Metaanalysis was performed via a genebased approach. Metasoft is a meta analysis software designed for performing a range of basic and advanced meta analytic methods. Apr 06, 2017 meta analysis learn how to interpret quickly duration. Glass, 1976, p3 metaanalysis techniques are needed because only. Transancestry metaanalyses identify rare and common.
It was first developed by goncalo abecasis, yun li and cristen willer. Metal analysis is important for environmental protection and public health. Metaanalysis for families of experiments in software. Since then, the statistical methods evolved from simply following the approaches used for intervention meta analyses to the summary roc sroc model also known as moseslittenberg model which takes in to account the threshold effect, and then to more advanced. Thomas lumley meta and guido schwarzer meta propose macros for r software. We, and others, have used metal for performing metaanalysis of gwas to identify loci. The historical roots of meta analysis can be traced back to 17th century studies of astronomy, while a paper published in 1904 by the statistician karl pearson in the british medical journal which collated data from several studies of typhoid inoculation is seen as the first time a meta analytic approach was used to aggregate the outcomes of multiple clinical studies.
Metal provides a rich scripting interface and implements efficient memory management to allow analyses of very large data sets and to support a variety of input file formats. Meta analysis is a quantitative, formal, epidemiological study design used to systematically assess the results of previous research to derive. One potential design pitfall of meta analyses that is important to pay attention to is. Metal compiles and runs on most unix and linux systems, and on windows and mac workstations. Additional services on any aspect including writing can be included upon request. It is a userfriendly way of conducting stats without having to deal with the r code itself. However, completeness and userfriendliness are uncommon both in specialised meta analysis software packages and in mainstream statistical packages that have to rely on userwritten commands. Metal provides a computationally efficient tool for metaanalysis of genomewide association scans, which is a commonly used approach for improving power complex traits gene mapping studies.
A number of other, less updated meta analysis applications are available for download and use free of charge. Metaanalysis is a statistical procedure that integrates the results of several independent studies considered to be combinable. The metal software is designed to facilitate meta analysis of large datasets such as several whole genome scans in a convenient, rapid and memory efficient manner. The program combines ease of use with a wide array of computational options and sophisticated graphics. Metal is a tool for metaanalysis genomewide association scans. Effects of anthropogenic heavy metal contamination on. To estimate metaanalysis models, the opensource statistical environment r is quickly becoming a popular choice.
Early versions were used for the analyses presented in sanna et al 2008 and willer et al 2008. Metaanalysis of the copper, zinc, and cadmium absorption. Toxic metals in drinking water is strictly regulated. If you load data for additional studies and repeat the meta analysis command, those results will be stored in a file named metaanalysis2. A meta analysis of 70 articles is provided, the articles being selected on the basis of their tstatistics, standard errors, fstatistics, and sample sizes. Metal is a tool for meta analysis genomewide association scans. Meta analyses are now commonly based on effect sizes, although novel techniques such as pcurve analysis, require the test statistics of the effect of interest, not the effect size. Could anyone suggest a free software for meta analysis.
Provides a computationally efficient tool for metaanalysis of genomewide association scans, which. I would like to compare the effect column of this analysis to another dataset, but in order to do so i need to align the betas depending on which allele the effects refer to. Copy number variation metaanalysis reveals a novel. Now there are dozens of publications with meta analyses every day and it takes less than 5 years for the number published in a year to double. This is an open access article distributed under the terms of the creative. It says the operating system terminated metal due to memory access. It can be used in psychology, general medical practice, or detailed studies of particular diseases. Since that time, not only has meta analysis become a fundamental tool in medicine, but it is also becoming popular. Metal is a program that facilitates the meta analysis of genomewide association scans manuscript available here. A microsoftexcelbased tool for running and critically. When i try to process my one of my studies huge dataset metal software crashes.
For each study, snps with low expected minor allele counts in. When the effect varies from one study to the next, meta analysis may be used to identify the reason for the variation. In our metaanalysis, two genes containing cnvs with exonic overlap reached genomewide significance threshold of meta p value 2. Metal provides a rich scripting interface and implements efficient memory management to allow analyses of very large data sets and to support a.
The metal software is designed to facilitate metaanalysis of large datasets such as several whole genome scans in a convenient, rapid and memory efficient manner. A resource for finding data sources, filters, and standards to support systematic searches of the biomedical literature. We implemented the meta analysis methodology in an microsoft excel addin which is freely. The meta analytic community has contributed to this growth by developing numerous packages specific to metaanalysis. Software used for carrying out metaanalyses and to generate key. Meta analysis learn how to interpret quickly duration. It is freely available and, as it uses the silverlight browser plugin, can be run on just about any pc, thus facilitating its use in teaching environments such as pc labs. In this paper, we discuss the key steps of conducting a meta analysis. Since the term and modern approaches to research synthesis were first introduced in the 1970s, metaanalysis. Metal can combine either a test statistics and standard errors or b pvalues across studies taking sample size and direction of effect into account. Metaanalysis and the science of research synthesis nature. What is a meta analysis in 1976, glass coined the term meta analysis meta analysis refers to the analysis of analyses the statistical analysis of a large collection of analysis results from individual studies for the purpose of integrating the findings.
The tutorial of meta package can be accessed through general package for metaanalysis tutorial pdf. Metal provides a computationally efficient tool for meta analysis of genomewide association scans, which is a commonly used approach for improving power complex traits gene mapping studies. Numerous packages for meta analysis can be downloaded for free that work in r, and there are some great tutorials online. Meta analysis didnt start to spread until the 1970s. Hasselblad wrote an excellent article, with lots of examples and formulae that would be of great value for any researcher who wishes to initiate a metaanalysis 1. If enabled, metal checks if chromosome and position of a variant match across studies. In implementing our software for metaanalysis, a primary. A meta analysis addin for microsoft excel abstract.
Today we will conduct a metaanalysis of two previously conducted prostate cancer gwass in humans. Since that time, not only has meta analysis become a fundamental tool in medicine, but it is also. Epigenomewide metaanalysis of dna methylation and childhood. Software programs for the analysis of metadata are provided by sas, 18 the cochrane revman, 20 splus, 36 statsdirect, 37 statxact, 38 and true epistat. The only meta analysis of epigenomewide methylation in childhood asthma included 392 cases but did not examine newborn methylation. In this study, the meta analysis combined the effects and p values of 34,681. Ten simple rules for carrying out and writing metaanalyses plos. What is a metaanalysis in 1976, glass coined the term metaanalysis metaanalysis refers to the analysis of analyses the statistical analysis of a large collection of analysis results from individual studies for the purpose of integrating the findings. Meta analysis is the statistical procedure for combining data from multiple studies. Metal analysis is a convenient alternative to a direct analysis. Metaanalysis of genomewide association studies provides insights. The data underlying meta analyses consists of the empirical findings from individual studies.
Important issues that need to be considered when appraising a systematic. Quantitative pcr qpcr was employed to validate novel significant loci. The theory and statistical foundations of metaanalysis continually evolve, providing solutions to many new and challenging problems. Genomewide metaanalysis identifies multiple novel loci. I have run a meta analysis using metal, and i have an output file ending in. Jasp is a free, opensource program used to perform statistical analysis tests by using r packages. Hi all, i am using metal for meta analysis of some specific snps 6 snps of interest across three studies. Here, we carried out a meta analysis based on 38 primary studies to assess the overall effect of heavy metal contamination on litter decomposition and, most importantly, to identify methodological and environmental variables that can explain variation in the magnitude of the effect among studies. When the effect varies from one study to the next, metaanalysis may be used to identify the reason for the variation. The purpose of this study is to locate all publicly available meta analytic r packages. A meta analysis is the use of statistical methods to summarise the results of these studies.
Winbugs, a freely available bayesian software package, has been the most widely used software package to conduct network meta analyses. The term was apparently coined by statistician gene v glass in a 1976 speech he made to the american education research association. Glass first defined meta analysis in the social science literature as the statistical analysis of a large collection of analysis results from individual studies for the purpose of integrating the findings 9. Genecentric meta analysis in 87,736 individuals of european ancestry identifies multiple bloodpressurerelated loci. Deviations from given guidelines could cause the failure of metaanalysis software or the inclusion of wrong or mismatched variables in the. Metaanalysis is increasingly used as a key source of evidence synthesis to inform clinical practice. Metal metal is a tool for the metaanalysis of genomewide association studies. As you move up the pyramid the amount of available literature on a given topic decreases, but the relevancy and quality of that literature increases. Meta analysis is the quantitative analysis of the results included in an sr. The primary purpose of the meta analysis is to enable general conclusions to be drawn from the major published empirical studies regarding the relationships between international tourism. The use of network meta analysis has increased dramatically in recent years.
You can change default output file names with the outfile command. For our transethnic meta analysis across our meta analysis and the gugcbased study, we used mantra v. Numerous methodologic issues particularly with respect to biases and the use of meta analysis are still controversial. The chromosome and position fields are propagated to the meta analysis result file useful when generating manhattan or locuszoom plots.
Since then, metal has become quite a popular tool for the analysis of genomewide association scans. We therefore considered it timely to provide a systematic overview of the features, criterion validity, and usability of the currently available software that is dedicated to meta analysis of causal therapeutic and etiologic studies. Fixed effects model fe, random effects model re, han and eskins random effects model re2 and binary effects model be. This paper is a basic introduction to the process of meta analysis. Metaanalysis is the statistical procedure for combining data from multiple studies. To install, unpack the archive below, type make and follow. To identify families of experiments that used meta analysis, to investigate their methods for effect size construction and aggregation, and to assess the reproducibility and validity of their results. In most library databases, you can find meta analysis research articles by using meta analysis as a search term there are a few databases that have special limiters for publication type or methodology in the advanced searching section. The metaanalysis function of jasp is based on the aforementioned metafor r package. Other metal analysis needs to be preformed in groundwater, surface water, wastewater, solid waste, soils, and sludge.
Metaanalysis is the quantitative analysis of the results included in an sr. Im doing a meta analysis on a couple of gwas studies using metal genetics software. Genomewide metaanalysis identifies eight new susceptibility. The r codes and its guidance for metaanalysis done can be found in additional file 5. Meta analysis is a group of statistical techniques that enable data from more than one study to be combined and analyzed as a new dataset. However, it is not always suitable for metaanalysis of correlational data where it is preferable to use a good statistical program sas, stata, lisrel. Meta analysis results are stored in the file metaanalysis1. Metal analysis is a convenient alternative to a direct analysis of merged data from multiple studies. If you use metal please fill out a copy of the registration form or email goncalo.
Most of these packages are optimized for older operating systems, such as the msdos and earlier versions of microsoft windows. An extensive analysis of the available literature from 1995 up to 2015 was used to identify studies that calculated the capacity of aquatic plants to absorb heavy metals. In practice, this implies the combination of the results of several individual clinical trials using specialized statistical methodology. Correction for sample overlap in sample size weighted meta analysis developed by sebanti sengupta. Meta analysis is a statistical methodology that combines or integrates the results of several independent clinical trials considered by the analyst to be combinable huque 1988. Pdf metal provides a computationally efficient tool for metaanalysis of genomewide association. A metaanalysis is the use of statistical methods to summarise the results of these studies. In practice, most meta analyses are performed in general statistical packages or dedicated metaanalysis programs. Previous studies have raised concerns about the analysis and meta analysis of crossover experiments and we were aware of several families of experiments that used crossover designs and meta analysis. All literature surveyed for the meta analysis in this paper was from elsevier, wiley, or springer. Epi meta is a free meta analysis software developed. Metaanalysis is the quantitative, scientific synthesis of research results. Furthermore, critical appraisal of network meta analyses conducted in winbugs can be. Letter to the editor on the article the seroprevalence rate and population genetic structure of human cystic echinococcosis in the middle east.
The example is drawn from a recent study of the genetics of glucose levels chen et al, journal of clinical investigation, 2008. If you use metal please fill out a copy of the registration form or email goncalo abecasis. Metaanalysis of genome wide association studies angus 6. We recently performed a metaanalysis of gwas for bmi willer et al. A systematic comparison of software dedicated to meta. It has been around for more than 10 years and has been used in hundreds of analyses and publications. Jul 17, 2014 by joseph rickert broadly speaking, a meta analysis is any statistical analysis that attempts to combine the results of several individual studies. Comprehensive meta analysis is a powerful computer program for meta analysis. A meta analysis pools together the populations from different studies, such as randomized controlled trials, into one statistical analysis and treats them as one large study population with one conclusion. Such analyses are essentially observational, using trials as the unit of enrollment rather than individual patients. However, the learning curve for winbugs can be daunting, especially for new users. When the treatment effect or effect size is consistent from one study to the next, metaanalysis can be used to identify this common effect. Ten simple rules for carrying out and writing metaanalyses. The analysis included 15 studies, each with association statistics at 2.
From the within study results, i can see that results from two of the studies are in the same direction while the results from the 3rd study is null. A meta analysis of gwas was performed on the two duroc pig populations with metal using a zscore approach 54, 55. It has been almost 30 years since the publication of the first meta analysis of diagnostic test accuracy dta. This website includes a download page, brief documentation in our wiki and a registration page. The historical roots of metaanalysis can be traced back to 17th century studies of astronomy, while a paper published in 1904 by the statistician karl pearson in the british medical journal which collated data from several studies of typhoid inoculation is seen as the first time a meta analytic approach was used to aggregate the outcomes of multiple clinical studies. The gwama genomewide association metaanalysis software has been. When the treatment effect or effect size is consistent from one study to the next, meta analysis can be used to identify this common effect. The definition of a meta analysis is much narrower, referring to the statistical methods that are used to combine the results from different studies.
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