PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Epidemiologic Methods”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources
PubMed2000

[Epidemiological studies in evaluation of effectiveness of health promotion programmes].

Basic characteristics of modern epidemiology and basic characteristics of epidemiological study are presented. First of all, the description of the model of randomised controlled trial is taken into account, because of its importance for evaluation of effectiveness of treatment. Consequences of main elements of randomised controlled trial for scientific inference is explained and the possibility of application of these elements to evaluation of health promotion programmes is discussed. The main points in the discussion on the possibility of application of epidemiological methods to evaluation of health promotion programmes are mentioned.

Double-Blind Method↗
PubMedDate not supplied

Statistical epidemiological screening methods assessing certain biochemical markers.

The epidemiological studies have shown that it is difficult to define a "normal" value for the serum concentration of some biochemical markers with predictive significance for cardiovascular diseases (CVDs) as follows: total cholesterol (TC), total lipids (TL), triglycerides (TG), glycemia (G), and urea (U). Our study establishes the mean and limit values of the normality for the above mentioned markers, in an adult population from the Iaşi City, using the epidemiological screening method. The employed methodology includes the records of the results of 2788 biochemical determinations during a period of 5 years, in order to assess the state of health of the population, as well the data working up and interpretation by means of the EpiInfo computer program. By testing a series of "normal" limits, the values found with apparent healthy persons (n = 2691) and persons previously diagnosed with diabetes mellitus or CVDs (n = 97) were analyzed in a differentiated way. In the sample of apparent healthy individuals, with the age between 20 and up to 60, the mean values were: 210 mg% for TC; 6.74 g@1000--TL; 125.74 mg%--TG; 0.91 g%--G and 0.34 g%--U. Satisfactory correlations (correlation coefficient-"r") of age with the values of TC (r = 0.38); TG (r = 0.26) and G (r = 0.23) comparatively with U (r = 0.15) or TL (r = 0.14) were noticed. The comparison of the mean values between males and females did not reveal a significant difference (p > 0.05) for any of the assessed constants. The clinical and community studies of the CVD risk assessed in the Iaşi City area will have to be referred to the registered and analyzed values of this epidemiological screening in the interpretation of some biochemical markers data.

Adult↗
PubMed2005

[Tasks, principles and methods of applied infectious disease epidemiology/field epidemiology].

Applied infectious disease epidemiology/field epidemiology involves the application of epidemiologic methods to unexpected health problems when a rapid, on-site investigation is necessary for timely intervention. While field investigations of acute problems share the need of high methodological quality with prospectively planned studies, they may differ in several respects. In particular, because field investigations of ten start without a clear hypothesis, they may require the use of descriptive studies to generate a hypothesis before analytic studies are conducted. There also may be an immediate need to protect the population's health, pressure to intervene may conflict with the need to investigate and publicity may introduce bias. Outbreak investigations are paradigms of the use and methodology of applied infectious disease epidemiology/field epidemiology. The steps of an outbreak investigation include verification, confirming the diagnosis, developing a case definition and case finding, describing the data in terms of time, place and person, risk identification, formulating and testing of a hypothesis, planning for further studies, establishing control measures and communicating the findings.

Communicable Disease Control↗
PubMed1995

Comparison of random amplified polymorphic DNA with restriction fragment length polymorphism as epidemiological typing methods for Mycobacterium tuberculosis.

Aim-To compare restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) methods for the epidemiological typing of Mycobacterium tuberculosis.Methods-Thirty one M tuberculosis cultures originating from patients in the Canton of Berne in Switzerland, which had previously been typed by RFLP, were subjected to RAPD analysis. Cultures were coded so that the investigators were blind to the RFLP results until RAPD analysis was complete.Results-The 31 cultures of M tuberculosis were divided into nine groups by RFLP and eight groups by RAPD. Generally there was good correlation between the groups identified by the two techniques, with the exception of strains that had only one copy of IS6110. Both methods subdivided isolates that were placed in a single group by the other method.Conclusions-RAPD analysis is quick, simple, and useful for the comparison of small numbers of isolates. RFLP is more reproducible and therefore better suited for the accumulation of RFLP fingerprints for long term local surveillance and large epidemiological studies.

Journal Article↗
PubMed2004

Population-based studies of AD: message and methods: an epidemiologic view.

Dementia is a growing public health problem because the numbers suffering the disease is increasing rapidly as the population ages. Over the past decade several longitudinal population-based studies were initiated and are still on-going. These studies will provide valuable insight into the risk factors for, and progression of dementia. However, there are several design and statistical challenges that are unique to studying dementia in the population and that need to be addressed. These challenges include aspects of both ascertainment of disease and definition of exposure. To reduce bias from prospective epidemiologic studies, not only are new approaches to definition of disease and exposure needed, but new epidemiologic or statistical methods may be required as well.

Alzheimer Disease↗
PubMed1987

Outward Na-K-Cl cotransport in human red blood cells: a methodological evaluation of method for epidemiologic investigations.

The present report evaluates a method for the determination of the maximal velocity of the outward sodium, potassium, chlorine (Na-K-Cl) cotransport in erythrocytes. The loading procedure was carried out using the ionophore nystatin. The technical error for this assay, based on concurrent analysis of randomized blind duplicate samples, was 8.04% of the sample mean and 27.5% of the sample standard deviation. The assay was stable over time and reproducible. Fasting was not necessary. The ratio of intra- to interindividual variances was small. The cells can be safely preserved in an appropriate preservation solution without modification of the ion transport assay. The assay appears to be adequate for use in large-scale field trials.

Chlorides↗
PubMedDate not supplied

[Time series methods in epidemiological studies on air pollution].

The time series methods in the epidemiological studies on air pollution are reviewed, illustrated by means of an autoregressive Poisson regression which was employed in the APHEA and EMECAM Projects. A listing is provided of the variations in the daily number of deaths of people over age 70 (all causes, CIE-9:001-799) in Barcelona, 1991-1995, with the average variations in the daily smog pollution levels. A Poisson regression is used insofar as the dependent random variable presumably follows such a probability distribution. As variable possibly leading to confusion, the impact of weather variables (daily temperature and relative humidity averages), seasonal, tendency-related behaviours and day of the year on the death rate are taken into account (all estimated on a determinist basis), in addition to any other variable which behaves in a way that it can be related to the dependent variable (i.e. flu epidemics). The relationship between the death rate and the confusing-causing variables is modelled on a non-linear basis, and the foreseeable lag times are also taken into account (i.e. by using explicative variable time lags). However, due to control not being perfect, it has been decided to opt for estimating an autoregressive Poisson model (adding in some different explicative variables time giving rise to a lag in the death rate) offsetting the residual autocorrelation. The main advantage of the method of analysis described above is that of making it possible to control confusing variables from a determinist standpoint with a software to which all of the groups taking part in this Project had access. This also affords the possibility of using this method in a set, standardized manner, facilitating the comparison of results and making an objective point analysis possible.

Age Factors↗
PubMed1987

Application of DNA typing methods to epidemiology and taxonomy of Candida species.

Methods are described for extraction of DNA from the yeast form of Candida spp., followed by digestion and electrophoresis of DNA fragments. The resulting gel patterns (greater than 100 bands) were used to type Candida isolates. Four intense bands identified, three of which are present in each isolate (6 to 7, 3.7 or 4.2, and 2.5 to 3 kilobases), appear to be DNA encoding the rRNA. The methods proved to be both simple and reproducible. The patterns were shown to be stable through several hundred doublings from multiple single colonies. A survey of isolates showed that, on the basis of similarity of gel patterns, several Candida species could be sorted into mutually exclusive groups, and subgroups could be created. Analyses of this survey suggested the possible epidemiologic and taxonomic applications of these methods. DNA typing methods appear to offer important potential advantages over phenotyping methods. The methods provide a base for further epidemiologic studies and for further development of techniques, such as the use of cloned probes for studies of DNA homology.

Candida↗
PubMedDate not supplied

[Impact of guidelines in investigating foodborne disease outbreaks services in Lazio region, Italy].

Epidemiological investigation of foodborne disease outbreaks helps us to better define the risks, hazards and vehicles involved. In 1997 guidelines on epidemiological methods for investigating these outbreaks were implemented in the Lazio Region. Methods used in investigating the 410 foodborne disease outbreaks reported in the 1996-2000 period were analysed to evaluate the impact of the guide lines on health services. Specific food attack-rates (epidemiological methods) were calculated more frequently in outbreaks with setting of mass catering with many exposed people (46% of these outbreaks) than in outbreaks in home setting with few exposed people (13% of these cases). Inversely, in smaller outbreaks the proportion of cases with detected aetiology (microbiological method) was higher (66%) than in larger ones (43%). For foodborne disease outbreaks with at least 30 people exposed epidemiological methods of investigating showed temporal trend in the period 1996-2000: the epidemics in which attack rates were calculated increased from 50% to 83%, those in which epidemic curve was drawn increased from 17% to 79%, and those in which food specific attack rates were calculated increased from 33% to 58%. The hazard analysis of critical control points (HACCP) was performed only in 18.3% of the cases. In conclusion, the guide lines resulted in a wider application of epidemiological methods in large outbreaks with a well defined exposure resulting in an improved detection of vehicles of foodborne diseases. Epidemiological methods possibly are not adequate to investigate smaller foodborne outbreaks.

Cohort Studies↗
PubMed1995

The application of multidimensional scaling methods to epidemiological data.

This paper illustrates the use of multidimensional scaling methods (MDS) to examine space-time patterns in epidemic data. The paper begins by outlining the principles of MDS. The model is then formally specified and illustrated by application to two data sets. The first is partly a tutorial example. It uses monthly reported measles morbidity data for the 31-year period from January 1960 to December 1990, collected for the 50 states of the USA, plus New York City and the District of Columbia. These data are used to explore the various ways in which MDS may be used to identify changing spatial patterns in geographically-coded data. In addition to their tutorial use, the data are also employed to search for any substantive changes in the geographical structure of measles epidemics in the USA that may have followed the introduction of mass vaccination in 1965. New England appears to have developed an epidemic profile distinct from the rest of the USA, and there is tentative evidence of an urban-rural split in epidemic characteristics. The second data set takes annual reported measles mortality data for New Zealand and the states of Australia from 1860 to 1949. MDS is used to show how the spatial relationships among these geographical units have changed over time in response to changes in the sizes of local susceptible populations.

Australia↗
PubMed1992

Rapid method for epidemiological evaluation of gram-positive cocci by field inversion gel electrophoresis.

We report a rapid method for the isolation of intact chromosomal DNA from gram-positive cocci that is suitable for in situ restriction endonuclease digestion in agarose blocks. When combined with a rapid field inversion gel electrophoresis protocol, this approach allows the preparation and electrophoretic analysis of chromosomal restriction fragments produced by rare-cutting enzymes in a total time period of 2 days from start to finish. The utility of the method is demonstrated in the epidemiological evaluation of Staphylococcus epidermidis clusters from two hospitals as well as of additional representative staphylococci and enterococci.

DNA Restriction Enzymes↗
PubMed2001

[The HVR genotypes and their relationship with the resistance of methicillin-resistant staphylococci].

OBJECTIVE: To investigate the HVR-PCR genotype of methicillin-resistant Staphylococci in local hospitals and compare it with the antibiograms, with aview to selecting effective antibacterial agents, moreover, to discuss preliminarily its role in molecular epidemiology. METHODS: The minimal inhibitory concentrations(MICs) of 86 MRSA, 10 MRSE(Mc'S. epidemidis), 5 MSSE(Mc'S. epidemidis), 8 MRSH(Mc'S. haemolyticus) and 5 MSSH(Mc'S. haemolyticus) clinical isolates collected from 4 local hospitals were tested by serial two-fold agar dilution method; their DNA were extracted by moved basic lytic method, whose polymerase chain reaction(PCR) products amplified, based on the size of mec-associated hypervariable region(HVR) were analyzed by PAG vertical and agarose gel electrophoresis. RESULTS: MRSA, MRSE and MRSH were grouped into 4, 3 and 2 HVR genotypes respectively according to the size of the PCR products. The PCR products amplified from 9 of 10 MRSE isolates were the same as the products amplified from MRSA isolates. MRSA strains in this study were mainly HVR genotypes A and D, which accounted for 52.32% and 39.53%; Genotypes B and C were the most multi-drug resistant, but genotype D was multi-sensitive. The I genotype of MRSE was multi-drug resistant, but its genotype III was multi-drug sensitive. The genotype a of MRSH was more resistant than genotype b. CONCLUSION: These results suggest that HVR-PCR genotype method is an easy and fast method for epidemiological investigation of nosocomial infections caused by MRSA, and it is helpful for clinical selection of antibacterial agents. This method can compare the mec determinants of MRSA and Mc'CNSt isolates and hence to search for the origin of the mec determinant.

Complementarity Determining Regions↗
PubMed2000

[Occurrence of cleft defects of the central nervous system in the Czech Republic 1961-1999. Incidence, prenatal diagnosis and prevalence based on maternal age].

OBJECTIVE OF STUDY: Presentation of the incidence of neural tube defects (anencephaly, spina bifida, encephalocele) in the Czech Republic in 1961 to 1999. Analysis of the prevalence of these defects in different groups by maternal age. TYPE OF STUDY: Retrospective demographic-epidemiological study. METHOD: Epidemiological analysis of the incidence of neural tube defects diagnosed prenatally and postnatally in the Czech Republic in 1961-1999. Mathematical and statistical analysis of these defects by maternal age, the method of 95% confidence probability interval was used. Data from the nationwide register of inborn defects were used assembled in the Institute of Health Information and Statistics of the Czech Republic and data on the prenatal diagnosis from different departments of medical genetics. RESULTS: In the Czech Republic in 1961-1999 4629 cases of neural tube defects were recorded. This number comprised 1812 cases of anencephaly, 2420 cases of spina bifida and 397 cases of encephalocele. Of this total number of notified defects 386 cases of anencephaly were diagnosed prenatally and pregnancy was terminated. In spina bifida thus 261 pregnancies were terminated prematurely, in encephalocele 67 cases. CONCLUSION: A significant reduction of the incidence of anencephaly, spina bifida and encephalocele in the Czech Republic was found during the last decade of the investigation period (1961-1999). This decline is most probably due to advances of primary and secondary prevention. When evaluating maternal age as one of the risk factors for the development of neural tube defects, this risk was neither unequivocally confirmed nor ruled out.

Abortion, Eugenic↗
PubMed1994

Applications of molecular methods to epidemiologic investigations of nosocomial infections in a pediatric hospital.

Molecular typing methods are highly discriminatory for strains that cannot be separated by phenotypic methods. They are especially suited to monitoring outbreaks in children's hospitals. In many cases, molecular typing has improved the understanding of the mechanism of nosocomial acquisition of organisms by allowing distinction between endogenous and exogenous infections. Among exogenous infections, it has distinguished between individual and epidemic strains, thus differentiating cross-infection from independent acquisition.

Bacteria↗