Forward Selection Procedure Research Articles

Association of genetic variants with hemorrhagic stroke in Japanese individuals

Although genetic epidemiological studies have implicated several genetic variants as risk factors for hemorrhagic stroke, the genetic determinants of this condition remain largely unknown. We examined an association of genetic variants with intracerebral or subarachnoid hemorrhage among Japanese individuals. The study population comprised 4,304 unrelated Japanese individuals, including 377 subjects with intracerebral hemorrhage, 205 subjects with subarachnoid hemorrhage, and 3,722 controls. The 150 polymorphisms examined in the present study were selected by genome-wide association studies of ischemic stroke and myocardial infarction with the use of the GeneChip Human Mapping 500K Array Set. The chi-square test, multivariable logistic regression analysis with adjustment for covariates, as well as a stepwise forward selection procedure revealed that the C->T polymorphism (rs1324694) of ERLIN1, the C->T polymorphism (rs12679196) of TRAPPC9, and the G->T polymorphism (rs16936752) of WNK2 were significantly (P<0.05) associated with the prevalence of intracerebral hemorrhage, and that the A->G polymorphism (rs3111754) of ITM2C and the A->G polymorphism (rs10986769) of MAPKAP1 were significantly associated with the prevalence of subarachnoid hemorrhage. Genotypes for ERLIN1, TRAPPC9, and WNK2 may prove informative for assessment of the genetic risk for intracerebral hemorrhage, and those for ITM2C and MAPKAP1 may be beneficial in assessment of the genetic risk for subarachnoid hemorrhage in Japanese individuals.

Genome-wide association study identifies polymorphisms in LEPR as determinants of plasma soluble leptin receptor levels

Plasma soluble leptin receptor (sOB-R) levels were inversely associated with diabetes risk factors, including adiposity and insulin resistance, and highly correlated with the expression levels of leptin receptor, which is ubiquitously expressed in most tissues. We conducted a genome-wide association study of sOB-R in 1504 women of European ancestry from the Nurses' Health Study. The initial scan yielded 26 single nucleotide polymorphisms (SNPs) significantly associated with sOB-R levels (P < 5 x 10(-8)); all mapping to the leptin receptor gene (LEPR). Analysis of imputed genotypes on autosomal chromosomes revealed an additional 106 SNPs in and adjacent to this gene that reached genome-wide significance level. Of these 132 SNPs (including two non-synonymous SNPs, rs1137100 and rs1137101), rs2767485, rs1751492 and rs4655555 remained associated with sOB-R levels at the 0.05 level (P = 9.1 x 10(-9), 0.0105 and 0.0267, respectively) after adjustment for other univariately associated SNPs in a forward selection procedure. Significant associations with these SNPs were replicated in an independent sample of young males (n = 875) residing in Cyprus (P < 1 x 10(-4)). These data provide novel evidence revealing the role of polymorphisms in LEPR in modulating plasma levels of sOB-R and may further our understanding of the complex relationships among leptin, leptin receptor and diabetes-related traits.

Estimating and controlling for spatial structure in the study of ecological communities

ABSTRACTAim Variation partitioning based on canonical analysis is the most commonly used analysis to investigate community patterns according to environmental and spatial predictors. Ecologists use this method in order to understand the pure contribution of the environment independent of space, and vice versa, as well as to control for inflated type I error in assessing the environmental component under spatial autocorrelation. Our goal is to use numerical simulations to compare how different spatial predictors and model selection procedures perform in assessing the importance of the spatial component and in controlling for type I error while testing environmental predictors.Innovation We determine for the first time how the ability of commonly used (polynomial regressors) and novel methods based on eigenvector maps compare in the realm of spatial variation partitioning. We introduce a novel forward selection procedure to select spatial regressors for community analysis. Finally, we point out a number of issues that have not been previously considered about the joint explained variation between environment and space, which should be taken into account when reporting and testing the unique contributions of environment and space in patterning ecological communities.Main conclusions In tests of species‐environment relationships, spatial autocorrelation is known to inflate the level of type I error and make the tests of significance invalid. First, one must determine if the spatial component is significant using all spatial predictors (Moran's eigenvector maps). If it is, consider a model selection for the set of spatial predictors (an individual‐species forward selection procedure is to be preferred) and use the environmental and selected spatial predictors in a partial regression or partial canonical analysis scheme. This is an effective way of controlling for type I error in such tests. Polynomial regressors do not provide tests with a correct level of type I error.

Survival Prediction for Pancreatic Cancer Patients Receiving Gemcitabine Treatment

Although gemcitabine monotherapy is the standard treatment for advanced pancreatic cancer, patient outcome varies significantly, and a considerable number do not benefit adequately. We therefore searched for new biomarkers predictive of overall patient survival. Using LC-MS, we compared the base-line plasma proteome between 29 representative patients with advanced pancreatic cancer who died within 100 days and 31 patients who survived for more than 400 days after receiving at least two cycles of the same gemcitabine monotherapy. Identified biomarker candidates were then challenged in a larger cohort of 304 patients treated with the same protocol using reverse-phase protein microarray. Among a total of 45,277 peptide peaks, we identified 637 peaks whose intensities differed significantly between the two groups (p < 0.001, Welch's t test). Two MS peaks with the highest statistical significance (p = 2.6 x 10(-4) and p = 5.0 x 10(-4)) were revealed to be derived from alpha(1)-antitrypsin and alpha(1)-antichymotrypsin, respectively. The levels of alpha(1)-antitrypsin (p = 8.9 x 10(-8)) and alpha(1)-antichymotrypsin (p = 0.001) were significantly correlated with the overall survival of the 304 patients. We selected alpha(1)-antitrypsin (p = 0.0001), leukocyte count (p = 0.066), alkaline phosphatase (p = 8.3 x 10(-8)), and performance status (p = 0.003) using multivariate Cox regression analysis and constructed a scoring system (nomogram) that was able to identify a group of high risk patients having a short median survival time of 150 days (95% confidence interval, 123-187 days; p = 2.0 x 10(-15), log rank test). The accuracy of this model for prognostication was internally validated and showed good calibration and discrimination with a bootstrap-corrected concordance index of 0.672. In conclusion, an increased level of alpha(1)-antitrypsin is a biomarker that predicts short overall survival of patients with advanced pancreatic cancer receiving gemcitabine monotherapy. Although an external validation study will be necessary, the current model may be useful for identifying patients unsuitable for the standardized therapy.

Effect of the interaction between the amount and duration of alcohol consumption and tobacco smoking on the risk of esophageal cancer: A case-control study

The effects of alcohol consumption and tobacco smoking on the prevalence of esophageal cancer vary considerably by country, race and lifestyle. Few data exist on the effect of the interaction between the amount and duration of alcohol consumption and tobacco smoking on the incidence of esophageal cancer. In this case-control study, the cases included patients with histologically confirmed esophageal squamous cell carcinoma (ESCC) younger than 60 years of age and recruited between January 1, 2002 and December 31, 2006. The controls had no abnormality during a medical checkup. A total of 835 pairs were created by pairing each case to a gender- and age-matched control. Conditional logistic regression analysis was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals. Univariate conditional logistic regression analyses revealed that the ORs according to both duration of alcohol consumption and tobacco smoking increased monotonically. Alcohol consumption and tobacco smoking may have a synergistic effect on the incidence of ESCC. Conditional logistic regression analysis using a forward stepwise selection procedure revealed that the incidence of ESCC was associated with the duration of tobacco smoking, the interaction between the amount and duration of alcohol consumption, and a family history of cancer. In particular, groups with a long duration of alcohol consumption and high alcohol intake had much higher ORs than those with short duration and low intake, which highlights the importance of the interaction between the amount and duration of alcohol intake. This study confirmed the significance of the interaction between alcohol consumption and tobacco smoking in esophageal cancer. This interaction between amount and duration is an accurate indicator for estimating the risk of esophageal cancer attributable to alcohol consumption and tobacco smoking. These findings suggest that decreasing the number of young and middle-aged drinkers and smokers will reduce the incidence of esophageal cancer.

Association of a polymorphism of ROR2 and ischemic stroke in Japanese individuals with chronic kidney disease

Although chronic kidney disease (CKD) is recognized as an important risk factor for ischemic stroke, genetic factors underlying predisposition to ischemic stroke in individuals with or without CKD remain largely unknown. The aim of the present study was to identify genetic variants that confer susceptibility to ischemic stroke in individuals with or without CKD in order to allow prediction of genetic risk for such individuals separately. The study population comprised 974 individuals with CKD, including 227 subjects with ischemic stroke and 747 controls, and 3,470 individuals without CKD, including 612 subjects with ischemic stroke and 2,858 controls. The 150 polymorphisms examined in the present study were selected by genome-wide association studies of ischemic stroke and myocardial infarction with the use of the GeneChip Human Mapping 500K Array Set (Affymetrix). In individuals with CKD, an initial Chi-square test revealed that the A↷G polymorphism (rs10992119) of the receptor tyrosine kinase-like orphan receptor 2 gene (ROR2) was significantly (false discovery rate for allele frequency, 0.0478) associated with ischemic stroke. Multivariable logistic regression analysis with adjustment for covariates revealed that the A↷G polymorphism of ROR2 was significantly (P=0.0100) associated with ischemic stroke (recessive model; odds ratio 1.57; 95% CI 1.12-2.23), with the G allele representing a risk factor for this condition. A stepwise forward selection procedure demonstrated that this polymorphism was a significant (P=0.0095) and independent determinant of ischemic stroke. In individuals without CKD, no polymorphism was significantly related to ischemic stroke. Genotyping for ROR2 may prove informative for assessment of the genetic risk for ischemic stroke in Japanese individuals with CKD. Determination of the genotype for this polymorphism may prove informative for assessment of the genetic risk for ischemic stroke in such individuals.

Association of genetic variants with chronic kidney disease in Japanese individuals with or without hypertension or diabetes mellitus

Hypertension and diabetes mellitus are important risk factors for chronic kidney disease (CKD). The purpose of the present study was to identify genetic variants that confer susceptibility to CKD in individuals with or without hypertension or diabetes mellitus, thereby contributing to the personalized prevention of CKD in such individuals separately. The study population comprised 5835 unrelated Japanese individuals, including 1763 subjects with CKD and 4072 controls. The 150 polymorphisms were selected by genome-wide association studies of ischemic stroke and myocardial infarction with the use of the GeneChip Human Mapping 500K Array Set (Affymetrix). The genotypes for these polymorphisms were determined by a method that combines polymerase chain reaction and sequence-specific oligonucleotide probes with suspension array technology. The χ(2) test, multivariable logistic regression analysis with adjustment for covariates, as well as a stepwise forward selection procedure revealed that two different polymorphisms were significantly (P<0.005) associated with the prevalence of CKD in individuals with or without hypertension or diabetes mellitus: the A→G (Lys625Arg) polymorphism of CDH4 (rs6142884) in individuals without diabetes mellitus, and the C→T polymorphism of PTPRN2 (rs1638021) in individuals with hypertension and diabetes mellitus. No polymorphism was significantly associated with CKD in individuals with or without hypertension, in those with diabetes mellitus, or in those without hypertension or diabetes mellitus. Stratification of subjects based on hypertension or diabetes mellitus may thus be fundamental to achieving the personalized prevention of CKD with the use of genetic information.

Association of genetic variants with ischemic stroke in Japanese individuals with or without metabolic syndrome

Although metabolic syndrome has been recognized as a risk factor for ischemic stroke, genetic factors associated with ischemic stroke in individuals with metabolic syndrome remain unknown. We examined an association of genetic variants with ischemic stroke among individuals with or without metabolic syndrome. The study population comprised 4,387 unrelated Japanese individuals, including 1,884 individuals with metabolic syndrome (240 subjects with ischemic stroke and 1,644 controls) and 2,503 individuals without metabolic syndrome (280 subjects with ischemic stroke and 2,223 controls). The 150 polymorphisms examined in the present study were selected by genome-wide association studies of ischemic stroke and myocardial infarction with the use of the GeneChip Human Mapping 500K Array Set (Affymetrix). The initial chi-square test revealed that the Cright curved arrow T polymorphism (rs9925481) of CLEC16A and the Aright curved arrow G polymorphism (rs4923918) of SPTBN5 were significantly (P<0.005) associated with ischemic stroke among individuals with metabolic syndrome. No polymorphism was significantly associated with ischemic stroke among individuals without metabolic syndrome. Multivariable logistic regression analysis with adjustment for covariates and a stepwise forward selection procedure revealed that the Aright curved arrow G polymorphism (rs4923918) of SPTBN5 was significantly (P<0.005), and the Cright curved arrow T polymorphism (rs9925481) of CLEC16A was almost significantly, associated with ischemic stroke in individuals with metabolic syndrome. Genetic variants that confer susceptibility to ischemic stroke may differ among individuals with or without metabolic syndrome. Stratification of subjects according to the presence or absence of metabolic syndrome may thus be important for personalized prevention of ischemic stroke based on genetic information.

Association of genetic variants in SEMA3F, CLEC16A, LAMA3, and PCSK2 with myocardial infarction in Japanese individuals

ObjectiveThe purpose of the present study was to identify genetic variants that confer susceptibility to myocardial infarction (MI) in Japanese individuals. MethodsThe study population comprised 5014 Japanese individuals, including 1444 subjects with MI and 3570 controls. The 150 polymorphisms examined in the present study were selected by a genome-wide association study for ischemic stroke with the use of the GeneChip Human Mapping 500K Array Set (Affymetrix), and were determined by a method that combines the polymerase chain reaction and sequence-specific oligonucleotide probes with suspension array technology. ResultsAn initial screen by the chi-square test revealed that the A→G polymorphism of SEMA3F (rs12632110), the C→T polymorphism of CLEC16A (rs9925481), the A→G polymorphism of LAMA3 (rs12373237), and the C→G polymorphism of PCSK2 (rs6080699) were significantly (false discovery rate for allele frequencies of <0.05) associated with MI. Subsequent multivariable logistic regression analysis with adjustment for covariates and a stepwise forward selection procedure revealed that the A→G polymorphism of SEMA3F (dominant model; P=0.0014; odds ratio, 0.76), the C→T polymorphism of CLEC16A (dominant model; P=0.0009; odds ratio, 0.75), the A→G polymorphism of LAMA3 (recessive model; P=0.0099; odds ratio, 0.80), and the C→G polymorphism of PCSK2 (recessive model; P=0.0155; odds ratio, 1.19) were significantly (P<0.05) associated with the prevalence of MI. ConclusionDetermination of these genotypes may prove informative for assessment of the genetic risk for MI in Japanese individuals.

Tumour necrosis factor α blockade reduces circulating N-terminal pro-brain natriuretic peptide levels in patients with active rheumatoid arthritis: results from a prospective cohort study

BackgroundPatients with rheumatoid arthritis (RA) are at increased risk of heart failure and vascular events. Small increases in circulating N-terminal pro-brain natriuretic peptide (NT-proBNP) are associated with an increased risk...

Assessment of a Polymorphism of SDK1 With Hypertension in Japanese Individuals

Hypertension is a major risk factor for cardiovascular disease. Although genetic studies have suggested that several genetic variants increase the risk for hypertension, the genes that underlie genetic susceptibility to this condition remain to be identified definitively. The purpose of the present study was to identify genetic variants that confer susceptibility to hypertension in Japanese individuals. A total of 5,734 Japanese individuals from two independent populations were examined: subject panel A comprised 2,066 hypertensive individuals and 824 controls; and subject panel B comprised 834 hypertensive individuals and 2,010 controls. The 150 polymorphisms examined in the present study were selected by genome-wide association studies of myocardial infarction and ischemic stroke with the use of the GeneChip Human Mapping 500K Array Set (Affymetrix). The chi(2)-test revealed that 10 polymorphisms were significantly (P < 0.05) related to the prevalence of hypertension in subject panel A. To validate the relations, these polymorphisms were examined in subject panel B. The A-->G polymorphism (rs645106) of SDK1 and the C-->G polymorphism (rs12078839) of RABGAP1L were significantly associated with hypertension in subject panel B. Multivariable logistic regression analysis with adjustment for covariates, as well as a stepwise forward selection procedure revealed that the A-->G polymorphism of SDK1 was significantly associated with hypertension in both subject panels A and B, with the G allele protecting against this condition. SDK1 may be a susceptibility gene for hypertension in Japanese individuals, although the functional relevance of the identified polymorphism was not determined.

Association of genetic variants with myocardial infarction in individuals with or without hypertension or diabetes mellitus

Hypertension and diabetes mellitus are important risk factors for myocardial infarction (MI). The purpose of the present study was to identify genetic variants that confer susceptibility to MI in individuals with or without hypertension or diabetes mellitus, thereby contributing to the personalized prevention of MI in such individuals. The study population comprised 5,835 unrelated Japanese individuals, including 1,339 subjects with MI and 4,496 controls. The 150 polymorphisms were selected by genome-wide association studies of MI and ischemic stroke with the use of the GeneChip Human Mapping 500K Array Set. The genotypes for these polymorphisms were determined by a method that combines the polymerase chain reaction and sequence-specific oligonucleotide probes with suspension array technology. The chi-square test, multivariable logistic regression analysis with adjustment for covariates, as well as a stepwise forward selection procedure revealed that three different polymorphisms were significantly (P<0.005) associated with the prevalence of MI in individuals with or without hypertension or diabetes mellitus: the C --> T polymorphism of CLEC16A (rs9925481) in individuals without hypertension, the A --> G polymorphism of SEMA3F (rs12632110) in individuals without diabetes mellitus and the A --> G polymorphism of ALOX5 (rs7913948) in individuals without hypertension or diabetes mellitus. No polymorphism was significantly associated with MI in individuals with hypertension, in those with diabetes mellitus, or in those with both conditions. Stratification of subjects based on hypertension or diabetes mellitus may thus be important in order to achieve personalized prevention of MI with the use of genetic information.

Association of gene polymorphisms with chronic kidney disease in Japanese individuals

Chronic kidney disease (CKD) is recognized as a risk factor not only for end-stage renal disease but also for cardiovascular disease. Early detection and treatment of CKD is a likely key factor for prevention of its complications. Although genetic linkage analyses and association studies have implicated several loci and candidate genes in predisposition to CKD, the genes that underlie genetic susceptibility to this condition have remained largely unknown. The purpose of the present study was to identify genetic variants that confer susceptibility to CKD in Japanese individuals. The study population comprised 4,829 Japanese individuals (2,697 men, 2,132 women), including 757 subjects with CKD [464 men, 293 women; estimated glomerular filtration rate (eGFR) <50 ml min 1.73 m(-2)] and 4,072 controls (2,233 men, 1,839 women; eGFR >or=60 ml min 1.73 m(-2)). The genotypes for 40 polymorphisms of 39 candidate genes were determined. The chi-square test, multivariable logistic regression analysis with adjustment for covariates, as well as a stepwise forward selection procedure revealed that six polymorphisms of F10, PITRM1, PCSK2, JPH3, MYO7B, and AKAP12 were related (P<0.05) to the prevalence of CKD. Among these polymorphisms, the Cright curved arrow T polymorphism of F10 (rs5962) was most significantly associated with this condition. Determination of genotypes for the Cright curved arrow T polymorphism of F10 may prove informative for assessment of genetic risk for CKD in Japanese individuals.

Association of a polymorphism of BCHE with ischemic stroke in Japanese individuals with chronic kidney disease

Although chronic kidney disease (CKD) is an important risk factor for ischemic stroke, the genetic variants that confer susceptibility to ischemic stroke in individuals with CKD remain largely unknown. We performed an association study for candidate gene polymorphisms and ischemic stroke in individuals with CKD. The study population comprised 1041 Japanese individuals with CKD, including 228 subjects with ischemic stroke and 813 controls. The genotypes of 150 polymorphisms of 127 candidate genes were determined by a method that combines polymerase chain reaction and sequence-specific oligonucleotide probes with suspension array technology. An initial χ2 test (false discovery rate <0.05) and subsequent multivariate logistic regression analysis with adjustment for covariates (P<0.05) revealed that the 1615G↷A (Ala539Thr) polymorphism (rs1803274) of BCHE (OR=3.33; 95% CI 1.32-8.28) and the 2445G↷A (Ala54Thr) polymorphism (rs1799883) of FABP2 (OR=1.66; 95% CI 1.01-2.70) were significantly associated with ischemic stroke. The variant alleles of BCHE and FABP2 were risk factors for ischemic stroke. A stepwise forward selection procedure demonstrated that the BCHE genotype was a significant (P<0.05) and independent determinant of ischemic stroke. Genotyping for BCHE may prove informative for the assessment of the genetic risk of ischemic stroke in Japanese individuals with CKD.

A unified approach for analyzing exchangeable binary data with applications to developmental toxicity studies

In this article, we present a general procedure to analyze exchangeable binary data that may also be viewed as realizations of binomial mixtures. Our approach unifies existing models and is practical and computationally easy. Resulting from completely monotonic functions, we introduce a rich family of parametric parsimonious binomial mixtures, including the incomplete Beta-, Gamma-, Normal-, and Poisson-binomial, generalizing the Beta-binomial. We show that the family is closed under convex linear combinations, products, and composites. We also give the moments and the Markov property of the family. With such distributions, we can perform statistical inference on correlated binary data and, in particular, overdispersed data. We propose a regression procedure that generalizes logistic regression. We provide a forward model selection procedure. We run a small simulation to validate the inclusion of the binomial distribution. Finally, we apply the proposed procedure to analyze the 2, 4, 5-Trichlorophenoxyacetic acid and E2 data and compare the results with existing procedures.

Information-theoretic feature selection for functional data classification

The classification of functional or high-dimensional data requires to select a reduced subset of features among the initial set, both to help fighting the curse of dimensionality and to help interpreting the problem and the model. The mutual information criterion may be used in that context, but it suffers from the difficulty of its estimation through a finite set of samples. Efficient estimators are not designed specifically to be applied in a classification context, and thus suffer from further drawbacks and difficulties. This paper presents an estimator of mutual information that is specifically designed for classification tasks, including multi-class ones. It is combined to a recently published stopping criterion in a traditional forward feature selection procedure. Experiments on both traditional benchmarks and on an industrial functional classification problem show the added value of this estimator.

Assessment of polychlorinated biphenyl congeners, thyroid stimulating hormone, and free thyroxine among New York State anglers

Experimental literature suggests that polychlorinated biphenyls (PCBs) alter thyroid function however studies of non-occupational or acute exposures in human populations have presented equivocal results. This study considered associations between PCBs and thyroid function biomarkers in a specially selected subsample of participants from the New York State Angler Cohort Study, with the goal of hypotheses generation. Between 1995 and 1997, 38 subjects donated a blood specimen and completed a questionnaire. Sera were analyzed for 77 PCB congeners, beta-HCH, DDE, HCB, mirex, oxychlordane, and trans-nonachlor using GC-ECD, as well as for lipids components, thyroid stimulating hormone (TSH) and free thyroxine (FT(4)). A priori, the sum of all 77 measured PCB congeners, 27 individual PCB congeners with literature evidence for thyroid effects, their sum, DDE, and HCB were chosen as potential predictors for thyroid function. Age, body mass index, cigarette smoking, gender, and use of thyroid relevant medications were considered as important covariates. Adjusted for log total serum lipids, significant (P<0.05) bivariate correlations were demonstrated for log PCB IUPAC #s 153 (r=0.33), 170 (r=0.38), 171+156 (r=0.36), and 180 (r=0.35) with FT(4); however none were observed for log TSH. Using a forward stepwise selection procedure and confounder evaluation algorithm, log PCB #170 was a significant positive predictor of serum FT(4) (beta=1.55 95%CI 0.04-3.07), adjusted for mean centered log PCB #187 and log serum total lipids. This association may be explained by competitive binding to serum thyroid binding proteins by PCB #170, its hydroxylated metabolite 4'-OH-PCB172, or other related but unconsidered compounds. However, bias due to the use of a competitive analog assay for free hormone measurement, random error, or uncontrolled confounding cannot be excluded. The results of this study suggest that Lake Ontario sportfish consumers may comprise a high risk population for PCB related thyroid function alteration and warrant a larger confirmatory investigation.

Factors affecting the reproductive performance of Awassi sheep flocks in north-east of Jordan: An epidemiological study

A prospective cohort study was conducted using 32 randomly selected Awassi sheep flocks to identify factors hypothesized to be associated with the occurrence of pregnancy, twinning and fetal loss between August 2005 and May 2006 in the region of Al-Safawi (northeast of Jordan). Vitamins A and E and selenium concentrations were determined on 448 blood samples. Using the forward selection procedure of the logistic regression module, models with statistically significant risk factors (P < 0.05) were constructed for three outcomes; pregnancy, twinning and fetal loss. Serum vitamin A concentration levels were associated with pregnancy (OR = 2.26, 2.48), twinning (OR = 6.49, 17.74) and fetal loss (OR = 0.13, 0.19). Primiparous ewes were 48% less likely to become pregnant than fourth or higher parity ewes. The likelihood of twinning increased significantly in ewes up to the third parity. Ewes that were fed 700-900 g barley, 250-300 g wheat-bran per head per day and grazed on vegetables residues were 4.15 times more likely to have twins than ewes that were fed 600 g barley and 200 g wheat-bran per head per day. Fetal loss in first and second parity ewes was about 3 times more likely than that in third or higher-parity ewes. Ewes pregnant with twins were about 14 times more likely to have fetal loss than ewes carrying single fetus. Pregnant ewes of the stationary flocks were 37% less likely to have fetal loss than ewes of the semi-nomadic flocks. These results demonstrate that stationary Awassi sheep flocks had higher pregnancy and twinning rates and less pregnancy loss. Supplementation of vitamin A, providing sufficient quantity of dry feed and increasing ram: ewe ratio for primiparous ewes of semi-nomadic flocks is essential to improve Awassi sheep reproductive performance.

The predictors of information needs and different views of patients and relatives on disclosure and treatment participation: A multicentric survey study

e20526 Background: We wanted to explain if the views of patients and their relatives differed on disclosure and treatment participation or not, and if so, to evaluate the predictors of this difference. Methods: The survey aimed to unveil the attitude of patients and their relatives in 3 domains; disclosure of diagnosis, prognosis and participation to treatment. Multinomial logistic regression models with forward selection procedure were constructed for the multivariate analysis to explain the origins of discordance in these domains. Results: A total of 1,052 consecutive cases (526 patients and their 526 relatives) were interviewed. The relatives, when they were asked to imagine themselves with a new diagnosis of cancer, opted for disclosure of diagnosis, prognosis, and participation to treatment in 92.4%, 84.6%, and 86.3% of cases. When patients were asked for their information needs in disclosure of diagnosis, prognosis, and participation to treatment, 83.8%, 70.2%, and 70% wanted disclosure, whereas, their relatives wanted disclosure for their patients in these 3 domains in 32.9%, 40.5%, and 60.3% of cases, respectively. The multivariate predictors of discordance for disclosure of diagnosis between patients and relatives were patient age, social insurance, and oncology centers (P=0.003, 0.007, and &lt;0.001, respectively). The associates of discordance for disclosure of prognosis were again oncology centers and relatives’ relationship with the patients (P&lt;0.001 and 0.012). Likewise, the correlates of discordance for treatment participation were again oncology centers and patient age (P&lt;0.001 and 0.016). Conclusions: Information needs of patients and their relatives, when they imagine themselves as cancer patients, are quite similar. However, relatives are not in favor of disclosure to their patients of diagnosis and prognosis, moreover, in spite of this, they want their patients to actively participate in treatment decisions. We believe this paradox represents a desire of the relatives to escape from responsibility and emotional burden of the care of the cancer patients. This paradox, in addition, is a threat to a healthy patient and physician communication. No significant financial relationships to disclose.

Multiple correspondence analysis in predictive logistic modelling: Application to a living-donor kidney transplantation data

This work deals with the use of multiple correspondence analysis (MCA) and a weighted Euclidean distance (the tolerance distance) as an exploratory tool in developing predictive logistic models. The method was applied to a living-donor kidney transplant data set with 109 cases and 13 predictors. This approach, followed by backward and forward selection procedures, yielded two models, one with four and another with two predictors. These models were compared to two other models, ordinarily built by backward and forward stepwise selection, which yielded, respectively, five and two predictors. After internal validation, the models performance statistics showed similar results. Likelihood ratio tests suggested that backward approach achieved a better fit than the forward modelling in both methods and the Vuong's non-nested test between backward-built models suggested that these were undistinguishable. We conclude that the tolerance distance, in combination with MCA, could be a feasible method for variable selection in logistic modelling, when there are several categorical predictors.