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At least 1,441 records · Page 80Linked to original sources
PubMed1992

A statistical chronicle of tuberculosis in Canada: Part I. From the era of sanatorium treatment to the present.

This report marks over 50 years of publication by Statistics Canada of annual reports on tuberculosis statistics. These years have witnessed what has been described as a conquest of tuberculosis in Canada. To quote George Jasper Wherrett in The Miracle of the Empty Beds: One hundred years ago the word consumption (as tuberculosis was then called) struck horror in human hearts. Today, in the western world, it barely evokes any emotion save a too easy surprise that it still exists. This statistical chronicle of tuberculosis in Canada is divided into two parts. Part I: From the Era of Sanatorium Treatment to the Present pulls together data from yellowed-with-age reports on tuberculosis and vital statistics, historical accounts and modern computer files, to document the changes in tuberculosis incidence and mortality over past decades to the present. Part II: Risk Today and Control takes a closer look at those most vulnerable to contracting tuberculosis. It also looks at the future, the need for maintaining and, indeed, strengthening vigilance, and the work yet to be done to eradicate tuberculosis in Canada. The fight against tuberculosis is far from over.

Adolescent↗
PubMed2002

The value of a statistical life: theoretical and empirical evidence.

The value of a statistical life is an important concept in health and environmental economics. This paper provides definitions of the value of a statistical life, and considers single-period and life cycle models. It shows how the value of a statistical life can be measured simply in empirical studies, and addresses the important age profile issue. Available empirical evidence is briefly presented, and recent studies are included that use meta-analysis to determine which variables are appropriate to explain the variance of estimates of the value of statistical life.

Age Factors↗
PubMed1992

A statistical chronicle of tuberculosis in Canada: Part II. Risk today and control.

This report marks over 50 years of publication by Statistics Canada of annual reports on Tuberculosis Statistics. These years have witnessed what has been described as a conquest of tuberculosis in Canada. To quote George Jasper Wherrett in the Miracle of the Empty Beds: One hundred years ago the word consumption (as tuberculosis was then called) struck horror in human hearts. Today, in the western world, it barely evokes any emotion save a too easy surprise that it still exists. This statistical chronicle of tuberculosis in Canada is divided into two parts. Part I: From the Era of Sanatorium Treatment to the Present pulls together data from yellowed-with-age reports on tuberculosis and vital statistics, historical accounts, and modern computer files, to document the changes in tuberculosis incidence and mortality over past decades to the present. Part II: Risk Today and Control takes a closer look at those most vulnerable to contracting tuberculosis. It also looks at the future, the need for maintaining and, indeed, strengthening vigilance, and the work yet to be done to eradicate tuberculosis in Canada. The fight against tuberculosis is far from over.

Acquired Immunodeficiency Syndrome↗
PubMed2004

[Multiple nonlinear statistical method of population genetic structure based on the allelic polymorphism data].

The distribution and structure of the allelic polymorphism data are analyzed and it is pointed out that the distribution of allelic polymorphism data reveals the characteristic of closed data (also named as compositional data or data of constant sum). It is interpreted that the correlation structure of the allelic polymorphism data contains null correlations introduced by "closure" and the statistical distribution of the data is not normal because of its constant row sum, which resulted in great difficulties in analyzing the data with traditional multiple linear statistical methods such as principal component analysis, factor analysis, cluster analysis and canonical correlation analysis. Based on the theory of compositional data analysis proposed by Aitchison in 1982, a multiple nonlinear statistical method originating from the "logratios" approach to the statistical analysis of compositional data is put forward in this paper. As an example, the "logratios" method was used to analyze the genetic structure of TH01 polymorphic loci in Chinese population and the results were compared with those of multiple linear methods such as component principal. It is concluded that the "logratios" multiple nonlinear principle component analysis is a better method with the virtue of sensitivity and specificity for analyzing the genetic structure of population from the data of allelic polymorphism.

Alleles↗
PubMedDate not supplied

Statistical properties of the USP dissolution test with pooled samples.

The Montecarlo simulation method is used to study the statistical properties of the USP pooled dissolution test. In this paper, the statistical behavior of the dissolution test for pooled samples is studied, including: a) the operating characteristic curve showing the probability of passing the test versus the mean amount dissolved, b) the influence of measurement uncertainty on the result of the test, c) an analysis of the dependence of the statistical behavior on the underlying distribution of the individual amounts dissolved, d) a comparison of the statistical behavior of the unit dissolution test versus the pooled dissolution test, e) the average number of stages needed to reach a decision presented as a function of parameters of the lot, f) the relative influence of the three stages of the test on the probability of acceptance.

Algorithms↗
PubMed2006

Statistical, computational and visualization methodologies to unveil gene primary structure features.

OBJECTIVES: Gene sequence features such as codon bias, codon context, and codon expansion (e.g. trinucleotide repeats) can be better understood at the genomic scale level by combining statistical methodologies with advanced computer algorithms and data visualization through sophisticated graphical interfaces. This paper presents the ANACONDA system, a bioinformatics application for gene primary structure analysis. METHODS: Codon usage tables using absolute metrics and software for multivariate analysis of codon and amino acid usage are available in public databases. However, they do not provide easy computational and statistical tools to carry out detailed gene primary structure analysis on a genomic scale. We propose the usage of several statistical methods--contingency table analysis, residual analysis, multivariate analysis (cluster analysis)--to analyze the codon bias under various aspects (degree of association, contexts and clustering). RESULTS: The developed solution is a software application that provides a user-guided analysis of codon sequences considering several contexts and codon usage on a genomic scale. The utilization of this tool in our molecular biology laboratory is focused on particular genomes, especially those from Saccharomyces cerevisiae, Candida albicans and Escherichia coli. In order to illustrate the applicability and output layouts of the software these species are herein used as examples. CONCLUSIONS: The statistical tools incorporated in the system are allowing to obtain global views of important sequence features. It is expected that the results obtained will permit identification of general rules that govern codon context and codon usage in any genome. Additionally, identification of genes containing expanded codons that arise as a consequence of erroneous DNA replication events will permit uncovering new genes associated with human disease.

Algorithms↗
PubMedDate not supplied

Pancreatic fistula and relative mortality in malignant disease after pancreaticoduodenectomy. Review and statistical meta-analysis regarding 15 years of literature.

This paper analysed the literature published in the last 15 years regarding the onset of pancreatic fistula after pancreaticoduodenectony carried out for tumours in the periampullary region, in the head of the pancreas and in the distal common bile duct. Out of 8370 pancreatic resections we were able to go by only 2684 cases, which showed the type of treatment used in the remaining stump, the rates of leakage and relative mortality. The data collected were analysed statistically using the Cochran test and or the chi 2, evaluating the possible significant difference relative to the various methods of reconstruction. The onset of pancreatic fistrula was found to be statistically more frequent after ligation of the stump than after pancreatico-jejunal anastomosis (p = 0.001). Comparing the pancreatico-jejunal end-to-side anastomosis, to pancreatico-jejunal end-to-end and wirsung-jejunal end-to-side anastomosis the first one had shown a significantly higher rate only for leakage (respectively p = 0.008 and p = 0.010). The occlusion of the wirsung duct with biological substances showed better results compared to ligation (p = 0.001) only as regards onset of the fistula, while the comparison between the occlusion and the three types of anastomosis did not show any statistically difference, except for the pancreatico-jejunal end-to-side anastomosis, in which it was significant only as regards leakage (p = 0.009). The statistical analysis between pancreatico-gastrostomy and pancreatico-jejunal anastomoses indicated that the first technique had a lower morbidity rate than pancreatico-jejunal end-to-side (p = 0.001), pancreatico-jejunal end-to-end (p = 0.010) and wirsung-jejunal end-to-side (p = 0.011). We analysed and compared the results obtained before and after 1975, in order to discover whether was an improvement in the prevnetion or in the treatment of such a complication and its consequences. Furthermore, we tried to establish whether the transanastomotic drainage, the site of the neoplasm, the texture of pancreatic parenchyma and the patient's age could in any way influence the onset and course of the fistula.

Drainage↗
PubMed1991

[Statistical meta-analysis of multicenter clinical studies of ibuprofen with regard to cohort size].

The metaanalysis can be either understood as a confirmatory analysis, i.e., imposing a requirement for reproducibility, or it can be rated as a descriptive analysis. To derive confirmatory statements from the statistical metaanalysis of comparative studies, the same requirements prevail as for every individual clinical study: The statistical metaanalysis must be planned prospectively, operational target criteria must be specified ex ante, requirements for inclusion for the individual studies must be fulfilled (comparability of aim, design, inclusion and exclusion criteria, investigational methods of the individual studies). The statistical metaanalysis of comparative studies especially undergoes criticism then, when after inspection of the individual studies that show non-significant results, the summarization, i.e., the compilation of these individual studies leads to a significant overall result in the metaanalysis, which is possibly medically irrelevant. In addition to the metaanalysis, reviews or synopses of a preparation or a substance are also important, in which all available reports on a topic are taken into consideration for a summarizing medical assessment. The results of 28 comparative studies with ibuprofen in the treatment of osteoarthritis are classified in a synopsis. The results of these studies are classified as "ibuprofen better, ibuprofen worse, or ibuprofen equivalent to the respective reference substance". These results lead to the conclusion that ibuprofen at a daily dose of 1200 mg or more is superior to placebo, equivalent or superior to acetylsalicylic acid and, at an appropriate dosage, is comparable to other NSAIDs with regards to the efficacy. The tolerance of ibuprofen must be classified as excellent. The results of six non-comparative studies with ibuprofen carried out from 1985-1990, on a total of 45742 patients in 9115 study centers can be presented in a descriptive statistical metaanalysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Cohort Studies↗
PubMed1990

[Present situation of official statistics related to mortality from external causes].

A study was carried out on the basis of research data of the deaths due to all kinds of accidents and violence of 550 children of less than 15 years of age, resident in the municipality of S. Paulo, State of S. Paulo, Brazil, which occurred during 1985. The project sought to correlate the existing data of the files of the Institute of Legal Medicine (IML) with those of SEADE Foundation (official statistics) and then compare them with the investigator opinion (this latter based on all the additional information available) with a view to: analysing the reliability of the official statistics concerning the main cause of death; and discovering the possible deficiency in the transcription of the IML information to the SEADE Foundation in relation to the same cause. The results are as follows: existing IML information stands quite close to the interviewer's opinion (71.54%) when working at the level of the categories of the International Classification of Diseases (ICD-9), reaching 84.77% of agreement when grouping level is considered; in relation to the interviewer's opinion, official statistics proved to be more reliable when analysed at the grouping level than that at the 3rd digit (67.13% and 24.05%, respectively); comparison between IML and SEADE Foundation data shows only 40% of agreement concerning the ICD-9 categories, reaching 75% when grouping data are analysed. These figures corroborate the proposed hypothesis that the IML, though having files with highly-detailed information, does not transfer them to the SEADE Foundation, thus diminishing the reliability of the official statistics when the details of each cause of death are considered.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents↗
PubMed1986

Statistical quality control methods in standardization of BCG vaccines.

The quality control of the BCG vaccine lacks the requirements of exact statistical methods, although the principles of bioassay have been required in the control of other biological products for a long time. For a remedy and to eliminate controversies in the interpretation of the laboratory results of BCG products valid statistical control is needed. In the four major laboratory test systems generally used to control: the viability of the BCG products, the residual virulence of the BCG strains, the allergenic potency and 4) the immunogenic potency of the BCG vaccines the following statistical methods should be required: estimations of the unbiased point and 95% confidence interval of the viable units 10(6)/ml, the mean residual virulence, the mean allergizing and protective capacity in appropriate models, the expressions of the relative potency of the in vitro viability and the in vivo test systems to a Reference Preparation, hypothesis tests using the unbiased estimates for the comparison of the estimated parameters of the controlled vaccines (Anova) and testing the stability of the viability (Regranal), multiple comparison with the ranked estimates to diminish Type I error in rejected null hypotheses, test of concordance between the sets of ranked parameters of the different test systems. Valid models will promote the standardization of the BCG vaccine, will ensure the objective statistical inference of the control results, the interpretation of the immunogenicity and reactogenicity of the BCG vaccines and the understanding of the epidemiological processes in tuberculosis.

Animals↗
PubMed1986

Sample size for case-control studies using Cochran's statistic.

Sample size determination for case-control studies of chronic disease are often based on the simple 2 X 2 tabular cross-classification of exposure and disease, thereby ignoring stratification which may be considered in the analysis. One consequence of this approach is that the sample size may be inadequate to attain a specified power and size when performing a statistical analysis on J 2 X 2 tables using Cochran's (1954, Biometrics 10, 417-451) statistic or the Mantel-Haenszel (1959, Journal of the National Cancer Institute 22, 719-748) statistic. A sample size formula is derived from Cochran's statistic and it is compared with the corresponding one derived when the data are treated as unstratified, and also with two other formulas proposed for stratified data analysis. The formula developed yields values slightly higher than one recently proposed by Muñoz and Rosner (1984, Biometrics 40, 995-1004), which assumes that both margins of each 2 X 2 table are fixed, while the present study considers only the case-control margin to be fixed.

Biometry↗
PubMed1985

Test statistics for detecting aneuploidy and hyperdiploidy.

Possible approaches to the analytical evaluation of ploidy patterns are discussed and two specific problems are considered: detection of early onset of aneuploidy and detection of moderate hyperdiploidy. A statistical model for a euploid DNA pattern is formulated in terms of a mixture distribution. A test statistic for detecting deviations from this pattern is defined, and its performance is evaluated for simulated data representing differing degrees of severity of aneuploidy. An analysis based on a discriminant function using order statistics of the sample cumulative distribution functions is proposed for detecting hyperdiploidy. This procedure has the advantage of being relatively distribution-free; its performance is evaluated for simulated data and is compared with that of its classical counterparts. Although the results reported are only preliminary, they indicate that tailor-made statistical analyses can provide early detection of aneuploidy and hyperdiploidy with known and acceptable error rates using clinically reasonable sample sizes.

Aneuploidy↗
PubMed1969

Morbidity statistics: a report on current practice in member states of the World Health Organization.

This paper is based on an analysis of questionnaires sent to the health ministries of Member States of WHO asking for information about the extent, nature, and scope of morbidity statistical information. It is clear that most countries collect some statistics of morbidity and many countries collect extensive data. However, few countries relate their collection to the needs of health administrators for information, and many countries collect statistics principally for publication in annual volumes which may appear anything up to 3 years after the year to which they refer. The desiderata of morbidity statistics may be summarized as reliability, representativeness, and relevance to current health problems.

Morbidity↗
PubMedDate not supplied

The public health need for abortion statistics.

As with the delivery of any medical service, abortion has definite public health effects that should be evaluated. The Center for Disease Control (CDC) has monitored the impact of abortion in three ways: (a) conducting epidemiologic surveillance of legally induced abortion beginning in 1969. (b) funding a multicenter study of abortion morbidity beginning in 1971, and (c) undertaking surveillance of abortion-related mortality beginning in 1972. These activities are intended to identify health problems related to abortion, to assess the magnitude of these problems, and to make recommendations directed at eliminating the problems. In addition to the Programmatic uses of abortion data, the CDC statistics have also provided a basis for both legislative and judicial decisions that have had national and local impact. The CDC and the National Center for Health Statistics are currently working collectively to strengthen the reporting of national abortion statistics so that the public health need for abortion statistics can be met.

Abortion, Legal↗
PubMed1980

Atherosclerosis and mortality statistics.

WHO mortality statistics are subject to severe criticism all over the world due to the ICD code, the monocausal evaluation and th inhomogenity of data which are only partially verified by post mortem findings. Despite this fact WHO statistics are the only possibility to compare morality in different areas. In order to prove their reliability we have collected data of patients who have died in 9 Vienna hospitals. Our material consists of more than 15000 out of 25000 death cases in the year 1976. The autopsy rate was about 70%. To handle this amount of datas a computer system was used. In comparison with the official Austrian statistics our total atherosclerosis rate was higher due to the multicausal evaluation and the much higher percentage of CHD. Atherosclerosis of the brain was found in a lower percentage than officially mentioned when autopsy was performed. An example for single case studies is the myocardial infarction in a defined age group to support the importance of statistics based on a high rate of autopsies and the use of electronic data processing.

Aged↗
PubMed1995

PRESS-related statistics: regression tools for cross-validation and case diagnostics.

In the health science literature, a common approach of validating a regression equation is data-splitting, where a portion of the data fits the model (fitting sample) and the remainder (validation sample) estimates future performance. The R2 and SEE obtained by predicting the validation sample with the fitting sample equation is a proper estimate of future performance, tending to correct for the natural upward bias of the R2 and SEE obtained from fitting sample alone. Data-splitting has several disadvantages, however. These include: 1) difficulty, arbitrariness, and inconvenience of matching samples; 2) the need to report two sets of statistics to determine homogeneity; and 3) the lack of equation stability due to diluted sample size. The PRESS statistic and associated residuals do not require the data to be split, yield alternative unbiased estimates of R2 and SEE, and provide useful case diagnostics. This procedure is easy to use, is widely available in modern statistical packages, but is rarely utilized. The two methods are contrasted here using a simulation from original data for predicting body density from anthropometric measurements of a group of 117 women. The PRESS approach is particularly appropriate for smaller datasets; methods of reporting these statistics are recommended.

Adult↗
PubMed1994

Comparison of statistics for candidate-gene association studies using cases and parents.

Studies of association between candidate genes and disease can be designed to use cases with disease, and in place of nonrelated controls, their parents. The advantage of this design is the elimination of spurious differences due to ethnic differences between cases and nonrelated controls. However, several statistical methods of analysis have been proposed in the literature, and the choice of analysis is not always clear. We review some of the statistical methods currently developed and present two new statistical methods aimed at specific genetic hypotheses of dominance and recessivity of the candidate gene. These new methods can be more powerful than other current methods, as demonstrated by simulations. The basis of these new statistical methods is a likelihood approach. The advantage of the likelihood framework is that regression models can be developed to assess genotype-environment interactions, as well as the relative contribution that alleles at the candidate-gene locus make to the relative risk (RR) of disease. This latter development allows testing of (1) whether interactions between alleles exist, on the scale of log RR, and (2) whether alleles originating from the mother or father of a case impart different risks, i.e., genomic imprinting.

Alleles↗
PubMed1993

Trauma audit: clinical judgement or statistical analysis?

Comparisons have been made between two methods currently used to assess the effectiveness of management of major trauma. These are the review of fatal cases by senior clinicians and the use of statistical analysis of severity scores. The former was assessed by a re-examination of the Coroners' reports of 508 patients reviewed by senior clinicians at the request of The Royal College of Surgeons of England Working Party on the Management of Patients with Major Injuries. The latter was based on the 665 fatalities on the files of the UK Major Trauma Outcome Study. The two groups of patients had comparable age and sex profiles and broadly similar ranges of injury severity. There were major differences between and inconsistencies within the two assessments. Clinicians more frequently judged death avoidable in those with very severe injuries. In contrast, the statistical analysis suggested, paradoxically, that the proportion of avoidable deaths in those patients who had minor injuries was less than the proportion of avoidable deaths in those who had more serious injuries. These variations underline the limited values of retrospective peer review and will not encourage clinicians to adopt currently available statistical methods. Further refinements of anatomical and physiological scoring systems and their integration to provide a statistically valid and clinically acceptable measure of outcome are essential prerequisites to the wider introduction and success of trauma audit.

Adolescent↗