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Stratification
Kinds of Stratification Terms modified by Stratification Selected AbstractsDiabetes mellitus, hypertension and medial temporal lobe atrophy: the LADIS studyDIABETIC MEDICINE, Issue 2 2007E. S. C. Korf Abstract Hypothesis, Based on recent findings on the association between vascular risk factors and hippocampal atrophy, we hypothesized that hypertension and diabetes mellitus (DM) are associated with medial temporal lobe atrophy (MTA) in subjects without disability, independent of the severity of white matter hyperintensities. Methods, In the Leukoaraiosis And DISability in the elderly (LADIS) study, we investigated the relationships between DM, hypertension, blood pressure and MTA in 582 subjects, stratified by white matter hyperintensity severity, using multinomial logistic regression. MTA was visually scored for the left and right medial temporal lobe (score 0,4), and meaned. Results, Mean age was 73.5 years (sd 5.1), 54% was female. Of the subjects, 15% had DM, and 70% had a history of hypertension. The likelihood of having MTA score 3 was significantly higher in subjects with DM (OR 2.9; 95% CI: 1.1,7.8) compared with an MTA score of 0 (no atrophy). The odds ratio for MTA score 2 was not significantly increased (OR 1.8; CI: 0.9,4). Systolic and diastolic blood pressure and a history of hypertension were not associated with MTA. There was no interaction between DM and hypertension. Stratification on white matter hyperintensities (WMH) did not alter the associations. Conclusion Our study strengthens the observation that MTA is associated with DM, independently of the amount of small vessel disease as reflected by WMH. [source] Reporting of diabetes on death certificates using data from the UK Prospective Diabetes StudyDIABETIC MEDICINE, Issue 8 2005M. J. Thomason Abstract Aims To study the effect of age at death, sex, ethnic group, date of death, underlying cause of death and social class on the frequency of reporting diabetes on death certificates in known cases of diabetes. Methods Data were extracted from certificates recording 981 deaths which occurred between 1985 and 1999 in people aged 45 years or more who participated in the UK Prospective Diabetes Study, to which 23 English, Scottish and Northern Ireland centres contributed. Diabetes (9th revision of the International Classification of Diseases; ICD-9 250) entered on parts 1A,1C or 2A,2C of the death certificate was considered as reporting diabetes. Logistic regression analyses were used to determine independent factors associated with the reporting of diabetes. Results Diabetes was reported on 42% (419/981) of all death certificates and on 46% (249/546) of those with underlying cardiovascular disease causes. Reporting of diabetes was independently associated on all death certificates with per year of age increase (OR 1.02; 95% CI 1.001,1.04, P = 0.037), underlying cause of death (non-cardiovascular causes OR 0.76; 95% CI 0.59,0.98, P = 0.035) and social class (classes I,II OR 1.00; class III OR 1.35; 95% CI 0.96,1.89, P = 0.084, classes IV,V OR 1.48; 95% CI 1.05,2.10, P = 0.027). Stratification by age, sex, and underlying cause of death also revealed significant differences in the frequency of reporting diabetes over time. Conclusions The rate of reporting of diabetes on cardiovascular disease death certificates remains poor. This may indicate a lack of awareness of the importance of diabetes as a risk factor for cardiovascular disease. [source] Risk Stratification and Prognosis in Octogenarians Undergoing Stress Echocardiographic StudyECHOCARDIOGRAPHY, Issue 8 2007F. A. C. C., Farooq A. Chaudhry M.D. Background: The prognostic value of stress echocardiography (SE) for the diagnosis and risk stratification of coronary artery disease in octogenarians is not well defined. Methods: Follow-up of 5 years (mean 2.9 ± 1.0 years) for confirmed nonfatal myocardial infarction (n = 17) and cardiac death (n = 37) was obtained in 335 patients, age ,80 years (mean age 84 ± 3 years, 44% male), undergoing SE (33% treadmill, 67% dobutamine). Left ventricular (LV) regional wall motion was assessed by a consensus of two echocardiographers and scored as per standard five-point scale, 16-segment model of wall motion analysis. Ischemic LV wall segment was defined as deterioration in the thickening and excursion during stress (increase in wall-motion score index (WMSI) ,1). Results: By univariate analysis, inducible ischemia (chi-square = 38.4, P < 0.001), left ventricular ejection fraction (chi-square = 41.2, P < 0.001), a history of previous myocardial infarction (chi-square = 22.3, P < 0.01), hypertension (chi-square = 33, P < 0.01), and age (chi-square = 27.7, P < 0.01) were significant predictors of future cardiac events. WMSI, an index of inducible ischemia, provided incremental prognostic information when forced into a multivariable model where clinical and rest echocardiography variables were entered first. WMSI effectively stratified octogenarians into low- and high-risk groups (annualized event rates of 1.2 versus 5.8%/year, P < 0.001). Conclusions: Stress echocardiography yields incremental prognostic information in octogenarians and effectively stratifies them into low- and high-risk groups. Precise therapeutic decision making in very elderly patients should incorporate combined clinical and stress echocardiography data. [source] The CRHR1 gene: a marker for suicidality in depressed males exposed to low stressGENES, BRAIN AND BEHAVIOR, Issue 1 2008D. Wasserman The risk of suicide, which causes about 1 million deaths each year, is considered to augment as the levels of stress increases. Dysregulation in the stress response of the hypothalamic-pituitary-adrenocortical (HPA) axis, involving the corticotrophin-releasing hormone (CRH) and its main receptor (CRHR1), is associated with depression, frequent among suicidal males. Here we have analyzed single nucleotide polymorphisms (SNPs) in these genes, in family trios with suicide attempter offspring (n = 542), by using the transmission disequilibrium test both in a two-staged screening/replication sample design and in detailed reanalysis in the entire sample. Stratification based on the levels of lifetime stress showed reproducible association and linkage of an SNP in the CRHR1 gene (rs4792887) to suicide attempters exposed to low levels of stress (P = 0.002), among whom most males were depressed (P = 0.001). The identified allele may represent a part of the genetic susceptibility for suicidality by increasing HPA axis activity upon exposure to low levels of stress. [source] Stratification in Higher Education, Choice and Social Inequalities in GreeceHIGHER EDUCATION QUARTERLY, Issue 1 2010Eleni Sianou-Kyrgiou Higher education has expanded to a remarkable extent in many countries in recent decades. Although this has led to high levels of participation, inequalities not only persist but are also strengthened. The persistence of inequalities is partly the result of policies for the widening of participation having been accompanied by institutional stratification with educational choices being unequal and socially defined. There is evidence that with the development of new university departments and the increase in the number of university entrants in Greece, a stratified system of higher education has emerged. This study draws on quantitative data that provides evidence that choice has been driven largely by the students' social class: the close relationship between social class and educational opportunities has remained intact. Furthermore, social inequalities in access and distribution in higher education persist, despite the substantial increase in participation in higher education. Social class is a key factor in the interpretation of choice of study, which, along with the performance in the national level examinations that determines entrance into universities, has also led to the increase in the stratification of higher education institutions. [source] Description and validation of high-throughput simultaneous genotyping and mutation scanning by high-resolution melting curve analysis,HUMAN MUTATION, Issue 6 2009Tú Nguyen-Dumont Abstract Mutation scanning using high-resolution melting curve analysis (HR-melt) is an effective and sensitive method to detect sequence variations. However, the presence of a common SNP within a mutation scanning amplicon may considerably complicate the interpretation of results and increase the number of samples flagged for sequencing by interfering with the clustering of samples according to melting profiles. A protocol describing simultaneous high-resolution gene scanning and genotyping has been reported. Here, we show that it can improve the sensitivity and the efficiency of large-scale case,control mutation screening. Two exons of ATM, both containing an SNP interfering with standard mutation scanning, were selected for screening of 1,356 subjects from an international breast cancer genetics study. Asymmetric PCR was performed in the presence of an SNP-specific unlabeled probe. Stratification of the samples according to their probe-target melting was aided by customized HR-melt software. This approach improved identification of rare known and unknown variants, while dramatically reducing the sequencing effort. It even allowed genotyping of tandem SNPs using a single probe. Hence, HR-melt is a rapid, efficient, and cost-effective tool that can be used for high-throughput mutation screening for research, as well as for molecular diagnostic and clinical purposes.Hum Mutat 30:1,7, 2009. © 2009 Wiley-Liss, Inc. [source] Semen quality and sedentary work positionINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 1 2004Julie Støy Summary Increased scrotal temperature can, in experimental settings, markedly disturb the production of semen. Sedentary work position may increase the temperature of the scrotum, but previous studies have failed to determine whether changes in scrotal temperature caused by sedentary work actually do affect semen quality. This study was carried out to elucidate the possible harmful effects of sedentary work on sperm count and other semen characteristics. In 1981,1983 a semen sample was obtained from 3119 men who attended an infertility workup in one of four Danish fertility centres. A total of 2517 men returned a postal questionnaire with information on life style, leisure time activities, occupational history and job duties. Information on job specific work position was obtained from The Danish Work Environment Cohort study 1990 (DWECS). In this analysis DWECS data for a total of 1747 men was included from men aged 18,39 years with >30 h of work per week. For all job titles represented in the DWECS, the mean proportion of sedentary work was estimated. The sperm cell concentration was 30.6 million/mL among men in the quintile with lowest job specific sedentary work compared with 40.5 million/mL in the highest quintile. The difference was, however, not statistically significant. Stratification on infertility period, educational level of the man, fertility centre, and fertility-related disease of the spouse did not influence the results. The analyses do not suggest that sedentary work is a risk factor for abnormal semen characteristics. [source] Fruit and vegetable consumption and pancreatic cancer risk in the European Prospective Investigation into Cancer and NutritionINTERNATIONAL JOURNAL OF CANCER, Issue 8 2009Alina Vrieling Abstract Many case-control studies have suggested that higher consumption of fruit and vegetables is associated with a lower risk of pancreatic cancer, whereas cohort studies do not support such an association. We examined the associations of the consumption of fruits and vegetables and their main subgroups with pancreatic cancer risk within the European Prospective Investigation into Cancer and Nutrition (EPIC). EPIC is comprised of over 520,000 subjects recruited from 10 European countries. The present study included 555 exocrine pancreatic cancer cases after an average follow-up of 8.9 years. Estimates of risk were obtained by Cox proportional hazard models, stratified by age at recruitment, gender, and study center, and adjusted for total energy intake, weight, height, history of diabetes mellitus, and smoking status. Total consumption of fruit and vegetables, combined or separately, as well as subgroups of vegetables and fruits were unrelated to risk of pancreatic cancer. Hazard ratios (95% CI) for the highest versus the lowest quartile were 0.92 (0.68,1.25) for total fruit and vegetables combined, 0.99 (0.73,1.33) for total vegetables, and 1.02 (0.77,1.36) for total fruits. Stratification by gender or smoking status, restriction to microscopically verified cases, and exclusion of the first 2 years of follow-up did not materially change the results. These results from a large European prospective cohort suggest that higher consumption of fruit and vegetables is not associated with decreased risk of pancreatic cancer. © 2008 Wiley-Liss, Inc. [source] Stratification of foot ulcer risk in patients with diabetes: a population-based studyINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 5 2006G. P. Leese Summary This trial assessed whether a simple clinical tool can be used to stratify patients with diabetes, according to risk of developing foot ulceration. This was a prospective, observational follow-up study of 3526 patients with diabetes (91% type 2 diabetes) attending for routine diabetes care. Mean age was 64.7 (range 15,101) years and duration of diabetes was 8.8 (±1.5 SD) years. Patients were categorised into ,low' (64%), ,moderate' (23%) or ,high' (13%) risk of developing foot ulcers by trained staff using five clinical criteria during routine patient care. During follow-up (1.7 years), 166 (4.7%) patients developed an ulcer. Foot ulceration was 83 times more common in high risk and six times more in moderate risk, compared with low-risk patients. The negative predictive value of a ,low-risk score' was 99.6% (99.5,99.7%; 95% confidence interval). This clinical tool accurately predicted foot ulceration in routine practice and could be used direct scarce podiatry resources towards those at greatest need. [source] Ethnic Stratification and Inter-Generational Differences in Japan: A Comparative Study of Korean and Japanese Status AttainmentINTERNATIONAL JOURNAL OF JAPANESE SOCIOLOGY, Issue 1 2003Myungsoo Kim Abstract: There are plenty of stereotypical discourses concerning the Korean minority in Japan that are widely accepted, not because of their plausibility, but because of the lack of basic empirical data. In order to fill this intellectual vacuum, I conducted a social stratification and mobility survey focusing on resident Korean men in 1995, comparable with the Japanese sample. The purpose of this article is exploratory rather than aimed at hypothesis testing, given the extreme paucity of the earlier empirical data for the ana-lysis of Korean minority status attainment. The results show that: 1For the Korean minority in Japan, class resources translate into educational attainment to a much lower extent than for the Japanese. 2Korean status attainment patterns deviate from those of their Japanese counterparts. For the Japanese, the crucial status attainment path is secured through educational attainment, which is not the case among Koreans. 3Despite being denied access to such mainstream status attainment paths, major status indicators for Koreans are not significantly different than those of Japanese, and regarding this equality of outcomes, one of the possible explanations is that Korean ethnic disadvantages in the status attainment process may have been overcome by mobilizing informal bilateral ethnic networks. [source] An Introductory Note to the Special Issue on Social Stratification and Social MobilityINTERNATIONAL JOURNAL OF JAPANESE SOCIOLOGY, Issue 1 2000Article first published online: 29 JAN 200 No abstract is available for this article. [source] Education and Social Mobility in Postwar Japan: Trends and Some Institutional AspectsINTERNATIONAL JOURNAL OF JAPANESE SOCIOLOGY, Issue 1 2000Hiroyuki Kondo Abstract, This paper examines the trend in social mobility in postwar Japan, especially focusing on the mediating role of education. The data set is derived from the SSM (Social Stratification and Social Mobility) surveys. Applying log-linear models to the data of five periods, we analyze the trend of the relationship among origin, education, and destination. Occupations are classified according to type of job, and son's first job is used for the analysis. The result reveals that the unmediating transmission of position has declined, and education is becoming a more significant mediator between origin and destination. These changes proceed in the form of reduction in the random sphere of ,movers' as well as replacement of ,stayers' with ,movers'. However, the association between origin and destination has hardly changed for several decades. This stablity results from the inequality in educational resources available to families and the specificities, not universality, of relations surviving into the higher level of education. [source] Managing Contradiction: Civic Stratification and Migrants'Rights,INTERNATIONAL MIGRATION REVIEW, Issue 1 2003Lydia Morris Political and academic interest in cross-national migration has generated two very different and potentially polarized positions. One perspective emphasizes the continuing power of the nation state, while the other sees migration, and more specifically migrants' rights, as the manifestation of an emergent ,post-national' society. This article offers a conceptual framework which addresses this polarization through the concept of civic stratification (Lockwood, 1996). In illustrating its application, the study shows how such an approach goes beyond a traditional citizenship framework (e.g., Marshall, 1950) in considering degrees of partial membership, but remains cautious with respect to claims about universal, transnational rights. [source] A General Algorithm for Univariate StratificationINTERNATIONAL STATISTICAL REVIEW, Issue 3 2009Sophie Baillargeon Summary This paper presents a general algorithm for constructing strata in a population using,X, a univariate stratification variable known for all the units in the population. Stratum,h,consists of all the units with an,X,value in the interval[bh,1,,bh). The stratum boundaries{bh}are obtained by minimizing the anticipated sample size for estimating the population total of a survey variable,Y,with a given level of precision. The stratification criterion allows the presence of a take-none and of a take-all stratum. The sample is allocated to the strata using a general rule that features proportional allocation, Neyman allocation, and power allocation as special cases. The optimization can take into account a stratum-specific anticipated non-response and a model for the relationship between the stratification variable,X,and the survey variable,Y. A loglinear model with stratum-specific mortality for,Y,given,X,is presented in detail. Two numerical algorithms for determining the optimal stratum boundaries, attributable to Sethi and Kozak, are compared in a numerical study. Several examples illustrate the stratified designs that can be constructed with the proposed methodology. All the calculations presented in this paper were carried out with stratification, an R package that will be available on CRAN (Comprehensive R Archive Network). Résumé Cet article présente un algorithme général pour construire des strates dans une population à l'aide de,X, une variable de stratification unidimensionnelle connue pour toutes les unités de la population. La strate,h,contient toutes les unités ayant une valeur de,X,dans l'intervalle [bh,1,,bh). Les frontières des strates {bh} sont obtenues en minimisant la taille d'échantillon anticipée pour l'estimation du total de la variable d'intérêt,Y,avec un niveau de précision prédéterminé. Le critère de stratification permet la présence d'une strate à tirage nul et de strates recensement. L'échantillon est réparti dans les strates à l'aide d'une règle générale qui inclut l'allocation proportionnelle, l'allocation de Neyman et l'allocation de puissance comme des cas particuliers. L'optimisation peut tenir compte d'un taux de non réponse spécifique à la strate et d'un modèle reliant la variable de stratification,X,à la variable d'intérêt,Y. Un modèle loglinéaire avec un taux de mortalité propre à la strate est présenté en détail. Deux algorithmes numériques pour déterminer les frontières de strates optimales, dus à Sethi et Kozak, sont comparés dans une étude numérique. Plusieurs exemples illustrent les plans stratifiés qui peuvent être construits avec la méthodologie proposée. Tous les calculs présentés dans l'article ont été effectués avec stratification, un package R disponible auprès des auteurs. [source] Evaluation of the Mini-Mental State Examination's Internal Consistency in a Community-Based Sample of Mexican-American and European-American Elders: Results from the San Antonio Longitudinal Study of AgingJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 5 2004David V. Espino MD This study examined the effect of scoring method, education, and language usage on internal consistency of the Folstein Mini-Mental State Examination (MMSE). Trained bilingual staff administered the MMSE in participants' homes as part of the San Antonio Longitudinal Study of Aging home-based assessment battery. Subjects included 833 community-dwelling Mexican-American (MA) and European-American (EA) elders, aged 65 and older, residing in three socioculturally distinct neighborhoods in San Antonio, Texas. Three methods of scoring the MMSE were examined: serial sevens only, spelling only, and serial sevens or spelling, whichever was higher. Mean MMSE scores±standard deviation ranged from 27.7±2.4 to 28.5±1.9 for EAs, from 25.6±3.2 to 27.2±2.9 for MAs interviewed in English, and from 22.5±4.5 to 25.5±3.5 for MAs interviewed in Spanish, depending on scoring method. Across the three ethnic-language subgroups, the lowest mean scores, largest coefficients of variation, and highest alpha coefficients were observed using serial sevens only. Stratification by educational level showed that alpha coefficients for all three scoring methods were consistently lower in high school graduates than in less-educated groups. Serial sevens only was the only scoring method that yielded acceptably high alpha coefficients across all ethnic, language, and education subgroups. Thus, clinicians should use the serial sevens,only method when administering the MMSE and be alert to the increased potential for false-negatives in more highly educated EA and MA elders, particularly in EAs and MAs proficient in English. [source] Evaluation of an indirect serum ELISA and a bacteriological faecal culture test for diagnosis of Salmonella serotype Dublin in cattle using latent class modelsJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2004L.R. Nielsen Abstract Aims:, To evaluate a conventional bacteriological test based on faecal culture and an indirect serum ELISA for detection of S. Dublin infected cattle. To compare the predictive values of the two tests in relation to the prevalence. Methods and Results:, A total of 4531 paired samples from cattle in 29 dairy herds were analysed for presence of S. Dublin bacteria in faeces and immunoglobulins directed against S. Dublin lipopolysaccharide in an indirect serum ELISA. Sensitivity and specificity were estimated at two ELISA cut-off values using a validation method based on latent class models, which presumably provides less biased results than traditional validation methods. Stratification of data into three age groups gave significantly better estimates of test performance of the ELISA. Receiver operating characteristic (ROC) curves were constructed for comparison of overall performance of the ELISA between the three age groups. The sensitivity of the faecal culture test was low (6,14%). ELISA appeared to have a higher validity for animals aged 100,299 days of age than older or younger animals. Overall, the negative predictive value of the ELISA was 2,10 times higher than for the faecal culture test at realistic prevalence of infection in the test population. Conclusions:, The diagnostic sensitivity of the faecal culture test for detection of S. Dublin is poor, the specificity is 1. The superior sensitivity and negative predictive value of the serum ELISA makes this test preferable to faecal culture as an initial screening test and for certification of herds not infected with S. Dublin. Significance and Impact of the Study:, A quantitative estimate of the sensitivity of a faecal culture test for S. Dublin in a general population was provided. ELISA was shown to be an appropriate alternative diagnostic test. Preferably, samples from animals aged 100,299 days of age should be used as these give the best overall performance of the ELISA. Plots of ROC curves and predictive values in relation to prevalence facilitates optimisation of the ELISA cut-off value. [source] Hyperkyphotic Posture and Risk of Future Osteoporotic Fractures: The Rancho Bernardo Study,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 3 2006Mei-Hua Huang Abstract It is unknown whether kyphosis of the thoracic spine is an independent risk factor for future osteoporotic fractures. In 596 community-dwelling women, we found that with increasing kyphosis, there was a significant trend of increasing fracture risk that was independent of previous history of fractures or BMD. Introduction: It is unknown whether kyphosis of the thoracic spine is an independent risk factor for future osteoporotic fractures. Materials and Methods: We conducted a prospective cohort study of 596 community-dwelling women, 47-92 years of age. Between 1988 and 1991, BMD of the hip and spine and kyphosis were measured. Kyphosis was measured by counting the number of 1.7-cm blocks necessary to place under the occiput so participants could lie flat without neck hyperextension. New fractures were reported over an average follow-up of 4 years. Results: Using a cut-off of at least one block, 18% of the participants had hyperkyphotic posture (range, one to nine blocks). There were 107 women who reported at least one new fracture (hip, spine, wrist, clavicle, shoulder, arm, hand, rib, pelvis, leg, or ankle). In logistic regression analyses, older women with hyperkyphotic posture (defined as at least one block) had a 1.7-fold increased risk of having a future fracture independent of age, prior fracture, and spine or hip BMD (95% CI: 1.00-2.97; p = 0.049). There was a significant trend of increasing fracture risk with increasing number of blocks, with ORs ranging from 1.5 to 2.6 as the number of blocks increased from one to at least three blocks compared with those with zero blocks (trend p = 0.03; models adjusted for age, baseline fracture, spine or hip BMD). Stratification by baseline fracture status and controlling for other possible confounders or past year falls did not change the results. Conclusions: Whereas hyperkyphosis may often result from vertebral fractures, our study findings suggest that hyperkyphotic posture itself may be an important risk factor for future fractures, independent of low BMD or fracture history. [source] Clinical Course and Risk Stratification of Patients Affected with the Jervell and Lange-Nielsen SyndromeJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2006ILAN GOLDENBERG M.D. Introduction: Data regarding risk factors and clinical course of patients affected with Jervell and Lange-Nielsen syndrome (JLNS), an autosomal recesssive form of the congenital long-QT syndrome (LQTS), are limited to several reported cases and a retrospective analysis. Methods and Results: We prospectively followed-up 44 JLNS patients from the U.S. portion of the International LQTS Registry and compared their clinical course with 2,174 patients with the phenotypically determined dominant form of LQTS (Romano-Ward syndrome [RWS]) and a subgroup of 285 patients with type 1 LQTS (LQT1). Mean (±SD) corrected QT interval (QTc) in the JLNS, RWS, and LQT1 groups were 548 ± 73, 500 ± 48, and 502 ± 46 msec, respectively (P < 0.001). The cumulative rates of cardiac events from birth through age 40 among JLNS and RWS patients were 93% (mean [±SD] age: 5.0 ± 7.0 years) and 54% (mean [±SD] age: 14.2 ± 9.3 years), respectively (P < 0.001). The JLNS:RWS and JLNS:LQT1 adjusted hazard ratios (HR) for cardiac events were highest among patients with a baseline QTc ,550 msec (HR = 15.83 [P < 0.001] and 13.80 [P < 0.001], respectively). Among JLNS patients treated with beta-blockers, the cumulative probability of LQTS-related death was 35%; defibrillator therapy was associated with a 0% mortality rate during a mean (±SD) follow-up period of 4.9 ± 3.4 years. Conclusions: Patients with JLNS experience a high rate of cardiac and fatal events from early childhood despite medical therapy. Defibrillator therapy appears to improve outcome in this high-risk population, although longer follow-up is needed to establish its long-term efficacy. [source] Risk Stratification of Individuals with the Brugada Electrocardiogram: A Meta-AnalysisJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2006ANIL K. GEHI M.D. Objectives: We performed a meta-analysis of prognostic studies of patients with a Brugada ECG to assess predictors of events. Background: The Brugada syndrome is an increasingly recognized cause of idiopathic ventricular fibrillation; however, there is wide variation in the prognosis of patients with the Brugada ECG. Methods and Results: We retrieved 30 prospective studies of patients with the Brugada ECG, accumulating data on 1,545 patients. Summary estimates of the relative risk (RR) of events (sudden cardiac death [SCD], syncope, or internal defibrillator shock) for a variety of potential predictors were made using a random-effects model. The overall event rate at an average of 32 months follow-up was 10.0% (95% CI 8.5%, 11.5%). The RR of an event was increased (P < 0.001) among patients with a history of syncope or SCD (RR 3.24 [95% CI 2.13, 4.93]), men compared with women (RR 3.47 [95% CI 1.58, 7.63]), and patients with a spontaneous compared with sodium-channel blocker induced Type I Brugada ECG (RR 4.65 [95% CI 2.25, 9.58]). The RR of events was not significantly increased in patients with a family history of SCD (P = 0.97) or a mutation of the SCN5A gene (P = 0.18). The RR of events was also not significantly increased in patients inducible compared with noninducible by electrophysiologic study (EPS) (RR 1.88 [95% CI 0.62, 5.73], P = 0.27); however, there was significant heterogeneity of the studies included. Conclusions: Our findings suggest that a history of syncope or SCD, the presence of a spontaneous Type I Brugada ECG, and male gender predict a more malignant natural history. Our findings do not support the use of a family history of SCD, the presence of an SCN5A gene mutation, or EPS to guide the management of patients with a Brugada ECG. [source] Obstacles in large-scale epidemiological assessment of sensory impairments in a Dutch population with intellectual disabilitiesJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 8 2004H. Evenhuis Abstract Background A population-based epidemiological study on visual and hearing impairment was planned in a random sample of 2100 clients, drawn from a base population of 9012 users of Dutch residential and day-care intellectual disability (ID) services with the whole range of IDs. Stratification was applied for age 50 years and over and Down syndrome. Visual and hearing functions were assessed according to a standardized protocol, in cooperation with regular ophthalmologists and regional audiological centres. Anticipated obstacles in sample collection, random inclusion, informed consent, expertise of investigators, time and costs were eliminated by a careful preparation. However, inclusion and participation were incomplete. Method In a descriptive retrospective design, we collected data from our study files on inclusion and participation as well as reasons for non-participation, to identify unanticipated obstacles for this kind of research. Results Consent was obtained for 1660 clients, and 1598 clients participated in the data collection (76% of intended sample of 2100). Inclusion and participation rates were especially lower in community-based care organizations, resulting in unintentional skewing of the sample towards more severe levels of ID. Complete and reliable data to diagnose visual impairment were obtained for 1358/1598 (85%) and to diagnose hearing impairment for 1237/1598 participants (77%). Unanticipated obstacles had to do with the quality of coordination within care organizations, with characteristics of screening methods, and with collaboration with the regular health care system. Assessments of visual function were more easy to organize than were those of hearing. Based on our current experience, practical recommendations are given for future multicentre research, especially in community-based settings. [source] Seroepidemiology of hepatitis A among Greek children indicates that the virus is still prevalent: Implications for universal vaccinationJOURNAL OF MEDICAL VIROLOGY, Issue 4 2009A. Kyrka Abstract A national cross-sectional seroprevalence survey was conducted in order to evaluate the current seroepidemiology of hepatitis A among 1,383 children, aged 0,14 years, residing in Greece. Stratification of the study population was conducted according to age and area of residence. Sera from study participants were tested for the presence of anti-HAV IgG antibodies. Immigrant children, as well as children residing in rural areas, had lower immunization rates. Among unvaccinated children, the seroprevalence rate of anti-HAV was 17.1%. Nationality was shown to have a marginally significant effect since non-immunized immigrant children had a higher seroprevalence rate (22.4% vs. 15.9%, OR,=,1.52, P,=,0.064). Significant differences between geographic areas for both vaccination coverage and natural immunity were observed. The study findings indicate that hepatitis A is prevalent in Greece and therefore universal infant hepatitis A immunization should be implemented. J. Med. Virol. 81:582,587, 2009 © 2009 Wiley-Liss, Inc. [source] National Kidney Foundation Guidelines for Chronic Kidney Disease: Evaluation, Classification, and StratificationJOURNAL OF THE AMERICAN ACADEMY OF NURSE PRACTITIONERS, Issue 6 2002APRN-C, Mary Jo Goolsby EdD Chronic kidney disease is becoming more prevalent in the United States. The National Kidney Foundation has recently published a new set of guidelines to assist clinicians in providing earlier detection and treatment of kidney disease to minimize the progression to end-stage renal disease. As approximately 11% of the adult population has some degree of kidney disease, this new CPG should be applicable in many settings. [source] Factors Affecting Sediment Oxygen Demand in Commercial Channel Catfish PondsJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 3 2004James A. Steeby Sediment oxygen demand (SOD) measured in 45 commercial channel catfish ponds in northwest Mississippi using in situ respirometry (N = 167) ranged from 63 to 1,038 mg/m2 per h. Mean SOD in this study (359 mg/m2 per h) was greater than that reported previously for catfish ponds but was similar to SOD in semi-intensive marine shrimp ponds. Nine variables were selected and measured to assess their relative importance in accounting for variation in SOD. Six variables were included in multiple regression models that explained slightly more than half of the variation in SOD. These variables were: dissolved oxygen concentration at the beginning of respirometry incubation:, particulate organic matter concentration in water above the sediment surface: organic carbon concentration at the immediate sediment-water interface (flocculent or F-layer) combined with the upper 2 cm of sediment (S-layer); organic carbon concentration in the mature (M) underlying sediment layer: water temperature: and total depth of accumulated sediment. Sediment oxygen demand was most sensitive to changes in dissolved oxygen concentration in the overlying water, particulate organic matter concentration in the water, and the concentration of organic carbon in the combined flocculent and upper sediment (F+S) layer. Models for SOD in this research predict that the mass of sediment below the upper 2-cm surface layer on average contributes only ,20% of total SOD. Stratification and normal daily fluctuation of dissolved oxygen concentration in eutrophic culture ponds likely limit expression of sediment oxygen demand. Maintaining aerobic conditions at the sediment-water interface will minimize accumulation of organic matter in pond sediment. [source] Stratified resampling of phytosociological databases: some strategies for obtaining more representative data sets for classification studiesJOURNAL OF VEGETATION SCIENCE, Issue 4 2005Ilona Knollová Abstract Question: The heterogeneous origin of the data in large phytosociological databases may seriously influence the results of their analysis. Therefore we propose some strategies for stratified resampling of such databases, which may improve the representativeness of the data. We also explore the effects of different resampling options on vegetation classification. Methods: We used 6050 plot samples (relevés) of mesic grasslands from the Czech Republic. We stratified this database using (1) geographical stratification in a grid; (2) habitat stratification created by an overlay of digital maps in GIS; (3) habitat stratification with strata defined by traditional phytosociological associations; (4) habitat stratification by numerical classification and (5) habitat stratification by Ellenberg indicator values. Each time we resampled the database, taking equal numbers of relevés per stratum. We then carried out cluster analyses for the resampled data sets and compared the resulting classifications using a newly developed procedure. Results: Random resampling of the initial data set and geographically stratified resampling resulted in similar classifications. By contrast, classifications of the resampled data sets that were based on habitat stratifications (2,5) differed from each other and from the initial data set. Stratification 2 resulted in classifications that strongly reflected environmental factors with a coarse grain of spatial heterogeneity (e.g. macroclimate), whereas stratification 5 resulted in classifications emphasizing fine-grained factors (e.g. soil nutrient status). Stratification 3 led to the most deviating results, possibly due to the subjective nature of the traditional phytosociological classifications. Conclusions: Stratified resampling may increase the representativeness of phytosociological data sets, but different types of stratification may result in different classifications. No single resampling strategy is optimal or superior: the appropriate stratification method must be selected according to the objectives of specific studies. [source] The Bar Examination and the Dream Deferred: A Critical Analysis of the MBE, Social Closure, and Racial and Ethnic StratificationLAW & SOCIAL INQUIRY, Issue 3 2004William C. Kidder In this article, the author applies social closure theory to help explain why more than a dozen states have recently enacted more stringent bar exam passing standards and why others are considering similar changes. While higher standards are usually advocated as a way to protect the public from lower student "quality," the author applies social closure theory and argues that changes in passing standards are a response to a perceived oversupply of lawyers, especially among solo practitioners. In the 1990s, crowding among solo practitioners reached record levels, and real earnings eroded substantially. The author then links this labor market analysis to a critical examination of the knowledge claims that justify the bar exam to the legal profession and the public at large. The article's conclusion is that the psychometric research sponsored by the National Conference of Bar Examiners consistently minimizes and obscures the disparate impact and unfairness of the bar exam for people of color. [source] Case,control study of male germ cell tumors nested in a cohort of car-manufacturing workers: Findings from the occupational historyAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 10 2010Ingo Langner PhD Abstract Background To examine whether the previously observed excess risk of male germ cell cancer in a cohort of car-manufacturing workers can be attributed to occupational activities inside and/or outside the car industry. Methods A nested case,control study among workers in six plants included 205 cases of germ cell cancer and 1,105 controls, individually matched by year of birth (±2 years). Job periods of the individual occupational histories were coded based on the International Standard Classification of Occupations (ISCO) and the industrial classification of economic activities (NACE). Odds ratios (ORs) and corresponding 95%-confidence intervals (CI) for ever-never and cumulative employment were calculated by conditional multivariate logistic regression adjusted for cryptorchidism. Results Significantly increased risks were observed for machinery fitters and assemblers (A) (OR,=,1.8, 95% CI 1.25,2.53) and "workers not elsewhere classified" (OR,=,2.10, 95% CI 1.27,3.54), but no trend was observed for employment duration in either occupational group. Stratification of job group A by metal-cutting and non-cutting jobs yielded ORs of 1.87 (95% CI 1.31,2.67) and of 1.24 (95% CI 0.68,2.28), respectively. Among "plumbers, welders, sheet & structural metal workers" (adjusted OR 1.4, 95% CI 0.99,1.95) only "structural metal preparers and erectors" showed a substantially increased risk (OR,=,2.30; 95% CI 1.27,4.27). Conclusions Our results do not fully explain the increased incidence of germ cell cancer in the cohort, but support previous findings showing increased risks among metal workers. These risks were most strongly pronounced in metal-cutting activities. Am. J. Ind. Med. 53:1006,1018, 2010. © 2010 Wiley-Liss, Inc. [source] Fitness: The Ultimate Marker for Risk Stratification and Health Outcomes?PREVENTIVE CARDIOLOGY, Issue 1 2007Barry A Franklin PhD First page of article [source] Reflections on Cardiovascular Risk Stratification and PreventionPREVENTIVE CARDIOLOGY, Issue 1 2001Nathan D. Wong PhD No abstract is available for this article. [source] Women and class structure in contemporary Japan1THE BRITISH JOURNAL OF SOCIOLOGY, Issue 3 2001Sawako Shirahase ABSTRACT The main purpose of this study is to examine how to determine the class position of women, especially married women, in Japan. This study examines three different approaches to conceptualizing women's position in the class structure: the conventional approach, the individual approach, and the dominance approach. Since 1975, the overall rate of female labour force participation in Japan has increased, and given this growth, particularly of employees working outside home, I discuss whether the increased entry of women, particularly married women, into the labour market challenges the conventional way of assigning class positions to women by simply deriving them from their husband's class positions. The data set used in this study is derived from the 1995 Japanese Social Stratification and Mobility Survey. An examination of class distributions suggests that the pictures of macro-class structure provided by the conventional approach and the dominance approach show very little difference. Married women who belong to the female-dominant family still form a very small minority of all married women in the society. Furthermore, the male-dominant family shows the greatest stability over the life course whereas the female-dominant family, where the wife experiences with-drawal from the labour market, is least stable. The increasing number of married women in the labour market, thus, has not yet become a major threat to the conventional way of assigning women to a class position in contemporary Japan. Women, even among those working on a full-time basis, perceive their position in the stratification system using not only their own work, but also their husband's. In contrast, men's perception is determined by their own education and employment, not by their wives'. This asymmetry in the effect of the husband's class and of the wife's class on class identification is related not only to gender inequality within the labour market but also to the division of labour by gender within the household. [source] Subgroup Analyses in Randomized Controlled Trials: The Need for Risk Stratification in Kidney TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 10 2009M. Wagner Although randomized controlled trials (RCT) are the gold standard for establishing causation in clinical research, their aggregated results can be misleading when applied to individual patients. A treatment may be beneficial in some patients, but its harms may outweigh benefits in others. While conventional one-variable-at-a-time subgroup analyses have well-known limitations, multivariable risk-based analyses can help uncover clinically significant heterogeneity in treatment effects that may be otherwise obscured. Trials in kidney transplantation have yielded the finding that a reduction in acute rejection does not translate into a similar benefit in prolonging graft survival and improving graft function. This paradox might be explained by the variation in risk for acute rejection among included kidney transplant recipients varying the likelihood of benefit or harm from intense immunosuppressive regimens. Analyses that stratify patients by their immunological risk may resolve these otherwise puzzling results. Reliable risk models should be developed to investigate benefits and harms in rationally designed risk-based subgroups of patients in existing RCT data sets. These risk strata would need to be validated in future prospective clinical trials examining long-term effects on patient and graft survival. This approach may allow better individualized treatment choices for kidney transplant recipients. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||