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At least 19 recordsLinked to original sources
PubMed2001

Investigation of bias after data linkage of hospital admissions data to police road traffic crash reports.

RESEARCH QUESTION: Does a database of hospital admission data linked to police road traffic accident (RTA) reports produce less biased information for the injury prevention policymaker, planner, and practitioner than police RTA reports alone? DESIGN: Data linkage study. STUDY POPULATION: Non-fatal injury victims of road traffic crashes in southern England who were admitted to hospital. DATA SOURCES: Hospital admissions and police RTA reports. MAIN OUTCOME MEASURES: The estimated proportion of road traffic crashes admitted to hospital that were included on the linked database; distributions by age, sex, and road user groups: (A) for all RTA injury admissions and (B) for RTA serious injury admissions defined by length of stay or by nature of injury. RESULTS: An estimated 50% of RTA injury admissions were included on the linked database. When assessing bias, admissions data were regarded as the "gold standard". The distributions of casualties by age, sex, and type of road user showed major differences between the admissions data and the police RTA injury data of comparable severity. The linked data showed smaller differences when compared with admissions data. For RTA serious injury admissions, the distributions by age and sex were approximately the same for the linked data compared with admissions data, and there were small but statistically significant differences between the distributions across road user group for the linked data compared with hospital admissions. CONCLUSION: These results suggest that investigators could be misinformed if they base their analysis solely on police RTA data, and that information derived from the linked database is less biased than that from police RTA data alone. A national linked dataset of road traffic crash data should be produced from hospital admissions and police RTA data for use by policymakers, planners and practitioners.

Accidents, Traffic↗
PubMed1985

Construction of conditional lod tables from multiple-locus linkage data.

Although multipoint linkage data are becoming quite common, economical and efficient methods for presenting these data are not yet in use. Tables giving the full likelihood function would be very voluminous, whereas reduction to standard lods destroys part of the information. We suggest a special lod table representation which preserves nearly all the information about both gene order and genetic map distance at a great reduction in data presented. Conditional lods, coined "c-lods" to distinguish them clearly from ordinary lods, are calculated for distances between each adjacent pair of loci, with all distances among other loci in the system conditionally optimized. Thus, in an n-locus system, conditional lods are presented for the n - 1 adjacent pairs of loci only. The principal reason for reporting lod scores is the potential for combining data from separate studies to reach conclusive evidence for linkage and gene order. Because estimates of recombination are different in each set of data, the crux of the problem is to present scores that provide a close approximation to the true likelihood away from maximum likelihood (ML). The sum of conditional lods closely approximates the likelihood throughout the domain. Therefore, conditional lods contribute appropriately when mapping from several sources of data, so contradictory estimates can be reconciled efficiently.

Biometry↗
PubMed2000

LIAN 3.0: detecting linkage disequilibrium in multilocus data. Linkage Analysis.

SUMMARY: LIAN is a program to test the null hypothesis of linkage equilibrium for multilocus data. LIAN incorporates both a Monte Carlo method as well as a novel algebraic method to carry out the hypothesis test. The program further returns the genetic diversity of the sample and the pairwise distances between its members.

Chromosome Mapping↗
PubMed2005

[A new model of comprehensive data linkage--evaluation of its application in femoral neck fracture].

Aim of the project was a comprehensive assessment of short- and middle-term outcome of femoral neck fracture by linkage and analysis of available data from routine care. For this purpose, a generic model of data linkage was developed, agreed with the data security officer, and practically applied. Included were all patients of the AOK Westphalia-Lippe, who were treated in a general or trauma surgery hospital in 1995/1999 for a femoral neck fracture (ICD-9: 820). For these patients, the linkage was based on the following sources: the data regarding the initial hospital stay were provided by the office of quality assurance of the chamber of physicians of Westphalia-Lippe; the administrative data were provided by the AOKWestphalia-Lippe; and the data evaluating the nursing needs were obtained from the Medical Services of the Health Insurance of Westphalia-Lippe (MDK). This paper presents the model of data linkage and describes its practical implementation; it also presents medical data demonstrating that femoral neck fractures are associated with high mortality and increase of nursing needs in the course of disease. The benefit of the new model is manifold and can be easily extended to other clinical questions.

Aged↗
PubMed1986

Genetic linkage between X-linked retinitis pigmentosa and DNA probe DXS7 (L1.28): further linkage data, heterogeneity testing, and risk estimation.

Further linkage data relating X-linked retinitis pigmentosa and DNA probe DXS7 (L1.28) is presented in this paper. The current mean estimate of the recombination fraction (theta) including this and all published data, is 0.09, with confidence limits 0.04 to 0.17 (maximum Lod score of 14.01 at a theta of 0.08). There is no evidence for heterogeneity of recombination fraction between the 13 families for which data are available. However, it is argued that heterogeneity should be assumed to exist for the purposes of risk estimation. Mean estimates and variances of risk are calculated for hypothetical families each with different linkage data. In families in which no recombination has been observed, the mean and variance of risk are sufficiently small for the clinical use of this probe to be acceptable to many.

DNA↗
PubMed2000

The feasibility of routine mortality and morbidity register data linkage to study the occurrence of acute coronary heart disease events in Finland. The Finnish Cardiovascular Diseases Registers (CVDR) Project.

Validated population-based data on the occurrence of coronary heart disease in Finland have previously been obtained from myocardial infarction (MI) registers. Such registers cannot, however, cover large areas. Therefore, the Finnish Cardiovascular Diseases Registers (CVDR) Project was set up to obtain data for the whole of Finland. The CVDR Project is based on routine mortality and morbidity data linkage. We report here the overall approach used in the project, the results of the feasibility study and the first main results. In Finland, data on all hospitalizations are registered in the nationwide Hospital Discharge Register. Also, data on all deaths are collected in the nationwide Causes of Death Register. The unique personal identification number assigned to all persons residing in Finland was used for data linkage. Data have been validated using the FINMONICA MI registers. Sensitivity analyses showed that the data were robust and consistent between different geographical areas. Coronary heart disease (CHD) mortality as well as the incidence and event rates showed the same very clear geographical pattern, dividing Finland to a southwest area with a lower occurrence and a northeast area with nearly twice higher occurrence. Case fatality did not differ much between the areas and did not follow this Southwest-Northeast division. The differences between northeast and southwest Finland may be related to differences in risk factor levels but also to socioeconomic and genetic differences. The CVDR Project data will be instrumental in further research addressing these issues.

Acute Disease↗
PubMed2005

SMOOTH: a statistical method for successful removal of genotyping errors from high-density genetic linkage data.

High-density genetic linkage maps can be used for purposes such as fine-scale targeted gene cloning and anchoring of physical maps. However, their construction is significantly complicated by even relatively small amounts of scoring errors. Currently available software is not able to solve the ordering ambiguities in marker clusters, which inhibits the application of high-density maps. A statistical method named SMOOTH was developed to remove genotyping errors from genetic linkage data during the mapping process. The program SMOOTH calculates the difference between the observed and predicted values of data points based on data points of neighbouring loci in a given marker order. Highly improbable data points are removed by the program in an iterative process with a mapping algorithm that recalculates the map after cleaning. SMOOTH has been tested with simulated data and experimental mapping data from potato. The simulations prove that this method is able to detect a high amount of scoring errors and demonstrates that the program enables mapping software to successfully construct a very accurate high-density map. In potato the application of the program resulted in a reliable placement of nearly 1,000 markers in one linkage group.

Algorithms↗
PubMed1995

Health and environment in São Paulo, Brazil: methods of data linkage and questions of policy.

This article addresses the development of data linkage methods for the analysis of urban environmental health problems and the development of appropriate policies and discusses, based on existing experience of data linkage in São Paulo (Brazil), the potential for routine environmental health monitoring and management in a major developing country industrial centre. The article looks briefly at two major environmental health problems in São Paulo: first, air pollution which has potential impacts on health of the whole population; and second, environmental differentials in conditions between groups within cities, which have substantial health effects on the economically deprived. The article argues that the health impact of environmental differentials in São Paulo is large, but unmonitored as a serious environmental health threat. In contrast, air pollution is monitored routinely, although its health effects are relatively small at present. The paper concludes with a discussion of policy implications of environmental health monitoring--which potentially require a substantial shift in attitudes of the urban wealthy.

Air Pollution↗
PubMed1992

Chromlook: an interactive program for error detection and mapping in reference linkage data.

Preliminary genetic linkage maps of every human chromosome have been generated over the past few years, and efforts to extend and refine these maps are under way. However, fine-resolution mapping is tedious and difficult because the inevitable errors in the data confound estimates of both the placement of loci and the distances between them. Fortunately, in most cases these errors result in observed recombinants where no true recombinant has occurred. The simple strategy presented here identifies these recombinants by relying on the assumption that recombinants between two adjacent markers are relatively rare events. This strategy has been implemented in the computer program CHROMLOOK, and examples of its use are given. Identification of recombinants allows for the directed regenotyping of suspicious data, the quick mapping of new polymorphisms using recombination minimization, and the development of a meiotic breakpoint map.

Chromosome Mapping↗
PubMed1978

Linkage analysis in Dictyostelium discoideum using multiply marked tester strains: establishment of linkage group VII and the reassessment of earlier linkage data.

To aid linkage analysis and mapping studies in Dictyostelium discoideum, we have constructed several tester strains with easily scored mutations characterizing the six currently identified linkage groups. Use has been made of conditionally lethal mutants unable to grow upon Bacillus subtilis, and the locus of the mutation involved (bsgA) has been assigned to linkage group III. The mutation cobA1, which confers resistance to cobaltous chloride, has been assigned to a previously unidentified linkage group (VII). The temperature-sensitive growth mutation tsgC7, previously reported to define linkage group V, has been reassigned to group III, leaving linkage group V presently unmarked. The further use of genetic tester strains is described.

Chromosome Mapping↗
PubMed1987

Tests of gene order from three-locus linkage data.

Exact tests for gene order are derived and compared for three loci using linkage data from phase-known, completely informative marker loci (i.e. parents are heterozygotes with at most one allele identical at each locus), or from triple back-cross matings. A simulation method, based on resampling genotypes of children, is introduced to obtain approximations to the distribution of the test statistics for general mating types in families consisting of children and parents, with or without grandparents, as are used in many studies in human gene mapping. The method is illustrated by an application to linkage data on chromosome 13.

Chromosome Mapping↗
PubMed2003

[MapDraw: a microsoft excel macro for drawing genetic linkage maps based on given genetic linkage data].

MAPMAKER is one of the most widely used computer software package for constructing genetic linkage maps.However, the PC version, MAPMAKER 3.0 for PC, could not draw the genetic linkage maps that its Macintosh version, MAPMAKER 3.0 for Macintosh,was able to do. Especially in recent years, Macintosh computer is much less popular than PC. Most of the geneticists use PC to analyze their genetic linkage data. So a new computer software to draw the same genetic linkage maps on PC as the MAPMAKER for Macintosh to do on Macintosh has been crying for. Microsoft Excel,one component of Microsoft Office package, is one of the most popular software in laboratory data processing. Microsoft Visual Basic for Applications (VBA) is one of the most powerful functions of Microsoft Excel. Using this program language, we can take creative control of Excel, including genetic linkage map construction, automatic data processing and more. In this paper, a Microsoft Excel macro called MapDraw is constructed to draw genetic linkage maps on PC computer based on given genetic linkage data. Use this software,you can freely construct beautiful genetic linkage map in Excel and freely edit and copy it to Word or other application. This software is just an Excel format file. You can freely copy it from ftp://211.69.140.177 or ftp://brassica.hzau.edu.cn and the source code can be found in Excel's Visual Basic Editor.

English Abstract↗
PubMed2001

Enumeration of non-communicable disease in rural South Africa by electronic data linkage and capture-recapture techniques.

Non-communicable diseases (NCDs) are becoming increasingly common and important in developing countries, yet their enumeration is problematic. We have attempted to enumerate NCD patients in a rural district of KwazuluNatal, South Africa, using the techniques of electronic data linkage and capture-recapture (CR). We examined four major NCDs (hypertension, diabetes, asthma and epilepsy). Basic patient details were recorded onto EpiInfo software over a 6-week period, from the main hospital clinic at Hlabisa, as well as the 10 outlying peripheral health clinics. Using electronic data linkage of lists from the main hospital, the peripheral clinics, and repeat prescription cards, a district NCD register was produced of 2455 patients. The mean age was 51 +/- 16 years (1 SD) and 76% were female. Of the total NCD patients, 62% had hypertension (age 57 +/- 12 years, 82% female), 16% epilepsy (age 35 +/- 17 years, 49% female), 13% asthma (age 45 +/- 19 years, 60% female) and 12% diabetes (age 54 +/- 13 years, 61% female). Estimated population crude prevalence rates for known NCD cases on the register were 7.4% for hypertension, epilepsy 0.2%, asthma 0.2% and diabetes 0.2%. We also attempted a CR analysis to assess completeness of data, by comparing overlap between patients attending peripheral clinics, and the central Hlabisa Hospital clinic. Matching by name, age, and diagnosis proved feasible, but there was little overlap, and CR calculations were invalid because of the relative independence of sources. We conclude that NCDs are common in rural Africa, and that a simple NCD district register is a potentially feasible and inexpensive option. Capture-recapture analysis is feasible, but requires suitable lists with acceptable overlap of patients.

Adolescent↗
PubMed1992

Software for analysis and manipulation of genetic linkage data.

We present eight computer programs written in the C programming language that are designed to analyze genotypic data and to support existing software used to construct genetic linkage maps. Although each program has a unique purpose, they all share the common goals of affording a greater understanding of genetic linkage data and of automating tasks to make computers more effective tools for map building. The PIC/HET and FAMINFO programs automate calculation of relevant quantities such as heterozygosity, PIC, allele frequencies, and informativeness of markers and pedigrees. PREINPUT simplifies data submissions to the Centre d'Etude du Polymorphisme Humain (CEPH) data base by creating a file with genotype assignments that CEPH's INPUT program would otherwise require to be input manually. INHERIT is a program written specifically for mapping the X chromosome: by assigning a dummy allele to males, in the nonpseudoautosomal region, it eliminates falsely perceived noninheritances in the data set. The remaining four programs complement the previously published genetic linkage mapping software CRI-MAP and LINKAGE. TWOTABLE produces a more readable format for the output of CRI-MAP two-point calculations; UNMERGE is the converse to CRI-MAP's merge option; and GENLINK and LINKGEN automatically convert between the genotypic data file formats required by these packages. All eight applications read input from the same types of data files that are used by CRI-MAP and LINKAGE. Their use has simplified the management of data, has increased knowledge of the content of information in pedigrees, and has reduced the amount of time needed to construct genetic linkage maps of chromosomes.

Alleles↗
PubMed2002

Current evaluation and future needs of a mental health data linkage system in a remote region: a Canadian experience.

Linking client data across care sectors and agencies is becoming essential to ensure continuity of care, evaluation, and planning of mental health services delivery. The Data Linkage System (DLS), a record-linked, client-based, mental health database in northwestern Ontario, was established in response to this need. It is a voluntary system currently used by 30 of 40 mental health programs. The study surveyed program administrators to determine the system's utilization, perceived value, and future needs regarding data collection. The survey results delineated the perceived usefulness of the DLS in a remote region. The findings will provide direction for continued development of the DLS.

Community Mental Health Services↗
PubMed1992

Preliminary ordering of multiple linked loci using pairwise linkage data.

A method is presented for the preliminary ordering of loci on a chromosome using pairwise linkage data. The method is based on the biologically reasonable assumption that the "true" order of a set of linked loci will be the one that minimizes the total length of the chromosome segment. Here the "length" is defined as the sum of adjacent recombination fractions. The method searches for the optimal order, represented by a minimum distance map (MDMAP), even when it is not possible to examine the n!/2 possible distinct orders for n loci. A computerized approach, using the simulated annealing algorithm of Kirkpatrick et al. [1983], forms the basis of the method. It can be applied to data from radiation hybrid experiments as well as that from conventional family linkage studies. The technique is applied to several sets of published data to illustrate how it performs in practice. The advantages and the disadvantages of the method are discussed so that it will be clear under what conditions it is likely to work well. When data sets are "complete," in the sense that all possible pairwise recombination fractions have estimates, and when no large clusters of extremely tightly linked loci are present, the method produces ordered sets of loci that agree well with those generated by other, more complex methods. Any discrepancies that occur are likely to be with respect to the orientation of nearest-neighbor loci, where relative order cannot be reliably established by any method. The method thus provides a simple, rapid means of obtaining a preliminary order for a set of loci known to be in the same linkage group.

Algorithms↗