bias, for which there is no generally accepted categorisation. (etikkom.no)
  • This may include selection bias, sample bias, loss-to-follow-up bias, disease spectrum bias, referral bias, participation (response) bias, self-selection bias (i.e. that volunteer participants in a research study will often differ from those who do not accept the offer to participate). (etikkom.no)
  • argue that researchers should have the opportunity to "request a waiver of consent from the research ethics board" (Kho ME et al, 2009) wherever such a requirement for consent may result in biased study results. (etikkom.no)
  • The term "bias" is sometimes referred to the lack of internal validity which is of central importance in epidemiologic research 3 . (ispub.com)
  • Therefore, it is critical during the planning stage of research to address the possible sources of these two biases and consider expedient strategies to avoid or at least minimize them. (ispub.com)
  • The assortativity bias caused an overestimation of the odds ratio (OR) in the simulated study after perfect adjustment for the subjects' individual-level characteristics (adjusted OR 1·51 instead of 1·00). (cambridge.org)
  • The only domain that showed a statistically significant association with the treatment effect was selective outcome reporting: trials at unclear/high risk of bias for this domain significantly overestimated the treatment effects compared with those assessed at low risk of bias (ROR = 1.87, 95% confidence interval: 1.26-2.78). (mendeley.com)
  • It must be noted that such a difference in response will not lead to a bias as long as it is not also associated with a systematic difference in outcome between the two response groups. (transtutors.com)
  • Key recommendations include transparency and reproducibility of judgments, separating risk of bias from other constructs such as applicability and precision, and evaluating risk of bias per outcome. (rti.org)
  • Tackling the outcome bias related to the effectiveness of antibiotics against the common cold: results of a randomized controlled trial applying the Solomon four-group design. (bioportfolio.com)
  • The present study aims to address the misconception, also known as outcome bias, that antibiotics may be an effective treatment against the common cold by providing a "debiasing" risk communication intervention. (bioportfolio.com)
  • Statisticians have developed methods to adjust for this type of bias, which may assist somewhat in compensating for this problem when known and when it is quantifiable. (wikipedia.org)
  • The type of bias and the design affected is also given. (bmj.com)
  • Double blinding is a technique used to reduce this type of bias. (etikkom.no)
  • The most important biases are those produced in the definition and selection of the study population, data collection, and the association between different determinants of an effect in the population. (bmj.com)
  • There are several strategies to minimize testing bias, including selection of proper patient populations, measuring outcomes for all study participants, blind testing, or using imputation techniques to deal with missing data [ 8 - 10 ], but these techniques do not provide insight into size and direction of testing bias. (biomedcentral.com)
  • In a manner similar to Dale, our study further investigated the bias and precision of the PROBIT method for different sample sizes using simulated populations. (biomedcentral.com)
  • A study can yield biased results for many different reasons. (coursera.org)
  • In this course you will learn about the main types of bias and what effect they might have on your study findings. (coursera.org)
  • In epidemiology, a countable instance in the population or study group of a particular disease, health disorder, or condition under investigation. (cdc.gov)
  • The primary aims of the course are to provide working knowledge of the fundamentals of epidemiology as well as to serve as a foundation for more advanced study of epidemiologic methods. (bu.edu)
  • Each retrieved article was subjected to a primary and a secondary screening, summarized, and then assessed for bias, besides classification of the study design (Table 1 ). (springer.com)
  • 7 Immortal time bias is particularly problematic because it necessarily biases the results in favour of the treatment under study by conferring a spurious survival advantage to the treated group. (bmj.com)
  • While this may be an improvement over the breast cancer study ( 3 ), this method is still prone to time-window bias. (diabetesjournals.org)
  • CONCLUSIONS: This observational study of a sample of neonatal trials showed that most were at high risk of bias, indicating that there is room for improvement in the design, conduct and reporting of neonatal trials to ensure valid results for the most clinically important outcomes. (mendeley.com)
  • Epidemiology refers to the study of the distribution of health related states or events including diseases and the application of this study to the control of diseases and other health problems. (transtutors.com)
  • T helper bias towards Th1 cells is strongly associated with measures of atherosclerosis in the population-based study MESA-Inflammation (both coronary calcification and carotid wall thickness) after fully adjusting for traditional and novel CVD risk factors. (clinicaltrials.gov)
  • In this study, it was examined whether or not combined attentional and interpretational bias modifications with university students who display social anxiety symptoms may lead to a decrea. (bioportfolio.com)
  • Evaluation of non-response bias in a cohort study of World Trade Center terrorist attack survivors. (cdc.gov)
  • The phenomenon of selection bias encompasses more than skewness in the selection of the study population (Odierna DH et al. (etikkom.no)
  • This module will provide students with foundations of epidemiology, including basic concepts underpinning study design, how to pose an answerable question and to design a study to answer said question. (ljmu.ac.uk)
  • Maclure and Schneeweiss, 5 applying the causal diagram theory, offered an interesting explanation of the main sources of bias. (bmj.com)
  • In Norwegian, the word "skjevhet" (skewness) is often used instead of the English term "bias", as recommended in the advice to authors of the Journal of the Norwegian Medical Association (www.tidsskriftet.no). (etikkom.no)
  • The Internet Journal of Epidemiology. (ispub.com)
  • What is Attrition Bias? (transtutors.com)
  • An example of attrition bias is a test done by a shampoo company, regarding the effectiveness of the new product (anti-hair fall shampoo). (transtutors.com)
  • Attrition bias occurs as many participants withdraw from the trial or do not use the product in the specified time limit or fail to respond altogether. (transtutors.com)
  • attrition bias etc. (etikkom.no)
  • OBJECTIVE: Risk-of-bias assessment is a central component of systematic reviews but little conclusive empirical evidence exists on the validity of such assessments. (rti.org)
  • Conclusions We found little evidence of change in reporting bias among men since Natsal-2. (bmj.com)
  • Randomized, placebo-controlled trial of 9 sessions of computerized attentional bias training on attentional bias and on symptoms of Posttraumatic Stress Disorder. (bioportfolio.com)
  • Threat-related attentional biases have been identified as a possible precursor to the onset and maintenance of posttraumatic stress disorder (PTSD). (bioportfolio.com)
  • Bias should be distinguished from random error or lack of precision. (bmj.com)
  • assessed the PROBIT method for measuring global acute malnutrition measure and found that the method was biased and the precision was superior only for sample sizes less than 150 when compared to the standard method. (biomedcentral.com)
  • The PROBIT method will provide gains in precision regardless of the sample size, but the method may be biased. (biomedcentral.com)
  • Bias diminishes the accuracy (though not necessarily the precision) of an observation. (etikkom.no)
  • Two independent reviewers assessed risk of bias (RoB) on seven domains consisting of nine items. (mendeley.com)
  • and conducting, analyzing, and presenting results of risk-of-bias assessments. (rti.org)
  • We also assessed mindfulness-based therapy trial registrations for indications of possible reporting bias and reviewed recent systematic reviews and meta-analyses to determine whether reporting biases were identified. (isharonline.org)