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PubMed2001

Understanding the roles of genome and envirome: methods in genetic epidemiology.

BACKGROUND: In order to understand studies of psychiatric epidemiology focusing on the 'genome' and 'envirome', basic knowledge of the logic and methods is necessary. AIMS: To provide a review of typical methods used in genetic epidemiology. METHOD: Reviews of the research designs usually employed in quantitative and molecular genetic studies. Genotype-environment correlation and interaction are also discussed. RESULTS: Quantitative genetic studies indicate that genetic influences are important for both psychiatric disorders and behavioural traits. Specific gene loci can be tested for associations with both psychiatric risk and behavioural traits by means of molecular genetic techniques. There has been little examination of genotype-environment correlation and interaction, although the few reports that have appeared suggest that these complex relationships are important. CONCLUSIONS: Advances in quantitative and molecular genetics now permit more careful examination of genotype-environment interaction and correlation. Studies combining molecular genetic strategies with measurement of the environment are still at an early stage, however, and their results must be awaited.

Environment↗
PubMed1991

Draft results of a workshop to develop guidelines for studies involving microbial incidence or populations in the oral cavity.

The following five outlines are the results to date of the Workshop held in Rockville, Maryland, in January, 1990. The topics considered in these outlines are: (1) validation of immunological and/or nucleic acid identification probes, (2) cross-calibration of methods and/or laboratories for multi-laboratory cooperative studies, (3) choosing methods for identifying or describing microbial populations appropriate to the scientific question asked, (4) microbial ecology methods (e.g., population dynamics) for the oral cavity studies, and (5) epidemiological methods (e.g., incidence, risk factor analysis) for oral microbial studies. Each topic was considered by two independent groups of participants and later rationalized into one. These outlines are meant to be working outlines for evolution of a set of guidelines to advise on designing studies with microbial incidence and/or population components. We are publishing this preliminary version to elicit comment and criticism from people who did not attend the Workshop. (Attendance at the Workshop was necessarily limited by both space and funds). Some of the topic outlines have been condensed to save Journal space. The full document is available on request. The next stage will be an open forum to gather and discuss further amplification of the "Guidelines", planned for April 17, 1991, Acapulco, Mexico, in conjunction with the IADR/AADR Meeting. Written comments and requests for further information should be sent to the Workshop organizer (MIK) at the above address.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA, Bacterial↗
PubMed2004

Epidemiology of breastfeeding: advances and multidisciplinary applications.

Advancing understanding of the importance of breastfeeding (BF) has required advances in application of epidemiologic methods to BF research. This chapter considers, in the context of BF epidemiology, how different research designs complement each other to establish firmer causal inferences, the need for multidisciplinary collaborations, and the application of powerful analytical methods to strengthen epidemiologic studies. A recent global meta-analysis of 47 studies documenting the inverse association between lifetime BF duration and breast cancer risk illustrates the value of longitudinal (cohort) studies to establish the temporal sequence of events and to rule out differential recall biases that can threaten the internal validity of case-control studies. The discovery of the transmission of human immunodeficiency virus (HIV) via human milk has led epidemiologists to provide important hypotheses to be tested at the molecular and cellular level and in turn test hypotheses generated in laboratory studies. Application of powerful statistical methods to BF epidemiology has helped strengthen causal inferences. A retrospective analysis of the 1976--1977 Malaysian Family Life Survey found interactive multivariate statistical models to better understand how different socioeconomic and cultural contexts modify the influence of BF on child health. Further, a study conducted in Cebu City, Philippines, demonstrated how structural equation models can be used to test the pathways through which proximate (e.g., BF) and distal (e.g., socioeconomic status) determinants affect child health after adjusting for reverse causality (i.e., child health influencing maternal BF choice). For ethical reasons, BF randomized controlled trials (RCTs) have seldom been conducted. Recent RCTs examining the link between BF peer counseling and BF outcomes in diverse settings provides a unique opportunity to firmly establish the causal inferences regarding BF and the prevention of diarrheal diseases. The value of rapid assessment anthropologic methods to guide development of peer counseling interventions subsequently tested through RCTs is presented. This chapter also illustrates how Cox regression and logistic regression can be applied to BF research.

Breast Feeding↗
PubMed2003

Recent transmission of tuberculosis in Madrid: application of capture-recapture analysis to conventional and molecular epidemiology.

BACKGROUND: Population-based studies using a combination of molecular techniques and conventional epidemiological methods have been used to study the dynamics of tuberculosis (TB) transmission but the relative utility of each technique has not yet been established. METHODS: A prospective population-based molecular and epidemiological study of patients diagnosed with TB was conducted in three urban districts of Madrid (Spain) during 1997-1999. Analysis was performed using the capture-recapture method including covariates in which conventional epidemiological data and the information on clustered cases obtained by DNA fingerprinting were regarded as independent and complementary procedures. RESULTS: The estimate obtained by molecular analysis alone, that 31.6% of TB cases were due to recent transmission, was revised to 44.8% (95% CI: 31.4-58.2) using the capture-recapture method. The estimated completeness of the combined databases for identification of recent transmission was 59.2%. Underestimation of the true prevalence of recent transmission was higher with conventional epidemiology than molecular analysis, particularly for patients <35 years old and those with a history of imprisonment. CONCLUSIONS: In this study, use of the capture-recapture technique allowed us to combine epidemiological information obtained by conventional and molecular methods to quantify the number of cases of recently transmitted TB in the community and identify specific populations at high risk of disease. This information is clearly important because such groups are a prime target for improved TB control measures. In the long term, this combination of techniques may contribute significantly to control the spread of TB.

Adult↗
PubMed1998

Measurement of risk for mental disorders and competence in a psychiatric epidemiologic community survey: the National Institute of Mental Health Methods for the Epidemiology of Child and Adolescent Mental Disorders (MECA) Study.

This paper describes the implementation of the National Institute of Mental Health Methods for the Epidemiology of Child and Adolescent Mental Disorders (MECA) study's goals of measuring risk factors and competence. The emphasis is on the development and testing of the measures. Relevant constructs for measurement of risk and competence in relation to psychopathology were selected and pilot tested prior to the field trials. A structured interview was developed and field tested using lay interviewers. Using the full sample from the field trials (n = 1285 caretaker-youth pairs), sample means, standard deviations, internal consistencies, parent-youth agreement, and associations with childhood disorder were computed. Descriptive statistics reveal a range of scores and means consistent with norming samples, when available, Internal consistencies were moderate to high. Parent-youth agreement on factual items was excellent and on scales was consistent with the literature. Several strong associations were found between risk factors and disorder, although most were related to disorder in general and not specific to a diagnostic category. This instrument provides a means of obtaining data that will be useful to researchers conducting epidemiologic and clinical studies designed to contribute to the understanding of mental disorders in children and adolescents, including nosology, risk factors, context, adaptive functioning, and treatment.

Adolescent↗
PubMed1978

Analytic methods in matched pair epidemiological studies.

Two methods of analysis of matched pair epidemiologic studies are presented. The within pair difference between study and comparison individuals is evaluated with respect to additional confounding variables while simultaneously maintaining the matching. The effects of additional confounding variables are quantiated by their association with the response variable (i.e. exposure in a case-control study or disease in a cohort study). For a binary response variable a multiple logistic function is used and a method to estimate the odds ratio is given. For a continous response variable multiple regression is used and a method to estimate an odds ratio function is derived.

Epidemiologic Methods↗
PubMed2000

A population-based analytical approach to assessing patterns, determinants, and outcomes of health care with application to ectopic pregnancy.

OBJECTIVE: Health care has variable features, specific determinants, and consequences on people's health that should be investigated in a population perspective. We present a population-based analytical approach to assessing patterns, determinants, and outcomes of health care. METHODS: The approach uses standard epidemiological methods for sample selection and analysis, as well as statistical methods concerning model fitting and validation strategy. It also uses psychometric methods allowing pattern identification: factor analysis, cluster analysis, and polytomous logistic regression to investigate the factors associated with identified patterns of care. The approach is illustrated with an application to ectopic pregnancy (EP). RESULTS: EP diagnostic and therapeutic procedures appeared to be closely related, suggesting 3 differentiated patterns of care. Predictors of these patterns were not only the clinical features and the woman's prior gynecological history but also center characteristics and location. These patterns were found to influence immediate and middle-term outcomes and risk of recurrence of EP. CONCLUSIONS: We illustrate the feasibility and profitability of a population-based analytical approach to identify patterns, determinants, and consequences of care. This approach could be used to analyze other pathological conditions and health care systems.

Adolescent↗
PubMed1990

Epidemiology of HIV infections. Design options with special reference to developing countries.

Health research and planning need valid data for decision making. In a developing country cost-effectiveness in research design is of special significance. In such situations, population-based data are needed. This paper reviews the literature on HIV/AIDS studies published during 1982-88 with respect to epidemiological methods and study designs and with special relevance to developing countries. A methodological taxonomy is presented based on this review illustrating the special need for analytic epidemiology. The paper also presents experiences and results from an ongoing collaborative project on HIV infections between Tanzanian and Swedish researchers. The project, which was launched in 1987 in the Kagera region where the first AIDS cases were seen in 1983, applies both epidemiological and behavioural methods.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Evidence-based medicine: assessment of knowledge of basic epidemiological and research methods among medical doctors.

BACKGROUND: An understanding of statistical methods and basic epidemiology are crucial for the practice of modern medicine. AIMS: To assess (1) the knowledge of basic methods of conducting research and data analysis among residents and practicing doctors and (2) the effect of country of medical school graduation, professional status, medical article reading and writing experience on the level of this knowledge. METHODS: Data were collected by means of a supervised self-administered questionnaire, which was distributed among doctors at Soroka Medical Center, Beer-Sheva, Israel. The questionnaire included 10 multiple-choice questions on basic epidemiology and statistics, and respondent demographical data. RESULTS: Of the 260 eligible doctors, 219 (84.2%) returned completed questionnaires. Of the 219 doctors, 50% graduated more than 8.5 years ago, 39.7% were specialists and the remaining were residents. The most frequent specialty was internal medicine (37.4%). Israel was the most frequent country of graduation (45.7%), followed by the former Soviet Union (Eastern medical education; 38.4%). The median total score of knowledge was 4 of 10 questions (interquartile range 2-6). A higher score was associated with a Western medical education, being a specialist, shorter elapsed time since graduation, higher number of publications and self-reported reading of "methods" and "discussion" sections in scientific articles. CONCLUSION: This study found a low level of knowledge of basic principles of research methods and data analysis among doctors, and this knowledge considerably differed by country of medical school graduation.

Clinical Competence↗
PubMed1977

Cancer and occupation: status and needs of epidemiologic research.

In the United States about 15% of cancer in men and 5% of cancer in women is probably due to occupational exposures. Yet, among the populations actually exposed, occupational cancer is a major health hazard. Further, occupational carcinogenesis should be studied because of it scientific interest and the likely generalizability of findings to non-occupational exposures. The alert clinician remains the most important source of leads to occupational cancer. When groups of cases occur, particularly cases of rare tumors among relatively young persons, an occupational exposure should be suspect. A reasonably detailed occupation history should be included in every medical record. Formal evaluation, measurement of risk and identification of specific hazards is usually done by epidemiologic methods. Several approaches to the improvement of these methods and, possibly, to disease control are presented.

Adult↗
PubMed1994

[Recent trends in lung cancer epidemiology].

The number of deaths from lung cancer is almost 40,000 a year in Japan (the rate is 45 per 100,000 for men and 12 per 100,000 for women). The incidence of lung cancer was 64 and 18 per 100,000 for men and women, respectively, in Osaka in 1987-89. Both the mortality and incidence have been increasing over the last few decades. However, the rates are lower than those in other ethnic groups and in America and other Western countries. The relationship between active smoking and lung cancer is well established, but further epidemiologic and basic studies on passive smoking and lung cancer are required. The basic epidemiologic methods of cohort studies and case-control studies are presented, and the basic concepts of clinical epidemiology are also discussed.

Epidemiologic Methods↗
PubMed1979

Acquaintance networks among leukemia and lymphoma patients.

A case-control study of clustering through acquaintanceship among lymphoma and leukemia patients was conducted for the years 1967 through 1972 in Orleans County, New York. Twenty lymphoma and 17 leukemia cases met criteria for inclusion in the study. Data on acquaintanceship linkage were gathered from the source cases and controls, and from their acquaintances yielding a data base of 13,409 unique individuals linked by acquaintance. Three different analyses were carried out: a statistical analysis of linkage via intermediaries of case pairs in comparison with control pairs; a computer simulation of disease transmission from selected source cases to selected targets and controls based on the acquaintance data; and a secondary attack rate type analysis. The first two types of analysis yielded statistically significant case-control differences at the .05 level. The third method also yielded a positive result but was not subject to quantitative hypothesis testing. An additional conclusion is that these epidemiologic methods for disease with long induction periods merit further study.

Adolescent↗
PubMed1979

Industrial epidemiology.

Industrial epidemiology is a specialized discipline concerned with the study of disease occurrence in specific subgroups of the general population, i.e., of relatively healthy members of the work force for whom adequate records are available. Although the ultimate purpose of industrial epidemiology--the prevention of disease--is a logical extension of programs of industrial medicine and occupational and community health, epidemiologic methods must draw on interdisciplinary skills. The existence of centralized records kept in the course of business may make it easier to collect information about industrial populations than to gather data relative to other population subgroups. Many deficiencies in epidemiologic studies of worker groups, however, can be related to poor methods of data-gathering, inadequate record keeping, and an incomplete data base. Sources of information for epidemiologic studies of worker groups may include personnel and medical records, government reports, insurance files, production records, industrial hygiene measurements, surveys and questionnaires, and an organized follow-up program. In some cases, the ready availability of multiple sources of information may lead to differential information bias, and this should be avoided.

Animals↗
PubMed1999

[Contribution of clinical epidemiology to the management of HIV infections].

INTRODUCTION: The objective of this publication is to make clinicians more aware of clinical epidemiology through our experience in the field of human immunodefiency virus (HIV) infection. CURRENT KNOWLEDGE AND KEY POINTS: Clinical epidemiology is aimed at studying diagnostic, therapeutic and prognostic aspects of diseases, and their consequences, with the objective of improving both scientific knowledge and patient's management. Examples, including longitudinal studies and clinical trials, illustrate the value of clinical epidemiology. FUTURE PROSPECTS AND PROJECTS: Beyond HIV infection, the importance of both multidisciplinary collaboration and education of clinicians in regard to biostatistical and epidemiological methods is emphasized.

Biometry↗
PubMed1980

Department of Epidemiology and Public Health, School of Medicine, Yale University, New Haven, CT.

This paper distinguishes between 2 concepts for measuring the incidence of disease: risk and rate. Alternative procedures for estimating these measures from epidemiologic data are reviewed and illustrated. An attempt is made to integrate statistical principles with epidemiologic methods while minimizing the use of higher mathematics. Several theoretical and practical criteria are discussed for choosing the appropriate incidence measure in the planning of a study and for selecting the best method of estimation in the analysis.

Epidemiologic Methods↗
PubMedDate not supplied

Methodologic aspects of the study of modern-age diseases: the example of sick-building syndrome.

In recent decades, variously identified nebulous disorders such as sick-building syndrome, electrical hypersensitivity, and chronic fatigue syndrome, characterized by combinations of nonspecific symptoms and absence of demonstrable signs have appeared. Their similar nonspecific etiologic attributions have given rise to generic names such as "modern-age disease" and "symptom-based conditions." The lack of demonstrable biological correlates as well as the vagueness of the etiologic attributions makes modern-age diseases unusually problematic to study with epidemiologic methods, potentially leading to serious biases. Case studies of sick-building syndrome demonstrate that qualitative methods can help to elucidate the dynamic processes involved in syndrome development.

Epidemiologic Methods↗
PubMed1995

The effects of malnutrition on child mortality in developing countries.

Conventional methods of classifying causes of death suggest that about 70% of the deaths of children (aged 0-4 years) worldwide are due to diarrhoeal illness, acute respiratory infection, malaria, and immunizable diseases. The role of malnutrition in child mortality is not revealed by these conventional methods, despite the long-standing recognition of the synergism between malnutrition and infectious diseases. This paper describes a recently-developed epidemiological method to estimate the percentage of child deaths (aged 6-59 months) which could be attributed to the potentiating effects of malnutrition in infectious disease. The results from 53 developing countries with nationally representative data on child weight-for-age indicate that 56% of child deaths were attributable to malnutrition's potentiating effects, and 83% of these were attributable to mild-to-moderate as opposed to severe malnutrition. For individual countries, malnutrition's total potentiating effects on mortality ranged from 13% to 66%, with at least three-quarters of this arising from mild-to-moderate malnutrition in each case. These results show that malnutrition has a far more powerful impact on child mortality than is generally appreciated, and suggest that strategies involving only the screening and treatment of the severely malnourished will do little to address this impact. The methodology provided in this paper makes it possible to estimate the effects of malnutrition on child mortality in any population for which prevalence data exist.

Child Nutrition Disorders↗