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Adequate Sample Size (adequate + sample_size)
Selected AbstractsTargeted group antenatal prevention of postnatal depression: a reviewACTA PSYCHIATRICA SCANDINAVICA, Issue 4 2003M.-P. Austin Objective:, To review the efficacy of antenatal group interventions aimed at reducing postnatal depression (PND) in ,at risk' women. Method:, Medline, Psyclit, HEALTHSTAR, EMBASE, Cochrane library, UK National Research Register and CINHAL searches were performed from 1960 to December 2001 focussing on randomized controlled trials (RCTs). Results:, As statistical synthesis of the studies was not feasible, a qualitative review is provided. All five studies reviewed suffer from substantial limitations including small numbers; unrealistic effect sizes; large attrition rates; lack of a systematic approach in identifying those ,at risk' and thus clinically heterogenous samples. Three of the studies used unvalidated interventions that were educational or supportive in approach. While one such study reported a benefit of intervention, the largest study using a structured intervention, reported no effect. A very small study using interpersonal therapy, was promising but needs replication with an adequate sample size. Conclusion:, There is currently little evidence from RCTs to support the implementation of antenatal group interventions to reduce PND in ,at risk' women. Further studies addressing the significant methodological limitations are recommended before concluding that antenatal targeted interventions have no place in maternity care. [source] Risk factors for alcoholic liver diseaseADDICTION BIOLOGY, Issue 3 2000Stefano Bellentani Alcoholic liver disease (ALD) is still a frequent disorder, even though its incidence appears to be decreasing. In spite of intense investigation, the precise mechanisms leading to ALD are still imprecisely known. This is due in part to the lack of a reliable animal model; in part to the difficulty of obtaining clinical data of adequate sample size and derived from unblased populations and finally from the lack of uniformity of the criteria used to define ALD. This paper will review what is known of the various pieces of this puzzle, with particular emphasis not only on the total amount of alcohol consumed, but also on drinking patterns and type of alcoholic beverage ingested. The other potential factors such as age, gender, genetic background, nutritional status, occupational hazards and viral diseases (especially HCV infection) will be touched upon. [source] Basic Process Capability Indices: An Expository ReviewINTERNATIONAL STATISTICAL REVIEW, Issue 3 2008Mohammed Z. Anis Summary A review of the four basic process capability indices has been made. The interrelationship among these indices has been highlighted. Attention has been drawn to their drawbacks. The relation of these indices to the proportion nonconforming has been dwelt upon and the requirement of the adequate sample size has been emphasized. Cautionary remarks on the use of these indices in the case of nonnormal distributions, skewed distributions, and autocorrelated data are also presented. The effect of measurement error on process capability indices has been dealt with in great detail. Résumé Une revue des quatre index de capacité de procédé fondamentaux a été faite. L'inter-relation entre ces index a été soulignée. L'attention a été dessinée à leurs inconvénients. La relation de ces index au nonconformer de proportion a été demeurée sur et la condition de la taille d'échantillon suffisante a été soulignée. Les remarques d'avertissement sur l'usage de ces index dans le cas de distributions nonnormaux, les distributions déformés et les données d'auto-correspondu sont aussi présentés. L'effet d'erreur de mesure sur les index de capacité de procédé a été traité dans les moindres détails. [source] Thresholds for food allergens and their value to different stakeholdersALLERGY, Issue 5 2008R. W. R Crevel Thresholds constitute a critical piece of information in assessing the risk from allergenic foods at both the individual and population levels. Knowledge of the minimum dose that can elicit a reaction is of great interest to all food allergy stakeholders. For allergic individuals and health professionals, individual threshold data can inform allergy management. Population thresholds can help both the food industry and regulatory authorities assess the public health risk and design appropriate food safety objectives to guide risk management. Considerable experience has been gained with the double-blind placebo-controlled food challenge (DBPCFC), but only recently has the technique been adapted to provide data on thresholds. Available data thus vary greatly in quality, with relatively few studies providing the best quality individual data, using the low-dose DBPCFC. Such high quality individual data also form the foundation for population thresholds, but these also require, in addition to an adequate sample size, a good characterization of the tested population in relation to the whole allergic population. Determination of thresholds at both an individual level and at a population level is influenced by many factors. This review describes a low-dose challenge protocol developed as part of the European Community-funded Integrated Project Europrevall, and strongly recommends its wider use so that data are generated that can readily increase the power of existing studies. [source] SHORT COMMUNICATION: Recurrent Pregnancy Loss and Apolipoprotein E Gene Polymorphisms: A Case,Control Study from North IndiaAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 3 2010Meenal Agarwal Citation Agarwal M, Parveen F, Faridi RM, Phadke SR, Das V, Agrawal S. Recurrent pregnancy loss and apolipoprotein E gene polymorphisms: a case,control study from North India. Am J Reprod Immunol 2010; 64: 172,178 Problem, The role of apolipoprotein E gene polymorphisms in the etiology of recurrent pregnancy loss (RPL) is not clearly understood. We evaluated this polymorphism in unexplained pregnancy losses among North Indian women. Method of study, In a retrospective case,control study, 200 well-characterized RPL cases were examined for their APO-E genotypes based on restriction fragment length polymorphism analysis of PCR-amplified fragments including amino acid positions 112 and 158. The observed genotypes were compared with those obtained from an equal number of ethnically matched negative controls. Results, We found similar APO-E genotypes and E2, E3, and E4 allele frequency distribution among RPL patients and controls. The allele frequencies obtained in patients and controls respectively were as follows: E2 = 7.5% and 9.0% (P = 0.52; OR = 0.81; 95%CI = 0.49,1.35), E3 = 89.7% and 90% (P = 1.00; OR = 0.97; 95%CI = 0.61,1.54), and E4 = 2.8% and 1% (P = 0.12; OR = 2.79; 95%CI = 0.88,8.86). Conclusions, Our data did not support the association of APO-E gene polymorphisms with recurrent pregnancy loss as reported by some of the previous studies. We endorse adequate characterization of RPL cases, inclusion of appropriate negative controls, and adequate sample size prior to addressing such studies. [source] Deliberate self-harm in older adults: a review of the literature from 1995 to 2004INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 8 2007Jenifer Chan Abstract Background The prevention of suicide is a national and international policy priority. Old age is an important predictor of completed suicide. Suicide rates in old age differ markedly from country to country but there is a general trend towards increasing rates with increasing age. In 1996 Draper reviewed critically the evidence on attempted suicide in old age in the 10 years between 1985 and 1994. The review highlighted a need for prospective controlled studies in older people with more representative samples as well as studies examining the interaction of risk factors, precipitants, motivations, psychopathology and response to treatment. The aim of this paper is to update this review and to summarise the advances in our understanding of DSH in later life. Method We have critically reviewed relevant studies published between 1995 and 2004 to summarise the advances in our understanding of factors associated with deliberate self-harm in later life. Results The main advances in understanding have been to clarify the effect of personality and cultural factors, service utilisation pre and post attempt, and the (lesser) impact of socio-economic status and physical illness. Methodological weaknesses continue to include inadequate sample sizes performed on highly selected populations, inconsistent age criteria and lack of informant data on studies relating to role of personality. Conclusions Future studies should include prospective, cross-cultural research with adequate sample sizes and which are population-based. Such approaches might confirm or refute the results generated to date and improve knowledge on factors such as the biological correlates of deliberate self-harm, service utilisation, costs and barriers to health care, and the interaction of these factors. Intervention studies to elucidate the impact of modifying these factors and of specific treatment packages are also needed. Copyright © 2007 John Wiley & Sons, Ltd. [source] Virulence Frequences of Puccinia triticina in Germany and the European Regions of the Russian FederationJOURNAL OF PHYTOPATHOLOGY, Issue 1 2007V. Lind Abstract From 2001 to 2003, leaf rust was collected in different regions of Germany and the Russian Federation to generate single spore isolates and to study the structure of the pathogen populations by analyses of virulence. The virulence of isolates was tested with 38 near-isogenic lines each carrying a different resistance gene. The analyses of variance revealed significant effects for the frequency of virulent isolates, the regions and most interactions with years and regions, but no significance was found for the effects of years. In Germany, an increase of virulence frequencies was detected for Lr1 and Lr2a while a decrease was found for Lr3a, Lr3bg and Lr3ka. Such clear trends did not occur in Russia which may be due to the great agroclimatic differences between regions. The variance of the frequency of virulent isolates was used to estimate adequate sample sizes for the analysis of regional populations of leaf rust. This procedure resulted in more reliable information about the dynamic processes within the pathogen populations. In 2002 and 2003, all pathotypes in Germany had a combined virulence to Lr1, Lr2a, Lr2b, Lr15, Lr17 and Lr20 supplemented by a few other genes. The complexity of virulence was lower in the most frequent pathotypes. In Russia virulence to the alleles at locus Lr3 was very common. Using detached leaf segments in Germany and Russia it turned out that the most virulent pathotypes carry 34 and 32 virulence genes, respectively. Virulence to Lr9, Lr19, Lr24 and Lr38 was rare or even absent. The use of major genes, not overcome by corresponding virulent pathotypes, may contribute to more durable types of resistance in case they are combined with genes having different effects, e.g. adult plant resistance. [source] Using commercial telephone directories to obtain a population-based sample for mail survey of women of reproductive agePAEDIATRIC & PERINATAL EPIDEMIOLOGY, Issue 3 2003Danelle T. Lobdell Summary In the United States, sampling women of reproductive age from the general population for research purposes is a challenge. Even more difficult is conducting a population-based study of couples attempting pregnancy to assess fecundity and fertility or related impairments. To address the problem of obtaining representative samples from the population in order to study such health-related issues, a commercially and readily available CD-ROM telephone directory was used and tested as a sampling framework for studies aimed at enrolling gravid women aged 18,44 years. A self-administered questionnaire (SAQ) was mailed to a stratified random sample of 10 005 (3%) households in Erie County, NY, USA. Overall, 17% of the questionnaires were undeliverable despite updating all addresses with residential software before mailing. Thirteen per cent (n = 1089) of the households returned completed questionnaires, of which 35% (n = 377) were completed by women aged 18,44 years. Using 1990 census information for zip code, respondents were more likely to be white and to have higher median household incomes than non-respondents. Of the 377 women who completed the questionnaire, 79% had been pregnant at least once, 5% reported being unable to become pregnant, and 16% reporting never trying to become pregnant. Despite the overall low response to the SAQ, the sampling framework captured a diverse group of women of reproductive age who reported various fecundity and fertility outcomes. The use of low-cost commercially available software linked to census data for selecting samples of women or couples for reproductive and perinatal research may be possible; however, oversampling of households, use of incentives and follow-up of non-respondents is needed to ensure adequate sample sizes. [source] | |||||||||||||