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Over the past few decades, the case-control method has been mostly applied to risk-factor studies of chronic diseases. Recently, among its new applications is the use of the method to study the health effect of improvements in sanitation and water supply. The methodological considerations, prospects and constraints of the method for rapid assessment are reviewed.
A complex method for the epizootological and epidemiological surveillance of a number of bacterial and viral infections on the territories inside and outside their natural foci has been developed. The investigation techniques are described and the data on the isolation rate of each causative agent in different geographical zones are presented. In the natural foci of plague and tularemia, as well as on the territories outside such foci, the causative agents of intestinal yersiniosis, pseudotuberculosis, salmonellosis, erysipeloid, staphylococci and streptococci, arena- and arboviruses have been isolated from the rodents and ectoparasites under study. The results of this investigation suggest that the method may be recommended for use in medical institutions dealing with the problems of infections originating from natural foci.
The epidemiological methods of klebocin typing, antibiogram and plasmid DNA profile were evaluated using organisms isolated from a suspected epidemic of gentamicin-resistant Klebsiella pneumoniae and unrelated strains from different geographical areas as controls. The electrophoretic analysis of plasmid DNAs from Klebsiella pneumoniae showed the presence of at least one and up to as many as seven plasmids in each strain. The molecular weight of plasmid DNAs ranged from 1 to greater than 70 mega daltons. While none of the control Klebsiella pneumoniae strains showed identical plasmid profiles, 63% of the epidemic-related Klebsiella pneumoniae strains did. Klebocin typing and plasmid DNA profile gave different results for the same strains. Plasmid DNA profile was found to be a more valuable method than klebocin typing alone or klebocin typing in combination with antibiogram for differentiating epidemiologically related from unrelated isolates. Both plasmid DNA profile and klebocin typing methods were superior to antibiogram.
BACKGROUND: Tinea capitis in children is widely reported, whereas there have been only isolated reports on involvement of sites other than the scalp. The purpose of this study was to examine the epidemiological features and treatment responses of dermatophytosis of children in Kuwait. METHODS: Epidemiological features and the treatment responses of 202 consecutive children with dermatophytosis were studied. RESULTS: The 202 children constituted 44% of the total dermatophytic infections seen during a period of 1 year. Tinea capitis was the most commonly encountered infection (78%), followed by tinea corporis, tinea faciei, tinea cruris and manus, respectively. Microsporum canis was the most prevalent species (96%) in this region. A history of pets at home could be elicited in 52% of the cases. A familial occurrence of similar infections was seen in 56% of the patients. In patients with tinea capitis, addition of topical clotrimazole or ketoconazole to oral griseofulvin produced better therapeutic results compared to griseofulvin alone or in combination with selenium sulfide shampoo. CONCLUSIONS: Tinea capitis is the most common dermatophytic infection in children. Thirty percent of the children may have dermatophytosis at sites other than the scalp. A combination of topical clotrimazole or ketoconazole with oral griseofulvin is superior to griseofulvin alone or in combination with selenium sulfide shampoo in the treatment of tinea capitis.
Medical errors in emergency departments (EDs) may be an important "public health risk." Therefore, scientific public health approaches should be used to 1) assess the magnitude of emergency medical errors with surveillance methods, 2) identify causal factors of these medical errors with clinical epidemiologic methods, and 3) evaluate the effectiveness of interventions aimed at reducing or eliminating emergency medicine errors with health service research techniques. Since errors result from complex human-system interaction, research efforts should focus on actions taken by the patient, factors concerning the ED environment, and actions taken by health care workers. Other medical and nonmedical fields have already made great advancements in studying and reducing human error. Many of these advancements could readily be adapted to study emergency medical errors.
OBJECTIVES: To examine the recent epidemiological evidence on cancer risk among workers in the rubber industry. METHODS: Epidemiological studies published after the last detailed review by the International Agency for Research on Cancer (IARC) in 1982 were reviewed. 12 cohort studies in nine countries that examined distinct populations of workers in the rubber industry, seven industry based nested case-control studies, 48 community based case-control studies in 16 countries, and 23 studies based on administrative data that reported risks for employment in the rubber industry were identified. RESULTS: Excess risks of bladder cancer, lung cancer, and leukaemia were found in most studies, with risks above 1.5 in about half of the studies. A moderate excess risk for laryngeal cancer was consistent across studies. Excess risks were found in a few studies for cancers of the oesophagus, stomach, colon, liver, pancreas, skin, prostate, kidney, brain, and thyroid, and for malignant lymphoma and multiple myeloma, but overall results were not consistent for these neoplasms. CONCLUSIONS: Magnitude of the observed risks varied considerably between studies, but overall the findings indicate the presence of a widespread moderate increased cancer risk among rubber workers. The most consistent results were for bladder, laryngeal, and lung cancer and for leukaemia. Excess risks were also found for other neoplasms but an evaluation of the consistency of the findings is difficult because of the possible selective reporting of results. Recent studies do not provide information associating specific exposures with cancer risk. The preventive measures taken in the rubber industry in recent years may decrease risks, but this has not been documented yet in epidemiological studies.
OBJECTIVE: To estimate the benefits of reduced cocaine consumption in terms of reduced societal costs resulting from the introduction of a medication for cocaine dependence with a small incremental treatment effect. STUDY DESIGN: Cost-benefit analysis is applied to study the implications of reduced cocaine consumption. A modelling approach extrapolates the magnitude of treatment effects. METHODS: Epidemiological data on cocaine use and consumption as well as economic methods of cost-benefit analysis are utilised. Estimates of societal costs associated with heavy users of cocaine, who are most likely addicted and in need of immediate treatment, are developed using 1995 data. MAIN OUTCOME MEASURES AND RESULTS: In the first analysis, a postulated 1% reduction in consumption of cocaine among heavy users is examined to approximate a small treatment effect, resulting in a minimal consumption benefit. It is estimated that such a reduction would be valued at $US259 million. The cost-benefit analysis indicated that a cocaine medication with a small treatment effect (10 percentage point increase in abstinence rates) would result in a benefit to cost ratio in the range of 1.58 to 5.79, depending on prescribing behaviour and type of patient. CONCLUSIONS: Such estimates of the benefits of these small treatment effects are conservative, and they may be biased downwards since the willingness to pay for such a cocaine medication could far exceed the benefit to cost estimation used in this paper. Nevertheless, the substantial benefits found in this paper indicate how important investment in cocaine medication is for public health policy; costs may be reduced with efficient prescribing behaviour. Market and governmental barriers to the utilisation of a cocaine medication could reduce the benefits and increase costs. Clinical trials, cost-effectiveness studies, and cost-benefit studies must be conducted to establish the actual pattern of benefits and costs that could be obtained for an efficacious and effective cocaine medication.
AIM: To analyse the role of genetic susceptibility and environmental factors in the process of esophageal cancer (EC) formation in Xi'an, China. METHODS: A hospital based case-control study, combined with molecular epidemiological method, was carried out. A total of 127 EC cases and 101 controls were interviewed with questionnaires containing demographic items, habit of tobacco smoking, alcohol drinking, and family history of EC. Polymorphism of CYP1A1 and GSTM1 of 127 EC cases and 101 controls were detected by PCR method. The interactions between genetic susceptibility and environmental factors were also discussed. RESULTS: Tobacco smoking, alcohol drinking and a family history of EC were risk factors for EC with an OR of 2.04(95% CI 1.15-3.60), 3.45(95% CI 1.74-6.91), 3.14 (95% CI 1.28-7.94), respectively. Individuals carrying CYP1A1 Val/Val genotype compared to those with CYP1A1 Ile/Ile genotype had an increased risk for EC (OR 3.35, 95% CI 1.49-7.61). GSTM1 deletion genotype was a risk factor for EC (OR1.81, 95% CI 1.03-3.18). Gene-environment interaction analysis showed that CYP1A1 Val/Val genotype, GSTM1 deletion genotype had synergetic interactions with tobacco smoking, alcohol drinking and family history of EC. CONCLUSION: Tobacco smoking, alcohol drinking and a family history of EC are risk factors for EC. CYP1A1 Val/Val and GSTM1 deletion genotypes are genetic susceptibility biomarkers for EC. There are synergic interactions between genetic susceptibility and environmental factors.
OBJECTIVE: To study the hazards of gem dusts and the epidemiological features of the occurrence of gem worker's silicosis (GWS). METHODS: Epidemiological investigation in a gem factory in Guangdong province was carried out. RESULTS: The average dusts concentration in workshop was 2.3 mg/m(3), average free silica content was 94.64%. There were 47 patients diagnosed as silicosis. The prevalence of GWS was 4.58% (47/ 1,027). The age of patients suffering from silicosis and the duration of dust exposure were (27.04 +/- 3.25) years and (4.67 +/- 1.17) years respectively. Chest radiographic examination showed mainly small round opacities "q". The incidences of GWS complicated by pulmonary tuberculosis, spontaneous pneumothorax and pulmonary emphysema were 10.64%, 10.64%, 44.68% respectively. CONCLUSION: The hazards of gem dust to workers might be serious. Higher incidence, younger age suffered from silicosis, shorter duration of dust exposure, more complications, and poorer prognosis in gem workers appeared to be the main epidemiological features of GWS in Guangdong.
OBJECTIVE: To consummate the standard of macroscopic syndrome differentiation for diagnosis of dampness syndrome in patients with chronic gastritis (CG), based on the essentials of syndrome differentiation in TCM diagnostics and combined with the multivariant mathematical statistic method. And try to find out the methods and approaches for establishing standard for TCM syndrome differentiation. METHODS: Clinical investigation on CG patients was carried out adopting clinical epidemiological method. RESULTS: The meaningful symptoms for making diagnosis of Pi-Wei damp-heat syndrome in frequency order, were red tongue with yellow and greasy fur, sticky and greasy sensation in mouth, brown urine, constipation, dry stool, flushed face and ponderous extremities. Those for Pi deficiency with damp retention syndrome were swollen tongue with teeth-print, greasy fur, sticky and greasy sensation in mouth, tastelessness, and poor appetite. CONCLUSION: By combining the integrative medical theory with multivariant statistic method, the meaningful essentials for diagnosis of dampness syndrome can be screened out.
The expanded programme on immunization (E.P.I.) is a very concrete example of community health programme. In so far, it uses various methods which the medical personnel should be taught a better way: the epidemiological method, health planning, health management. The E.P.I. provides a great deal of actual conditions well-suited to the preparing of either tutorials or self-training modules within various fields such as epidemiological surveys with estimate or evaluation purposes, planning for a prevention strategy, supply management. Aiming at the enlargement to community health and with a much more participative pedagogical spirit, the author points out the importance of making the educators aware of unequalled capabilities of training provided by the E.P.I.
The probability of recording infectious diseases and injuries to the musculoskeletal system during sports events with a large number of participants is very high. From an historical perspective the distribution and trends of diseases that have an impact on public health have been evaluated by means of epidemiological surveillance systems. However, the application of these epidemiological methods to sports medicine is relatively recent. The utilization of an epidemiological surveillance system during sports events with a large number of participating athletes and countries has been reported in a limited number of competitions. In this article we describe the design of a system for epidemiological surveillance utilized during the XVII Central American and Caribbean Sports Games held in Puerto Rico in 1993, as an example of a surveillance system that could be regularly established in this type of event.
This paper assesses the mortality dynamics of the populations of the CSFR, CR and SR from 1950 to 1985 using medical demography techniques and secondary analyses of primary demographic data. Major diseases focussed on include malignant neoplasms and circulatory diseases in adult and pediatric populations. Attention is drawn to risk population groups and predictions are made using a number of statistical methods. The model POPUL is then used to simulate population development given the elimination of causes of mortality. This approach can be used to monitor the mortality dynamics at the level of the population and the model method can be further supplemented with single tests, selective surveys and epidemiological methods. The outcome of this research is a proposed research institute and graduate programme to furnish a body of expertise in the CSFR to pay long term attention to and research on the health status and mortality in this region.
OBJECTIVES: To compare genotypic methods for epidemiologic typing of Legionella pneumophila serogroup (sg) 1, in order to determine the best available method within Europe for implementation and standardization by members of the European Working Group on Legionella Infections. METHODS: Coded isolates (114) of L. pneumophila sg 1 comprising one epidemiologically 'unrelated' (79) and one 'related' panel of isolates (35) were sent to 12 laboratories in 11 European countries. Analysis was undertaken in each laboratory using one or more of the following methods: ribotyping, restriction fragment length polymorphism analysis, restriction endonuclease analysis, pulsed-field gel electrophoresis (PFGE), PCR using arbitrary/repeat sequence primers (AP-, AP/rep-PCR), and amplified fragment length polymorphism (AFLP) analysis. Results were analyzed visually or using gel analysis software. Each method was assessed for its: index of discrimination (D), epidemiologic concordance (E), speed of application and ease of use. In addition, phenotypic analysis was performed in two laboratories using monoclonal antibodies (mAbs). RESULTS: The D of each of the genotypic methods ranged from 0.840 for ribotyping to 0.990 for PFGE using Sfil: E ranged from 0.06 for AP- and AP/rep-PCR to 1.00 for ribotyping using Pstl/EcoRI and AFLP: in general, E was inversely related to D. Although offering only limited discrimination (D=0.838), mAb typing was both rapid and highly epidemiologically concordant (E=1.00). CONCLUSIONS: Two methods, PFGE using Sfil and AFLP, were selected for further study. AFLP is rapid and highly epidemiologically concordant (E=1.00), but is not highly discriminatory. This method will be developed as a rapid screening tool. PFGE using Sfil is highly discriminatory but, in the present study, yielded low values of E (0.12-0.71). Attempts will be made to rigorously standardize this method for use as the reference method. Primary screening of isolates by mAb subgrouping is recommended.
PURPOSE: To provide a synthesis of current approaches to the discovery of genes associated with complex human diseases by examining the joint potential of traditional epidemiologic methods and current molecular techniques for gene discovery. METHODS: A discussion of optimal approaches for defining complex disease phenotypes in genetic epidemiology, ascertainment strategies for estimating genetic influences on disease risk, genomic approaches for localizing complex-disease-susceptibility genes, and the potential synergistic effects of integrating genetic and traditional epidemiologic expertise is provided in the second part of a three-part series on the importance of genetics in epidemiologic research. RESULTS: The ability to quantify genetic influences on disease risk appears highly dependent on the measurement of specific risk factor traits, ascertainment strategies for recruiting study subjects, and a variety of genomic approaches that are rapidly facilitating our ability to identify genes influencing inherited human diseases and to quantify genetic influences on disease risk. CONCLUSIONS: Integrating population-based methods of assessing disease risk with human genetics and genome technology is critical for identifying genetic polymorphisms that influence risk of disease and for defining genetic effects on complex disease etiology.
Tuberculosis continues to be one of the predominant infectious diseases. Effective control of its spread requires that sources of infection and routes of transmission be disclosed as quickly as possible. At present such investigations are still performed by conventional epidemiological methods. In the recent past, however, molecular typing systems were added to the spectrum of epidemiological tools. Unfortunately, they were applied to retrospective investigations rather than used as an aid in the health care system. In this study, 515 Mycobacterium tuberculosis strains isolated during 1997 and 1998 in Vienna were analysed by spoligotyping, a molecular technique requiring no further cultivation of mycobacteria. The study was aimed to assess the suitability of the method as a quick means of disclosing new cases. Thus, clusters obtained by spoligotyping were analysed along with demographic and epidemiological data and compared with clusters obtained by conventional epidemiological techniques alone. In addition, spoligotype-forming clusters were matched with an international database containing spoligotypes from four different studies. Of 515 isolates, 107 showed an unique pattern. The remaining 408 isolates were distributed into two large clusters of 82 and 73 isolates and into 49 smaller ones consisting of 2 to 33 isolates each. The two spoligotypes forming the large clusters were identical with the most prevalent spoligotypes in the world. Therefore, for the tuberculosis authorities, information was only gained by excluding rather than tracing possible ways of transmission. Twenty-two of the 49 spoligotypes forming smaller clusters were identical with strains found in other parts of the world. Seventeen of 22 infection chains assumed by conventional investigations were confirmed by spoligotyping. In small clusters, an additional 24 infections were assumed due to similarities such as living conditions or socioeconomic status. In 27 clusters, all patients sharing the same strain belong to the same country or geographical area. In conclusion, spoligotyping proved suitable as an early guide in conventional investigations to trace routes of M. tuberculosis transmission in a community. However, when a strain isolated from a patient belongs to a spoligotype shared by many isolates, a second molecular typing method is required.
The clinico-epidemiological method was used to examine the patients' population suffering from attack-like schizophrenia with a disease standing of 25 and more years. There were altogether 245 persons. Depressive attacks of the endogenous type were revealed in 1/3 of the patients, amounting to 153 attacks in total. Of these, 76.5% occurred at the disease onset, namely from the first to the fifth attack. A comparative all-round study was made of the efficacy of neuroleptics, antidepressants and combined therapy of neuroleptics and antidepressants, insulin coma ++ therapy and symptomatic remedies bearing in mind such criteria as the rate of attack removal, remission duration and quality, the character of the maintenance therapy. It has been established that the use of psychopharmacotherapy removes a depressive attack of the endogenous type more swiftly but long and stable remissions are only ensured by antidepressants.
The bottom line here is how or whether our toxicological studies relate to ourselves, to human neoplasia--but the latter is, in important ways, imperfectly defined by the best that can so far be arranged using morphological and epidemiologic methods. There are at least three basic questions: 1) with what precision can the histopathologist define and diagnose cancer in humans--hence emphasis here upon human cancer models, 2) to what extents can difficulties be resolved using animal models, where some similar difficulties are met, and 3) to what extents can epidemiology resolve these difficulties. Not all these problems can be resolved, and the investigator is left with a residue of questions for which no answers are presently available. Some of these are exemplified or precipitated by inconclusive or mistaken diagnoses. In the future awaits practical help from specific biochemical markers and morphometry, but in the present, vigilance and consultation should limit error to a small fraction of observations. In the meantime, existing methods and data are perfectly adequate for study and action in various clinical problems, eg. transmission of familial polyposis of colon, definition and control of various adverse drug reactions.