Indoor biofuel air pollution and respiratory health: the role of confounding factors among women in highland Guatemala.

PubMed

Bruce, N; Neufeld, L; Boy, E; West, C

1998-06-01

A number of studies have reported associations between indoor biofuel air pollution in developing countries and chronic obstructive lung disease (COLD) in adults and acute lower respiratory infection (ALRI) in children. Most of these studies have used indirect measures of exposure and generally dealt inadequately with confounding. More reliable, quantified information about this presumed effect is an important pre-requisite for prevention, not least because of the technical, economic and cultural barriers to achieving substantial exposure reductions in the world's poorest households, where ambient pollution levels are typically between ten and a hundred times higher than recommended standards. This study was carried out as part of a programme of research designed to inform the development of intervention studies capable of providing quantified estimates of health benefits. The association between respiratory symptoms and the use of open fires and chimney woodstoves ('planchas'), and the distribution of confounding factors, were examined in a cross-sectional study of 340 women aged 15-45 years, living in a poor rural area in the western highlands of Guatemala. The prevalence of reported cough and phlegm was significantly higher for three of six symptom measures among women using open fires. Although this finding is consistent with a number of other studies, none has systematically examined the extent to which strong associations with confounding variables in these settings limit the ability of observational studies to define the effect of indoor air pollution adequately. Very strong associations (P < 0.0001) were found between the type of fire and a number of household and socioeconomic factors including the arrangement of rooms, floor type, and possession of a radio and television. The spouse's economic activity type was also significantly associated (P < 0.05). Thus, while 82% of open fire users had dirt floors and only 18% cement or tile floors, the situation was

Confounding factors in the detection of species responses to habitat fragmentation.

PubMed

Ewers, Robert M; Didham, Raphael K

2006-02-01

Habitat loss has pervasive and disruptive impacts on biodiversity in habitat remnants. The magnitude of the ecological impacts of habitat loss can be exacerbated by the spatial arrangement -- or fragmentation -- of remaining habitat. Fragmentation per se is a landscape-level phenomenon in which species that survive in habitat remnants are confronted with a modified environment of reduced area, increased isolation and novel ecological boundaries. The implications of this for individual organisms are many and varied, because species with differing life history strategies are differentially affected by habitat fragmentation. Here, we review the extensive literature on species responses to habitat fragmentation, and detail the numerous ways in which confounding factors have either masked the detection, or prevented the manifestation, of predicted fragmentation effects. Large numbers of empirical studies continue to document changes in species richness with decreasing habitat area, with positive, negative and no relationships regularly reported. The debate surrounding such widely contrasting results is beginning to be resolved by findings that the expected positive species-area relationship can be masked by matrix-derived spatial subsidies of resources to fragment-dwelling species and by the invasion of matrix-dwelling species into habitat edges. Significant advances have been made recently in our understanding of how species interactions are altered at habitat edges as a result of these changes. Interestingly, changes in biotic and abiotic parameters at edges also make ecological processes more variable than in habitat interiors. Individuals are more likely to encounter habitat edges in fragments with convoluted shapes, leading to increased turnover and variability in population size than in fragments that are compact in shape. Habitat isolation in both space and time disrupts species distribution patterns, with consequent effects on metapopulation dynamics and the

Influence of GSTM1 and GSTT1 genotypes and confounding factors on the frequency of sister chromatid exchange and micronucleus among road construction workers.

PubMed

Kumar, Anil; Yadav, Anita; Giri, Shiv Kumar; Dev, Kapil; Gautam, Sanjeev Kumar; Gupta, Ranjan; Aggarwal, Neeraj

2011-07-01

In the present study, we have investigated the influence of polymorphism of GSTM1 and GSTT1 genes and confounding factors such as age, sex, exposure duration and consumption habits on cytogenetic biomarkers. Frequency of sister chromatid exchanges (SCEs), high frequency cell (HFC) and cytokinesis blocked micronuclei (CBMN) were evaluated in peripheral blood lymphocytes of 115 occupationally exposed road construction workers and 105 unexposed individuals. The distribution of null and positive genotypes of glutathione-S transferase gene was evaluated by multiplex PCR among control and exposed subjects. An increased frequency of CBMN (7.03±2.08); SCE (6.95±1.76) and HFC (6.28±1.69) were found in exposed subjects when compared to referent (CBMN - 3.35±1.10; SCE - 4.13±1.30 and HFC - 3.98±1.56). These results were found statistically significant at p<0.05. When the effect of confounding factors on the frequency of studied biomarkers was evaluated, a strong positive interaction was found. The individuals having GSTM1 and GSTT1 null genotypes had higher frequency of CBMN, SCE and HFC. The association between GSTM1 and GSTT1 genotypes and studied biomarkers was found statistically significant at p<0.05. Our findings suggest that individuals having null type of GST are more susceptible to cytogenetic damage by occupational exposure regardless of confounding factors. There is a significant effect of polymorphism of these genes on cytogenetic biomarkers which are considered as early effects of genotoxic carcinogens. Copyright © 2011 Elsevier Ltd. All rights reserved.

Phenotypic variation as an indicator of pesticide stress in gudgeon: Accounting for confounding factors in the wild.

PubMed

Shinn, Cândida; Blanchet, Simon; Loot, Géraldine; Lek, Sovan; Grenouillet, Gaël

2015-12-15

The response of organisms to environmental stress is currently used in the assessment of ecosystem health. Morphological changes integrate the multiple effects of one or several stress factors upon the development of the exposed organisms. In a natural environment, many factors determine the patterns of morphological differentiation between individuals. However, few studies have sought to distinguish and measure the independent effect of these factors (genetic diversity and structure, spatial structuring of populations, physical-chemical conditions, etc.). Here we investigated the relationship between pesticide levels measured at 11 sites sampled in rivers of the Garonne river basin (SW France) and morphological changes of a freshwater fish species, the gudgeon (Gobio gobio). Each individual sampled was genotyped using 8 microsatellite markers and their phenotype characterized via 17 morphological traits. Our analysis detected a link between population genetic structure (revealed by a Bayesian method) and morphometry (linear discriminant analysis) of the studied populations. We then developed an original method based on general linear models using distance matrices, an extension of the partial Mantel test beyond 3 matrices. This method was used to test the relationship between contamination (toxicity index) and morphometry (PST of morphometric traits), taking into account (1) genetic differentiation between populations (FST), (2) geographical distances between sites, (3) site catchment area, and (4) various physical-chemical parameters for each sampling site. Upon removal of confounding effects, 3 of the 17 morphological traits studied were significantly correlated with pesticide toxicity, suggesting a response of these traits to the anthropogenic stress. These results underline the importance of taking into account the different sources of phenotypic variability between organisms when identifying the stress factors involved. The separation and quantification of

An overview of confounding. Part 2: how to identify it and special situations.

PubMed

Howards, Penelope P

2018-04-01

Confounding biases study results when the effect of the exposure on the outcome mixes with the effects of other risk and protective factors for the outcome that are present differentially by exposure status. However, not all differences between the exposed and unexposed group cause confounding. Thus, sources of confounding must be identified before they can be addressed. Confounding is absent in an ideal study where all of the population of interest is exposed in one universe and is unexposed in a parallel universe. In an actual study, an observed unexposed population represents the unobserved parallel universe. Thinking about differences between this substitute population and the unexposed parallel universe helps identify sources of confounding. These differences can then be represented in a diagram that shows how risk and protective factors for the outcome are related to the exposure. Sources of confounding identified in the diagram should be addressed analytically and through study design. However, treating all factors that differ by exposure status as confounders without considering the structure of their relation to the exposure can introduce bias. For example, conditions affected by the exposure are not confounders. There are also special types of confounding, such as time-varying confounding and unfixable confounding. It is important to evaluate carefully whether factors of interest contribute to confounding because bias can be introduced both by ignoring potential confounders and by adjusting for factors that are not confounders. The resulting bias can result in misleading conclusions about the effect of the exposure of interest on the outcome. © 2018 Nordic Federation of Societies of Obstetrics and Gynecology.

An overview of confounding. Part 1: the concept and how to address it.

PubMed

Howards, Penelope P

2018-04-01

Confounding is an important source of bias, but it is often misunderstood. We consider how confounding occurs and how to address confounding using examples. Study results are confounded when the effect of the exposure on the outcome, mixes with the effects of other risk and protective factors for the outcome. This problem arises when these factors are present to different degrees among the exposed and unexposed study participants, but not all differences between the groups result in confounding. Thinking about an ideal study where all of the population of interest is exposed in one universe and is unexposed in a parallel universe helps to distinguish confounders from other differences. In an actual study, an observed unexposed population is chosen to stand in for the unobserved parallel universe. Differences between this substitute population and the parallel universe result in confounding. Confounding by identified factors can be addressed analytically and through study design, but only randomization has the potential to address confounding by unmeasured factors. Nevertheless, a given randomized study may still be confounded. Confounded study results can lead to incorrect conclusions about the effect of the exposure of interest on the outcome. © 2018 Nordic Federation of Societies of Obstetrics and Gynecology.

Factors confounding the assessment of reflection: a critical review

PubMed Central

2011-01-01

Background Reflection on experience is an increasingly critical part of professional development and lifelong learning. There is, however, continuing uncertainty about how best to put principle into practice, particularly as regards assessment. This article explores those uncertainties in order to find practical ways of assessing reflection. Discussion We critically review four problems: 1. Inconsistent definitions of reflection; 2. Lack of standards to determine (in)adequate reflection; 3. Factors that complicate assessment; 4. Internal and external contextual factors affecting the assessment of reflection. Summary To address the problem of inconsistency, we identified processes that were common to a number of widely quoted theories and synthesised a model, which yielded six indicators that could be used in assessment instruments. We arrived at the conclusion that, until further progress has been made in defining standards, assessment must depend on developing and communicating local consensus between stakeholders (students, practitioners, teachers, supervisors, curriculum developers) about what is expected in exercises and formal tests. Major factors that complicate assessment are the subjective nature of reflection's content and the dependency on descriptions by persons being assessed about their reflection process, without any objective means of verification. To counter these validity threats, we suggest that assessment should focus on generic process skills rather than the subjective content of reflection and where possible to consider objective information about the triggering situation to verify described reflections. Finally, internal and external contextual factors such as motivation, instruction, character of assessment (formative or summative) and the ability of individual learning environments to stimulate reflection should be considered. PMID:22204704

Brief Communication: Latent toxoplasmosis and salivary testosterone concentration--important confounding factors in second to fourth digit ratio studies.

PubMed

Flegr, Jaroslav; Lindová, Jitka; Pivoñková, Vera; Havlícek, Jan

2008-12-01

A sexually dimorphic characteristic, the second to fourth digit ratio (2D:4D ratio), has been shown to reflect the prenatal concentration of sex steroid hormones and to correlate with many personality, physiological, and life history traits. The correlations are usually stronger for the right than the left hand. Most studies have shown that the 2D:4D ratio does not vary with age or postnatal concentration of sex steroid hormones. Recently, a strong association between left hand 2D:4D ratio and infection with a common human parasite Toxoplasma has been reported. We hypothesized that the confounding effect of Toxoplasma infection on left hand 2D:4D ratio could be responsible for the stronger association between different traits and right hand rather than left hand 2D:4D ratio. This confounding effect of toxoplasmosis could also be responsible for the difficulty in finding an association between 2D:4D ratio and age or postnatal steroid hormone concentration. To test this hypothesis, we analyzed the association between sex and age and 2D:4D ratio in a population of 194 female and 106 male students with and without controlling for the confounding variables of Toxoplasma infection and testosterone concentration. Our results showed that the relationship between age and sex and 2D:4D ratio increased sharply when Toxoplasma infection and testosterone concentration were controlled. These results suggest that left hand 2D:4D ratio is more susceptible to postnatal influences and that the confounding factors of Toxoplasma infection, testosterone concentration and possibly also age, should be controlled in future 2D:4D ratio studies. Because of a stronger 2D:4D dimorphism in Toxoplasma-infected than Toxoplasma-free subjects, we predict that 2D:4D ratio dimorphism as well as right hand/left hand 2D:4D ratio dimorphism will be higher in countries with a high prevalence of Toxoplasma infection than in those with a low prevalence. (c) 2008 Wiley-Liss, Inc.

Commentary: How can family-based quasi-experimental designs and national registers be used to address confounding in risk factor studies of psychopathology? A reflection on Obel et al. (2016).

PubMed

Larsson, Henrik

2016-04-01

Standard observational studies have reported a robust correlation between maternal smoking during pregnancy and risk of ADHD in offspring. In the accompanying article, Obel et al. used sibling-comparisons to explore the extent to which unmeasured familial confounding explains this association. This commentary highlights three important implications of the study. At a general level, Obel et al. illustrates how (1) family-based quasi-experimental designs and (2) national registers can be used to address confounding in risk factor studies of psychopathology. At a more specific level, the study suggests that maternal smoking during pregnancy is probably not a causal risk factor for ADHD. © 2016 Association for Child and Adolescent Mental Health.

The ACCE method: an approach for obtaining quantitative or qualitative estimates of residual confounding that includes unmeasured confounding

PubMed Central

Smith, Eric G.

2015-01-01

Background:  Nonrandomized studies typically cannot account for confounding from unmeasured factors.  Method:  A method is presented that exploits the recently-identified phenomenon of  “confounding amplification” to produce, in principle, a quantitative estimate of total residual confounding resulting from both measured and unmeasured factors.  Two nested propensity score models are constructed that differ only in the deliberate introduction of an additional variable(s) that substantially predicts treatment exposure.  Residual confounding is then estimated by dividing the change in treatment effect estimate between models by the degree of confounding amplification estimated to occur, adjusting for any association between the additional variable(s) and outcome. Results:  Several hypothetical examples are provided to illustrate how the method produces a quantitative estimate of residual confounding if the method’s requirements and assumptions are met.  Previously published data is used to illustrate that, whether or not the method routinely provides precise quantitative estimates of residual confounding, the method appears to produce a valuable qualitative estimate of the likely direction and general size of residual confounding. Limitations:  Uncertainties exist, including identifying the best approaches for: 1) predicting the amount of confounding amplification, 2) minimizing changes between the nested models unrelated to confounding amplification, 3) adjusting for the association of the introduced variable(s) with outcome, and 4) deriving confidence intervals for the method’s estimates (although bootstrapping is one plausible approach). Conclusions:  To this author’s knowledge, it has not been previously suggested that the phenomenon of confounding amplification, if such amplification is as predictable as suggested by a recent simulation, provides a logical basis for estimating total residual confounding. The method's basic approach is

The use of aquatic bioconcentration factors in ecological risk assessments: Confounding issues, laboratory v/s modeled results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brandt, C.; Blanton, M.L.; Dirkes, R.

1995-12-31

Bioconcentration in aquatic systems is generally taken to refer to contaminant uptake through non-ingestion pathways (i.e., dermal and respiration uptake). Ecological risk assessments performed on aquatic systems often rely on published data on bioconcentration factors to calibrate models of exposure. However, many published BCFs, especially those from in situ studies, are confounded by uptake from ingestion of prey. As part of exposure assessment and risk analysis of the Columbia River`s Hanford Reach, the authors tested a methodology to estimate radionuclide BCFs for several aquatic species in the Hanford Reach of the Columbia River. The iterative methodology solves for BCFs frommore » known body burdens and environmental media concentrations. This paper provides BCF methodology description comparisons of BCF from literature and modeled values and how they were used in the exposure assessment and risk analysis of the Columbia River`s Hanford Reach.« less

On the Influence of Confounding Factors in Multisite Brain Morphometry Studies of Developmental Pathologies: Application to Autism Spectrum Disorder.

PubMed

Auzias, G; Takerkart, S; Deruelle, C

2016-05-01

Pooling data acquired on different MR scanners is a commonly used practice to increase the statistical power of studies based on MRI-derived measurements. Such studies are very appealing since they should make it possible to detect more subtle effects related to pathologies. However, the influence of confounds introduced by scanner-related variations remains unclear. When studying brain morphometry descriptors, it is crucial to investigate whether scanner-induced errors can exceed the effect of the disease itself. More specifically, in the context of developmental pathologies such as autism spectrum disorders (ASD), it is essential to evaluate the influence of the scanner on age-related effects. In this paper, we studied a dataset composed of 159 anatomical MR images pooled from three different scanners, including 75 ASD patients and 84 healthy controls. We quantitatively assessed the effects of the age, pathology, and scanner factors on cortical thickness measurements. Our results indicate that scan pooling from different sites would be less fruitful in some cortical regions than in others. Although the effect of age is consistent across scanners, the interaction between the age and scanner factors is important and significant in some specific cortical areas.

Risk Factors in Adolescent Hypertension

PubMed Central

Ewald, D. Rose; Haldeman, Lauren A.

2016-01-01

Hypertension is a complex and multifaceted disease, with many contributing factors. While diet and nutrition are important influences, the confounding effects of overweight and obesity, metabolic and genetic factors, racial and ethnic predispositions, socioeconomic status, cultural influences, growth rate, and pubertal stage have even more influence and make diagnosis quite challenging. The prevalence of hypertension in adolescents far exceeds the numbers who have been diagnosed; studies have found that 75% or more go undiagnosed. This literature review summarizes the challenges of blood pressure classification in adolescents, discusses the impact of these confounding influences, and identifies actions that will improve diagnosis and treatment outcomes. PMID:27335997

Confounding factors in determining causal soil moisture-precipitation feedback

NASA Astrophysics Data System (ADS)

Tuttle, Samuel E.; Salvucci, Guido D.

2017-07-01

Identification of causal links in the land-atmosphere system is important for construction and testing of land surface and general circulation models. However, the land and atmosphere are highly coupled and linked by a vast number of complex, interdependent processes. Statistical methods, such as Granger causality, can help to identify feedbacks from observational data, independent of the different parameterizations of physical processes and spatiotemporal resolution effects that influence feedbacks in models. However, statistical causal identification methods can easily be misapplied, leading to erroneous conclusions about feedback strength and sign. Here, we discuss three factors that must be accounted for in determination of causal soil moisture-precipitation feedback in observations and model output: seasonal and interannual variability, precipitation persistence, and endogeneity. The effect of neglecting these factors is demonstrated in simulated and observational data. The results show that long-timescale variability and precipitation persistence can have a substantial effect on detected soil moisture-precipitation feedback strength, while endogeneity has a smaller effect that is often masked by measurement error and thus is more likely to be an issue when analyzing model data or highly accurate observational data.

phMRI: methodological considerations for mitigating potential confounding factors

PubMed Central

Bourke, Julius H.; Wall, Matthew B.

2015-01-01

Pharmacological Magnetic Resonance Imaging (phMRI) is a variant of conventional MRI that adds pharmacological manipulations in order to study the effects of drugs, or uses pharmacological probes to investigate basic or applied (e.g., clinical) neuroscience questions. Issues that may confound the interpretation of results from various types of phMRI studies are briefly discussed, and a set of methodological strategies that can mitigate these problems are described. These include strategies that can be employed at every stage of investigation, from study design to interpretation of resulting data, and additional techniques suited for use with clinical populations are also featured. Pharmacological MRI is a challenging area of research that has both significant advantages and formidable difficulties, however with due consideration and use of these strategies many of the key obstacles can be overcome. PMID:25999812

Developing hazelnut tissue culture medium free of ion confounding

USDA-ARS?s Scientific Manuscript database

The general approach for tissue culture medium optimization is to use salts as factors in experimental design and analysis. However, using salts as factors leads to ion confounding, making it difficult to detect the effects of individual ions on particular growth responses. This study focused on tes...

Pattern classification of brain activation during emotional processing in subclinical depression: psychosis proneness as potential confounding factor.

PubMed

Modinos, Gemma; Mechelli, Andrea; Pettersson-Yeo, William; Allen, Paul; McGuire, Philip; Aleman, Andre

2013-01-01

We used Support Vector Machine (SVM) to perform multivariate pattern classification based on brain activation during emotional processing in healthy participants with subclinical depressive symptoms. Six-hundred undergraduate students completed the Beck Depression Inventory II (BDI-II). Two groups were subsequently formed: (i) subclinical (mild) mood disturbance (n = 17) and (ii) no mood disturbance (n = 17). Participants also completed a self-report questionnaire on subclinical psychotic symptoms, the Community Assessment of Psychic Experiences Questionnaire (CAPE) positive subscale. The functional magnetic resonance imaging (fMRI) paradigm entailed passive viewing of negative emotional and neutral scenes. The pattern of brain activity during emotional processing allowed correct group classification with an overall accuracy of 77% (p = 0.002), within a network of regions including the amygdala, insula, anterior cingulate cortex and medial prefrontal cortex. However, further analysis suggested that the classification accuracy could also be explained by subclinical psychotic symptom scores (correlation with SVM weights r = 0.459, p = 0.006). Psychosis proneness may thus be a confounding factor for neuroimaging studies in subclinical depression.

Educational differences in cardiovascular mortality: The role of shared family factors and cardiovascular risk factors.

PubMed

Kjøllesdal, M K R; Ariansen, I; Mortensen, L H; Davey Smith, G; Næss, Ø

2016-12-01

To explore the confounding effects of early family factors shared by siblings and cardiovascular risk factors in midlife on the educational differences in mortality from cardiovascular disease (CVD). Data from national and regional health surveys in Norway (1974-2003) were linked with data from the Norwegian Family Based Life Course Study, the National Educational Registry and the Cause of Death Registry. The study population consisted of participants with at least one full sibling among the health survey participants ( n=271,310). Data were available on CVD risk factors, including weight, height, blood pressure, total cholesterol and smoking. The hazards ratio (HR) of CVD mortality was 3.44 (95% confidence interval (CI) 2.98-3.96) in the lowest educational group relative to the highest. The HRs were little altered in the within-sibship analyses. Adjusted for risk factors, the HR for CVD mortality in the cohort analyses was 2.05 (CI 1.77-2.37) in the lowest educational group relative to the highest. The respective HR in the within-sibship analyses was 2.46 (CI 1.48-2.24). Using a sibling design, we did not find that the association between education and CVD mortality was confounded by early life factors shared by siblings, but it was explained to a large extent by CVD risk factors. These results suggest that reducing levels of CVD risk factors could have the greatest effect on mortality in less well-educated people.

Understanding Confounding Effects in Linguistic Coordination: An Information-Theoretic Approach

PubMed Central

Gao, Shuyang; Ver Steeg, Greg; Galstyan, Aram

2015-01-01

We suggest an information-theoretic approach for measuring stylistic coordination in dialogues. The proposed measure has a simple predictive interpretation and can account for various confounding factors through proper conditioning. We revisit some of the previous studies that reported strong signatures of stylistic accommodation, and find that a significant part of the observed coordination can be attributed to a simple confounding effect—length coordination. Specifically, longer utterances tend to be followed by longer responses, which gives rise to spurious correlations in the other stylistic features. We propose a test to distinguish correlations in length due to contextual factors (topic of conversation, user verbosity, etc.) and turn-by-turn coordination. We also suggest a test to identify whether stylistic coordination persists even after accounting for length coordination and contextual factors. PMID:26115446

Addressing unmeasured confounding in comparative observational research.

PubMed

Zhang, Xiang; Faries, Douglas E; Li, Hu; Stamey, James D; Imbens, Guido W

2018-04-01

Observational pharmacoepidemiological studies can provide valuable information on the effectiveness or safety of interventions in the real world, but one major challenge is the existence of unmeasured confounder(s). While many analytical methods have been developed for dealing with this challenge, they appear under-utilized, perhaps due to the complexity and varied requirements for implementation. Thus, there is an unmet need to improve understanding the appropriate course of action to address unmeasured confounding under a variety of research scenarios. We implemented a stepwise search strategy to find articles discussing the assessment of unmeasured confounding in electronic literature databases. Identified publications were reviewed and characterized by the applicable research settings and information requirements required for implementing each method. We further used this information to develop a best practice recommendation to help guide the selection of appropriate analytical methods for assessing the potential impact of unmeasured confounding. Over 100 papers were reviewed, and 15 methods were identified. We used a flowchart to illustrate the best practice recommendation which was driven by 2 critical components: (1) availability of information on the unmeasured confounders; and (2) goals of the unmeasured confounding assessment. Key factors for implementation of each method were summarized in a checklist to provide further assistance to researchers for implementing these methods. When assessing comparative effectiveness or safety in observational research, the impact of unmeasured confounding should not be ignored. Instead, we suggest quantitatively evaluating the impact of unmeasured confounding and provided a best practice recommendation for selecting appropriate analytical methods. Copyright © 2018 John Wiley & Sons, Ltd.

Overview of potential procedural and participant-related confounds for neuroimaging of the resting state

PubMed Central

Duncan, Niall W.; Northoff, Georg

2013-01-01

Studies of intrinsic brain activity in the resting state have become increasingly common. A productive discussion of what analysis methods are appropriate, of the importance of physiologic correction and of the potential interpretations of results has been ongoing. However, less attention has been paid to factors other than physiologic noise that may confound resting-state experiments. These range from straightforward factors, such as ensuring that participants are all instructed in the same manner, to more obscure participant-related factors, such as body weight. We provide an overview of such potentially confounding factors, along with some suggested approaches for minimizing their impact. A particular theme that emerges from the overview is the range of systematic differences between types of study groups (e.g., between patients and controls) that may influence resting-state study results. PMID:22964258

Weight bearing of the limb as a confounding factor in assessment of mechanical allodynia in the rat.

PubMed

Kauppila, T; Kontinen, V K; Pertovaara, A

1998-01-01

Effect of weight bearing of the hindlimbs on the assessment of mechanically-induced hindlimb withdrawal threshold was determined in intact rats and in rats with various pathophysiological conditions causing allodynia or hyperalgesia. Hindlimb withdrawal was elicited by applying a series of calibrated monofilaments to the plantar or the dorsal surface of the paw. During testing the rat was either in a restraint tube with hindlimbs hanging semi-extended without weight bearing or it was standing on a metal grid (bearing its own weight). In intact rats, the withdrawal thresholds were significantly lower when the stimulus site was the dorsal hairy skin rather than the plantar glabrous skin. Also, thresholds were significantly lower when the hindlimbs were not bearing weight. Following carrageenan-induced unilateral inflammation of the plantar paw or a tibial nerve cut there was a marked threshold decrease to test stimuli applied to plantar or dorsal paw, respectively, ipsilateral to the pathological condition in standing rats. However, when the hindlimbs were not weight bearing the unilateral threshold decrease was markedly attenuated (carrageenan-treated rats) or completely abolished (tibial cut). In contrast, in rats with a unilateral spinal nerve ligation the threshold decrease ipsilateral to the nerve lesion was highly significant independent of the weight bearing of the hindlimbs. The results indicate that weight bearing of hindlimbs is an important confounding factor in the assessment of tactile allodynia in rats.

Genetic Instrumental Variable Studies of Effects of Prenatal Risk Factors

PubMed Central

von Hinke Kessler Scholder, Stephanie

2013-01-01

Identifying the effects of maternal risk factors during pregnancy on infant and child health is an area of tremendous research interest. However, of interest to policy makers is unraveling the causal effects of prenatal risk factors, not their associations with child health, which may be confounded by several unobserved factors. In this paper, we evaluate the utility of genetic variants in three genes that have unequivocal evidence of being related to three major risk factors – CHRNA3 for smoking, ADH1B for alcohol use, and FTO for obesity – as instrumental variables for identifying the causal effects of such factors during pregnancy. Using two independent datasets, we find that these variants are overall predictive of the risk factors and are not systematically related to observed confounders, suggesting that they may be useful instruments. We also find some suggestive evidence that genetic effects are stronger during than before pregnancy. We provide an empirical example illustrating the use of these genetic variants as instruments to evaluate the effects of risk factors on birth weight. Finally, we offer suggestions for researchers contemplating the use of these variants as instruments. PMID:23701534

Confounding by dietary patterns of the inverse association between alcohol consumption and type 2 diabetes risk.

PubMed

Imamura, Fumiaki; Lichtenstein, Alice H; Dallal, Gerard E; Meigs, James B; Jacques, Paul F

2009-07-01

The ability to interpret epidemiologic observations is limited because of potential residual confounding by correlated dietary components. Dietary pattern analyses by factor analysis or partial least squares may overcome the limitation. To examine confounding by dietary pattern as well as standard risk factors and selected nutrients, the authors modeled the longitudinal association between alcohol consumption and 7-year risk of type 2 diabetes mellitus in 2,879 healthy adults enrolled in the Framingham Offspring Study (1991-2001) by Cox proportional hazard models. After adjustment for standard risk factors, consumers of > or =9.0 drinks/week had a significantly lower risk of type 2 diabetes mellitus compared with abstainers (hazard ratio = 0.47, 95% confidence interval (CI): 0.27, 0.81). Adjustment for selected nutrients had little effect on the hazard ratio, whereas adjustment for dietary pattern variables by factor analysis significantly shifted the hazard ratio away from null (hazard ratio = 0.33, 95% CI: 0.17, 0.64) by 40.0% (95% CI: 16.8, 57.0; P = 0.002). Dietary pattern variables by partial least squares showed similar results. Therefore, the observed inverse association, consistent with past studies, was confounded by dietary patterns, and this confounding was not captured by individual nutrient adjustment. The data suggest that alcohol intake, not dietary patterns associated with alcohol intake, is responsible for the observed inverse association with type 2 diabetes mellitus risk.

Confounding by dietary pattern of the inverse association between alcohol consumption and type 2 diabetes risk

USDA-ARS?s Scientific Manuscript database

Epidemiology of dietary components and disease risk limits interpretability due to potential residual confounding by correlated dietary components. Dietary pattern analyses by factor analysis or partial least squares may overcome the limitation. To examine confounding by dietary pattern as well as ...

Confounding by dietary patterns of the inverse association between alcohol consumption and type 2 diabetes risk

USDA-ARS?s Scientific Manuscript database

Epidemiology of dietary components and disease risk limits interpretability due to potential residual confounding by correlated dietary components. Dietary pattern analyses by factor analysis or partial least squares may overcome this limitation. To examine confounding by dietary pattern as well as ...

Directed acyclic graphs (DAGs): an aid to assess confounding in dental research.

PubMed

Merchant, Anwar T; Pitiphat, Waranuch

2002-12-01

Confounding, a special type of bias, occurs when an extraneous factor is associated with the exposure and independently affects the outcome. In order to get an unbiased estimate of the exposure-outcome relationship, we need to identify potential confounders, collect information on them, design appropriate studies, and adjust for confounding in data analysis. However, it is not always clear which variables to collect information on and adjust for in the analyses. Inappropriate adjustment for confounding can even introduce bias where none existed. Directed acyclic graphs (DAGs) provide a method to select potential confounders and minimize bias in the design and analysis of epidemiological studies. DAGs have been used extensively in expert systems and robotics. Robins (1987) introduced the application of DAGs in epidemiology to overcome shortcomings of traditional methods to control for confounding, especially as they related to unmeasured confounding. DAGs provide a quick and visual way to assess confounding without making parametric assumptions. We introduce DAGs, starting with definitions and rules for basic manipulation, stressing more on applications than theory. We then demonstrate their application in the control of confounding through examples of observational and cross-sectional epidemiological studies.

Birth weight and mortality: causality or confounding?

PubMed

Basso, Olga; Wilcox, Allen J; Weinberg, Clarice R

2006-08-15

The association between birth weight and mortality is among the strongest seen in epidemiology. While preterm delivery causes both small babies and high mortality, it does not explain this association. Fetal growth restriction has also been proposed, although its features are unclear because it lacks a definition independent of weight. If, as some postulate, birth weight is not itself on the causal path to mortality, its relation with mortality would have to be explained by confounding factors that decrease birth weight and increase mortality. In this paper, the authors explore the characteristics such confounders would require in order to achieve the observed association between birth weight and mortality. Through a simple simulation, they found that the observed steep gradient of risk for small babies at term can be produced by a rare condition or conditions (with a total prevalence of 0.5%) having profound effects on both fetal growth (-1.7 standard deviations) and mortality (relative risk = 160). Candidate conditions might include malformations, fetal or placental aneuploidy, infections, or imprinting disorders. If such rare factors underlie the association of birth weight with mortality, it would have broad implications for the study of fetal growth restriction and birth weight, and for the prevention of infant mortality.

How Confounder Strength Can Affect Allocation of Resources in Electronic Health Records.

PubMed

Lynch, Kristine E; Whitcomb, Brian W; DuVall, Scott L

2018-01-01

When electronic health record (EHR) data are used, multiple approaches may be available for measuring the same variable, introducing potentially confounding factors. While additional information may be gleaned and residual confounding reduced through resource-intensive assessment methods such as natural language processing (NLP), whether the added benefits offset the added cost of the additional resources is not straightforward. We evaluated the implications of misclassification of a confounder when using EHRs. Using a combination of simulations and real data surrounding hospital readmission, we considered smoking as a potential confounder. We compared ICD-9 diagnostic code assignment, which is an easily available measure but has the possibility of substantial misclassification of smoking status, with NLP, a method of determining smoking status that more expensive and time-consuming than ICD-9 code assignment but has less potential for misclassification. Classification of smoking status with NLP consistently produced less residual confounding than the use of ICD-9 codes; however, when minimal confounding was present, differences between the approaches were small. When considerable confounding is present, investing in a superior measurement tool becomes advantageous.

Clinical and evoked pain, personality traits, and emotional states: can familial confounding explain the associations?

PubMed

Strachan, Eric; Poeschla, Brian; Dansie, Elizabeth; Succop, Annemarie; Chopko, Laura; Afari, Niloofar

2015-01-01

Pain is a complex phenomenon influenced by context and person-specific factors. Affective dimensions of pain involve both enduring personality traits and fleeting emotional states. We examined how personality traits and emotional states are linked with clinical and evoked pain in a twin sample. 99 female twin pairs were evaluated for clinical and evoked pain using the McGill Pain Questionnaire (MPQ) and dolorimetry, and completed the 120-item International Personality Item Pool (IPIP), the Positive and Negative Affect Scale (PANAS), and ratings of stress and mood. Using a co-twin control design we examined a) the relationship of personality traits and emotional states with clinical and evoked pain and b) whether genetics and common environment (i.e. familial factors) may account for the associations. Neuroticism was associated with the sensory component of the MPQ; this relationship was not confounded by familial factors. None of the emotional state measures was associated with the MPQ. PANAS negative affect was associated with lower evoked pressure pain threshold and tolerance; these associations were confounded by familial factors. There were no associations between IPIP traits and evoked pain. A relationship exists between neuroticism and clinical pain that is not confounded by familial factors. There is no similar relationship between negative emotional states and clinical pain. In contrast, the relationship between negative emotional states and evoked pain is strong while the relationship with enduring personality traits is weak. The relationship between negative emotional states and evoked pain appears to be non-causal and due to familial factors. Copyright © 2014 Elsevier Inc. All rights reserved.

Using ecological propensity score to adjust for missing confounders in small area studies.

PubMed

Wang, Yingbo; Pirani, Monica; Hansell, Anna L; Richardson, Sylvia; Blangiardo, Marta

2017-11-09

Small area ecological studies are commonly used in epidemiology to assess the impact of area level risk factors on health outcomes when data are only available in an aggregated form. However, the resulting estimates are often biased due to unmeasured confounders, which typically are not available from the standard administrative registries used for these studies. Extra information on confounders can be provided through external data sets such as surveys or cohorts, where the data are available at the individual level rather than at the area level; however, such data typically lack the geographical coverage of administrative registries. We develop a framework of analysis which combines ecological and individual level data from different sources to provide an adjusted estimate of area level risk factors which is less biased. Our method (i) summarizes all available individual level confounders into an area level scalar variable, which we call ecological propensity score (EPS), (ii) implements a hierarchical structured approach to impute the values of EPS whenever they are missing, and (iii) includes the estimated and imputed EPS into the ecological regression linking the risk factors to the health outcome. Through a simulation study, we show that integrating individual level data into small area analyses via EPS is a promising method to reduce the bias intrinsic in ecological studies due to unmeasured confounders; we also apply the method to a real case study to evaluate the effect of air pollution on coronary heart disease hospital admissions in Greater London. © The Author 2017. Published by Oxford University Press.

Changes in Landscape Greenness and Climatic Factors over ...

EPA Pesticide Factsheets

Monitoring and quantifying changes in vegetation cover over large areas using remote sensing can be achieved using the Normalized Difference Vegetation Index (NDVI), an indicator of greenness. However, distinguishing gradual shifts in NDVI (e.g. climate change) versus direct and rapid changes (e.g., fire, land development) is challenging as changes can be confounded by time-dependent patterns, and variation associated with climatic factors. In the present study we leveraged a method, that we previously developed for a pilot study, to address these confounding factors by evaluating NDVI change using autoregression techniques that compare results from univariate (NDVI vs. time) and multivariate analyses (NDVI vs. time and climatic factors) for ~7,660,636 1-km2 pixels comprising the 48 contiguous states of the USA, over a 25-year period (1989−2013). NDVI changed significantly for 48% of the nation over the 25-year in the univariate analyses where most significant trends (85%) indicated an increase in greenness over time. By including climatic factors in the multivariate analyses of NDVI over time, the detection of significant NDVI trends increased to 53% (an increase of 5%). Comparisons of univariate and multivariate analyses for each pixel showed that less than 4% of the pixels had a significant NDVI trend attributable to gradual climatic changes while the remainder of pixels with a significant NDVI trend indicated that changes were due to direct factors. Whi

Poppers, Kaposi's sarcoma, and HIV infection: empirical example of a strong confounding effect?

PubMed

Morabia, A

1995-01-01

Are there empirical examples of strong confounding effects? Textbooks usually show examples of weak confounding or use hypothetical examples of strong confounding to illustrate the paradoxical consequences of not separating out the effect of the studied exposure from that of second factor acting as a confounder. HIV infection is a candidate strong confounder of the spuriously high association reported between consumption of poppers, a sexual stimulant, and risk of Kaposi's sarcoma in the early phase of the AIDS epidemic. To examine this hypothesis, assumptions must be made on the prevalence of HIV infection among cases of Kaposi's sarcoma and on the prevalence of heavy popper consumption according to HIV infection in cases and controls. Results show that HIV infection may have confounded the poppers-Kaposi's sarcoma association. However, it cannot be ruled out that HIV did not qualify as a confounder because it was either an intermediate variable or an effect modifier of the association between popper inhalation and Kaposi's sarcoma. This example provides a basis to discuss the mechanism by which confounding occurs as well as the practical importance of confounding in epidemiologic research.

Bias, Confounding, and Interaction: Lions and Tigers, and Bears, Oh My!

PubMed

Vetter, Thomas R; Mascha, Edward J

2017-09-01

Epidemiologists seek to make a valid inference about the causal effect between an exposure and a disease in a specific population, using representative sample data from a specific population. Clinical researchers likewise seek to make a valid inference about the association between an intervention and outcome(s) in a specific population, based upon their randomly collected, representative sample data. Both do so by using the available data about the sample variable to make a valid estimate about its corresponding or underlying, but unknown population parameter. Random error in an experiment can be due to the natural, periodic fluctuation or variation in the accuracy or precision of virtually any data sampling technique or health measurement tool or scale. In a clinical research study, random error can be due to not only innate human variability but also purely chance. Systematic error in an experiment arises from an innate flaw in the data sampling technique or measurement instrument. In the clinical research setting, systematic error is more commonly referred to as systematic bias. The most commonly encountered types of bias in anesthesia, perioperative, critical care, and pain medicine research include recall bias, observational bias (Hawthorne effect), attrition bias, misclassification or informational bias, and selection bias. A confounding variable is a factor associated with both the exposure of interest and the outcome of interest. A confounding variable (confounding factor or confounder) is a variable that correlates (positively or negatively) with both the exposure and outcome. Confounding is typically not an issue in a randomized trial because the randomized groups are sufficiently balanced on all potential confounding variables, both observed and nonobserved. However, confounding can be a major problem with any observational (nonrandomized) study. Ignoring confounding in an observational study will often result in a "distorted" or incorrect estimate of

Assay dilution factors confound measures of total antioxidant capacity in polyphenol-rich juices

USDA-ARS?s Scientific Manuscript database

The extent to which sample dilution factor (DF) affects Total Antioxidant Capacity (TAC) values is poorly understood. Thus, we examined the impact of DF on the ORAC, FRAP, DPPH, and Total Phenols (TP) assays using pomegranate juice (PJ), grape juice (GJ), selected flavonoids, ascorbic acid, and ella...

Factors Influencing Observed Tillage Impacts on Herbicide Transport

USDA-ARS?s Scientific Manuscript database

The widespread use and potential human health effects of the herbicides atrazine and glyphosate have generated interest in establishing how no-tillage impacts loading of these herbicides to runoff water in comparison to other tillage practices. In this study, potentially confounding factors such as ...

Identification of confounders in the assessment of the relationship between lead exposure and child development.

PubMed

Tong, I S; Lu, Y

2001-01-01

To explore the best approach to identify and adjust for confounders in epidemiologic practice. In the Port Pirie cohort study, the selection of covariates was based on both a priori and an empirical consideration. In an assessment of the relationship between exposure to environmental lead and child development, change-in-estimate (CE) and significance testing (ST) criteria were compared in identifying potential confounders. The Pearson correlation coefficients were used to evaluate the potential for collinearity between pairs of major quantitative covariates. In multivariate analyses, the effects of confounding factors were assessed with multiple linear regression models. The nature and number of covariates selected varied with different confounder selection criteria and different cutoffs. Four covariates (i.e., quality of home environment, socioeconomic status (SES), maternal intelligence, and parental smoking behaviour) met the conventional CE criterion (> or =10%), whereas 14 variables met the ST criterion (p < or = 0.25). However, the magnitude of the relationship between blood lead concentration and children's IQ differed slightly after adjustment for confounding, using either the CE (partial regression coefficient: -4.4; 95% confidence interval (CI): -0.5 to -8.3) or ST criterion (-4.3; 95% CI: -0.2 to -8.4). Identification and selection of confounding factors need to be viewed cautiously in epidemiologic studies. Either the CE (e.g., > or = 10%) or ST (e.g., p < or = 0.25) criterion may be implemented in identification of a potential confounder if a study sample is sufficiently large, and both the methods are subject to arbitrariness of selecting a cut-off point. In this study, the CE criterion (i.e., > or = 10%) appears to be more stringent than the ST method (i.e., p < or = 0.25) in the identification of confounders. However, the ST rule cannot be used to determine the trueness of confounding because it cannot reflect the causal relationship between the

Homocysteine is the confounding factor of metabolic syndrome-confirmed by siMS score.

PubMed

Srećković, Branko; Soldatovic, Ivan; Colak, Emina; Mrdovic, Igor; Sumarac-Dumanovic, Mirjana; Janeski, Hristina; Janeski, Nenad; Gacic, Jasna; Dimitrijevic-Sreckovic, Vesna

2018-04-06

Abdominal adiposity has a central role in developing insulin resistance (IR) by releasing pro-inflammatory cytokines. Patients with metabolic syndrome (MS) have higher values of homocysteine. Hyperhomocysteinemia correlates with IR, increasing the oxidative stress. Oxidative stress causes endothelial dysfunction, hypertension and atherosclerosis. The objective of the study was to examine the correlation of homocysteine with siMS score and siMS risk score and with other MS co-founding factors. The study included 69 obese individuals (age over 30, body mass index [BMI] >25 kg/m2), classified into two groups: I-with MS (33 patients); II-without MS (36 patients). Measurements included: anthropometric parameters, lipids, glucose regulation parameters and inflammation parameters. IR was determined by homeostatic model assessment for insulin resistance (HOMA-IR). ATP III classification was applied for diagnosing MS. SiMS score was used as continuous measure of metabolic syndrome. A significant difference between groups was found for C-reactive protein (CRP) (p<0.01) apolipoprotein (Apo) B, HOMA-IR and acidum uricum (p<0.05). siMS risk score showed a positive correlation with homocysteine (p=0.023), while siMS score correlated positively with fibrinogen (p=0.013), CRP and acidum uricum (p=0.000) and homocysteine (p=0.08). Homocysteine correlated positively with ApoB (p=0.036), HbA1c (p=0.047), HOMA-IR (p=0.008) and negatively with ApoE (p=0.042). Correlation of siMS score with homocysteine, fibrinogen, CRP and acidum uricum indicates that they are co-founding factors of MS. siMS risk score correlation with homocysteine indicates that hyperhomocysteinemia increases with age. Hyperhomocysteinemia is linked with genetic factors and family nutritional scheme, increasing the risk for atherosclerosis.

Associations between workplace factors and carpal tunnel syndrome: A multi-site cross sectional study.

PubMed

Fan, Z Joyce; Harris-Adamson, Carisa; Gerr, Fred; Eisen, Ellen A; Hegmann, Kurt T; Bao, Stephen; Silverstein, Barbara; Evanoff, Bradley; Dale, Ann Marie; Thiese, Matthew S; Garg, Arun; Kapellusch, Jay; Burt, Susan; Merlino, Linda; Rempel, David

2015-05-01

Few large epidemiologic studies have used rigorous case criteria, individual-level exposure measurements, and appropriate control for confounders to examine associations between workplace psychosocial and biomechanical factors and carpal tunnel syndrome (CTS). Pooling data from five independent research studies, we assessed associations between prevalent CTS and personal, work psychosocial, and biomechanical factors while adjusting for confounders using multivariable logistic regression. Prevalent CTS was associated with personal factors of older age, obesity, female sex, medical conditions, previous distal upper extremity disorders, workplace measures of peak forceful hand activity, a composite measure of force and repetition (ACGIH Threshold Limit Value for Hand Activity Level), and hand vibration. In this cross-sectional analysis of production and service workers, CTS prevalence was associated with workplace and biomechanical factors. The findings were similar to those from a prospective analysis of the same cohort with differences that may be due to recall bias and other factors. © 2015 Wiley Periodicals, Inc.

Procedural Factors That Affect Psychophysical Measures of Spatial Selectivity in Cochlear Implant Users

PubMed Central

Deeks, John M.; Carlyon, Robert P.

2015-01-01

Behavioral measures of spatial selectivity in cochlear implants are important both for guiding the programing of individual users’ implants and for the evaluation of different stimulation methods. However, the methods used are subject to a number of confounding factors that can contaminate estimates of spatial selectivity. These factors include off-site listening, charge interactions between masker and probe pulses in interleaved masking paradigms, and confusion effects in forward masking. We review the effects of these confounds and discuss methods for minimizing them. We describe one such method in which the level of a 125-pps masker is adjusted so as to mask a 125-pps probe, and where the masker and probe pulses are temporally interleaved. Five experiments describe the method and evaluate the potential roles of the different potential confounding factors. No evidence was obtained for off-site listening of the type observed in acoustic hearing. The choice of the masking paradigm was shown to alter the measured spatial selectivity. For short gaps between masker and probe pulses, both facilitation and refractory mechanisms had an effect on masking; this finding should inform the choice of stimulation rate in interleaved masking experiments. No evidence for confusion effects in forward masking was revealed. It is concluded that the proposed method avoids many potential confounds but that the choice of method should depend on the research question under investigation. PMID:26420785

Association Between Cardiovascular Risk Factors and Carpal Tunnel Syndrome in Pooled Occupational Cohorts.

PubMed

Hegmann, Kurt T; Thiese, Matthew Steven; Kapellusch, Jay; Merryweather, Andrew S; Bao, Stephen; Silverstein, Barbara; Wood, Eric M; Kendall, Richard; Wertsch, Jacqueline; Foster, James; Garg, Arun; Drury, David L

2016-01-01

The aim of the study was to ascertain if cardiovascular (CVD) risk factors are carpal tunnel syndrome (CTS) risk factors. Analysis of pooled baseline data from two large prospective cohort studies (n = 1824) assessed the relationships between a modified Framingham Heart Study CVD risk score both CTS and abnormal nerve conduction study prevalence. Quantified job exposures, personal and psychosocial confounders were statistically controlled. Odds ratio and 95% confidence intervals were calculated for individual risk scores. There was a strong relationship between CVD risk score and both CTS and abnormal nerve conduction study after adjustment for confounders, with odds ratios as high as 4.16 and 7.35, respectively. Dose responses were also observed. In this workplace population, there is a strong association between CVD risk scores and both CTS and abnormal nerve conduction study that persisted after controlling for confounders. These data suggest a potentially modifiable disease mechanism.

Survey material choices in haematology EQA: a confounding factor in automated counting performance assessment.

PubMed

De la Salle, Barbara

2017-02-15

The complete blood count (CBC) is one of the most frequently requested tests in laboratory medicine, performed in a range of healthcare situations. The provision of an ideal assay material for external quality assessment is confounded by the fragility of the cellular components of blood, the lack of commutability of stabilised whole blood material and the lack of certified reference materials and methods to which CBC results can be traced. The choice of assay material between fresh blood, extended life assay material and fully stabilised, commercially prepared, whole blood material depends upon the scope and objectives of the EQA scheme. The introduction of new technologies in blood counting and the wider clinical application of parameters from the extended CBC will bring additional challenges for the EQA provider.

The association between cannabis use and earlier age at onset of schizophrenia and other psychoses: meta-analysis of possible confounding factors.

PubMed

Myles, Nicholas; Newall, Hannah; Nielssen, Olav; Large, Matthew

2012-01-01

A recent meta-analysis showed that the mean age of onset of psychosis among cannabis users was almost three years earlier than that of non-cannabis users. However, because cannabis users usually smoke tobacco, the use of tobacco might independently contribute to the earlier onset of psychosis. We aimed to use meta-analysis to compare the extent to which cannabis and tobacco use are each associated with an earlier age at onset of schizophrenia and other psychoses. We also examined other factors that might have contributed to the finding of an earlier age of onset among cannabis users, including the proportion of males in the samples, the diagnostic inclusion criteria and aspects of study quality. The electronic databases MEDLINE, EMBASE, PsycINFO and ISI Web of Science, were searched for English-language peer-reviewed publications that reported age at onset of schizophrenia and other psychoses separately for cannabis users and non-users, or for tobaccosmokers and non-smokers. Meta-analysis showed that the age at onset of psychosis for cannabis users was 32 months earlier than for cannabis non-users (SMD=- 0.399, 95%CI -0.493 - -0.306, z=-8.34, p < 0.001), and was two weeks later in tobacco smokers compared with non-smokers (SMD=0.002, 95%CI -0.094 - 0.097, z=0.03, p=0.974). The main results were not affected by subgroup analyses examining studies of a single sex, the methods for making psychiatric diagnoses and measures of study quality. The results suggest that the association between cannabis use and earlier onset of psychosis is robust and is not the result either of tobacco smoking by cannabis using patients or the other potentially confounding factors we examined. This supports the hypothesis that, in some patients, cannabis use plays a causal role in the development of schizophrenia and raises the possibility of treating schizophrenia with new pharmacological treatments that have an affinity for endo-cannabinoid receptors.

Factor structure of the Japanese Interpersonal Competence Scale.

PubMed

Matsudaira, Tomomi; Fukuhara, Taihei; Kitamura, Toshinori

2008-04-01

Assessing social competence is important for clinical and preventive interventions of depression. The aim of the present paper was to examine the factor structure of the Japanese Interpersonal Competence Scale (JICS). Exploratory and confirmatory factor analysis was performed on the survey responses of 730 participants. Simultaneous multigroup analyses were conducted to confirm factor stability across psychological health status and sex differences. Two factors, which represent Perceptive Ability and Self-Restraint, were confirmed to show a moderate correlation. Perceptive Ability involves a more cognitive aspect of social competence, while Self-Restraint involves a more behavioral aspect, both of which are considered to reflect the emotion-based relating style specific to the Japanese people: indulgent dependence (amae) and harmony (wa). In addition, Self-Restraint may be linked to social functioning. Both constructs may confound a respondent's perceived confidence. Despite its shortcomings, the JICS is a unique measure of social competence in the Japanese cultural context.

Evaluation of uncontrolled confounding in studies of environmental exposures and neurobehavioral testing in children.

PubMed

Mink, Pamela J; Goodman, Michael; Barraj, Leila M; Imrey, Harriet; Kelsh, Michael A; Yager, Janice

2004-07-01

Neurobehavioral tests are commonly used in studies of children exposed to low-level environmental concentrations of compounds known to be neurotoxic at higher levels. However, uncontrolled or incomplete control for confounding makes interpretation of results problematic because effects of confounders are often stronger than the effects of primary interest. We examined a priori the potential impact of confounding in a hypothetical study evaluating the association of a potentially neurotoxic environmental exposure with neurobehavioral function in children. We used 2 outcome measures: the Bayley Scales of Infant Development Mental Development Index and the Stanford-Binet Intelligence Scale Composite Score. We selected 3 potential confounders: maternal intelligence, home environment, and socioeconomic status as measured by years of parental education. We conducted 3 sets of analyses measuring the effect of each of the 3 confounding factors alone, 2 confounders acting simultaneously, and all 3 confounders acting simultaneously. Relatively small differences (0.5 standard deviations) in confounding variables between "exposed" and "unexposed" groups, if unmeasured and unaccounted for in the analysis, could produce spurious differences in cognitive test scores. The magnitude of this difference (3-10 points) has been suggested to have a meaningful impact in populations. The method of measuring confounders (eg, maternal intelligence) could also substantially affect the results. It is important to carefully consider the impact of potential confounders during the planning stages of an observational study. Study-to-study differences in neurobehavioral outcomes with similar environmental exposures could be partially explained by differences in the adjustment for confounding variables. Copyright 2004 Lippincott Williams and Wilkins

Are apparent negative effects of feeding GM MON810 maize to Atlantic salmon, Salmo salar, caused by confounding factors?

PubMed

Sissener, Nini H; Hemre, Gro-Ingunn; Lall, Santosh P; Sagstad, Anita; Petersen, Kjell; Williams, Jason; Rohloff, Jens; Sanden, Monica

2011-07-01

The present study was conducted to follow up on apparent differences in growth, relative organ sizes, cellular stress and immune function in Atlantic salmon fed feed containing GM Bacillus thuringiensis maize compared with feed containing the non-modified parental maize line. Gene expression profiling on the distal intestinal segment and liver was performed by microarray, and selected genes were followed up by quantitative PCR (qPCR). In the liver, qPCR revealed some differentially regulated genes, including up-regulation of gelsolin precursor, down-regulation of ferritin heavy subunit and a tendency towards down-regulation of metallothionein (MT)-B. This, combined with the up-regulation of anti-apoptotic protein NR13 and similar tendencies for ferritin heavy chain and MT-A and -B in the distal intestine, suggests changes in cellular stress/antioxidant status. This corresponds well with and strengthens previous findings in these fish. To exclude possible confounding factors, the maize ingredients were analysed for mycotoxins and metabolites. The GM maize contained 90 μg/kg of deoxynivalenol (DON), while the non-GM maize was below the detection limit. Differences were also observed in the metabolite profiles of the two maize varieties, some of which seemed connected to the mycotoxin level. The effects on salmon observed in the present and previous studies correspond relatively well with the effects of DON as reported in the literature for other production animals, but knowledge regarding effects and harmful dose levels in fish is scarce. Thus, it is difficult to conclude whether the observed effects are caused by the DON level or by some other aspect of the GM maize ingredient.

Prevalence of cholera risk factors between migrant Haitians and Dominicans in the Dominican Republic.

PubMed

Lund, Andrea J; Keys, Hunter M; Leventhal, Stephanie; Foster, Jennifer W; Freeman, Matthew C

2015-03-01

To determine whether cholera risk factor prevalence in the Dominican Republic can be explained by nationality, independent of other factors, given the vulnerability of many Haitians in the country and the need for targeted prevention. A cross-sectional, observational household survey (103 Haitian and 260 Dominican) was completed in 18 communities in July 2012. The survey included modules for demographics, knowledge, socioeconomic status, and access to adequate water, sanitation, and hygiene (WASH) infrastructure. Logistic regression assessed differential access to WASH infrastructure and Poisson regression assessed differences in cholera knowledge, controlling for potential confounders. Dominican and Haitian households differed on demographic characteristics. Haitians had lower educational attainment, socioeconomic status, and less knowledge of cholera than Dominicans (adjusted odds ratio [aOR] = 0.66; 95% confidence interval [95%CI] = 0.55-0.81). Access to improved drinking water was low for both groups, but particularly low among rural Haitians (aOR = 0.21; 95%CI: 0.04-1.01). No differences were found in access to sanitation after adjusting for sociodemographic confounders (aOR = 1.00; 95%CI: 0.57-1.76). Urban/rural geography and socioeconomic status play a larger role in cholera risk factor prevalence than nationality, indicating that Haitians' perceived vulnerability to cholera is confounded by contextual factors. Understanding the social dynamics that lead to cholera risk can inform control strategies, leading to better targeting and the possibility of eliminating cholera from the island.

A Systematic Review of Risk Factors for Intimate Partner Violence

PubMed Central

Capaldi, Deborah M.; Knoble, Naomi B.; Shortt, Joann Wu; Kim, Hyoun K.

2012-01-01

A systematic review of risk factors for intimate partner violence was conducted. Inclusion criteria included publication in a peer-reviewed journal, a representative community sample or a clinical sample with a control-group comparison, a response rate of at least 50%, use of a physical or sexual violence outcome measure, and control of confounding factors in the analyses. A total of 228 articles were included (170 articles with adult and 58 with adolescent samples). Organized by levels of a dynamic developmental systems perspective, risk factors included: (a) contextual characteristics of partners (demographic, neighborhood, community and school factors), (b) developmental characteristics and behaviors of the partners (e.g., family, peer, psychological/behavioral, and cognitive factors), and (c) relationship influences and interactional patterns. Comparisons to a prior review highlight developments in the field in the past 10 years. Recommendations for intervention and policy along with future directions for intimate partner violence (IPV) risk factor research are presented. PMID:22754606

An assessment of the possible extent of confounding in epidemiological studies of lung cancer risk among roofers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mundt, D.J.; van Wijngaarden, E.; Mundt, K.A.

2007-07-01

We evaluated the likelihood and extent to which the observed increased risk of lung cancer may be due to confounding (a mixing of effects of multiple exposures) by co-exposure to other potential carcinogens present in roofing or to lifestyle variables. We conducted a review of the epidemiological and industrial hygiene literature of asphalt-exposed workers. Peer-reviewed epidemiological studies of asphalt fumes, related occupational exposures, and confounding factors were identified from MEDLINE (1966 early 2004). Industrial hygiene studies of asphalt workers were identified through MEDLINE, publicly available government documents, and asphalt industry documents. Using well established statistical methods, we quantified the extentmore » to which lung cancer relative risk estimates among roofers reflect confounding from other exposures, using different prevalence and risk scenarios. The relative risk of lung cancer varied from 1.2 to 5.0 in 13 epidemiological studies of roofers; most studies reported a relative risk between 1.2 and 1.4. Smoking, asbestos and coal tar were the most likely confounders, but the prevalence of these factors varied over time. The results of the study indicate that much of the observed risk reported in epidemiological studies of cancer among roofers is well within the range of what may have resulted from confounding by reasonable and expected levels of smoking, asbestos or coal tar. This may be particularly true for those studies that did not adjust for these confounders and where the exposure was defined as employment in the roofing industry. In addition to poorly defined asphalt exposure, uncontrolled confounding cannot reliably be ruled out in studies of lung cancer among asphalt-exposed roofers. Therefore, it is not possible to conclude whether roofers are at increased risk of lung cancer due to asphalt exposure.« less

[Tuberculosis recurrence and its risk factors].

PubMed

de Oliveira, H B; Moreira Filho, D de C

2000-04-01

The persistence of tuberculosis bacilli in patients who are cured, thus causing recurrence, is an important issue. This case-control study investigated individual and institutional risk factors for relapse by analyzing independent variables related to the patient, the use of antituberculosis drugs, and the service delivered at health care institutions; 56 cases and 105 controls were interviewed. Recurrence was defined as a new tuberculosis episode after the patient had been successfully treated. Controls were selected from among patients who were treated and cured of pulmonary tuberculosis and who did not experience a relapse. Regression models were proposed to control confounding factors or effect modifiers. The variables identified as risk factors for relapse were those related to erratic patient behavior (missing medical appointments and therefore not picking up the medication, not taking the medication, taking the wrong dosage), age, and stress from life events; adverse reactions to antituberculosis drugs; and problems in the organization of health care services that resulted in patients receiving insufficient dosages or amounts of antituberculosis drugs. Receiving information regarding treatment duration provided protection against recurrence. The knowledge regarding these risk factors should result in more intensive follow-up and in more use of directly observed treatment of tuberculosis in order to prevent relapse.

Depression and Physical Inactivity as Confounding the Effect of Obesity on Atrial Fibrillation.

PubMed

Garimella, Roja S; Sears, Samuel F; Gehi, Anil K

2016-06-01

Obesity is associated with an increased likelihood for the development of atrial fibrillation (AF) and with worsened AF symptom severity. However, other factors that are correlated with obesity may confound or mediate the relation of obesity with AF symptom severity. The purpose of this study was to determine if depression and physical inactivity may confound the association of obesity and AF symptom severity. Health status and demographic data were captured by questionnaire for 332 outpatients with documented AF. Weight/height was measured and body mass index (kg/m(2)) calculated. Recent depression symptom severity was assessed using the Patient Health Questionnaire-9 questionnaire. Physical activity during the last month was assessed by questionnaire. AF symptom severity was assessed using the University of Toronto AF Severity scale. Multivariate linear regression was used to evaluate which factors were associated with AF symptom severity. Obesity in patients with AF is associated with increased depression severity. In bivariate analysis, increasing body mass index (p = 0.001), lower levels of physical activity (p <0.001), and more severe depression (p <0.001) were associated with worsened AF symptom severity. In multivariate analysis, only physical activity and depression persisted as significant predictors of AF symptom severity. In conclusion, although obesity likely contributes to the substrate predisposing to the development of AF, other factors may contribute to or mediate the worsened AF symptoms associated with obesity. Depression symptoms and physical inactivity, factors closely correlated with obesity, may exacerbate symptoms in patients with AF. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of Age at First Childbirth and Other Factors on Central Obesity in Postmenopausal Women: The 2013–2015 Korean National Health and Nutrition Examination Survey

PubMed Central

Lee, Wang Jin; Lee, Joo Ha; Kwag, Byoung Gyu; Chang, Shin Hae; Choi, Yu Jin

2018-01-01

Background Waist circumference is one of the key components of metabolic syndrome. Recent studies demonstrated that the reproductive profile was associated with metabolic syndrome in postmenopausal women. This study focused on the association between central obesity and age at first childbirth. It also considered other factors associated with central obesity in postmenopausal women. Methods This study was based on the 2013–2015 Korean National Health and Nutrition Examination Survey and involved 3,143 naturally postmenopausal women. These women were divided into three groups according to their age at first childbirth: 19 years or younger (n=252), 20–29 years (n=2,695), and 30 years or older (n=196). Multivariate analysis using logistic regression was performed to evaluate the effects of various reproductive factors, including other confounding factors. Results During adjustment for confounding factors, in the early age at first childbirth group, odds ratios (95% confidence intervals) for central obesity decreased. In the final model, younger age at first childbirth was not significantly related to central obesity (waist circumference more than 85 cm) in naturally postmenopausal women after adjusting for other confounding factors. Conclusion Younger age at first childbirth was not significantly associated with central obesity after adjustment for confounding factors. PMID:29788703

Breast milk and cognitive development—the role of confounders: a systematic review

PubMed Central

Walfisch, Asnat; Sermer, Corey; Cressman, Alex; Koren, Gideon

2013-01-01

Objectives The association between breastfeeding and child cognitive development is conflicted by studies reporting positive and null effects. This relationship may be confounded by factors associated with breastfeeding, specifically maternal socioeconomic class and IQ. Design Systematic review of the literature. Setting and participants Any prospective or retrospective study, in any language, evaluating the association between breastfeeding and cognitive development using a validated method in healthy term infants, children or adults, was included. Primary and secondary outcome measures Extracted data included the study design, target population and sample size, breastfeeding exposure, cognitive development assessment tool used and participants’ age, summary of the results prior to, and following, adjustment for confounders, and all confounders adjusted for. Study quality was assessed as well. Results 84 studies met our inclusion criteria (34 rated as high quality, 26 moderate and 24 low quality). Critical assessment of accepted studies revealed the following associations: 21 null, 28 positive, 18 null after adjusting for confounders and 17 positive—diminished after adjusting for confounders. Directionality of effect did not correlate with study quality; however, studies showing a decreased effect after multivariate analysis were of superior quality compared with other study groupings (14/17 high quality, 82%). Further, studies that showed null or diminished effect after multivariate analysis corrected for significantly more confounders (7.7±3.4) as compared with those that found no change following adjustment (5.6±4.5, p=0.04). The majority of included studies were carried out during childhood (75%) and set in high-income countries (85.5%). Conclusions Much of the reported effect of breastfeeding on child neurodevelopment is due to confounding. It is unlikely that additional work will change the current synthesis. Future studies should attempt to rigorously

A causal examination of the effects of confounding factors on multimetric indices

USGS Publications Warehouse

Schoolmaster, Donald R.; Grace, James B.; Schweiger, E. William; Mitchell, Brian R.; Guntenspergen, Glenn R.

2013-01-01

The development of multimetric indices (MMIs) as a means of providing integrative measures of ecosystem condition is becoming widespread. An increasingly recognized problem for the interpretability of MMIs is controlling for the potentially confounding influences of environmental covariates. Most common approaches to handling covariates are based on simple notions of statistical control, leaving the causal implications of covariates and their adjustment unstated. In this paper, we use graphical models to examine some of the potential impacts of environmental covariates on the observed signals between human disturbance and potential response metrics. Using simulations based on various causal networks, we show how environmental covariates can both obscure and exaggerate the effects of human disturbance on individual metrics. We then examine from a causal interpretation standpoint the common practice of adjusting ecological metrics for environmental influences using only the set of sites deemed to be in reference condition. We present and examine the performance of an alternative approach to metric adjustment that uses the whole set of sites and models both environmental and human disturbance effects simultaneously. The findings from our analyses indicate that failing to model and adjust metrics can result in a systematic bias towards those metrics in which environmental covariates function to artificially strengthen the metric–disturbance relationship resulting in MMIs that do not accurately measure impacts of human disturbance. We also find that a “whole-set modeling approach” requires fewer assumptions and is more efficient with the given information than the more commonly applied “reference-set” approach.

Modifiable risk factors for chronic back pain: insights using the co-twin control design.

PubMed

Suri, Pradeep; Boyko, Edward J; Smith, Nicholas L; Jarvik, Jeffrey G; Williams, Frances M K; Jarvik, Gail P; Goldberg, Jack

2017-01-01

Inconsistent associations between modifiable risk factors and chronic back pain (CBP) may be due to the inability of traditional epidemiologic study designs to properly account for an array of potential genetic and environmental confounding factors. The co-twin control research design, comparing modifiable risk factors in twins discordant for CBP, offers a unique way to remove numerous confounding factors. The study aimed to examine the association of modifiable lifestyle and psychological factors with lifetime CBP. This is a cross-sectional co-twin control study in a nationwide sample of male twin members of the Vietnam Era Twin Registry. The sample is composed of 7,108 participants, including 1,308 monozygotic (MZ) pairs and 793 dizygotic pairs. The outcome measure is the self-reported lifetime history of CBP. Lifestyle factors included body mass index (BMI), smoking history, alcohol consumption, habitual physical activity, and typical sleep duration. Psychological factors included depression (Patient Health Questionnaire-9) and posttraumatic stress disorder (PTSD) symptoms (PTSD Checklist). Covariates included age, race, education, and income. Odds ratios (ORs) and 95% confidence intervals (CI) were estimated for the association of risk factors with lifetime CBP when considering twins as individuals, and a within-pair co-twin control analysis that accounted for familial and genetic factors. Funding was through VA Grant 5IK2RX001515; there were no study-specific conflicts of interest. The mean age of respondents was 62 years and the prevalence of lifetime CBP was 28%. All lifestyle factors were associated with CBP in the individual level analysis. However, none of these persisted in the within-pair analyses, except for severe obesity (BMI ≥35.0), which was associated with lifetime CBP in both individual-level (OR=1.6, 95% CI: 1.3-1.9) and within-pair analyses (MZ analysis: OR=3.7, 95% CI: 1.2-11.4). Symptoms of PTSD and depression were strongly associated with

The Impact of Magnesium Sulfate Therapy on Angiogenic Factors in Preeclampsia.

PubMed

Vadnais, Mary A; Rana, Sarosh; Quant, Hayley S; Salahuddin, Saira; Dodge, Laura E; Lim, Kee-Hak; Karumanchi, S Ananth; Hacker, Michele R

2012-01-01

OBJECTIVE: The objective was to evaluate whether intravenous magnesium sulfate (magnesium) alters levels of angiogenic factors in women with preeclampsia. STUDY DESIGN: This was a prospective cohort study comparing women with preeclampsia treated with magnesium for seizure prophylaxis to those who were not. Serum levels of angiogenic factors, soluble fms-like tyrosine kinase 1, soluble endoglin and placental growth factor, were measured at the time of diagnosis and approximately 24 hours later. Secondary analysis compared women receiving magnesium for preeclampsia to women receiving magnesium for preterm labor. Analysis of covariance was used to compare levels at 24 hours, adjusting for levels at enrollment and potential confounders. RESULTS: Angiogenic factor levels did not differ between preeclampsia groups with and without magnesium or between preeclampsia and preterm labor groups treated with magnesium (all P > 0.05). CONCLUSION: Magnesium likely decreases seizure risk in preeclampsia by a mechanism other than altering angiogenic factor levels.

Is cannabis a risk factor for suicide attempts in men and women with psychotic illness?

PubMed

Waterreus, A; Di Prinzio, P; Badcock, J C; Martin-Iverson, M; Jablensky, A; Morgan, V A

2018-05-16

To investigate whether recent cannabis use by men and women with psychotic disorders was associated with increased risk of suicide attempt, and to determine associated factors, stratified by sex. Data from 1065 men and 725 women interviewed in the Australian national survey of psychosis were analysed to model separately, for each sex, the impact of daily, casual or no past-year cannabis use and other risk factors including age, on a past-year suicide attempt. In the past year, 168 (9.4%) participants attempted suicide. Unadjusted analyses showed daily cannabis users of both sexes had significantly increased odds of attempting suicide compared to non-users. After adjusting for confounding factors, this relationship was no longer significant. Depression had the strongest association with attempting suicide for both sexes. Sex differences in other risk factors were observed. In post hoc analysis, daily cannabis use was associated with higher odds of attempting suicide in older men compared to non-users; this was not found in younger men or women. Associations between past-year cannabis use and suicide attempts were confounded by other factors (depression, loneliness, homelessness and hallucinations). The possibility of greater risk of suicidal behaviour with regular cannabis use for older men should be considered.

Confounding adjustment in comparative effectiveness research conducted within distributed research networks.

PubMed

Toh, Sengwee; Gagne, Joshua J; Rassen, Jeremy A; Fireman, Bruce H; Kulldorff, Martin; Brown, Jeffrey S

2013-08-01

A distributed research network (DRN) of electronic health care databases, in which data reside behind the firewall of each data partner, can support a wide range of comparative effectiveness research (CER) activities. An essential component of a fully functional DRN is the capability to perform robust statistical analyses to produce valid, actionable evidence without compromising patient privacy, data security, or proprietary interests. We describe the strengths and limitations of different confounding adjustment approaches that can be considered in observational CER studies conducted within DRNs, and the theoretical and practical issues to consider when selecting among them in various study settings. Several methods can be used to adjust for multiple confounders simultaneously, either as individual covariates or as confounder summary scores (eg, propensity scores and disease risk scores), including: (1) centralized analysis of patient-level data, (2) case-centered logistic regression of risk set data, (3) stratified or matched analysis of aggregated data, (4) distributed regression analysis, and (5) meta-analysis of site-specific effect estimates. These methods require different granularities of information be shared across sites and afford investigators different levels of analytic flexibility. DRNs are growing in use and sharing of highly detailed patient-level information is not always feasible in DRNs. Methods that incorporate confounder summary scores allow investigators to adjust for a large number of confounding factors without the need to transfer potentially identifiable information in DRNs. They have the potential to let investigators perform many analyses traditionally conducted through a centralized dataset with detailed patient-level information.

Low socioeconomic status is a risk factor for preeclampsia: the Generation R Study.

PubMed

Silva, Lindsay M; Coolman, Marianne; Steegers, Eric Ap; Jaddoe, Vincent Wv; Moll, Henriëtte A; Hofman, Albert; Mackenbach, Johan P; Raat, Hein

2008-06-01

To examine whether maternal socioeconomic status, as indicated by maternal educational level, is associated with preeclampsia, and if so, to what extent known risk factors for preeclampsia mediate the effect of educational level. In the Generation R Study, a population-based cohort study, we examined data of 3547 pregnant women. Odds ratios of preeclampsia for low, mid-low and mid-high educational level compared with high educational level were calculated after adjustment for confounders and additional adjustment for a selection of potential mediators (family history, material factors, psychosocial factors, substance use, working conditions, preexisting medical conditions, maternal anthropometrics and blood pressure at enrollment) that individually caused more than 10% change in the odds ratio for low education. Adjusted for the confounding effects of age, gravidity and multiple pregnancy, women with low educational level were more likely to develop preeclampsia (odds ratio 5.12; 95% confidence interval: 2.20, 11.93) than women with high educational level. After additional adjustment for financial difficulties, smoking in pregnancy, working conditions, body mass index and blood pressure at enrollment, the odds ratio was 4.91 (95% confidence interval: 1.93, 12.52). Low maternal socioeconomic status is a strong risk factor for preeclampsia. Only a small part of this association can be explained by the mediating effects of established risk factors for preeclampsia. Further research is needed to disentangle the pathway from low socioeconomic status to preeclampsia.

Control selection and confounding factors: A lesson from a Japanese case-control study to examine acellular pertussis vaccine effectiveness.

PubMed

Ohfuji, Satoko; Okada, Kenji; Nakano, Takashi; Ito, Hiroaki; Hara, Megumi; Kuroki, Haruo; Hirota, Yoshio

2017-08-24

When using a case-control study design to examine vaccine effectiveness, both the selection of control subjects and the consideration of potential confounders must be the important issues to ensure accurate results. In this report, we described our experience from a case-control study conducted to evaluate the effectiveness of acellular pertussis vaccine combined with diphtheria-tetanus toxoids (DTaP vaccine). Newly diagnosed pertussis cases and age- and sex-matched friend-controls were enrolled, and the history of DTaP vaccination was compared between groups. Logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) of vaccination for development of pertussis. After adjustment for potential confounders, four doses of DTaP vaccination showed a lower OR for pediatrician-diagnosed pertussis (OR=0.11, 95% CI, 0.01-0.99). In addition, the decreasing OR of four doses vaccination was more pronounced for laboratory-confirmed pertussis (OR=0.07, 95%CI, 0.01-0.82). Besides, positive association with pertussis was observed in subjects with a history of steroid treatment (OR=5.67) and those with a recent contact with a lasting cough (OR=4.12). When using a case-control study to evaluate the effectiveness of vaccines, particularly those for uncommon infectious diseases such as pertussis, the use of friend-controls may be optimal due to the fact that they shared a similar experience for exposure to the pathogen as the cases. In addition, to assess vaccine effectiveness as accurately as possible, the effects of confounding should be adequately controlled with a matching or analysis technique. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

The Impact of Magnesium Sulfate Therapy on Angiogenic Factors in Preeclampsia

PubMed Central

VADNAIS, Mary A.; RANA, Sarosh; QUANT, Hayley S.; SALAHUDDIN, Saira; DODGE, Laura E.; LIM, Kee-Hak; KARUMANCHI, S. Ananth; HACKER, Michele R.

2011-01-01

Objective The objective was to evaluate whether intravenous magnesium sulfate (magnesium) alters levels of angiogenic factors in women with preeclampsia. Study Design This was a prospective cohort study comparing women with preeclampsia treated with magnesium for seizure prophylaxis to those who were not. Serum levels of angiogenic factors, soluble fms-like tyrosine kinase 1, soluble endoglin and placental growth factor, were measured at the time of diagnosis and approximately 24 hours later. Secondary analysis compared women receiving magnesium for preeclampsia to women receiving magnesium for preterm labor. Analysis of covariance was used to compare levels at 24 hours, adjusting for levels at enrollment and potential confounders. Results Angiogenic factor levels did not differ between preeclampsia groups with and without magnesium or between preeclampsia and preterm labor groups treated with magnesium (all P > 0.05). Conclusion Magnesium likely decreases seizure risk in preeclampsia by a mechanism other than altering angiogenic factor levels. PMID:22247820

Prevention of motor‐vehicle deaths by changing vehicle factors

PubMed Central

Robertson, Leon S

2007-01-01

Objective To estimate the effect of changing vehicle factors to reduce mortality in a comprehensive study. Design/methods Odds of death in the United States during 2000–2005 were analyzed, involving specific makes and models of 1999–2005 model year cars, minivans, and sport utility vehicles using logistic regression after selection of factors to be included by examination of least‐squares correlations of vehicle factors to maximize independence of predictors. Based on the regression coefficients, percentages of deaths preventable by changes in selected factors were calculated. Correlations of vehicle characteristics to environmental and behavioral risk factors were also examined to assess any potential confounding. Results Deaths in the studied vehicles would have been 42% lower had all had electronic stability control (ESC) systems. Improved crashworthiness as measured by offset frontal and side crash tests would have produced an additional 28% reduction, and static stability improvement would have reduced the deaths 11%. Although weight–power that reduces fuel economy is associated with lower risk to drivers, it increases risk of deaths to pedestrians and bicyclists but has an overall minor effect compared to the other factors. Conclusion A large majority of motor‐vehicle‐related fatalities could be avoided by universal adoption of the most effective technologies. PMID:17916886

Risk factors for retained placenta.

PubMed

Coviello, Elizabeth M; Grantz, Katherine L; Huang, Chun-Chih; Kelly, Tara E; Landy, Helain J

2015-12-01

Retained placenta complicates 2-3% of vaginal deliveries and is a known cause of postpartum hemorrhage. Treatment includes manual or operative placental extraction, potentially increasing risks of hemorrhage, infections, and prolonged hospital stays. We sought to evaluate risk factors for retained placenta, defined as more than 30 minutes between the delivery of the fetus and placenta, in a large US obstetrical cohort. We included singleton, vaginal deliveries ≥24 weeks (n = 91,291) from the Consortium of Safe Labor from 12 US institutions (2002-2008). Multivariable logistic regression analyses estimated the adjusted odds ratios (OR) and 95% confidence intervals (CI) for potential risk factors for retained placenta stratified by parity, adjusting for relevant confounding factors. Characteristics such as stillbirth, maternal age, race, and admission body mass index were examined. Retained placenta complicated 1047 vaginal deliveries (1.12%). Regardless of parity, significant predictors of retained placenta included stillbirth (nulliparous adjusted OR, 5.67; 95% CI, 3.10-10.37; multiparous adjusted OR, 4.56; 95% CI, 2.08-9.94), maternal age ≥30 years, delivery at 24 0/7 to 27 6/7 compared with 34 weeks or later and delivery in a teaching hospital. In nulliparous women, additional risk factors were identified: longer first- or second-stage labor duration, whereas non-Hispanic black compared with non-Hispanic white race was found to be protective. Body mass index was not associated with an increased risk. Multiple risk factors for retained placenta were identified, particularly the strong association with stillbirth. It is plausible that there could be something intrinsic about stillbirth that causes a retained placenta, or perhaps there are shared pathways of certain etiologies of stillbirth and a risk of retained placenta. Copyright © 2015 Elsevier Inc. All rights reserved.

Prevalence and associated factors for temporomandibular disorders in Chinese civilian pilots.

PubMed

Yu, Qing; Liu, Yang; Chen, Xi; Chen, Duanjing; Xie, Lu; Hong, Xiao; Wang, Xingyuan; Huang, Haili; Yu, Haiyang

2015-10-01

Piloting is a special profession with prolonged stress, which could induce the occurrence of TMD. This sample is useful to reduce the effect of confounders in the analyses. Based on this, the present study aims to determine the prevalence and associated factors for TMD in civilian pilots of China. A cross-sectional epidemiological survey was carried out in 616 male subjects (aged 23-52 years). The questionnaire included general information, chewing preference (bilateral or unilateral), and Trait Anxiety section of Spielberger State-Trait Anxiety Inventory (STAI-T). The clinical examination contained TMD screening per research diagnostic criteria for TMD and diagnosis of sleep bruxism per American Academy of Sleep Medicine standards. The level of statistical significance was set at P ≤ 0.05. The program was conducted from June 2012 to April 2013, in which period, and the percentage of TMD in the samples we examined was 33.3 % (=205/616). Only high anxiety (OR 2.48; 95 % CI 1.25-4.90) and unilateral chewing preference (OR 12.67; 95 % CI 7.77-20.65) were the most significant associated factors with TMD. Also, salivary cortisol and the STAI-T score had a significant correlation (r = 0.47, P < 0.001). It was more reliable to study the associated factors on TMD with the exclusion of the possible confounding factors, and only unilateral chewing preference and psychological stress had a significant association with TMD. In addition, the salivary cortisol levels might assist to assess psychological stress in epidemiological research.

The confounding factors leading to plagiarism in academic writing and some suggested remedies: A systematic review.

PubMed

Guraya, Salman Yousuf; Guraya, Shaista Salman

2017-05-01

There is a staggering upsurge in the incidence of plagiarism of scientific literature. Literature shows divergent views about the factors that make plagiarism reprehensible. This review explores the causes and remedies for the perennial academic problem of plagiarism. Data sources were searched for full text English language articles published from 2000 to 2015. Data selection was done using medical subject headline (MeSH) terms plagiarism, unethical writing, academic theft, retraction, medical field, and plagiarism detection software. Data extraction was undertaken by selecting titles from retrieved references and data synthesis identified key factors leading to plagiarism such as unawareness of research ethics, poor writing skills and pressure or publish mantra. Plagiarism can be managed by a balance among its prevention, detection by plagiarism detection software, and institutional sanctions against proven plagiarists. Educating researchers about ethical principles of academic writing and institutional support in training writers about academic integrity and ethical publications can curtail plagiarism.

Selection bias and patterns of confounding in cohort studies: the case of the NINFEA web-based birth cohort.

PubMed

Pizzi, Costanza; De Stavola, Bianca L; Pearce, Neil; Lazzarato, Fulvio; Ghiotti, Paola; Merletti, Franco; Richiardi, Lorenzo

2012-11-01

Several studies have examined the effects of sample selection on the exposure-outcome association estimates in cohort studies, but the reasons why this selection may induce bias have not been fully explored. To investigate how sample selection of the web-based NINFEA birth cohort may change the confounding patterns present in the source population. The characteristics of the NINFEA participants (n=1105) were compared with those of the wider source population-the Piedmont Birth Registry (PBR)-(n=36 092), and the association of two exposures (parity and educational level) with two outcomes (low birth weight and birth by caesarean section), while controlling for other risk factors, was studied. Specifically the associations among measured risk factors within each dataset were examined and the exposure-outcome estimates compared in terms of relative ORs. The associations of educational level with the other risk factors (alcohol consumption, folic acid intake, maternal age, pregnancy weight gain, previous miscarriages) partly differed between PBR and NINFEA. This was not observed for parity. Overall, the exposure-outcome estimates derived from NINFEA only differed moderately from those obtained in PBR, with relative ORs ranging between 0.74 and 1.03. Sample selection in cohort studies may alter the confounding patterns originally present in the general population. However, this does not necessarily introduce selection bias in the exposure-outcome estimates, as sample selection may reduce some of the residual confounding present in the general population.

Ultrasound Elastography and MR Elastography for Assessing Liver Fibrosis: Part 2, Diagnostic Performance, Confounders, and Future Directions

PubMed Central

Tang, An; Cloutier, Guy; Szeverenyi, Nikolaus M.; Sirlin, Claude B.

2016-01-01

OBJECTIVE The purpose of the article is to review the diagnostic performance of ultrasound and MR elastography techniques for detection and staging of liver fibrosis, the main current clinical applications of elastography in the abdomen. CONCLUSION Technical and instrument-related factors and biologic and patient-related factors may constitute potential confounders of stiffness measurements for assessment of liver fibrosis. Future developments may expand the scope of elastography for monitoring liver fibrosis and predict complications of chronic liver disease. PMID:25905762

Can statistic adjustment of OR minimize the potential confounding bias for meta-analysis of case-control study? A secondary data analysis.

PubMed

Liu, Tianyi; Nie, Xiaolu; Wu, Zehao; Zhang, Ying; Feng, Guoshuang; Cai, Siyu; Lv, Yaqi; Peng, Xiaoxia

2017-12-29

Different confounder adjustment strategies were used to estimate odds ratios (ORs) in case-control study, i.e. how many confounders original studies adjusted and what the variables are. This secondary data analysis is aimed to detect whether there are potential biases caused by difference of confounding factor adjustment strategies in case-control study, and whether such bias would impact the summary effect size of meta-analysis. We included all meta-analyses that focused on the association between breast cancer and passive smoking among non-smoking women, as well as each original case-control studies included in these meta-analyses. The relative deviations (RDs) of each original study were calculated to detect how magnitude the adjustment would impact the estimation of ORs, compared with crude ORs. At the same time, a scatter diagram was sketched to describe the distribution of adjusted ORs with different number of adjusted confounders. Substantial inconsistency existed in meta-analysis of case-control studies, which would influence the precision of the summary effect size. First, mixed unadjusted and adjusted ORs were used to combine individual OR in majority of meta-analysis. Second, original studies with different adjustment strategies of confounders were combined, i.e. the number of adjusted confounders and different factors being adjusted in each original study. Third, adjustment did not make the effect size of original studies trend to constringency, which suggested that model fitting might have failed to correct the systematic error caused by confounding. The heterogeneity of confounder adjustment strategies in case-control studies may lead to further bias for summary effect size in meta-analyses, especially for weak or medium associations so that the direction of causal inference would be even reversed. Therefore, further methodological researches are needed, referring to the assessment of confounder adjustment strategies, as well as how to take this kind

Why does early sexual intercourse predict subsequent maladjustment? Exploring potential familial confounds.

PubMed

Donahue, Kelly L; Lichtenstein, Paul; Långström, Niklas; D'Onofrio, Brian M

2013-02-01

Previous studies have found an association between early age at first sexual intercourse and subsequent psychosocial maladjustment. Using a quasi-experimental approach, we examined the extent to which this observed association may be due to familial confounds not explored in prior research. Using a population-based cohort of Swedish adult twins (ages 19-47; N = 12,126), we examined the nature of the association between early sexual intercourse (i.e., first intercourse occurring before age 16) and various outcomes reflecting psychosocial health, including substance use, depression, criminal convictions, and adolescent childbearing. We used two methods--discordant-twin analyses and bivariate twin modeling--to estimate the extent to which genetic and environmental confounds explained observed associations. Individuals who engaged in early intercourse were at greater risk for most of the adverse psychosocial health outcomes measured in this study. However, twin pairs discordant for engaging in early intercourse did not differ significantly in their risk for psychosocial maladjustment. Our results indicated that early age at first sexual intercourse and subsequent psychosocial maladjustment may be associated because of familial factors shared by twins. Early intercourse may be associated with poor psychosocial health largely due to shared familial influences rather than through a direct causal connection. Therefore, effective and efficient interventions should address other risk factors common to early intercourse and poor psychosocial health.

Contribution of host, bacterial factors and antibiotic treatment to mortality in adult patients with bacteraemic pneumococcal pneumonia.

PubMed

Naucler, Pontus; Darenberg, Jessica; Morfeldt, Eva; Ortqvist, Ake; Henriques Normark, Birgitta

2013-06-01

Host and bacterial factors as well as different treatment regimens are likely to influence the outcome in patients with bacteraemic pneumococcal pneumonia. To estimate the relative contribution of host factors as well as bacterial factors and antibiotic treatment to mortality in bacteraemic pneumococcal pneumonia. A cohort study of 1580 adult patients with community-acquired bacteraemic pneumococcal pneumonia was conducted between 2007 and 2009 in Sweden. Data on host factors and initial antibiotic treatment were collected from patient records. Antibiotic resistance and serotype were determined for bacterial isolates. Logistic regression analyses were performed to assess risk factors for 30-day mortality. Smoking, alcohol abuse, solid tumour, liver disease and renal disease attributed to 14.9%, 13.1%, 13.1%, 8.0% and 7.4% of the mortality, respectively. Age was the strongest predictor, and mortality increased exponentially from 1.3% in patients <45 years of age to 26.1% in patients aged ≥85 years. There was considerable confounding by host factors on the association between serotype and mortality. Increasing age, liver disease and serotype were associated with mortality in patients admitted to the ICU. Combined treatment with β-lactam antibiotics and macrolide/quinolone was associated with reduced mortality in patients in the ICU, although confounding could not be ruled out. Host factors appear to be more important than the specific serotype as determinants of mortality in patients with bacteraemic pneumococcal pneumonia. Several host factors were identified that contribute to mortality, which is important for prognosis and to guide targeted prevention strategies.

A prospective cohort study of disability pension due to mental diagnoses: the importance of health factors and behaviors

PubMed Central

2013-01-01

Background Previous studies have found associations between various health factors and behaviors and mental disorders. However, knowledge of such associations with disability pension (DP) due to mental diagnoses is scarce. Moreover, the influence of familial factors (genetics and family background) on the associations are mainly unknown. The aim of the study was to investigate associations between health factors and behaviors and future DP due to mental diagnoses in a twin cohort, accounting for familial confounding. Methods A prospective cohort study of Swedish twins (N=28 613), including survey data and national register data on DP and other background factors was conducted. Cox proportional hazards regression models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI) for the whole twin cohort, and for discordant twin pairs. Results During follow-up 1998–2008 (median 10 years), 2.2% of the cohort was granted a DP with a mental diagnosis. In the fully adjusted analyses of the whole cohort, the associations of poor or moderate self-rated health (SRH), under- or overweight, former or current tobacco use, or being an abstainer from alcohol were significantly associated with risk of DP due to mental diagnoses. Analyses of discordant twin pairs confirmed all these associations, except for current tobacco use, being independent from familial confounding. Exclusion of individuals with current or previous depression or anxiety at baseline did not influence the associations found. Conclusions Poor or moderate SRH, under- or overweight, former tobacco use or being an abstainer from alcohol seem to be strong direct predictors of DP due to mental diagnoses, independently of several confounders of this study, including familial factors. PMID:23816331

Exercise-induced neuroprotective effects on neurodegenerative diseases: the key role of trophic factors.

PubMed

Campos, Carlos; Rocha, Nuno Barbosa F; Lattari, Eduardo; Paes, Flávia; Nardi, António E; Machado, Sérgio

2016-06-01

Age-related neurodegenerative disorders, like Alzheimer's or Parkinson's disease, are becoming a major issue to public health care. Currently, there is no effective pharmacological treatment to address cognitive impairment in these patients. Here, we aim to explore the role of exercise-induced trophic factor enhancement in the prevention or delay of cognitive decline in patients with neurodegenerative diseases. There is a significant amount of evidence from animal and human studies that links neurodegenerative related cognitive deficits with changes on brain and peripheral trophic factor levels. Several trials with elderly individuals and patients with neurodegenerative diseases report exercise induced cognitive improvements and changes on trophic factor levels including BDNF, IGF-I, among others. Further studies with healthy aging and clinical populations are needed to understand how diverse exercise interventions produce different variations in trophic factor signaling. Genetic profiles and potential confounders regarding trophic factors should also be addressed in future trials.

Prognostic factors in canine appendicular osteosarcoma - a meta-analysis.

PubMed

Boerman, Ilse; Selvarajah, Gayathri T; Nielen, Mirjam; Kirpensteijn, Jolle

2012-05-15

Appendicular osteosarcoma is the most common malignant primary canine bone tumor. When treated by amputation or tumor removal alone, median survival times (MST) do not exceed 5 months, with the majority of dogs suffering from metastatic disease. This period can be extended with adequate local intervention and adjuvant chemotherapy, which has become common practice. Several prognostic factors have been reported in many different studies, e.g. age, breed, weight, sex, neuter status, location of tumor, serum alkaline phosphatase (SALP), bone alkaline phosphatase (BALP), infection, percentage of bone length affected, histological grade or histological subtype of tumor. Most of these factors are, however, only reported as confounding factors in larger studies. Insight in truly significant prognostic factors at time of diagnosis may contribute to tailoring adjuvant therapy for individual dogs suffering from osteosarcoma. The objective of this study was to systematically review the prognostic factors that are described for canine appendicular osteosarcoma and validate their scientific importance. A literature review was performed on selected studies and eligible data were extracted. Meta-analyses were done for two of the three selected possible prognostic factors (SALP and location), looking at both survival time (ST) and disease free interval (DFI). The third factor (age) was studied in a qualitative manner. Both elevated SALP level and the (proximal) humerus as location of the primary tumor are significant negative prognostic factors for both ST and DFI in dogs with appendicular osteosarcoma. Increasing age was associated with shorter ST and DFI, however, was not statistically significant because information of this factor was available in only a limited number of papers. Elevated SALP and proximal humeral location are significant negative prognosticators for canine osteosarcoma.

Correction of confounding bias in non-randomized studies by appropriate weighting.

PubMed

Schmoor, Claudia; Gall, Christine; Stampf, Susanne; Graf, Erika

2011-03-01

In non-randomized studies, the assessment of a causal effect of treatment or exposure on outcome is hampered by possible confounding. Applying multiple regression models including the effects of treatment and covariates on outcome is the well-known classical approach to adjust for confounding. In recent years other approaches have been promoted. One of them is based on the propensity score and considers the effect of possible confounders on treatment as a relevant criterion for adjustment. Another proposal is based on using an instrumental variable. Here inference relies on a factor, the instrument, which affects treatment but is thought to be otherwise unrelated to outcome, so that it mimics randomization. Each of these approaches can basically be interpreted as a simple reweighting scheme, designed to address confounding. The procedures will be compared with respect to their fundamental properties, namely, which bias they aim to eliminate, which effect they aim to estimate, and which parameter is modelled. We will expand our overview of methods for analysis of non-randomized studies to methods for analysis of randomized controlled trials and show that analyses of both study types may target different effects and different parameters. The considerations will be illustrated using a breast cancer study with a so-called Comprehensive Cohort Study design, including a randomized controlled trial and a non-randomized study in the same patient population as sub-cohorts. This design offers ideal opportunities to discuss and illustrate the properties of the different approaches. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Assay Dilution Factors Confound Measures of Total Antioxidant Capacity in Polyphenol-Rich Juices

PubMed Central

Bolling, Bradley W.; Chen, Ya-Yen; Kamil, Alison G.; Chen, C-Y. Oliver

2016-01-01

The extent to which sample dilution factor (DF) affects total antioxidant capacity (TAC) values is poorly understood. Thus, we examined the impact of DF on the ORAC, FRAP, DPPH, and total phenols (TP) assays using pomegranate juice (PJ), grape juice (GJ), selected flavonoids, ascorbic acid, and ellagic acid. For ORAC, GJ was comparable to PJ at DF 750, but at DF 2000, the ORAC value of GJ was 40% more than PJ. Increasing DF increased GJ and PJ, DPPH, TP, and FRAP values 11% and 14%, respectively. Increased test concentrations of quercetin and catechin resulted in 51% and 126% greater ORAC values, but decreased naringenin by 68%. Flavonoids, but not ellagic acid or ascorbic acid, may contribute to the dilution effect on the variation of final TAC values. Thus, reporting TAC or TP using a single DF may introduce uncertainty about the confidence of TAC assay values, especially when comparing different juices. These results underscore the importance of using compatible test standards for reporting TAC values. PMID:22251245

Soil acidification as a confounding factor on metal phytotoxicity in soils spiked with copper-rich mine wastes.

PubMed

Ginocchio, Rosanna; De la Fuente, Luz María; Sánchez, Pablo; Bustamante, Elena; Silva, Yasna; Urrestarazu, Paola; Rodríguez, Patricio H

2009-10-01

Pollution of soil with mine wastes results in both Cu enrichment and soil acidification. This confounding effect may be very important in terms of phytotoxicity, because pH is a key parameter influencing Cu solubility in soil solution. Laboratory toxicity tests were used to assess the effect of acidification by acidic mine wastes on Cu solubility and on root elongation of barley (Hordeum vulgare L.). Three contrasting substrates (two soils and a commercial sand) and two acidic, Cu-rich mine wastes (oxidized tailings [OxT] and smelter dust [SmD]) were selected as experimental materials. Substrates were spiked with a fixed amount of either SmD or OxT, and the pH of experimental mixtures was then modified in the range of 4.0 to 6.0 and 7.0 using PIPES (piperazine-1,4-bis(2-ethanesulfonic acid)), MES (2-(N-morpholino)ethanesulfonic acid), and MOPS (3-(N-Morpholino)-propanesulfonic acid) buffers. Chemical (pore-water Cu and pH) and toxicological (root length of barley plants) parameters were determined for experimental mixtures. Addition of SmD and OxT to substrates resulted in acidification (0.11-1.16 pH units) and high levels of soluble Cu and Zn. Neutralization of experimental mixtures with MES (pH 6.0) and MOPS (pH 7.0) buffers resulted in a marked decrease in soluble Cu and Zn, but the intensity of the effect was substrate-dependent. Adjustment of soil pH above the range normally considered to be toxic to plants (pH in water extract, > 5.5) significantly reduced metal toxicity in barley, but phytotoxicity was not completely eliminated. The present results stress the importance of considering confounding effects on derivation of toxicity thresholds to plants when using laboratory phytotoxicity tests.

Lifestyle factors and sperm aneuploidy.

PubMed

Jurewicz, Joanna; Radwan, Michał; Sobala, Wojciech; Radwan, Paweł; Jakubowski, Lucjusz; Hawuła, Wanda; Ulańska, Anna; Hanke, Wojciech

2014-09-01

Different environmental and lifestyle factors may interfere with the normal disjunction of sister chromatids/chromosomes during meiosis and may cause aneuploidy. The aim of the study was to examine the association between lifestyle factors and sperm aneuploidy. The study population consisted of 212 healthy men under 45 years of age attending an infertility clinic for diagnostic purposes and who had a normal semen concentration of 20-300×10⁶mL or slight oligozoospermia (semen concentration of 15-20×10⁶/mL). All participants were interviewed and provided a semen sample. Sperm aneuploidy was assessed using multicolor FISH (DNA probes specific for chromosomes X, Y, 18, 13, 21). Results from the study suggest that lifestyle factors are related to sperm aneuploidy. A positive relationship was found between coffee drinking everyday and the lack of chromosome X or Y, as well as coffee drinking 1-6 times per week and additional chromosome 18. Wearing boxer shorts decrease the copy number changes in the whole chromosome 18, the number of additional chromosome 18 and the lack of chromosome 13. Additionally, obesity (BMI 30-40 kg/m²) was positively associated with additional chromosome 21 after being adjusted for potential confounders. These findings demonstrate that changing the men's lifestyle habits may contribute to reduction of the incidence of sperm aneuploidy. It is necessary that men continue to follow sensible health advice concerning excess weight, coffee drinking and wearing tight fitting underwear. As this is the first such study to examine different lifestyle factors and sperm aneuploidy, the results need to be confirmed on larger population. Copyright © 2014 Society for Biology of Reproduction & the Institute of Animal Reproduction and Food Research of Polish Academy of Sciences in Olsztyn. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Effects of psychosocial work factors on lifestyle changes: a cohort study.

PubMed

Allard, Karin Olofsson; Thomsen, Jane Frølund; Mikkelsen, Sigurd; Rugulies, Reiner; Mors, Ole; Kærgaard, Anette; Kolstad, Henrik A; Kaerlev, Linda; Andersen, Johan Hviid; Hansen, Ase Marie; Bonde, Jens Peter

2011-12-01

To evaluate the effect of the demand-control-support model, the effort-reward imbalance model, and emotional demands on smoking, alcohol consumption, physical activity, and body mass index. This is a 2-year prospective cohort study of 3224 public sector employees. Measures were assessed with questionnaires. Multiple regression analyses were used to predict changes in lifestyle factors. Low reward predicted smoking, low-decision latitude predicted being inactive, and high demands predicted high-alcohol consumption but only for men at follow-up even after controlling for potential confounders. There were no other significant findings in the expected direction except for some of the confounders. We found only limited and inconsistent support for the hypothesis that a poor psychosocial work environment is associated with an adverse lifestyle.

Risk factors for recurrent gastroesophageal reflux disease after fundoplication in pediatric patients: a case-control study.

PubMed

Ngerncham, Monawat; Barnhart, Douglas C; Haricharan, Ramanath N; Roseman, Jeffrey M; Georgeson, Keith E; Harmon, Carroll M

2007-09-01

Recurrent gastroesophageal reflux disease (rGERD) is a common problem after fundoplication. Previous studies attempting to identify risk factors for rGERD have failed to control for confounding variables. The purpose of this study was to identify significant risk factors for rGERD after controlling for potential confounding variables. A retrospective, matched case-control study was conducted at a tertiary children's hospital. Cases (n = 116) met 1 of these criteria: reoperation for rGERD, symptomatic rGERD (confirmed by upper gastrointestinal series, esophagogastroduodenoscopy, or pH monitoring), or postoperative reinstitution of antireflux medication for more than 8 weeks. Controls (n = 209) were matched for surgeon, approach (laparoscopic/open), technique (partial/complete), and approximate operative date. Univariate and multivariable associations were analyzed by conditional logistic regression. Significant risk factors for rGERD were age of less than 6 years (odds ratio [OR], 3.6; 95% confidence interval [CI], 1.7-7.5), preoperative hiatal hernia (OR, 3.2; 95% CI, 1.4-7.3), postoperative retching (OR, 5.1; 95% CI, 2.6-10.0), and postoperative esophageal dilatation (OR, 10.8; 95% CI, 1.8-65.4). Interestingly, significant association was not found between neurologic impairment and rGERD after controlling for potential confounding variables. Age of less than 6 years, preoperative hiatal hernia, postoperative retching, and postoperative esophageal dilatation are independently associated with increased risk of rGERD. Neurologic impairment alone does not increase the risk of developing rGERD.

Association between obesity and glomerular hyperfiltration: the confounding effect of smoking and sodium and protein intakes.

PubMed

Ogna, Adam; Forni Ogna, Valentina; Bochud, Murielle; Guessous, Idris; Paccaud, Fred; Burnier, Michel; Wuerzner, Gregoire

2016-04-01

Glomerular hyperfiltration has been suggested as a possible mechanism linking obesity and chronic kidney disease (CKD), independently of classical risk factors. We explored the association of overweight and obesity with glomerular hyperfiltration in a large sample of the Swiss adult population, accounting for several confounders including dietary factors. Data from a 2010 to 2012 cross-sectional population-based survey in Switzerland were used. Creatinine clearance (CrCl) was determined from 24-h urine collection; CrCl > 140 ml/min was used to define glomerular hyperfiltration. Participants were categorized into lean (<25 kg/m(2)), overweight (25-29.9 kg/m(2)) and obese (≥30 kg/m(2)) according to body mass index (BMI). A total of 1339 participants were included in the analysis [median (IQR) age 49.4 (34.3-63.5) years, 48.9 % men]. The prevalences of overweight and obesity were 32.2 and 14.2 %, respectively. Median CrCl was 102[84-121] ml/min in lean, 110 [87-136] ml/min in overweight and 124 [97-150] ml/min in obese participants (p < 0.001). The prevalence of glomerular hyperfiltration increased across BMI categories (10.4, 20.8 and 34.7 %, respectively; p < 0.001). This positive association remained significant after adjusting for age, sex, hypertension, diabetes, smoking and dietary factors (sodium and protein intakes): odds ratio [95 %CI] 2.39 [1.52-3.76] (p < 0.001) for overweight versus lean and 4.10[2.31-7.27] (p < 0.001) for obesity versus lean. BMI categories and glomerular hyperfiltration are positively associated, independently of other known CKD risk factors and dietary confounders, suggesting that glomerular hyperfiltration may represent an early renal phenotype in obesity. Our observations confirm the significant association of glomerular hyperfiltration with sodium and protein intakes and identify sodium intake as an important modifying factor of the association between hyperfiltration and obesity.

Analytic Couple Modeling Introducing Device Design Factor, Fin Factor, Thermal Diffusivity Factor, and Inductance Factor

NASA Technical Reports Server (NTRS)

Mackey, Jon; Sehirlioglu, Alp; Dynys, Fred

2014-01-01

A set of convenient thermoelectric device solutions have been derived in order to capture a number of factors which are previously only resolved with numerical techniques. The concise conversion efficiency equations derived from governing equations provide intuitive and straight-forward design guidelines. These guidelines allow for better device design without requiring detailed numerical modeling. The analytical modeling accounts for factors such as i) variable temperature boundary conditions, ii) lateral heat transfer, iii) temperature variable material properties, and iv) transient operation. New dimensionless parameters, similar to the figure of merit, are introduced including the device design factor, fin factor, thermal diffusivity factor, and inductance factor. These new device factors allow for the straight-forward description of phenomenon generally only captured with numerical work otherwise. As an example a device design factor of 0.38, which accounts for thermal resistance of the hot and cold shoes, can be used to calculate a conversion efficiency of 2.28 while the ideal conversion efficiency based on figure of merit alone would be 6.15. Likewise an ideal couple with efficiency of 6.15 will be reduced to 5.33 when lateral heat is accounted for with a fin factor of 1.0.

MAOA promoter methylation and susceptibility to carotid atherosclerosis: role of familial factors in a monozygotic twin sample

PubMed Central

2012-01-01

Background Atherosclerosis is a complex process involving both genetic and epigenetic factors. The monoamine oxidase A (MAOA) gene regulates the metabolism of key neurotransmitters and has been associated with cardiovascular risk factors. This study investigates whether MAOA promoter methylation is associated with atherosclerosis, and whether this association is confounded by familial factors in a monozygotic (MZ) twin sample. Methods We studied 84 monozygotic (MZ) twin pairs drawn from the Vietnam Era Twin Registry. Carotid intima-media thickness (IMT) was measured by ultrasound. DNA methylation in the MAOA promoter region was quantified by bisulfite pyrosequencing using genomic DNA isolated from peripheral blood leukocytes. The association between DNA methylation and IMT was first examined by generalized estimating equation, followed by matched pair analyses to determine whether the association was confounded by familial factors. Results When twins were analyzed as individuals, increased methylation level was associated with decreased IMT at four of the seven studied CpG sites. However, this association substantially reduced in the matched pair analyses. Further adjustment for MAOA genotype also considerably attenuated this association. Conclusions The association between MAOA promoter methylation and carotid IMT is largely explained by familial factors shared by the twins. Because twins reared together share early life experience, which may leave a long-lasting epigenetic mark, aberrant MAOA methylation may represent an early biomarker for unhealthy familial environment. Clarification of familial factors associated with DNA methylation and early atherosclerosis will provide important information to uncover clinical correlates of disease. PMID:23116433

MAOA promoter methylation and susceptibility to carotid atherosclerosis: role of familial factors in a monozygotic twin sample.

PubMed

Zhao, Jinying; Forsberg, Christopher W; Goldberg, Jack; Smith, Nicholas L; Vaccarino, Viola

2012-11-02

Atherosclerosis is a complex process involving both genetic and epigenetic factors. The monoamine oxidase A (MAOA) gene regulates the metabolism of key neurotransmitters and has been associated with cardiovascular risk factors. This study investigates whether MAOA promoter methylation is associated with atherosclerosis, and whether this association is confounded by familial factors in a monozygotic (MZ) twin sample. We studied 84 monozygotic (MZ) twin pairs drawn from the Vietnam Era Twin Registry. Carotid intima-media thickness (IMT) was measured by ultrasound. DNA methylation in the MAOA promoter region was quantified by bisulfite pyrosequencing using genomic DNA isolated from peripheral blood leukocytes. The association between DNA methylation and IMT was first examined by generalized estimating equation, followed by matched pair analyses to determine whether the association was confounded by familial factors. When twins were analyzed as individuals, increased methylation level was associated with decreased IMT at four of the seven studied CpG sites. However, this association substantially reduced in the matched pair analyses. Further adjustment for MAOA genotype also considerably attenuated this association. The association between MAOA promoter methylation and carotid IMT is largely explained by familial factors shared by the twins. Because twins reared together share early life experience, which may leave a long-lasting epigenetic mark, aberrant MAOA methylation may represent an early biomarker for unhealthy familial environment. Clarification of familial factors associated with DNA methylation and early atherosclerosis will provide important information to uncover clinical correlates of disease.

Factors associated with higher oxytocin requirements in labor.

PubMed

Frey, Heather A; Tuuli, Methodius G; England, Sarah K; Roehl, Kimberly A; Odibo, Anthony O; Macones, George A; Cahill, Alison G

2015-09-01

To identify clinical characteristics associated with high maximum oxytocin doses in women who achieve complete cervical dilation. A retrospective nested case-control study was performed within a cohort of all term women at a single center between 2004 and 2008 who reached the second stage of labor. Cases were defined as women who had a maximum oxytocin dose during labor >20 mu/min, while women in the control group had a maximum oxytocin dose during labor of ≤20 mu/min. Exclusion criteria included no oxytocin administration during labor, multiple gestations, major fetal anomalies, nonvertex presentation, and prior cesarean delivery. Multiple maternal, fetal, and labor factors were evaluated with univariable analysis and multivariable logistic regression. Maximum oxytocin doses >20 mu/min were administered to 108 women (3.6%), while 2864 women received doses ≤20 mu/min. Factors associated with higher maximum oxytocin dose after adjusting for relevant confounders included maternal diabetes, birthweight >4000 g, intrapartum fever, administration of magnesium, and induction of labor. Few women who achieve complete cervical dilation require high doses of oxytocin. We identified maternal, fetal and labor factors that characterize this group of parturients.

Is the association between posttraumatic stress disorder symptoms and poor health due to a common familial or genetic factor?

PubMed Central

Roy-Byrne, Peter P.; Noonan, Carolyn; Afari, Niloofar; Buchwald, Dedra; Goldberg, Jack

2010-01-01

Objective The objective of this study was to identify genetic, familial and environmental contributions to the association between posttraumatic stress disorder (PTSD) symptoms and poor health. Methods A community sample of 1852 twin pairs was assessed for symptoms of PTSD [with the Impact of Events Scale (IES)] and self-reported global health status using a single five-level question. An ordinal logistic regression model estimated odds ratio/s (OR) for the association between PTSD and health status. Within-pair analysis assessed confounding by familial and genetic factors and adjusted for the possible confounding influence of age, sex, race, education and self-reported physician diagnosis of depression. Results The IES was strongly and significantly associated with self-reported health [OR = 1.8; 95% confidence interval (95% CI) = 1.5–2.2; highest quartile vs. lowest quartile]. This association remained significant in within-pair analysis (OR = 1.3; 95% CI=1.0–1.7), but after further adjustment for sociodemographics and depression, it was no longer significant (Ptrend=.17). Separate analysis by zygosity did not show differential effect in monozygotic or dizygotic pairs. Conclusion These findings suggest that the association between PTSD symptoms and poor health is, in part, due to familial confounding and sociodemographic factors. Little evidence of confounding by genetic factors was found. These findings suggest that early prevention efforts would have the greatest potential for improving poor health in PTSD-prone patients, whereas later intervention efforts directed at treating PTSD may have a more limited impact on improving poor health. PMID:16950376

Factors Influencing Cognitive Function in Subjects With COPD.

PubMed

Dag, Ersel; Bulcun, Emel; Turkel, Yakup; Ekici, Aydanur; Ekici, Mehmet

2016-08-01

The aim of this study was to assess the association between cognitive function and age, pulmonary function, comorbidity index, and the 6-min walk distance in subjects with COPD as well as to compare the Mini Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) in terms of their ability to identify cognitive dysfunction in subjects with COPD. A total of 52 individuals with stable COPD were included in this study. Cognitive function was assessed using MMSE and MoCA. Age, body mass index, the Modified Cumulative Illness Rating Scale, 6-min walk distance, arterial blood gases, and pulmonary function tests were assessed and recorded. The range and SD of scores in subjects with COPD were larger with MoCA than with MMSE. MMSE and MoCA scores are associated with 6-min walk distance and comorbidity index in subjects with COPD. General cognitive function measured by MoCA was negatively correlated with the comorbidity index but was positively associated with 6-min walk distance in subjects with COPD after controlling for possible confounding factors in the multivariate model. However, general cognitive function measured by MMSE was not correlated with the comorbidity index and 6-min walk distance in subjects with COPD, after controlling for possible confounding factors in the multivariate model. MoCA may be a more reliable screening test than MMSE in detecting cognitive impairment in subjects with COPD. The addition of cognitive tests on assessment of subjects with COPD can provide further benefit. Copyright © 2016 by Daedalus Enterprises.

Association between the severity of symptomatic knee osteoarthritis and cumulative metabolic factors.

PubMed

Yasuda, Emi; Nakamura, Ryuichi; Matsugi, Ryo; Goto, Shinsuke; Ikenaga, Yasunori; Kuroda, Kazunari; Nakamura, Syunsuke; Katsuki, Yasuo; Katsuki, Tatsuo

2018-05-01

The association between cumulative metabolic syndrome (MS) factors and knee osteoarthritis (KOA) has been highlighted over the past two decades. To clarify the relationship between cumulative MS factors and symptomatic KOA. A cross-sectional survey involving 119 women aged 45-88 years who were scheduled to undergo knee surgery was conducted. They were stratified into tertiles of symptoms as assessed by the Japanese Orthopedic Association score for KOA. Multinomial logistic regressions were performed using the severity of symptomatic KOA as the dependent variable and each MS factor or the cumulative MS factors as the independent variables. Logistic regression analyses were performed with the upper tertile of stratified symptoms of subjects used as the reference group. After adjustment for confounders, KOA patients who had two (p = 0.004) or three or more (p < 0.0001) MS factors were significantly more likely to have severe symptoms compared to those who had no MS factors. MS factors excluding obesity were similarly analyzed. Even after additional adjustment for body mass index (BMI), KOA patients who had two or more (p = 0.005) MS factors were significantly more likely to have severe symptoms. Among KOA female patients diagnosed using radiographic definition, the severity of symptomatic KOA was significantly associated with hypertension, dyslipidemia, and the number of MS factors after adjustment for age, BMI, strength of the knee extensor, and Kellgren-Lawrence grade. The severity of radiographic KOA was not associated with any MS factor or cumulative MS factors.

The role of prenatal care and social risk factors in the relationship between immigrant status and neonatal morbidity: a retrospective cohort study.

PubMed

Paz-Zulueta, María; Llorca, Javier; Sarabia-Lavín, Raquel; Bolumar, Francisco; Rioja, Luis; Delgado, Abraham; Santibáñez, Miguel

2015-01-01

Literature evaluating association between neonatal morbidity and immigrant status presents contradictory results. Poorer compliance with prenatal care and greater social risk factors among immigrants could play roles as major confounding variables, thus explaining contradictions. We examined whether prenatal care and social risk factors are confounding variables in the relationship between immigrant status and neonatal morbidity. Retrospective cohort study: 231 pregnant African immigrant women were recruited from 2007-2010 in northern Spain. A Spanish population sample was obtained by simple random sampling at 1:3 ratio. Immigrant status (Spanish, Sub-Saharan and Northern African), prenatal care (Kessner Index adequate, intermediate or inadequate), and social risk factors were treated as independent variables. Low birth weight (LBW < 2500 grams) and preterm birth (< 37 weeks) were collected as neonatal morbidity variables. Crude and adjusted odds ratios (OR) were estimated by unconditional logistic regression with 95% confidence intervals (95% CI). Positive associations between immigrant women and higher risk of neonatal morbidity were obtained. Crude OR for preterm births in Northern Africans with respect to nonimmigrants was 2.28 (95% CI: 1.04-5.00), and crude OR for LBW was 1.77 (95% CI: 0.74-4.22). However, after adjusting for prenatal care and social risk factors, associations became protective: adjusted OR for preterm birth = 0.42 (95% CI: 0.14-1.32); LBW = 0.48 (95% CI: 0.15-1.52). Poor compliance with prenatal care was the main independent risk factor associated with both preterm birth (adjusted OR inadequate care = 17.05; 95% CI: 3.92-74.24) and LBW (adjusted OR inadequate care = 6.25; 95% CI: 1.28-30.46). Social risk was an important independent risk factor associated with LBW (adjusted OR = 5.42; 95% CI: 1.58-18.62). Prenatal care and social risk factors were major confounding variables in the relationship between immigrant status and neonatal morbidity.

[Biases in the study of prognostic factors].

PubMed

Delgado-Rodríguez, M

1999-01-01

The main objective is to detail the main biases in the study of prognostic factors. Confounding bias is illustrated with social class, a prognostic factor still discussed. Within selection bias several cases are commented: response bias, specially frequent when the patients of a clinical trial are used; the shortcomings in the formation of an inception cohort; the fallacy of Neyman (bias due to the duration of disease) when the study begins with a cross-sectional study; the selection bias in the treatment of survivors for the different treatment opportunity of those living longer; the bias due to the inclusion of heterogeneous diagnostic groups; and the selection bias due to differential information losses and the use of statistical multivariate procedures. Within the biases during follow-up, an empiric rule to value the impact of the number of losses is given. In information bias the Will Rogers' phenomenon and the usefulness of clinical databases are discussed. Lastly, a recommendation against the use of cutoff points yielded by bivariate analyses to select the variable to be included in multivariate analysis is given.

The Association Between Headaches and Temporomandibular Disorders is Confounded by Bruxism and Somatic Symptoms.

PubMed

van der Meer, Hedwig A; Speksnijder, Caroline M; Engelbert, Raoul H H; Lobbezoo, Frank; Nijhuis-van der Sanden, Maria W G; Visscher, Corine M

2017-09-01

The objective of this observational study was to establish the possible presence of confounders on the association between temporomandibular disorders (TMD) and headaches in a patient population from a TMD and Orofacial Pain Clinic. Several subtypes of headaches have been diagnosed: self-reported headache, (probable) migraine, (probable) tension-type headache, and secondary headache attributed to TMD. The presence of TMD was subdivided into 2 subtypes: painful TMD and function-related TMD. The associations between the subtypes of TMD and headaches were evaluated by single regression models. To study the influence of possible confounding factors on this association, the regression models were extended with age, sex, bruxism, stress, depression, and somatic symptoms. Of the included patients (n=203), 67.5% experienced headaches. In the subsample of patients with a painful TMD (n=58), the prevalence of self-reported headaches increased to 82.8%. The associations found between self-reported headache and (1) painful TMD and (2) function-related TMD were confounded by the presence of somatic symptoms. For probable migraine, both somatic symptoms and bruxism confounded the initial association found with painful TMD. The findings of this study imply that there is a central working mechanism overlapping TMD and headache. Health care providers should not regard these disorders separately, but rather look at the bigger picture to appreciate the complex nature of the diagnostic and therapeutic process.

Interpretational Confounding or Confounded Interpretations of Causal Indicators?

ERIC Educational Resources Information Center

Bainter, Sierra A.; Bollen, Kenneth A.

2014-01-01

In measurement theory, causal indicators are controversial and little understood. Methodological disagreement concerning causal indicators has centered on the question of whether causal indicators are inherently sensitive to interpretational confounding, which occurs when the empirical meaning of a latent construct departs from the meaning…

Is male factor infertility associated with midlife low-grade inflammation? A population based study.

PubMed

Hærvig, Katia Keglberg; Kierkegaard, Lene; Lund, Rikke; Bruunsgaard, Helle; Osler, Merete; Schmidt, Lone

2018-06-01

Male factor infertility is associated with an increased risk of disease and mortality, which has been related to markers of chronic systemic inflammation. The objective of this study was to investigate the association between male factor infertility and low-grade inflammation and furthermore to examine the lifetime prevalence of male factor infertility and overall infertility (also including female and couple infertility). The study population consisted of 2140 members of the Metropolit 1953 Danish Male Birth Cohort who had participated in the Copenhagen Aging and Midlife Biobank data collection in 2009-2011. Information on male factor infertility and overall infertility was obtained from a questionnaire, and low-grade inflammation was evaluated as the highest plasma levels of C-reactive protein, interleukin-6 and tumour necrosis factor-alpha in the population. The level of interleukin-6 was significantly higher among men with male factor infertility compared with other men adjusted for potential confounders. This was not found for the two other inflammatory markers. The lifetime prevalence of male factor infertility and overall infertility were 10.2% and 17.9%, respectively. The findings suggest that male factor infertility might be associated with an increased level of interleukin-6.

Sensitivity, specificity, and confounding factors of novel serological tests used for the rapid diagnosis of bovine tuberculosis in farmed red deer (Cervus elaphus).

PubMed

Buddle, Bryce M; Wilson, Tania; Denis, Michel; Greenwald, Rena; Esfandiari, Javan; Lyashchenko, Konstantin P; Liggett, Simon; Mackintosh, Colin G

2010-04-01

In this study, novel serological tests were used to detect tuberculosis (TB) in groups of farmed red deer (Cervus elaphus) varying in disease status or possible confounding factors. Groups of deer naturally or experimentally infected with Mycobacterium bovis and animals vaccinated against paratuberculosis were studied, as were uninfected animals and animals naturally or experimentally infected with Mycobacterium avium subsp. paratuberculosis. Sera were assayed using two rapid lateral-flow tests, Chembio's CervidTB STAT-PAK and DPP VetTB tests, and results were compared to those from tuberculin skin tests. Both serological tests had a high sensitivity, but specificity was adversely affected after animals had received a vaccine against paratuberculosis and were subsequently skin tested. The specificity of the DPP VetTB test was higher than that of the CervidTB STAT-PAK test, with natural infection with M. avium subsp. paratuberculosis adversely affecting the specificity of only the CervidTB STAT-PAK test. The sera from M. avium subsp. paratuberculosis-infected deer that produced false-positive reactions in the CervidTB STAT-PAK test were retested with a multiantigen print immunoassay (MAPIA), and some of these sera were shown to react with the MPB83 antigen. Combining the results from the serological tests and the skin tests showed only a slight increase in the sensitivity of detection of M. bovis-infected animals. It is concluded that both the CervidTB STAT-PAK and DPP VetTB tests offer rapid, convenient, and easy detection of bovine tuberculosis in deer, albeit with significant interference from paratuberculosis vaccination status and subsequent skin testing. The latter finding illustrates one of the limitations of currently available vaccines against paratuberculosis.

The relationship between type D personality and chronic heart failure is not confounded by disease severity as assessed by BNP.

PubMed

Pelle, Aline J; van den Broek, Krista C; Szabó, Balázs; Kupper, Nina

2010-11-05

Psychological factors, like Type D personality (i.e., the tendency to experience negative emotions and to inhibit emotional distress) have been linked to impaired health outcomes. Criticism on the role of psychological factors in cardiac disease has postulated that such constructs may be confounded by disease severity. Hence, we examined whether Type D personality is associated with brain natriuretic peptide (BNP), a sensitive marker of disease severity in chronic heart failure (CHF), in 202 consecutive CHF outpatients. No differences in logBNP levels were found between Type D and non-Type D patients (t(200) = -1.03, p = .30). After adjusting for demographic and clinical confounders, Type D personality remained unassociated with logBNP levels (β=.04, p = .55), whereas older age (β = .27, p<.001), being prescribed beta-blockers (β = .15, p = .02), lower left ventricular ejection fraction (β = -.38, p<.0001), and kidney dysfunction (β = .17, p = .01) were associated with higher logBNP. To conclude, Type D personality was not associated with BNP in CHF outpatients, whereas clinical variables were associated with BNP. These findings oppose the suggestion that Type D personality is confounded by indicators of disease severity. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

Modifiable risk factors associated with bronchiolitis

PubMed Central

Nenna, Raffaella; Cutrera, Renato; Frassanito, Antonella; Alessandroni, Claudia; Nicolai, Ambra; Cangiano, Giulia; Petrarca, Laura; Arima, Serena; Caggiano, Serena; Ullmann, Nicola; Papoff, Paola; Bonci, Enea; Moretti, Corrado; Midulla, Fabio

2017-01-01

Background: We sought to clarify possibly modifiable risk factors related to pollution responsible for acute bronchiolitis in hospitalized infants. Methods: For this observational study, we recruited 213 consecutive infants with bronchiolitis (cases: median age: 2 months; age range: 0.5–12 months; boys: 55.4%) and 213 children aged <3 years (controls: median age: 12 months; age range: 0.5–36 months; boys: 54.5%) with a negative medical history for lower respiratory tract diseases hospitalized at ‘Sapienza’ University Rome and IRCCS Bambino Gesù Hospital. Infants’ parents completed a standardized 53-item questionnaire seeking information on social-demographic and clinical characteristics, indoor pollution, eating habits and outdoor air pollution. Multivariate logistic regression analyses were run to assess the independent effect of risk factors, accounting for confounders and effect modifiers. Results: In the 213 hospitalized infants the questionnaire identified the following risk factors for acute bronchiolitis: breastfeeding ⩾3 months (OR: 2.1, 95% confidence interval [CI]: 1.2–3.6), presence of older siblings (OR: 2.8, 95% CI: 1.7–4.7), ⩾4 cohabitants (OR: 1.5, 95% CI: 1.1–2.1), and using seed oil for cooking (OR: 1.7, 95% CI: 1.2–2.6). Having renovated their home in the past 12 months and concurrently being exposed daily to smoking, involving more than 11 cigarettes and two or more smoking cohabitants, were more frequent factors in cases than in controls (p = 0.021 and 0.05), whereas self-estimated proximity to road and traffic was similar in the two groups. Conclusions: We identified several risk factors for acute bronchiolitis related to indoor and outdoor pollution, including inhaling cooking oil fumes. Having this information would help public health authorities draw up effective preventive measures – for example, teach mothers to avoid handling their child when they have a cold and eliminate exposure to second-hand tobacco smoke

On the definition of a confounder

PubMed Central

VanderWeele, Tyler J.; Shpitser, Ilya

2014-01-01

Summary The causal inference literature has provided a clear formal definition of confounding expressed in terms of counterfactual independence. The causal inference literature has not, however, produced a clear formal definition of a confounder, as it has given priority to the concept of confounding over that of a confounder. We consider a number of candidate definitions arising from various more informal statements made in the literature. We consider the properties satisfied by each candidate definition, principally focusing on (i) whether under the candidate definition control for all “confounders” suffices to control for “confounding” and (ii) whether each confounder in some context helps eliminate or reduce confounding bias. Several of the candidate definitions do not have these two properties. Only one candidate definition of those considered satisfies both properties. We propose that a “confounder” be defined as a pre-exposure covariate C for which there exists a set of other covariates X such that effect of the exposure on the outcome is unconfounded conditional on (X, C) but such that for no proper subset of (X, C) is the effect of the exposure on the outcome unconfounded given the subset. A variable that helps reduce bias but not eliminate bias we propose referring to as a “surrogate confounder.” PMID:25544784

Pattern identification in time-course gene expression data with the CoGAPS matrix factorization.

PubMed

Fertig, Elana J; Stein-O'Brien, Genevieve; Jaffe, Andrew; Colantuoni, Carlo

2014-01-01

Patterns in time-course gene expression data can represent the biological processes that are active over the measured time period. However, the orthogonality constraint in standard pattern-finding algorithms, including notably principal components analysis (PCA), confounds expression changes resulting from simultaneous, non-orthogonal biological processes. Previously, we have shown that Markov chain Monte Carlo nonnegative matrix factorization algorithms are particularly adept at distinguishing such concurrent patterns. One such matrix factorization is implemented in the software package CoGAPS. We describe the application of this software and several technical considerations for identification of age-related patterns in a public, prefrontal cortex gene expression dataset.

Prognostic factors in canine appendicular osteosarcoma – a meta-analysis

PubMed Central

2012-01-01

Background Appendicular osteosarcoma is the most common malignant primary canine bone tumor. When treated by amputation or tumor removal alone, median survival times (MST) do not exceed 5 months, with the majority of dogs suffering from metastatic disease. This period can be extended with adequate local intervention and adjuvant chemotherapy, which has become common practice. Several prognostic factors have been reported in many different studies, e.g. age, breed, weight, sex, neuter status, location of tumor, serum alkaline phosphatase (SALP), bone alkaline phosphatase (BALP), infection, percentage of bone length affected, histological grade or histological subtype of tumor. Most of these factors are, however, only reported as confounding factors in larger studies. Insight in truly significant prognostic factors at time of diagnosis may contribute to tailoring adjuvant therapy for individual dogs suffering from osteosarcoma. The objective of this study was to systematically review the prognostic factors that are described for canine appendicular osteosarcoma and validate their scientific importance. Results A literature review was performed on selected studies and eligible data were extracted. Meta-analyses were done for two of the three selected possible prognostic factors (SALP and location), looking at both survival time (ST) and disease free interval (DFI). The third factor (age) was studied in a qualitative manner. Both elevated SALP level and the (proximal) humerus as location of the primary tumor are significant negative prognostic factors for both ST and DFI in dogs with appendicular osteosarcoma. Increasing age was associated with shorter ST and DFI, however, was not statistically significant because information of this factor was available in only a limited number of papers. Conclusions Elevated SALP and proximal humeral location are significant negative prognosticators for canine osteosarcoma. PMID:22587466

Inverse Association between Fruit and Vegetable Intake and BMI even after Controlling for Demographic, Socioeconomic and Lifestyle Factors

PubMed Central

Heo, Moonseong; Kim, Ryung S.; Wylie-Rosett, Judith; Allison, David B.; Heymsfield, Steve B.; Faith, Myles S.

2011-01-01

Objective To estimate fruit and vegetable (FV) intake levels of US adult population and evaluate the association between FV intake and BMI status after controlling for confounding demographic, socioeconomic and lifestyle factors. We also sought to identify moderating factors. Methods We used 2007 Behavior Risk Factors Surveillance System (N > 400,000) data. FV intake was dichotomized as ≥5 servings (FV5+) versus <5 servings/day. BMI status was categorized as normal, overweight, and obese. Identification of moderators was performed by testing interactions between BMI status and other variables using bivariate analyses followed by multiple logistic regression analysis incorporating complex survey sampling design features. Results Only 24.6% of US adults consumed ≥5 servings per day and less than 4% consumed 9 or more servings. Overweight (% FV5+ = 23.9%) and obese (21.9%) groups consumed significantly less FV than the normal-weight (27.4%) group (p < 0.0001). This inverse association remained significant even after controlling for potential confounding factors. Multivariate analysis identified five significant moderators (p < 0.0001) after controlling for all evaluated variables: race, sex, smoking status, health coverage, and physical activity. Notably, physically inactive obese males tended to consume the least FV (% FV5+ = 14.7%). Conclusion Current US population FV intake level is below recommended levels. The inverse association between FV intake and obesity was significant and was moderated by demographic, socioeconomic status, and lifestyle factors. These factors should be considered when developing policies and interventions to increase FV intake. PMID:22248995

Purification and characterization of an abnormal factor IX (Christmas factor) molecule. Factor IX Chapel Hill.

PubMed Central

Chung, K S; Madar, D A; Goldsmith, J C; Kingdon, H S; Roberts, H R

1978-01-01

Human Factor IX (Christmas factor) was isolated from the plasma of a patient with mild hemophilia B. The patient's plasma contained 5% Factor IX clotting activity but 100% Factor IX antigenic activity as determined by immunological assays, which included inhibitor neutralization and a radioimmunoassay for Factor IX. This abnormal Factor IX is called Factor IX Chapel Hill (Factor IXCH). Both normal Factor IX and Factor IXCH have tyrosine as the NH2-terminal amino acid. The two proteins have a similar molecular weight, a similar amino acid analysis, the same number of gamma-carboxyglutamic acid residues (10 gamma-carboxyglutamic acid residues), and a similar carbohydrate content. Both exist as a single-chain glycoprotein in plasma. The major difference between normal Factor IX and Factor IXCH is that the latter exhibits delayed activation to Factor IXa in the presence of Factor XIa and Ca2+. Thus, Factor IXCH differs from other previously described abnormal Factor IX molecules. Images PMID:711853

The influence of confounding factors on the relationship between muscle contraction level and MF and MPF values of EMG signal: a review.

PubMed

Roman-Liu, Danuta

2016-01-01

The purpose of this article is to gather results of studies on the relationship between median frequency (MF) and mean power frequency (MPF) and the level of muscle contraction, and to use those results to discuss the differences in the trends according to factors related to measurement technique and subject. Twenty-one studies with 63 cases for upper limb muscles and nine studies with 31 cases for lower limb muscles were analysed. Most results showed an increase in parameters with an increased level of muscle contraction, only some studies showed a decrease. The influence on parameters of the level of muscle contraction and factors such as subjects, type of contraction, muscle length and electrodes was analysed for each muscle. It was concluded that when analysing the influence of different factors on MF and MPF, because those factors interact they should be considered together, not separately.

The influence of confounding factors on the relationship between muscle contraction level and MF and MPF values of EMG signal: a review

PubMed Central

Roman-Liu, Danuta

2016-01-01

The purpose of this article is to gather results of studies on the relationship between median frequency (MF) and mean power frequency (MPF) and the level of muscle contraction, and to use those results to discuss the differences in the trends according to factors related to measurement technique and subject. Twenty-one studies with 63 cases for upper limb muscles and nine studies with 31 cases for lower limb muscles were analysed. Most results showed an increase in parameters with an increased level of muscle contraction, only some studies showed a decrease. The influence on parameters of the level of muscle contraction and factors such as subjects, type of contraction, muscle length and electrodes was analysed for each muscle. It was concluded that when analysing the influence of different factors on MF and MPF, because those factors interact they should be considered together, not separately. PMID:26654476

Factors influencing tests of auditory processing: a perspective on current issues and relevant concerns.

PubMed

Cacace, Anthony T; McFarland, Dennis J

2013-01-01

Tests of auditory perception, such as those used in the assessment of central auditory processing disorders ([C]APDs), represent a domain in audiological assessment where measurement of this theoretical construct is often confounded by nonauditory abilities due to methodological shortcomings. These confounds include the effects of cognitive variables such as memory and attention and suboptimal testing paradigms, including the use of verbal reproduction as a form of response selection. We argue that these factors need to be controlled more carefully and/or modified so that their impact on tests of auditory and visual perception is only minimal. To advocate for a stronger theoretical framework than currently exists and to suggest better methodological strategies to improve assessment of auditory processing disorders (APDs). Emphasis is placed on adaptive forced-choice psychophysical methods and the use of matched tasks in multiple sensory modalities to achieve these goals. Together, this approach has potential to improve the construct validity of the diagnosis, enhance and develop theory, and evolve into a preferred method of testing. Examination of methods commonly used in studies of APDs. Where possible, currently used methodology is compared to contemporary psychophysical methods that emphasize computer-controlled forced-choice paradigms. In many cases, the procedures used in studies of APD introduce confounding factors that could be minimized if computer-controlled forced-choice psychophysical methods were utilized. Ambiguities of interpretation, indeterminate diagnoses, and unwanted confounds can be avoided by minimizing memory and attentional demands on the input end and precluding the use of response-selection strategies that use complex motor processes on the output end. Advocated are the use of computer-controlled forced-choice psychophysical paradigms in combination with matched tasks in multiple sensory modalities to enhance the prospect of obtaining a

The activation of plasminogen by Hageman factor (Factor XII) and Hageman factor fragments.

PubMed Central

Goldsmith, G H; Saito, H; Ratnoff, O S

1978-01-01

Activation of plasminogen through surface-mediated reactions is well recognized. In the presence of kaolin, purified Hageman factor (Factor XII) changed plasminogen to plasmin, as assayed upon a synthetic amide substrate and by fibrinolysis. Kinetic studies suggested an enzymatic action of Hageman factor upon its substrate, plasminogen. Hageman factor fragments, at a protein concentration equivalent to whole Hageman factor, activated plasminogen to a lesser extent. These protein preparations were not contaminated with other agents implicated in surface-mediated fibrinolysis. Diisopropyl fluorophosphate treatment of plasminogen did not inhibit its activation by Hageman factor. These studies indicate that Hageman factor has a hitherto unsuspected function, the direct activation of plasminogen. PMID:659637

Approaches for Strengthening Causal Inference Regarding Prenatal Risk Factors for Childhood Behavioural and Psychiatric Disorders

ERIC Educational Resources Information Center

Lewis, Sarah J.; Relton, Caroline; Zammit, Stanley; Smith, George Davey

2013-01-01

Background: The risk of childhood behavioural and psychiatric diseases could be substantially reduced if modifiable risk factors for these disorders were identified. The critical period for many of these exposures is likely to be in utero as this is the time when brain development is most rapid. However, due to confounding and other limitations of…

Evaluating the impact of implementation factors on family-based prevention programming: methods for strengthening causal inference.

PubMed

Crowley, D Max; Coffman, Donna L; Feinberg, Mark E; Greenberg, Mark T; Spoth, Richard L

2014-04-01

Despite growing recognition of the important role implementation plays in successful prevention efforts, relatively little work has sought to demonstrate a causal relationship between implementation factors and participant outcomes. In turn, failure to explore the implementation-to-outcome link limits our understanding of the mechanisms essential to successful programming. This gap is partially due to the inability of current methodological procedures within prevention science to account for the multitude of confounders responsible for variation in implementation factors (i.e., selection bias). The current paper illustrates how propensity and marginal structural models can be used to improve causal inferences involving implementation factors not easily randomized (e.g., participant attendance). We first present analytic steps for simultaneously evaluating the impact of multiple implementation factors on prevention program outcome. Then, we demonstrate this approach for evaluating the impact of enrollment and attendance in a family program, over and above the impact of a school-based program, within PROSPER, a large-scale real-world prevention trial. Findings illustrate the capacity of this approach to successfully account for confounders that influence enrollment and attendance, thereby more accurately representing true causal relations. For instance, after accounting for selection bias, we observed a 5% reduction in the prevalence of 11th grade underage drinking for those who chose to receive a family program and school program compared to those who received only the school program. Further, we detected a 7% reduction in underage drinking for those with high attendance in the family program.

Factors associated with employment status before and during pregnancy: Implications for studies of pregnancy outcomes.

PubMed

Rocheleau, Carissa M; Bertke, Stephen J; Lawson, Christina C; Romitti, Paul A; Desrosiers, Tania A; Agopian, Aaron J; Bell, Erin; Gilboa, Suzanne M

2017-04-01

Potential confounding or effect modification by employment status is frequently overlooked in pregnancy outcome studies. To characterize how employed and non-employed women differ, we compared demographics, behaviors, and reproductive histories by maternal employment status for 8,343 mothers of control (non-malformed) infants in the National Birth Defects Prevention Study (1997-2007) and developed a multivariable model for employment status anytime during pregnancy and the 3 months before conception. Sixteen factors were independently associated with employment before or during pregnancy, including: maternal age, pre-pregnancy body mass index, pregnancy intention, periconceptional/first trimester smoking and alcohol consumption, and household income. Employment status was significantly associated with many common risk factors for adverse pregnancy outcomes. Pregnancy outcome studies should consider adjustment or stratification by employment status. In studies of occupational exposures, these differences may cause uncontrollable confounding if non-employed women are treated as unexposed instead of excluded from analysis. Am. J. Ind. Med. 60:329-341, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Understanding Antipsychotic Drug Treatment Effects: A Novel Method to Reduce Pseudospecificity of the Positive and Negative Syndrome Scale (PANSS) Factors.

PubMed

Hopkins, Seth C; Ogirala, Ajay; Loebel, Antony; Koblan, Kenneth S

2017-12-01

The Positive and Negative Syndrome Scale (PANSS) is the most widely used efficacy measure in acute treatment studies of schizophrenia. However, interpretation of the efficacy of antipsychotics in improving specific symptom domains is confounded by moderate-to-high correlations among standard (Marder) PANSS factors. The authors review the results of an uncorrelated PANSS score matrix (UPSM) transform designed to reduce pseudospecificity in assessment of symptom change in patients with schizophrenia. Based on a factor analysis of five pooled, placebo-controlled lurasidone clinical trials (N=1,710 patients), a UPSM transform was identified that generated PANSS factors with high face validity (good correlation with standard Marder PANSS factors), and high specificity/orthogonality (low levels of between-factor correlation measuring change during treatment). Between-factor correlations were low at baseline for both standard (Marder) PANSS factors and transformed PANSS factors. However, when measured change in symptom severity was measured during treatment (in a pooled 5-study analysis), there was a notable difference for standard PANSS factors, where changes across factors were found to be highly correlated (factors exhibited pseudospecificity), compared to transformed PANSS factors, where factor change scores exhibited the same low levels of between-factor correlation observed at baseline. At Week 6-endpoint, correlations among PANSS factor severity scores were moderate-to-high for standard factors (0.34-0.68), but continued to be low for the transformed factors (-0.22-0.20). As an additional validity check, we analyzed data from one of the original five pooled clinical trials that included other well-validated assessment scales (MADRS, Negative Symptom Assessment scale [NSA]). In this baseline analysis, UPSM-transformed PANSS factor severity scores (negative and depression factors) were found to correlate well with the MADRS and NSA. The availability of transformed

Education and smoking: confounding or effect modification by phenotypic personality traits?

PubMed

Chapman, Benjamin; Fiscella, Kevin; Duberstein, Paul; Kawachi, Ichiro

2009-12-01

Little is known about whether educational gradients in smoking patterns can be explained by financial measures of socioeconomic status (SES) and/or personality traits. To assess whether the relationship of education to (1) never smoking and (2) having quit smoking would be confounded by financial measures of SES or by personality; whether lower Neuroticism and higher Conscientiousness would be associated with having abstained from or quit smoking; and whether education effects were modified by personality. Using data from the Midlife Development in the US National Survey, 2,429 individuals were classified as current (n = 695), former (n = 999), or never (n = 735) smokers. Multinomial logistic regressions examined study questions. Greater education was strongly associated with both never and former smoking, with no confounding by financial status and personality. Never smoking was associated with lower Openness and higher Conscientiousness, while have quit was associated with higher Neuroticism. Education interacted additively with Conscientiousness to increase and with Openness to decrease the probability of never smoking. Education and personality should be considered unconfounded smoking risks in epidemiologic and clinical studies. Educational associations with smoking may vary by personality dispositions, and prevention and intervention programs should consider both sets of factors.

Disentangling the relationships between maternal smoking during pregnancy and co-occurring risk factors

PubMed Central

Ellingson, Jarrod M.; Rickert, Martin E.; Lichtenstein, Paul; Långström, Niklas; D’Onofrio, Brian M.

2013-01-01

Background Maternal smoking during pregnancy (SDP) has been extensively studied as a risk factor for adverse offspring outcomes and is known to co-occur with other familial risk factors. Accounting for general familial risk factors has attenuated associations between SDP and adverse offspring outcomes, and identifying these confounds will be critical to elucidating the relationship between SDP and its psychological correlates. Methods The current study aimed to disentangle the relationship between maternal SDP and co-occurring risk factors (maternal criminal activity, drug problems, teen pregnancy, educational attainment, and cohabitation at childbirth) using a population-based sample of full- (n=206,313) and half-sister pairs (n=19,363) from Sweden. Logistic regression models estimated the strength of association between SDP and co-occurring risk factors. Bivariate behavioral genetic models estimated the degree to which associations between SDP and co-occurring risk factors are attributable to genetic and environmental factors. Results Maternal SDP was associated with an increase in all co-occurring risk factors. Of the variance associated with SDP, 45% was attributed to genetic factors and 53% was attributed to unshared environmental factors. In bivariate models, genetic factors accounted for 21% (non- drug-, non-violence-related crimes) to 35% (drug-related crimes) of the covariance between SDP and co-occurring risk factors. Unshared environmental factors accounted for the remaining covariance. Conclusions The genetic factors that influence a woman’s criminal behavior, substance abuse, and her offspring’s rearing environment also influence SDP. Therefore, the intergenerational transmission of genes conferring risk for antisocial behavior and substance misuse may influence the associations between maternal SDP and adverse offspring outcomes. PMID:22115276

The crowding factor method applied to parafoveal vision

PubMed Central

Ghahghaei, Saeideh; Walker, Laura

2016-01-01

Crowding increases with eccentricity and is most readily observed in the periphery. During natural, active vision, however, central vision plays an important role. Measures of critical distance to estimate crowding are difficult in central vision, as these distances are small. Any overlap of flankers with the target may create an overlay masking confound. The crowding factor method avoids this issue by simultaneously modulating target size and flanker distance and using a ratio to compare crowded to uncrowded conditions. This method was developed and applied in the periphery (Petrov & Meleshkevich, 2011b). In this work, we apply the method to characterize crowding in parafoveal vision (<3.5 visual degrees) with spatial uncertainty. We find that eccentricity and hemifield have less impact on crowding than in the periphery, yet radial/tangential asymmetries are clearly preserved. There are considerable idiosyncratic differences observed between participants. The crowding factor method provides a powerful tool for examining crowding in central and peripheral vision, which will be useful in future studies that seek to understand visual processing under natural, active viewing conditions. PMID:27690170

Socioeconomic Factors and Women's Use of Complementary and Alternative Medicine in Four Racial/Ethnic Groups

PubMed Central

Chao, Maria T.; Wade, Christine M.

2014-01-01

Objective Higher socioeconomic status (SES) is associated with using complementary and alternative medicine (CAM) in national surveys. Less is known about how socioeconomic factors affect CAM use in US subpopulations. We examined whether the relationship between SES and CAM use differs by racial/ethnic groups. Methods Using national survey data, we assessed education and income effects on women's CAM use in four racial/ethnic groups (Whites, Blacks, Mexican Americans, and Chinese Americans), controlling for age, health status, and geographic region. CAM use was defined as using any of 11 domains in the prior year. Results Adjusted effects of SES on CAM use were similar among Mexican American and non-Hispanic White women—education had a distinct gradient effect, with each increasing level of education significantly more likely to use CAM; household income ≥$60,000 was associated with CAM use compared to income <$20,000. For Chinese American women, socioeconomic factors were not associated with CAM use when controlling for confounders. Although income was not associated with CAM use among African American women, college graduates were three times more likely to use CAM than those with less than a high school education, adjusting for confounders. Conclusion SES effects on CAM use are not uniform across racial/ethnic populations. Other factors, such as culture and social networks, may interact with SES to influence CAM use in minority populations. PMID:18447102

Keeping children safe at home: protocol for three matched case–control studies of modifiable risk factors for falls

PubMed Central

Kendrick, Denise; Stewart, Jane; Clacy, Rose; Coffey, Frank; Cooper, Nicola; Coupland, Carol; Hayes, Mike; McColl, Elaine; Reading, Richard; Sutton, Alex; M L Towner, Elizabeth; Craig Watson, Michael

2012-01-01

Background Childhood falls result in considerable morbidity, mortality and health service use. Despite this, little evidence exists on protective factors or effective falls prevention interventions in young children. Objectives To estimate ORs for three types of medically attended fall injuries in young children in relation to safety equipment, safety behaviours and hazard reduction and explore differential effects by child and family factors and injury severity. Design Three multicentre case–control studies in UK hospitals with validation of parental reported exposures using home observations. Cases are aged 0–4 years with a medically attended fall injury occurring at home, matched on age and sex with community controls. Children attending hospital for other types of injury will serve as unmatched hospital controls. Matched analyses will use conditional logistic regression to adjust for potential confounding variables. Unmatched analyses will use unconditional logistic regression, adjusted for age, sex, deprivation and distance from hospital in addition to other confounders. Each study requires 496 cases and 1984 controls to detect an OR of 0.7, with 80% power, 5% significance level, a correlation between cases and controls of 0.1 and a range of exposure prevalences. Main outcome measures Falls on stairs, on one level and from furniture. Discussion As the largest in the field to date, these case control studies will adjust for potential confounders, validate measures of exposure and investigate modifiable risk factors for specific falls injury mechanisms. Findings should enhance the evidence base for falls prevention for young children. PMID:22628151

A propensity score approach to correction for bias due to population stratification using genetic and non-genetic factors.

PubMed

Zhao, Huaqing; Rebbeck, Timothy R; Mitra, Nandita

2009-12-01

Confounding due to population stratification (PS) arises when differences in both allele and disease frequencies exist in a population of mixed racial/ethnic subpopulations. Genomic control, structured association, principal components analysis (PCA), and multidimensional scaling (MDS) approaches have been proposed to address this bias using genetic markers. However, confounding due to PS can also be due to non-genetic factors. Propensity scores are widely used to address confounding in observational studies but have not been adapted to deal with PS in genetic association studies. We propose a genomic propensity score (GPS) approach to correct for bias due to PS that considers both genetic and non-genetic factors. We compare the GPS method with PCA and MDS using simulation studies. Our results show that GPS can adequately adjust and consistently correct for bias due to PS. Under no/mild, moderate, and severe PS, GPS yielded estimated with bias close to 0 (mean=-0.0044, standard error=0.0087). Under moderate or severe PS, the GPS method consistently outperforms the PCA method in terms of bias, coverage probability (CP), and type I error. Under moderate PS, the GPS method consistently outperforms the MDS method in terms of CP. PCA maintains relatively high power compared to both MDS and GPS methods under the simulated situations. GPS and MDS are comparable in terms of statistical properties such as bias, type I error, and power. The GPS method provides a novel and robust tool for obtaining less-biased estimates of genetic associations that can consider both genetic and non-genetic factors. 2009 Wiley-Liss, Inc.

Wine and tobacco: risk factors for gastric cancer in France.

PubMed

Hoey, J; Montvernay, C; Lambert, R

1981-06-01

Cross-sectional studies in France have shown strong regional correlations between death rates from alcohol related diseases and death rates from gastric cancer. The present study involved 40 cases of newly diagnosed adenocarcinoma of the stomach and 168 control subjects with one of four other gastrointestinal diagnoses selected from the same hospital service during the same time period, 1978-1980. On the basis of a standard nutritional interview alcohol and particularly red wine were seen to be significant risk factors for this cancer (relative risks of 6.9 with 95% confidence limits (CL) of 3.3-14.3 for alcohol and 6.3 with CL 3.1-12.7 for wine). Smoking of one or more cigarettes per day was associated with a relative risk for gastric cancer of 4.8 with CL of 1.6-14.8. The presence of both risk factors was associated with a relative risk of 9.3 with 95% CL of 4.6-19.0. Possible confounding by age, smoking, and eating lettuce (a reported protective factor for gastric cancer in other studies) did not explain these results. The relative risks were consistently found and remained significant when each diagnostic group of control subjects was analyzed separately. These results suggest that alcohol, and particularly red wine, may be important risk factors for adenocarcinoma of the stomach in France. In addition, cigarette smoking, a risk factor in itself, when coupled with alcohol appears markedly to increase the risk.

Preoperative prognostic factors for mortality in peptic ulcer perforation: a systematic review.

PubMed

Møller, Morten Hylander; Adamsen, Sven; Thomsen, Reimar Wernich; Møller, Ann Merete

2010-08-01

Mortality and morbidity following perforated peptic ulcer (PPU) is substantial and probably related to the development of sepsis. During the last three decades a large number of preoperative prognostic factors in patients with PPU have been examined. The aim of this systematic review was to summarize available evidence on these prognostic factors. MEDLINE (January 1966 to June 2009), EMBASE (January 1980 to June 2009), and the Cochrane Library (Issue 3, 2009) were screened for studies reporting preoperative prognostic factors for mortality in patients with PPU. The methodological quality of the included studies was assessed. Summary relative risks with 95% confidence intervals for the identified prognostic factors were calculated and presented as Forest plots. Fifty prognostic studies with 37 prognostic factors comprising a total of 29,782 patients were included in the review. The overall methodological quality was acceptable, yet only two-thirds of the studies provided confounder adjusted estimates. The studies provided strong evidence for an association of older age, comorbidity, and use of NSAIDs or steroids with mortality. Shock upon admission, preoperative metabolic acidosis, tachycardia, acute renal failure, low serum albumin level, high American Society of Anaesthesiologists score, and preoperative delay >24 h were associated with poor prognosis. In patients with PPU, a number of negative prognostic factors can be identified prior to surgery, and many of these seem to be related to presence of the sepsis syndrome.

Neuroticism explains unwanted variance in Implicit Association Tests of personality: possible evidence for an affective valence confound.

PubMed

Fleischhauer, Monika; Enge, Sören; Miller, Robert; Strobel, Alexander; Strobel, Anja

2013-01-01

Meta-analytic data highlight the value of the Implicit Association Test (IAT) as an indirect measure of personality. Based on evidence suggesting that confounding factors such as cognitive abilities contribute to the IAT effect, this study provides a first investigation of whether basic personality traits explain unwanted variance in the IAT. In a gender-balanced sample of 204 volunteers, the Big-Five dimensions were assessed via self-report, peer-report, and IAT. By means of structural equation modeling (SEM), latent Big-Five personality factors (based on self- and peer-report) were estimated and their predictive value for unwanted variance in the IAT was examined. In a first analysis, unwanted variance was defined in the sense of method-specific variance which may result from differences in task demands between the two IAT block conditions and which can be mirrored by the absolute size of the IAT effects. In a second analysis, unwanted variance was examined in a broader sense defined as those systematic variance components in the raw IAT scores that are not explained by the latent implicit personality factors. In contrast to the absolute IAT scores, this also considers biases associated with the direction of IAT effects (i.e., whether they are positive or negative in sign), biases that might result, for example, from the IAT's stimulus or category features. None of the explicit Big-Five factors was predictive for method-specific variance in the IATs (first analysis). However, when considering unwanted variance that goes beyond pure method-specific variance (second analysis), a substantial effect of neuroticism occurred that may have been driven by the affective valence of IAT attribute categories and the facilitated processing of negative stimuli, typically associated with neuroticism. The findings thus point to the necessity of using attribute category labels and stimuli of similar affective valence in personality IATs to avoid confounding due to recoding.

A Bayesian Framework to Account for Complex Non-Genetic Factors in Gene Expression Levels Greatly Increases Power in eQTL Studies

PubMed Central

Durbin, Richard; Winn, John

2010-01-01

Gene expression measurements are influenced by a wide range of factors, such as the state of the cell, experimental conditions and variants in the sequence of regulatory regions. To understand the effect of a variable of interest, such as the genotype of a locus, it is important to account for variation that is due to confounding causes. Here, we present VBQTL, a probabilistic approach for mapping expression quantitative trait loci (eQTLs) that jointly models contributions from genotype as well as known and hidden confounding factors. VBQTL is implemented within an efficient and flexible inference framework, making it fast and tractable on large-scale problems. We compare the performance of VBQTL with alternative methods for dealing with confounding variability on eQTL mapping datasets from simulations, yeast, mouse, and human. Employing Bayesian complexity control and joint modelling is shown to result in more precise estimates of the contribution of different confounding factors resulting in additional associations to measured transcript levels compared to alternative approaches. We present a threefold larger collection of cis eQTLs than previously found in a whole-genome eQTL scan of an outbred human population. Altogether, 27% of the tested probes show a significant genetic association in cis, and we validate that the additional eQTLs are likely to be real by replicating them in different sets of individuals. Our method is the next step in the analysis of high-dimensional phenotype data, and its application has revealed insights into genetic regulation of gene expression by demonstrating more abundant cis-acting eQTLs in human than previously shown. Our software is freely available online at http://www.sanger.ac.uk/resources/software/peer/. PMID:20463871

[Adoption of new technologies by health services: the challenge of analyzing relevant factors].

PubMed

Trindade, Evelinda

2008-05-01

The exponential increase in the incorporation of health technologies has been considered a key factor in increased expenditures by the health sector. Such decisions involve multiple levels and stakeholders. Decentralization has multiplied the decision-making levels, with numerous difficult choices and limited resources. The interrelationship between stakeholders is complex, in creative systems with multiple determinants and confounders. The current review discusses the interaction between the factors influencing the decisions to incorporate technologies by health services, and proposes a structure for their analysis. The application and intensity of these factors in decision-making and the incorporation of products and programs by health services shapes the installed capacity of local and regional networks and modifies the health system. Empirical observation of decision-making and technology incorporation in Brazilian health services poses an important challenge. The structured recognition and measurement of these variables can assist proactive planning of health services.

Examining confounding by diet in the association between perfluoroalkyl acids and serum cholesterol in pregnancy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skuladottir, Margret; Ramel, Alfons; Unit for Nutrition Research, Landspitali National University Hospital, Reykjavik

Background: Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have consistently been associated with higher cholesterol levels in cross sectional studies. Concerns have, however, been raised about potential confounding by diet and clinical relevance. Objective: To examine the association between concentrations of PFOS and PFOA and total cholesterol in serum during pregnancy taking into considerations confounding by diet. Methods: 854 Danish women who gave birth in 1988–89 and provided a blood sample and reported their diet in week 30 of gestation. Results: Mean serum PFOS, PFOA and total cholesterol concentrations were 22.3 ng/mL, 4.1 ng/mL and 7.3 mmol/L, respectively. Maternal dietmore » was a significant predictor of serum PFOS and PFOA concentrations. In particular intake of meat and meat products was positively associated while intake of vegetables was inversely associated (P for trend <0.01) with relative difference between the highest and lowest quartile in PFOS and PFOA concentrations ranging between 6% and 25% of mean values. After adjustment for dietary factors both PFOA and PFOS were positively and similarly associated with serum cholesterol (P for trend ≤0.01). For example, the mean increase in serum cholesterol was 0.39 mmol/L (95%CI: 0.09, 0.68) when comparing women in the highest to lowest quintile of PFOA concentrations. In comparison the mean increase in serum cholesterol was 0.61 mmol/L (95%CI: 0.17, 1.05) when comparing women in the highest to lowest quintile of saturated fat intake. Conclusion: In this study associations between PFOS and PFOA with serum cholesterol appeared unrelated to dietary intake and were similar in magnitude as the associations between saturated fat intake and serum cholesterol. - Highlights: • PFOS and PFOA have consistently been linked with raised serum cholesterol • Clinical relevance remains uncertain and confounding by diet has been suggested • The aim of this study was to address these

On Estimation of the Survivor Average Causal Effect in Observational Studies when Important Confounders are Missing Due to Death

PubMed Central

Egleston, Brian L.; Scharfstein, Daniel O.; MacKenzie, Ellen

2008-01-01

We focus on estimation of the causal effect of treatment on the functional status of individuals at a fixed point in time t* after they have experienced a catastrophic event, from observational data with the following features: (1) treatment is imposed shortly after the event and is non-randomized, (2) individuals who survive to t* are scheduled to be interviewed, (3) there is interview non-response, (4) individuals who die prior to t* are missing information on pre-event confounders, (5) medical records are abstracted on all individuals to obtain information on post-event, pre-treatment confounding factors. To address the issue of survivor bias, we seek to estimate the survivor average causal effect (SACE), the effect of treatment on functional status among the cohort of individuals who would survive to t* regardless of whether or not assigned to treatment. To estimate this effect from observational data, we need to impose untestable assumptions, which depend on the collection of all confounding factors. Since pre-event information is missing on those who die prior to t*, it is unlikely that these data are missing at random (MAR). We introduce a sensitivity analysis methodology to evaluate the robustness of SACE inferences to deviations from the MAR assumption. We apply our methodology to the evaluation of the effect of trauma center care on vitality outcomes using data from the National Study on Costs and Outcomes of Trauma Care. PMID:18759833

Potential confounding in the association between short birth intervals and increased neonatal, infant, and child mortality

PubMed Central

Perin, Jamie; Walker, Neff

2015-01-01

Background Recent steep declines in child mortality have been attributed in part to increased use of contraceptives and the resulting change in fertility behaviour, including an increase in the time between births. Previous observational studies have documented strong associations between short birth spacing and an increase in the risk of neonatal, infant, and under-five mortality, compared to births with longer preceding birth intervals. In this analysis, we compare two methods to estimate the association between short birth intervals and mortality risk to better inform modelling efforts linking family planning and mortality in children. Objectives Our goal was to estimate the mortality risk for neonates, infants, and young children by preceding birth space using household survey data, controlling for mother-level factors and to compare the results to those from previous analyses with survey data. Design We assessed the potential for confounding when estimating the relative mortality risk by preceding birth interval and estimated mortality risk by birth interval in four categories: less than 18 months, 18–23 months, 24–35 months, and 36 months or longer. We estimated the relative risks among women who were 35 and older at the time of the survey with two methods: in a Cox proportional hazards regression adjusting for potential confounders and also by stratifying Cox regression by mother, to control for all factors that remain constant over a woman's childbearing years. We estimated the overall effects for birth spacing in a meta-analysis with random survey effects. Results We identified several factors known for their associations with neonatal, infant, and child mortality that are also associated with preceding birth interval. When estimating the effect of birth spacing on mortality, we found that regression adjustment for these factors does not substantially change the risk ratio for short birth intervals compared to an unadjusted mortality ratio. For birth

Potential confounding in the association between short birth intervals and increased neonatal, infant, and child mortality.

PubMed

Perin, Jamie; Walker, Neff

2015-01-01

Recent steep declines in child mortality have been attributed in part to increased use of contraceptives and the resulting change in fertility behaviour, including an increase in the time between births. Previous observational studies have documented strong associations between short birth spacing and an increase in the risk of neonatal, infant, and under-five mortality, compared to births with longer preceding birth intervals. In this analysis, we compare two methods to estimate the association between short birth intervals and mortality risk to better inform modelling efforts linking family planning and mortality in children. Our goal was to estimate the mortality risk for neonates, infants, and young children by preceding birth space using household survey data, controlling for mother-level factors and to compare the results to those from previous analyses with survey data. We assessed the potential for confounding when estimating the relative mortality risk by preceding birth interval and estimated mortality risk by birth interval in four categories: less than 18 months, 18-23 months, 24-35 months, and 36 months or longer. We estimated the relative risks among women who were 35 and older at the time of the survey with two methods: in a Cox proportional hazards regression adjusting for potential confounders and also by stratifying Cox regression by mother, to control for all factors that remain constant over a woman's childbearing years. We estimated the overall effects for birth spacing in a meta-analysis with random survey effects. We identified several factors known for their associations with neonatal, infant, and child mortality that are also associated with preceding birth interval. When estimating the effect of birth spacing on mortality, we found that regression adjustment for these factors does not substantially change the risk ratio for short birth intervals compared to an unadjusted mortality ratio. For birth intervals less than 18 months, standard

Evaluating the Impact of Implementation Factors on Family-Based Prevention Programming: Methods for Strengthening Causal Inference

PubMed Central

Crowley, D. Max; Coffman, Donna L.; Feinberg, Mark; Greenberg, Mark; Spoth, Richard

2013-01-01

Despite growing recognition of the important role implementation plays in successful prevention efforts, relatively little work has sought to demonstrate a causal relationship between implementation factors and participant outcomes. In turn, failure to explore the implementation-to-outcome link limits our understanding of the mechanisms essential to successful programming. This gap is partially due to the inability of current methodological procedures within prevention science to account for the multitude of confounders responsible for variation in implementation factors (i.e., selection bias). The current paper illustrates how propensity and marginal structural models can be used to improve causal inferences involving implementation factors not easily randomized (e.g., participant attendance). We first present analytic steps for simultaneously evaluating the impact of multiple implementation factors on prevention program outcome. Then we demonstrate this approach for evaluating the impact of enrollment and attendance in a family program, over and above the impact of a school-based program, within PROSPER, a large scale real-world prevention trial. Findings illustrate the capacity of this approach to successfully account for confounders that influence enrollment and attendance, thereby more accurately representing true causal relations. For instance, after accounting for selection bias, we observed a 5% reduction in the prevalence of 11th grade underage drinking for those who chose to receive a family program and school program compared to those who received only the school program. Further, we detected a 7% reduction in underage drinking for those with high attendance in the family program. PMID:23430578

[Risk factors of stillbirths in Fortaleza-Brazil: a case-control study].

PubMed

Rouquayrol, M Z; Correia, L L; Barbosa, L M; Xavier, L G; Oliveira, J W; Fonseca, W

1996-01-01

Stillbirths are a common event in areas where reproductive health care is poorly delivered, such as the Northeast region of Brazil. This case-control study aimed to identify risk factors associated to foetal deaths occurred in a major obstetric facility of Fortaleza, 1.7 million inhabitants, Northeastern Brazil. 125 stillborn foetus over 20 weeks of gestation (cases) were compared to 250 healthy newborns (controls), in relation to socioeconomic, reproductive, behavioral and morbidity characteristics of their mothers. Crude and adjusted Odds Ratios were then calculated. After adjustment for confounders, the following characteristics of the mother remained as risk factors for stillbirths, with OR statistically significant at the 95% level: attending <5 antenatal consultations during pregnancy (OR=3.30; CI=1.92 - 5.07 ), illiterate mother (OR=3.30; CI=1.84 - 5.92 ), mother's age above 19 (OR=2.73; CI=1.42 - 5.24 ), monthly family income of 1 minimum wage or less (OR=2.12; CI=1.03 - 4.35 ) and severe illnesses or complication during pregnancy (OR=1.75; CI=1.01 - 3.03 ). Inadequate attendance to antenatal care consultations was the risk factor most strongly associated to stillbirths. Similarly, it was the condition most amenable to change in a short term, among those identified as risk factors.

Is the association between general cognitive ability and violent crime caused by family-level confounders?

PubMed

Frisell, Thomas; Pawitan, Yudi; Långström, Niklas

2012-01-01

Research has consistently found lower cognitive ability to be related to increased risk for violent and other antisocial behaviour. Since this association has remained when adjusting for childhood socioeconomic position, ethnicity, and parental characteristics, it is often assumed to be causal, potentially mediated through school adjustment problems and conduct disorder. Socioeconomic differences are notoriously difficult to quantify, however, and it is possible that the association between intelligence and delinquency suffer substantial residual confounding. We linked longitudinal Swedish total population registers to study the association of general cognitive ability (intelligence) at age 18 (the Conscript Register, 1980-1993) with the incidence proportion of violent criminal convictions (the Crime Register, 1973-2009), among all men born in Sweden 1961-1975 (N = 700,514). Using probit regression, we controlled for measured childhood socioeconomic variables, and further employed sibling comparisons (family pedigree data from the Multi-Generation Register) to adjust for shared familial characteristics. Cognitive ability in early adulthood was inversely associated to having been convicted of a violent crime (β = -0.19, 95% CI: -0.19; -0.18), the association remained when adjusting for childhood socioeconomic factors (β = -0.18, 95% CI: -0.18; -0.17). The association was somewhat lower within half-brothers raised apart (β = -0.16, 95% CI: -0.18; -0.14), within half-brothers raised together (β = -0.13, 95% CI: (-0.15; -0.11), and lower still in full-brother pairs (β = -0.10, 95% CI: -0.11; -0.09). The attenuation among half-brothers raised together and full brothers was too strong to be attributed solely to attenuation from measurement error. Our results suggest that the association between general cognitive ability and violent criminality is confounded partly by factors shared by brothers. However, most of the association remains even

Detecting and correcting the bias of unmeasured factors using perturbation analysis: a data-mining approach.

PubMed

Lee, Wen-Chung

2014-02-05

The randomized controlled study is the gold-standard research method in biomedicine. In contrast, the validity of a (nonrandomized) observational study is often questioned because of unknown/unmeasured factors, which may have confounding and/or effect-modifying potential. In this paper, the author proposes a perturbation test to detect the bias of unmeasured factors and a perturbation adjustment to correct for such bias. The proposed method circumvents the problem of measuring unknowns by collecting the perturbations of unmeasured factors instead. Specifically, a perturbation is a variable that is readily available (or can be measured easily) and is potentially associated, though perhaps only very weakly, with unmeasured factors. The author conducted extensive computer simulations to provide a proof of concept. Computer simulations show that, as the number of perturbation variables increases from data mining, the power of the perturbation test increased progressively, up to nearly 100%. In addition, after the perturbation adjustment, the bias decreased progressively, down to nearly 0%. The data-mining perturbation analysis described here is recommended for use in detecting and correcting the bias of unmeasured factors in observational studies.

Risk factors and birth outcomes of anaemia in early pregnancy in a nulliparous cohort.

PubMed

Masukume, Gwinyai; Khashan, Ali S; Kenny, Louise C; Baker, Philip N; Nelson, Gill

2015-01-01

Anaemia in pregnancy is a major public health and economic problem worldwide, that contributes to both maternal and fetal morbidity and mortality. The aim of the study was to calculate the prevalence of anaemia in early pregnancy in a cohort of 'low risk' women participating in a large international multicentre prospective study (n = 5 609), to identify the modifiable risk factors for anaemia in pregnancy in this cohort, and to compare the birth outcomes between pregnancies with and without anaemia in early gestation. The study is an analysis of data that were collected prospectively during the Screening for Pregnancy Endpoints study. Anaemia was defined according to the World Health Organization's definition of anaemia in pregnancy (haemoglobin < 11g/dL). Binary logistic regression with adjustment for potential confounders (country, maternal age, having a marital partner, ethnic origin, years of schooling, and having paid work) was the main method of analysis. The hallmark findings were the low prevalence of anaemia (2.2%), that having no marital partner was an independent risk factor for having anaemia (OR 1.34, 95% CI 1.01-1.78), and that there was no statistically significant effect of anaemia on adverse pregnancy outcomes (small for gestational age, pre-tem birth, mode of delivery, low birth weight, APGAR score < 7 at one and five minutes). Adverse pregnancy outcomes were however more common in those with anaemia than in those without. In this low risk healthy pregnant population we found a low anaemia rate. The absence of a marital partner was a non-modifiable factor, albeit one which may reflect a variety of confounding factors, that should be considered for addition to anaemia's conceptual framework of determinants. Although not statistically significant, clinically, a trend towards a higher risk of adverse pregnancy outcomes was observed in women that were anaemic in early pregnancy.

Abdominal strength in voiding cystometry: a risk factor for recurrent urinary tract infections in women.

PubMed

Salinas, Jesus; Virseda, Miguel; Méndez, Santiago; Menéndez, Pablo; Esteban, Manuel; Moreno, Jesus

2015-12-01

Recurrent urinary tract infections are a common condition in women. The aim of this study is the evaluation of lower urinary tract dysfunctions that are risk factors for recurrent urinary tract infections in women. We conducted a case-control study in 49 women with recurrent urinary tract infections (rUTIs) and 49 control women without rUTIs, comparing the urinary symptoms and urodynamic data of both groups. The main significant differences between these groups were age (the women were older in the control group) and the value of abdominal pressure during voiding cystometry (this was higher in the group with rUTIs). After controlling age as a confounding factor, it was confirmed that the value of maximum abdominal pressure during voiding was the only factor to facilitate the rUTIs and the ideal cut-off was 28 cm H(2)O. Abdominal strength in the voiding phase constitutes a risk factor for recurrent urinary tract infections in women.

Factors that encourage females to pursue physical science careers: Testing five common hypotheses

NASA Astrophysics Data System (ADS)

Hazari, Zahra; Potvin, Geoff; Lock, Robynne M.; Lung, Florin; Sadler, Philip M.; Sonnert, Gerhard

2012-03-01

There are many hypotheses regarding factors that may encourage female students to pursue careers in the physical sciences. Using Propensity Score Matching (PSM) on national data (n=7505) drawn from the Persistence Research in Science and Engineering (PRiSE) project, we test five commonly held beliefs including having a single-sex physics class, having a female physics teacher, having female scientist guest speakers in physics class, discussing the work of women scientists in physics class, and discussing the under-representation of women in physics class. The effect of these experiences is compared for female students who are matched on several factors, including parental education, prior science/math interests, and academic background, thereby controlling for the effect of many confounding variables.

Infection with parasitic nematodes confounds vaccination efficacy

PubMed Central

Urban, Joseph F.; Steenhard, Nina R.; Solano-Aguilar, Gloria I.; Dawson, Harry D.; Iweala, Onyinye I.; Nagler, Cathryn R.; Noland, Gregory S.; Kumar, Nirbhay; Anthony, Robert M.; Shea-Donohue, Terez; Weinstock, Joel; Gause, William C.

2007-01-01

T helper (Th) cells produce signature cytokine patterns, induced largely by intracellular versus extracellular pathogens that provide the cellular and molecular basis for counter regulatory expression of protective immunity during concurrent infections. The production of IL-12 and IFN-γ, for example, resulting from exposure to many bacterial, viral, and protozoan pathogens is responsible for Th1-derived protective responses that also can inhibit development of Th2-cells expressing IL-4-dependent immunity to extracellular helminth parasites and vice versa. In a similar manner, concurrent helminth infection alters optimal vaccine-induced responses in humans and livestock; however, the consequences of this condition have not been adequately studied especially in the context of a challenge infection following vaccination. Demands for new and effective vaccines to control chronic and emerging diseases, and the need for rapid deployment of vaccines for bio security concerns requires a systematic evaluation of confounding factors that limit vaccine efficacy. One common albeit overlooked confounder is the presence of gastrointestinal nematode parasites in populations of humans and livestock targeted for vaccination. This is particularly important in areas of the world were helminth infections are prevalent, but the interplay between parasites and emerging diseases that can be transmitted worldwide make this a global issue. In addition, it is not clear if the epidemic in allergic disease in industrialized countries substitutes for geohelminth infection to interfere with effective vaccination regimens. This presentation will focus on recent vaccination studies in mice experimentally infected with Heligmosomoides polygyrus to model the condition of gastrointestinal parasite infestation in mammalian populations targeted for vaccination. In addition, a large animal vaccination and challenge model against Mycoplasma hyopneumonia in swine exposed to Ascaris suum will provide a

Relationships of colorectal cancer with dietary factors and public health indicators: an ecological study.

PubMed

Abbastabar, Hedayat; Roustazadeh, Abazar; Alizadeh, Ali; Hamidifard, Parvin; Valipour, Mehrdad; Valipour, Ali Asghar

2015-01-01

Colorectal cancer (CRC) is the third most common cancer in Iranian women and fifth in men. The aims of this study were to investigate the relation of dietary factors and public health indicators to its development. The required information (2001-2006) about risk factors was obtained from the Non- Communicable Disease Surveillance Centre (NCDSC) of Iran. Risk factor data (RFD) from 89,404 individuals (15-64 years old) were gathered by questionnaire and laboratory examinations through a cross sectional study in all provinces by systematic clustering sampling method. CRC incidence segregated by age and gender was obtained from Cancer Registry Ministry of Health (CRMH) of Iran. First, correlation coefficients were used for data analysis and then multiple regression analysis was performed to control for confounding factors. Colorectal cancer incidence showed a positive relationship with diabetes mellitus, hypertension, lacking or low physical activity, high education, high intake of dairy products, and non-consumption of vegetables and fruits. We concluded that many dietary factors and public health indicators have positive relationships with CRC and might therefore be targets of preliminary prevention. However, since this is an ecological study limited by potential ecological fallacy the results must be interpreted with caution.

Environmental risk factors and Parkinson's disease: An umbrella review of meta-analyses.

PubMed

Bellou, Vanesa; Belbasis, Lazaros; Tzoulaki, Ioanna; Evangelou, Evangelos; Ioannidis, John P A

2016-02-01

Parkinson's disease is a neurological disorder with complex pathogenesis implicating both environmental and genetic factors. We aimed to summarise the environmental risk factors that have been studied for potential association with Parkinson's disease, assess the presence of diverse biases, and identify the risk factors with the strongest support. We searched PubMed from inception to September 18, 2015, to identify systematic reviews and meta-analyses of observational studies that examined associations between environmental factors and Parkinson's disease. For each meta-analysis we estimated the summary effect size by random-effects and fixed-effects models, the 95% confidence interval and the 95% prediction interval. We estimated the between-study heterogeneity expressed by I(2), evidence of small-study effects and evidence of excess significance bias. Overall, 75 unique meta-analyses on different risk factors for Parkinson's disease were examined, covering diverse biomarkers, dietary factors, drugs, medical history or comorbid diseases, exposure to toxic environmental agents and habits. 21 of 75 meta-analyses had results that were significant at p < 0.001 by random-effects. Evidence for an association was convincing (more than 1000 cases, p < 10(-6) by random-effects, not large heterogeneity, 95% prediction interval excluding the null value and absence of hints for small-study effects and excess significance bias) for constipation, and physical activity. Many environmental factors have substantial evidence of association with Parkinson's disease, but several, perhaps most, of them may reflect reverse causation, residual confounding, information bias, sponsor conflicts or other caveats. Copyright © 2016. Published by Elsevier Ltd.

More inflammation but less brain-derived neurotrophic factor in antisocial personality disorder.

PubMed

Wang, Tzu-Yun; Lee, Sheng-Yu; Hu, Ming-Chuan; Chen, Shiou-Lan; Chang, Yun-Hsuan; Chu, Chun-Hsien; Lin, Shih-Hsien; Li, Chia-Ling; Wang, Liang-Jen; Chen, Po See; Chen, Shih-Heng; Huang, San-Yuan; Tzeng, Nian-Sheng; Lee, I Hui; Chen, Kao Chin; Yang, Yen Kuang; Hong, Jau-Shyong; Lu, Ru-Band

2017-11-01

Antisocial personality disorder (ASPD) is highly comorbid with substance use disorders (SUDs). We hypothesize that chronic neuroinflammation and the loss of neurotrophic factors prompts the pathogenesis of both disorders. We used ELISA to measure plasma levels of proinflammatory (tumor necrosis factor-α [TNF-α], C-reactive protein [CRP]) and anti-inflammatory factors (transforming growth factor-β1 [TGF-β1] and interleukin-10 [IL-10]), and brain-derived neurotrophic factor (BDNF) in male patients with ASPD (n=74), SUDs (n=168), ASPD comorbid with SUDs (ASPD+SUDs) (n=438), and Healthy Controls (HCs) (n=81). A multivariate analysis of covariance (MANCOVA) controlled for possible confounders was used to compare cytokines and BDNF levels between groups. The results of MANCOVA adjusted for age showed a significant (p<0.001) main effect of diagnosis on inflammatory factors and BDNF expression in these groups. ASPD, SUDs, and ASPD+SUDs patients had significantly (p<0.001) higher TNF-α levels but lower TGF-β1 and BDNF levels. SUDs and ASPD+SUDs patients had higher IL-10 levels than did ASPD patients and HCs. There was no difference in IL-10 levels between HCs and ASPD. Moreover, subgrouping SUDs and ASPD±SUDs into opioid use disorder (OUD) and other SUDs groups showed that the IL-10 levels were specifically higher in OUD and ASPD±OUD groups than other SUDs (P≤0.001). We conclude that uncontrolled inflammation and losing neurotrophic factors, with or without comorbid SUDs, underlies ASPD. IL-10 expression might be more specifically associated with OUD. Copyright © 2017 Elsevier Ltd. All rights reserved.

Oxidative stress in drug-naïve first episode patients with schizophrenia and major depression: effects of disease acuity and potential confounders.

PubMed

Jordan, Wolfgang; Dobrowolny, Henrik; Bahn, Sabine; Bernstein, Hans-Gert; Brigadski, Tanja; Frodl, Thomas; Isermann, Berend; Lessmann, Volkmar; Pilz, Jürgen; Rodenbeck, Andrea; Schiltz, Kolja; Schwedhelm, Edzard; Tumani, Hayrettin; Wiltfang, Jens; Guest, Paul C; Steiner, Johann

2018-03-01

Oxidative stress and immune dysregulation have been linked to schizophrenia and depression. However, it is unknown whether these factors are related to the pathophysiology or whether they are an epiphenomenon. Inconsistent oxidative stress-related findings in previous studies may have resulted from the use of different biomarkers which show disparate aspects of oxidative stress. Additionally, disease severity, medication, smoking, endocrine stress axis activation and obesity are potential confounders. In order to address some of these shortcomings, we have analyzed a broader set of oxidative stress biomarkers in our exploratory study, including urinary 8-iso-prostaglandin F2α (8-iso-PGF2α), 8-OH-2-deoyxguanosine (8-OH-2-dG), and blood levels of malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione S-transferase (GST) in acutely ill drug-naïve first episode patients with schizophrenia (n = 22), major depression (n = 18), and controls (n = 43). Possible confounding factors were considered, and patients were followed-up after 6 weeks of treatment. No differences were observed regarding 8-OH-2-dG, MDA and GST. At baseline, 8-iso-PGF2α levels were higher in patients with schizophrenia (p = 0.004) and major depression (p = 0.037), with a trend toward higher SOD concentrations in schizophrenia (p = 0.053). After treatment, schizophrenia patients showed a further increase in 8-iso-PGF2α (p = 0.016). These results were not related to age, sex, disease severity, medication or adipose tissue mass. However, 8-iso-PGF2α was associated with smoking, endocrine stress axis activation, C-reactive protein levels and low plasma concentrations of brain-derived neurotrophic factor. This study suggests a role of lipid peroxidation particularly in drug-naïve acutely ill schizophrenia patients and highlights the importance of taking into account other confounding factors in biomarker studies.

Small intestinal permeability is increased in diarrhoea predominant IBS, while alterations in gastroduodenal permeability in all IBS subtypes are largely attributable to confounders.

PubMed

Mujagic, Z; Ludidi, S; Keszthelyi, D; Hesselink, M A M; Kruimel, J W; Lenaerts, K; Hanssen, N M J; Conchillo, J M; Jonkers, D M A E; Masclee, A A M

2014-08-01

Intestinal permeability has been studied in small groups of IBS patients with contrasting findings. To assess intestinal permeability at different sites of the GI tract in different subtypes of well-characterised IBS patients and healthy controls (HC), and to assess potential confounding factors. IBS patients and HC underwent a multi-sugar test to assess site-specific intestinal permeability. Sucrose excretion and lactulose/rhamnose ratio in 0-5 h urine indicated gastroduodenal and small intestinal permeability, respectively. Sucralose/erythritol ratio in 0-24 h and 5-24 h urine indicated whole gut and colonic permeability, respectively. Linear regression analysis was used to assess the association between IBS groups and intestinal permeability and to adjust for age, sex, BMI, anxiety or depression, smoking, alcohol intake and use of medication. Ninety-one IBS patients, i.e. 37% IBS-D, 23% IBS-C, 33% IBS-M and 7% IBS-U and 94 HC were enrolled. Urinary sucrose excretion was significantly increased in the total IBS group [μmol, median (Q1;Q3): 5.26 (1.82;11.03) vs. 2.44 (0.91;5.85), P < 0.05], as well as in IBS-C and IBS-D vs. HC. However, differences attenuated when adjusting for confounders. The lactulose/rhamnose ratio was increased in IBS-D vs. HC [0.023 (0.013;0.038) vs. 0.014 (0.008;0.025), P < 0.05], which remained significant after adjustment for confounders. No difference was found in 0-24 and 5-24 h sucralose/erythritol ratio between groups. Small intestinal permeability is increased in patients with IBS-D compared to healthy controls, irrespective of confounding factors. Adjustment for confounders is necessary when studying intestinal permeability, especially in a heterogeneous disorder such as IBS. © 2014 John Wiley & Sons Ltd.

Transmission of sporadic Creutzfeldt-Jakob disease by blood transfusion: risk factor or possible biases.

PubMed

Puopolo, Maria; Ladogana, Anna; Vetrugno, Vito; Pocchiari, Maurizio

2011-07-01

The occurrence of transfusion transmissions of variant Creutzfeldt-Jakob disease (CJD) cases has reawakened attention to the possible similar risk posed by other forms of CJD. CJD with a definite or probable diagnosis (sporadic CJD, n = 741; genetic CJD, n = 175) and no-CJD patients with definite alternative diagnosis (n = 482) with available blood transfusion history were included in the study. The risk of exposure to blood transfusion occurring more than 10 years before disease onset and for some possible confounding factors was evaluated by calculating crude odds ratios (ORs). Variables with significant ORs in univariate analyses were included in multivariate logistic regression analyses. In the univariate model, blood transfusion occurring more than 10 years before clinical onset is 4.1-fold more frequent in sporadic CJD than in other neurologic disorders. This significance is lost when the 10-year lag time was not considered. Multivariate analyses show that the risk of developing sporadic CJD after transfusion increases (OR, 5.05) after adjusting for possible confounding factors. Analysis conducted on patients with genetic CJD did not reveal any significant risk factor associated with transfusion. This is the first case-control study showing a significant risk of transfusion occurring more than 10 years before clinical onset in sporadic CJD patients. It remains questionable whether the significance of these data is biologically plausible or the consequence of biases in the design of the study, but they counterbalance previous epidemiologic negative reports that might have overestimated the assessment of blood safety in sporadic CJD. © 2010 American Association of Blood Banks.

Desire thinking as a confounder in the relationship between mindfulness and craving: Evidence from a cross-cultural validation of the Desire Thinking Questionnaire.

PubMed

Chakroun-Baggioni, Nadia; Corman, Maya; Spada, Marcantonio M; Caselli, Gabriele; Gierski, Fabien

2017-10-01

Desire thinking and mindfulness have been associated with craving. The aim of the present study was to validate the French version of the Desire Thinking Questionnaire (DTQ) and to investigate the relationship between mindfulness, desire thinking and craving among a sample of university students. Four hundred and ninety six university students completed the DTQ and measures of mindfulness, craving and alcohol use. Results from confirmatory factor analyses showed that the two-factor structure proposed in the original DTQ exhibited suitable goodness-of-fit statistics. The DTQ also demonstrated good internal reliability, temporal stability and predictive validity. A set of linear regressions revealed that desire thinking had a confounding effect in the relationship between mindfulness and craving. The confounding role of desire thinking in the relationship between mindfulness and craving suggests that interrupting desire thinking may be a viable clinical option aimed at reducing craving. Copyright © 2017 Elsevier B.V. All rights reserved.

Risk factors for acute toxoplasmosis in England and Wales.

PubMed

Said, B; Halsby, K D; O'Connor, C M; Francis, J; Hewitt, K; Verlander, N Q; Guy, E; Morgan, D

2017-01-01

Over 300 cases of acute toxoplasmosis are confirmed by reference testing in England and Wales annually. We conducted a case-control study to identify risk factors for Toxoplasma gondii infection to inform prevention strategies. Twenty-eight cases and 27 seronegative controls participated. We compared their food history and environmental exposures using logistic regression to calculate odds ratios (OR) and 95% confidence intervals in a model controlling for age and sex. Univariable analysis showed that the odds of eating beef (OR 10·7, P < 0·001), poultry (OR 6·4, P = 0·01) or lamb/mutton (OR 4·9, P = 0·01) was higher for cases than controls. After adjustment for potential confounders a strong association between beef and infection remained (OR 5·6, P = 0·01). The small sample size was a significant limitation and larger studies are needed to fully investigate potential risk factors. The study findings emphasize the need to ensure food is thoroughly cooked and handled hygienically, especially for those in vulnerable groups.

Environmental risk factors for allergy and socioeconomic status in a birth cohort (BAMSE).

PubMed

Lannerö, E; Kull, I; Wickman, M; Pershagen, G; Nordvall, S L

2002-06-01

Associations between parental educational level and possible risk factors for atopic disease during the first months of life were explored in a cohort of 4089 neonate children born 1994-96 in Stockholm, Sweden. Reports concerning a number of life style factors during pregnancy and after the baby was born were obtained by questionnaire. There was a strong negative association between duration of education and maternal smoking during pregnancy, parental smoking after the baby was born and keeping of cat and dog (p-trend < 0.001), respectively. For example, smoking during pregnancy was reported by 6.7% (95% CI 5.5-7.9) of mothers with college or university degree and by 22.2% (95% CI 20.1-24.5) of those with the shortest education. Indicators of dampness and poor ventilation were also more common in homes of those with the shortest education. The results show that the educational level has an influence on risk factors for development of atopic disease in childhood and indicates a need of deeper understanding of life style in different socioeconomic groups. The data also indicate that various possible confounding factors need to be thoroughly investigated when analysing studies of risk factors for allergic disease in childhood.

Factors affecting construction performance: exploratory factor analysis

NASA Astrophysics Data System (ADS)

Soewin, E.; Chinda, T.

2018-04-01

The present work attempts to develop a multidimensional performance evaluation framework for a construction company by considering all relevant measures of performance. Based on the previous studies, this study hypothesizes nine key factors, with a total of 57 associated items. The hypothesized factors, with their associated items, are then used to develop questionnaire survey to gather data. The exploratory factor analysis (EFA) was applied to the collected data which gave rise 10 factors with 57 items affecting construction performance. The findings further reveal that the items constituting ten key performance factors (KPIs) namely; 1) Time, 2) Cost, 3) Quality, 4) Safety & Health, 5) Internal Stakeholder, 6) External Stakeholder, 7) Client Satisfaction, 8) Financial Performance, 9) Environment, and 10) Information, Technology & Innovation. The analysis helps to develop multi-dimensional performance evaluation framework for an effective measurement of the construction performance. The 10 key performance factors can be broadly categorized into economic aspect, social aspect, environmental aspect, and technology aspects. It is important to understand a multi-dimension performance evaluation framework by including all key factors affecting the construction performance of a company, so that the management level can effectively plan to implement an effective performance development plan to match with the mission and vision of the company.

Do the wealthy have a health advantage? Cardiovascular disease risk factors and wealth.

PubMed

Hajat, A; Kaufman, J S; Rose, K M; Siddiqi, A; Thomas, J C

2010-12-01

The use of wealth as a measure of socioeconomic status (SES) remains uncommon in epidemiological studies. When used, wealth is often measured crudely and at a single point in time. Our study explores the relationship between wealth and three cardiovascular disease (CVD) risk factors (smoking, obesity and hypertension) in a US population. We improve upon existing literature by using a detailed and validated measure of wealth in a longitudinal setting. We used four waves of data from the Panel Study of Income Dynamics (PSID) collected between 1999 and 2005. Inverse probability weights were employed to control for time-varying confounding and to estimate both relative (risk ratio) and absolute (risk difference) measures of effect. Wealth was defined as inflation-adjusted net worth and specified as a six category variable: one category for those with less than or equal to zero wealth and quintiles of positive wealth. After adjusting for income and other time-varying confounders, as well as baseline covariates, the risk of becoming obese was inversely related to wealth. There was a 40%-89% higher risk of becoming obese among the less wealthy relative to the wealthiest quintile and 11 to 25 excess cases (per 1000 persons) among the less wealthy groups over six years of follow up. Smoking initiation had similar but more moderate effects; risk ratios and differences both revealed a smaller magnitude of effect compared to obesity. Of the three CVD risk factors examined here, hypertension incidence had the weakest association with wealth, showing a smaller increased risk and fewer excess cases among the less wealthy groups. In conclusion, this study found a strong inverse association between wealth and obesity incidence, a moderate inverse association between wealth and smoking initiation and a weak inverse association between wealth and hypertension incidence after controlling for income and other time-varying confounders. Copyright © 2010 Elsevier Ltd. All rights reserved.

Duration of breast-feeding and cardiovascular risk factors among Iranian children and adolescents: the CASPIAN III study.

PubMed

Izadi, Vajihe; Kelishadi, Roya; Qorbani, Mostafa; Esmaeilmotlagh, Mohammad; Taslimi, Mahnaz; Heshmat, Ramin; Ardalan, Gelayol; Azadbakht, Leila

2013-05-01

Studies examining the relationship between breast-feeding (BF) duration and cardiovascular disease (CVD) risk factors have reached contradictory results. This study aims to investigate the relationship between BF duration and CVD risk factors in adolescents. This national population-based study was conducted among 5258 Iranian students, ages 10 to 18 y living in central cities of 27 provinces of Iran. Association was examined between duration of BF and adolescent blood pressure, overweight, obesity, and fasting blood glucose and lipid profiles. Analyses were adjusted for potential confounders. Low birth weight was less frequent in the longer than in the shorter BF duration categories (P < 0.0001). Number of children was lower in individuals with longer BF duration (P = 0.01). Individuals with longer BF duration used more homemade food than those with shorter BF duration (P < 0.0001). Means of total cholesterol and systolic blood pressure were lower in participants with the longest BF period compared with those with the shortest BF duration; this difference was marginally significant (P = 0.06). No significant association was found between BF duration and CVD risk factors in logistic regression after adjustment for potential confounders. Although the long-term benefits of BF on preventing CVDs are well documented, controversies exist as to the association of BF duration with such beneficial effects. In this study, there was no substantial evidence that longer BF duration was protective against CVD risk factors among adolescents. More prospective studies are recommended to clarify this association. Copyright © 2013 Elsevier Inc. All rights reserved.

LD Score Regression Distinguishes Confounding from Polygenicity in Genome-Wide Association Studies

PubMed Central

Bulik-Sullivan, Brendan K.; Loh, Po-Ru; Finucane, Hilary; Ripke, Stephan; Yang, Jian; Patterson, Nick; Daly, Mark J.; Price, Alkes L.; Neale, Benjamin M.

2015-01-01

Both polygenicity (i.e., many small genetic effects) and confounding biases, such as cryptic relatedness and population stratification, can yield an inflated distribution of test statistics in genome-wide association studies (GWAS). However, current methods cannot distinguish between inflation from true polygenic signal and bias. We have developed an approach, LD Score regression, that quantifies the contribution of each by examining the relationship between test statistics and linkage disequilibrium (LD). The LD Score regression intercept can be used to estimate a more powerful and accurate correction factor than genomic control. We find strong evidence that polygenicity accounts for the majority of test statistic inflation in many GWAS of large sample size. PMID:25642630

Second-generation corneal deformation signal waveform analysis in normal, forme fruste keratoconic, and manifest keratoconic corneas after statistical correction for potentially confounding factors.

PubMed

Zhang, Lijun; Danesh, Jennifer; Tannan, Anjali; Phan, Vivian; Yu, Fei; Hamilton, D Rex

2015-10-01

To evaluate the difference in corneal biomechanical waveform parameters between manifest keratoconus, forme fruste keratoconus, and healthy eyes with a second-generation biomechanical waveform analyzer (Ocular Response Analyzer 2). Jules Stein Eye Institute, University of California, Los Angeles, California, USA. Retrospective chart review. The biomechanical waveform analyzer was used to obtain corneal hysteresis (CH), corneal resistance factor (CRF), and 37 biomechanical waveform parameters in manifest keratoconus eyes, forme fruste keratoconus eyes, and healthy eyes. Useful distinguishing parameters were found using t tests and a multivariable logistic regression model with stepwise variable selection. Potential confounders were controlled for. The study included 68 manifest keratoconus eyes, 64 forme fruste keratoconus eyes, and 249 healthy eyes. There was a statistical difference in the mean CRF between the normal group (10.2 mm Hg ± 1.7 [SD]) and keratoconus group (6.3 ± 1.9 mm Hg) (P = .003), and between the normal group and the forme fruste keratoconus group (7.8 ± 1.4 mm Hg) (P < .0001). There was no statistical difference in the mean CH between the normal group and the keratoconus group or the forme fruste keratoconus group. The CRF, height of peak 1 (P1) (P = .001), downslope of P1 (dslope1) (P = .027), upslope of peak 2 (P2) (P = .004), and downslope of P2 (P = .006) distinguished the normal group from the keratoconus groups. The CRF, downslope of P2 derived from upper 50% of applanation peak (P = .035), dslope1 (P = .014), and upslope of P1 (P = .008) distinguished the normal group from the forme fruste keratoconus group. Differences in multiple biomechanical waveform parameters can differentiate between healthy and diseased conditions and might improve early diagnosis of keratoconus and forme fruste keratoconus. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by

FACTORS INFLUENCING THE DESIGN OF BIOACCUMULATION FACTOR AND BIOTA-SEDIMENT ACCUMULATION FACTOR FIELD STUDIES

EPA Science Inventory

A series of modeling simulations were performed to develop an understanding of the underlying factors and principles involved in developing field sampling designs for measuring bioaccumulation factors (BAFs) and biota-sediment accumulation factors (BSAFs. These simulations reveal...

Impact Factor? Shmimpact Factor!

PubMed Central

2007-01-01

The journal impact factor is a measure of the citability of articles published in that journal—the more citations generated, the more important that article is considered to be, and as a consequence the prestige of the journal is enhanced. The impact factor is not without controversy, and it can be manipulated. It no longer dominates the choices of journals to search for information. Online search engines, such as PubMed, can locate articles of interest in seconds across journals regardless of high or low impact factors. Editors desiring to increase their influence will need to focus on a fast and friendly submission and review process, early online and speedy print publication, and encourage the rapid turnaround of high-quality peer reviews. Authors desiring to have their results known to the world have never had it so good—the internet permits anyone with computer access to find the author's work. PMID:20806031

Efficient and accurate causal inference with hidden confounders from genome-transcriptome variation data

PubMed Central

2017-01-01

Mapping gene expression as a quantitative trait using whole genome-sequencing and transcriptome analysis allows to discover the functional consequences of genetic variation. We developed a novel method and ultra-fast software Findr for higly accurate causal inference between gene expression traits using cis-regulatory DNA variations as causal anchors, which improves current methods by taking into consideration hidden confounders and weak regulations. Findr outperformed existing methods on the DREAM5 Systems Genetics challenge and on the prediction of microRNA and transcription factor targets in human lymphoblastoid cells, while being nearly a million times faster. Findr is publicly available at https://github.com/lingfeiwang/findr. PMID:28821014

FACTORS INFLUENCING THE DESIGN OF BIOACCUMULATION FACTOR AND BIOTA-SEDIMENT ACCUMULATION FACTOR FIELD STUDIES

EPA Science Inventory

General guidance for designing field studies to measure bioaccumulation factors (BAFs) and biota-sediment accumulation factors (BSAFs) is not available. To develop such guidance, a series of modeling simulations were performed to evaluate the underlying factors and principles th...

Cardiovascular risk factors in the normoglycaemic Asian-Indian population--influence of urbanisation.

PubMed

Snehalatha, C; Ramachandran, A

2009-04-01

The aim of this study was to investigate the prevalence of cardiovascular risk factors in normoglycaemic Asian-Indians and its association with urbanisation and plasma glucose. Data on 5,517 normoglycaemic individuals aged >/=20 years (1,521, 1,851 and 2,145 inhabitants of a city, a town and villages, respectively), from a 2006 diabetes survey, were used. The presence of single and multiple abnormalities, including obesity, abdominal obesity, hypertension and dyslipidaemia, was analysed. Risk associations for hypertension and dyslipidaemia were analysed using multivariate analysis after adjusting for confounding variables. Both the prevalence and clustering of cardiovascular risk variables were higher in urban areas than in villages, and were higher in the city than in the town. Nearly half (47%) of the normoglycaemic individuals from villages had at least one risk factor. Age, male sex, BMI, waist circumference, lack of physical activity and living in an urban environment were associated with hypertension and dyslipidaemia; postprandial glucose level showed no association with hypertension or dyslipidaemia after adjusting for these risk factors. Fasting plasma glucose level showed an independent association with dyslipidaemia. There is a high prevalence of cardiovascular risk factors even among normoglycaemic individuals, and this is highest in urban areas. Fasting plasma glucose level showed an association with dyslipidaemia but not hypertension.

Associations of cardiovascular risk factors in Al Ain- United Arab Emirates

PubMed Central

Baynouna, Latifa M; Revel, Anthony D; Nagelkerke, Nico JD; Jaber, Tariq M; Omar, Aziza O; Ahmed, Nader M; Nazirudeen, Mohammad K; Al Sayed, Mamdouh F; Nour, Fuad A; Abdouni, Sameh

2009-01-01

Background Over the last 30 years the citizens of the United Arab Emirates have experienced major changes in life-style secondary to increased affluence. Currently, 1 in 5 adults have diabetes mellitus, but the associations (clustering) among risk factors, as well as the relevance of the concept of the metabolic syndrome, in this population is unknown. Aim To investigate the prevalence and associations among cardiovascular risk factors in this population, and explore to what extent associations can be explained by the metabolic syndrome according to ATP-III criteria. Method A community based survey, of conventional risk factors for cardiovascular disease was conducted among 817 national residents of Al Ain city, UAE. These factors were fasting blood sugar, blood pressure, lipid profile, BMI, waist circumference, smoking, or CHD family history. Odds ratios between risks factors, both unadjusted and adjusted for age and sex as well as adjusted for age, sex, and metabolic syndrome were calculated. Results Various risk factors were positively associated in this population; associations that are mostly unexplained by confounding by age and sex. For example, hypertension and diabetes were still strongly related (OR 2.5; 95% CI 1.7–3.7) after adjustment. An increased waist circumference showed similar relationship with hypertension (OR 2.3; 95% CI 1.5–3.5). Diabetes was related to an increased BMI (OR 1.5; 96% CI 1.0–2.3). Smoking was also associated with diabetes (OR 1.9, 95% CI 1.0–3.3). Further adjustment for metabolic syndrome reduced some associations but several remained. Conclusion In this population risk-factors cluster, but associations do not appear to be explained by the presence/absence of the ATP-III metabolic syndrome. Associations provide valuable information in planning interventions for screening and management. PMID:19371412

Land surface controls on afternoon precipitation diagnosed from observational data: Uncertainties, confounding factors and the possible role of interception storage

NASA Astrophysics Data System (ADS)

Guillod, B. P.; Orlowsky, B.; Seneviratne, S. I.

2013-12-01

://www.nature.com/doifinder/10.1038/ngeo1174. Guillod, B. P., et al.: 'Land surface controls on afternoon precipitation diagnosed from observational data: Uncertainties, confounding factors and the possible role of interception storage', manuscript in preparation. Miralles, D. G., et al., 2011: Global land-surface evaporation estimated from satellite-based observations. Hydrol. Earth Syst. Sci., 15 (2), 453-469, doi:10.5194/hess-15-453-2011, URL http://www.hydrol-earth-syst-sci.net/15/453/2011/. Acknowledgement: We thank a number of people for their comments and contributions: Diego Miralles, Kirsten Findell, Adriaan Teuling, Nina Buchmann, Philippe Ciais, Bart Van den Hurk, Pierre Gentine, Benjamin Lintner, Markus Reichstein, Han Dolman and PIs from the used Fluxnet sites as well as the FLUXNET community.

Identifying high-risk areas of bacillary dysentery and associated meteorological factors in Wuhan, China.

PubMed

Li, Zhenjun; Wang, Ligui; Sun, Weige; Hou, Xuexin; Yang, Haiyan; Sun, Lina; Xu, Shuai; Sun, Qiangzheng; Zhang, Jingshan; Song, Hongbin; Lin, Hualiang

2013-11-21

Spatial distribution of bacillary dysentery incidence was mapped at the district level in Wuhan, China. And a generalized additive time series model was used to examine the effect of daily weather factors on bacillary dysentery in the high-risk areas, after controlling for potential confounding factors. Central districts were found to be the high-risk areas. The time series analysis found an acute effect of meteorological factors on bacillary dysentery occurrence. A positive association was found for mean temperature (excess risk (ER) for 1°C increase being 0.94% (95% confidence interval (CI): 0.46% to 1.43% on the lag day 2), while a negative effect was observed for relative humidity and rainfall, the ER for 1% increase in relative humidity was -0.21% (95% CI: -0.34% to -0.08%), and the ER for 1 mm increase in rainfall was -0.23% (95% CI: -0.37% to -0.09%). This study suggests that bacillary dysentery prevention and control strategy should consider local weather variations.

Assessing Sensitivity to Unmeasured Confounding Using a Simulated Potential Confounder

ERIC Educational Resources Information Center

Carnegie, Nicole Bohme; Harada, Masataka; Hill, Jennifer L.

2016-01-01

A major obstacle to developing evidenced-based policy is the difficulty of implementing randomized experiments to answer all causal questions of interest. When using a nonexperimental study, it is critical to assess how much the results could be affected by unmeasured confounding. We present a set of graphical and numeric tools to explore the…

Factor IX assay

MedlinePlus

... factor assay; Serum factor IX; Hemophilic factor B; Plasma thromboplastin component; PTC ... BJ. Factor IX (Christmas factor, hemophilic factor B, plasma thromboplastin component, PTC) - blood. In: Chernecky CC, Berger ...

'Mechanical restraint-confounders, risk, alliance score': testing the clinical validity of a new risk assessment instrument.

PubMed

Deichmann Nielsen, Lea; Bech, Per; Hounsgaard, Lise; Alkier Gildberg, Frederik

2017-08-01

Unstructured risk assessment, as well as confounders (underlying reasons for the patient's risk behaviour and alliance), risk behaviour, and parameters of alliance, have been identified as factors that prolong the duration of mechanical restraint among forensic mental health inpatients. To clinically validate a new, structured short-term risk assessment instrument called the Mechanical Restraint-Confounders, Risk, Alliance Score (MR-CRAS), with the intended purpose of supporting the clinicians' observation and assessment of the patient's readiness to be released from mechanical restraint. The content and layout of MR-CRAS and its user manual were evaluated using face validation by forensic mental health clinicians, content validation by an expert panel, and pilot testing within two, closed forensic mental health inpatient units. The three sub-scales (Confounders, Risk, and a parameter of Alliance) showed excellent content validity. The clinical validations also showed that MR-CRAS was perceived and experienced as a comprehensible, relevant, comprehensive, and useable risk assessment instrument. MR-CRAS contains 18 clinically valid items, and the instrument can be used to support the clinical decision-making regarding the possibility of releasing the patient from mechanical restraint. The present three studies have clinically validated a short MR-CRAS scale that is currently being psychometrically tested in a larger study.

Random measurement error: Why worry? An example of cardiovascular risk factors.

PubMed

Brakenhoff, Timo B; van Smeden, Maarten; Visseren, Frank L J; Groenwold, Rolf H H

2018-01-01

With the increased use of data not originally recorded for research, such as routine care data (or 'big data'), measurement error is bound to become an increasingly relevant problem in medical research. A common view among medical researchers on the influence of random measurement error (i.e. classical measurement error) is that its presence leads to some degree of systematic underestimation of studied exposure-outcome relations (i.e. attenuation of the effect estimate). For the common situation where the analysis involves at least one exposure and one confounder, we demonstrate that the direction of effect of random measurement error on the estimated exposure-outcome relations can be difficult to anticipate. Using three example studies on cardiovascular risk factors, we illustrate that random measurement error in the exposure and/or confounder can lead to underestimation as well as overestimation of exposure-outcome relations. We therefore advise medical researchers to refrain from making claims about the direction of effect of measurement error in their manuscripts, unless the appropriate inferential tools are used to study or alleviate the impact of measurement error from the analysis.

Disruptive behaviour disorders: a systematic review of environmental antenatal and early years risk factors.

PubMed

Latimer, K; Wilson, P; Kemp, J; Thompson, L; Sim, F; Gillberg, C; Puckering, C; Minnis, H

2012-09-01

Disruptive behaviour disorders (DBDs), including attention-deficit/hyperactivity disorder (ADHD), oppositional defiant disorder (ODD) and conduct disorder (CD) are chronic disorders with significant overlap in aetiology and presentation. An integrative examination of environmental risk factors is lacking. Six literature searches of web-based bibliographic databases were completed to identify literature on DBDs in general and five disorders in particular: CD, ODD, ADHD, deficits of attention, motor control and perception, and reactive attachment disorder. Searches were filtered to focus on studies including diagnostic assessment, focussing on environmental risk and protective factors in the first 4 years of life. The database searches generated 9806 papers of which 47 were reviewed after filters had been applied. The evidence suggests links between a number of early life risk factors and DBDs, including prenatal cigarette smoking and alcohol use, prenatal viral illness, maternal stress and anxiety, low birthweight, peri-partum and early neonatal complications, parental stress and parenting styles in infancy, early deprivation, adoption and separation. Despite the understanding that there is sharing of risk factors between the DBDs, there has been a disproportionate focus on the role of certain risk factors at the expense of others and the field is weakened by difficulties in controlling for all potential confounding variables. © 2012 Blackwell Publishing Ltd.

Paternal Risk Factors for Oral Clefts in Northern Africans, Southeast Asians, and Central Americans

PubMed Central

Ly, Stephanie; Burg, Madeleine L.; Ihenacho, Ugonna; Brindopke, Frederick; Auslander, Allyn; Magee, Kathleen S.; Sanchez-Lara, Pedro A.; Nguyen, Thi-Hai-Duc; Nguyen, Viet; Tangco, Maria Irene; Hernandez, Angela Rose; Giron, Melissa; Mahmoudi, Fouzia J.; DeClerck, Yves A.; Magee, William P.; Figueiredo, Jane C.

2017-01-01

While several studies have investigated maternal exposures as risk factors for oral clefts, few have examined paternal factors. We conducted an international multi-centered case–control study to better understand paternal risk exposures for oral clefts (cases = 392 and controls = 234). Participants were recruited from local hospitals and oral cleft repair surgical missions in Vietnam, the Philippines, Honduras, and Morocco. Questionnaires were administered to fathers and mothers separately to elicit risk factor and family history data. Associations between paternal exposures and risk of clefts were assessed using logistic regression adjusting for potential confounders. A father’s personal/family history of clefts was associated with significantly increased risk (adjusted OR: 4.77; 95% CI: 2.41–9.45). No other significant associations were identified for other suspected risk factors, including education (none/primary school v. university adjusted OR: 1.29; 95% CI: 0.74–2.24), advanced paternal age (5-year adjusted OR: 0.98; 95% CI: 0.84–1.16), or pre-pregnancy tobacco use (adjusted OR: 0.96; 95% CI: 0.67–1.37). Although sample size was limited, significantly decreased risks were observed for fathers with selected occupations. Further research is needed to investigate paternal environmental exposures as cleft risk factors. PMID:28629204

Assessing Omitted Confounder Bias in Multilevel Mediation Models.

PubMed

Tofighi, Davood; Kelley, Ken

2016-01-01

To draw valid inference about an indirect effect in a mediation model, there must be no omitted confounders. No omitted confounders means that there are no common causes of hypothesized causal relationships. When the no-omitted-confounder assumption is violated, inference about indirect effects can be severely biased and the results potentially misleading. Despite the increasing attention to address confounder bias in single-level mediation, this topic has received little attention in the growing area of multilevel mediation analysis. A formidable challenge is that the no-omitted-confounder assumption is untestable. To address this challenge, we first analytically examined the biasing effects of potential violations of this critical assumption in a two-level mediation model with random intercepts and slopes, in which all the variables are measured at Level 1. Our analytic results show that omitting a Level 1 confounder can yield misleading results about key quantities of interest, such as Level 1 and Level 2 indirect effects. Second, we proposed a sensitivity analysis technique to assess the extent to which potential violation of the no-omitted-confounder assumption might invalidate or alter the conclusions about the indirect effects observed. We illustrated the methods using an empirical study and provided computer code so that researchers can implement the methods discussed.

Prenatal Risk Factors and the Etiology of ADHD-Review of Existing Evidence.

PubMed

Sciberras, Emma; Mulraney, Melissa; Silva, Desiree; Coghill, David

2017-01-01

While it is well accepted that attention-deficit/hyperactivity disorder (ADHD) is a highly heritable disorder, not all of the risk is genetic. It is estimated that between 10 and 40% of the variance associated with ADHD is likely to be accounted for by environmental factors. There is considerable interest in the role that the prenatal environment might play in the development of ADHD with previous reviews concluding that despite demonstration of associations between prenatal risk factors (e.g. prematurity, maternal smoking during pregnancy) and ADHD, there remains insufficient evidence to support a definite causal relationship. This article provides an update of research investigating the relationship between prenatal risk factors and ADHD published over the past 3 years. Recently, several epidemiological and data linkage studies have made substantial contributions to our understanding of this relationship. In particular, these studies have started to account for some of the genetic and familial confounds that, when taken into account, throw several established findings into doubt. None of the proposed prenatal risk factors can be confirmed as causal for ADHD, and the stronger the study design, the less likely it is to support an association. We need a new benchmark for studies investigating the etiology of ADHD whereby there is an expectation not only that data will be collected prospectively but also that the design allows the broad range of genetic and familial factors to be accounted for.

Risk factors for early miscarriage among Chinese: a hospital-based case-control study.

PubMed

Xu, Guangli; Wu, Yiming; Yang, Liming; Yuan, Lu; Guo, Huafeng; Zhang, Fuqing; Guan, Yichun; Yao, Wu

2014-06-01

To investigate the risk factors for early miscarriage among Chinese women. Hospital-based matched case-control study. Academic medical center and maternal health hospital. 620 women with early miscarriage (less than 13 weeks of gestation) and 1,240 normal pregnant women. Face-to-face questionnaire. Multivariable conditional odds ratio (OR) and 95% confidence interval (CI) to measure risk factors. After adjustment for confounding factors, the following were independently associated with increased risk: history of miscarriage, repeated induced abortion, working night shifts, and frequent staying up late. Vitamin supplementation and regular physical activity reduced the risk of miscarriage. We did not find paternal age, alcohol consumption, or smoking status to be linked with early miscarriage. Our findings suggest that a healthy diet, regular physical activity, and planned pregnancy may be advantageous for women in pre-pregnancy or early pregnancy. Induced abortion, working night shifts, and frequent staying up late were associated with an increased risk of miscarriage. Further work in larger populations is warranted. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Betel nut usage is a major risk factor for coronary artery disease.

PubMed

Khan, Muhammad Shahzeb; Bawany, Faizan Imran; Ahmed, Muhammad Umer; Hussain, Mehwish; Khan, Asadullah; Lashari, Muhammad Nawaz

2013-12-27

The objective of our study was to assess betel nut usage as one of the major risk factors associated with coronary artery disease. This case control study consisted of 300 controls and 300 cases. A structured questionnaire was administered to the participants to assess consumption of betel nut and confounding variables. A respondent was considered a regular consumer of betel nut if he/she consumed one or more pieces of betel nut every day for a period of greater than 6 months. About 8 in 10 betel nut chewers developed coronary artery disease. After adjusting for diabetes and hypertension, the odds ratio analysis depicted 7.72 times greater likelihood for coronary artery disease in patients who chewed betel nut for more than 10 years. Our study concludes that betel nut chewing is a significant risk factor leading to the development of coronary artery disease.

Betel Nut Usage Is a Major Risk Factor for Coronary Artery Disease

PubMed Central

Khan, Muhammad Shahzeb; Bawany, Faizan Imran; Ahmed, Muhammad Umer; Hussain, Mehwish; Khan, Asadullah; Lashari, Muhammad Nawaz

2014-01-01

Aim: The objective of our study was to assess betel nut usage as one of the major risk factors associated with coronary artery disease. Methods: This case control study consisted of 300 controls and 300 cases. A structured questionnaire was administered to the participants to assess consumption of betel nut and confounding variables. A respondent was considered a regular consumer of betel nut if he/she consumed one or more pieces of betel nut every day for a period of greater than 6 months. Results: About 8 in 10 betel nut chewers developed coronary artery disease. After adjusting for diabetes and hypertension, the odds ratio analysis depicted 7.72 times greater likelihood for coronary artery disease in patients who chewed betel nut for more than 10 years. Conclusion: Our study concludes that betel nut chewing is a significant risk factor leading to the development of coronary artery disease. PMID:24576380

Mycobacterium ulcerans dynamics in aquatic ecosystems are driven by a complex interplay of abiotic and biotic factors

PubMed Central

Garchitorena, Andrés; Guégan, Jean-François; Léger, Lucas; Eyangoh, Sara; Marsollier, Laurent; Roche, Benjamin

2015-01-01

Host–parasite interactions are often embedded within complex host communities and can be influenced by a variety of environmental factors, such as seasonal variations in climate or abiotic conditions in water and soil, which confounds our understanding of the main drivers of many multi-host pathogens. Here, we take advantage of a combination of large environmental data sets on Mycobacterium ulcerans (MU), an environmentally persistent microorganism associated to freshwater ecosystems and present in a large variety of aquatic hosts, to characterize abiotic and biotic factors driving the dynamics of this pathogen in two regions of Cameroon. We find that MU dynamics are largely driven by seasonal climatic factors and certain physico-chemical conditions in stagnant and slow-flowing ecosystems, with an important role of pH as limiting factor. Furthermore, water conditions can modify the effect of abundance and diversity of aquatic organisms on MU dynamics, which suggests a different contribution of two MU transmission routes for aquatic hosts (trophic vs environmental transmission) depending on local abiotic factors. DOI: http://dx.doi.org/10.7554/eLife.07616.001 PMID:26216042

Risk Factors and Birth Outcomes of Anaemia in Early Pregnancy in a Nulliparous Cohort

PubMed Central

Masukume, Gwinyai; Khashan, Ali S.; Kenny, Louise C.; Baker, Philip N.; Nelson, Gill

2015-01-01

Background Anaemia in pregnancy is a major public health and economic problem worldwide, that contributes to both maternal and fetal morbidity and mortality. Objective The aim of the study was to calculate the prevalence of anaemia in early pregnancy in a cohort of ‘low risk’ women participating in a large international multicentre prospective study (n = 5 609), to identify the modifiable risk factors for anaemia in pregnancy in this cohort, and to compare the birth outcomes between pregnancies with and without anaemia in early gestation. Methods The study is an analysis of data that were collected prospectively during the Screening for Pregnancy Endpoints study. Anaemia was defined according to the World Health Organization’s definition of anaemia in pregnancy (haemoglobin < 11g/dL). Binary logistic regression with adjustment for potential confounders (country, maternal age, having a marital partner, ethnic origin, years of schooling, and having paid work) was the main method of analysis. Results The hallmark findings were the low prevalence of anaemia (2.2%), that having no marital partner was an independent risk factor for having anaemia (OR 1.34, 95% CI 1.01-1.78), and that there was no statistically significant effect of anaemia on adverse pregnancy outcomes (small for gestational age, pre-tem birth, mode of delivery, low birth weight, APGAR score < 7 at one and five minutes). Adverse pregnancy outcomes were however more common in those with anaemia than in those without. Conclusion In this low risk healthy pregnant population we found a low anaemia rate. The absence of a marital partner was a non-modifiable factor, albeit one which may reflect a variety of confounding factors, that should be considered for addition to anaemia’s conceptual framework of determinants. Although not statistically significant, clinically, a trend towards a higher risk of adverse pregnancy outcomes was observed in women that were anaemic in early pregnancy. PMID:25875012

Latent Constructs in Psychosocial Factors Associated with Cardiovascular Disease: An Examination by Race and Sex

PubMed Central

Clark, Cari Jo; Henderson, Kimberly M.; de Leon, Carlos F. Mendes; Guo, Hongfei; Lunos, Scott; Evans, Denis A.; Everson-Rose, Susan A.

2012-01-01

This study examines race and sex differences in the latent structure of 10 psychosocial measures and the association of identified factors with self-reported history of coronary heart disease (CHD). Participants were 4,128 older adults from the Chicago Health and Aging Project. Exploratory factor analysis (EFA) with oblique geomin rotation was used to identify latent factors among the psychosocial measures. Multi-group comparisons of the EFA model were conducted using exploratory structural equation modeling to test for measurement invariance across race and sex subgroups. A factor-based scale score was created for invariant factor(s). Logistic regression was used to test the relationship between the factor score(s) and CHD adjusting for relevant confounders. Effect modification of the relationship by race–sex subgroup was tested. A two-factor model fit the data well (comparative fit index = 0.986; Tucker–Lewis index = 0.969; root mean square error of approximation = 0.039). Depressive symptoms, neuroticism, perceived stress, and low life satisfaction loaded on Factor I. Social engagement, spirituality, social networks, and extraversion loaded on Factor II. Only Factor I, re-named distress, showed measurement invariance across subgroups. Distress was associated with a 37% increased odds of self-reported CHD (odds ratio: 1.37; 95% confidence intervals: 1.25, 1.50; p-value < 0.0001). This effect did not differ by race or sex (interaction p-value = 0.43). This study identified two underlying latent constructs among a large range of psychosocial variables; only one, distress, was validly measured across race–sex subgroups. This construct was robustly related to prevalent CHD, highlighting the potential importance of latent constructs as predictors of cardiovascular disease. PMID:22347196

Determining the Number of Factors in P-Technique Factor Analysis

ERIC Educational Resources Information Center

Lo, Lawrence L.; Molenaar, Peter C. M.; Rovine, Michael

2017-01-01

Determining the number of factors is a critical first step in exploratory factor analysis. Although various criteria and methods for determining the number of factors have been evaluated in the usual between-subjects R-technique factor analysis, there is still question of how these methods perform in within-subjects P-technique factor analysis. A…

Is the Association between General Cognitive Ability and Violent Crime Caused by Family-Level Confounders?

PubMed Central

Frisell, Thomas; Pawitan, Yudi; Långström, Niklas

2012-01-01

Background Research has consistently found lower cognitive ability to be related to increased risk for violent and other antisocial behaviour. Since this association has remained when adjusting for childhood socioeconomic position, ethnicity, and parental characteristics, it is often assumed to be causal, potentially mediated through school adjustment problems and conduct disorder. Socioeconomic differences are notoriously difficult to quantify, however, and it is possible that the association between intelligence and delinquency suffer substantial residual confounding. Methods We linked longitudinal Swedish total population registers to study the association of general cognitive ability (intelligence) at age 18 (the Conscript Register, 1980–1993) with the incidence proportion of violent criminal convictions (the Crime Register, 1973–2009), among all men born in Sweden 1961–1975 (N = 700,514). Using probit regression, we controlled for measured childhood socioeconomic variables, and further employed sibling comparisons (family pedigree data from the Multi-Generation Register) to adjust for shared familial characteristics. Results Cognitive ability in early adulthood was inversely associated to having been convicted of a violent crime (β = −0.19, 95% CI: −0.19; −0.18), the association remained when adjusting for childhood socioeconomic factors (β = −0.18, 95% CI: −0.18; −0.17). The association was somewhat lower within half-brothers raised apart (β = −0.16, 95% CI: −0.18; −0.14), within half-brothers raised together (β = −0.13, 95% CI: (−0.15; −0.11), and lower still in full-brother pairs (β = −0.10, 95% CI: −0.11; −0.09). The attenuation among half-brothers raised together and full brothers was too strong to be attributed solely to attenuation from measurement error. Discussion Our results suggest that the association between general cognitive ability and violent criminality is confounded partly by

Perinatal factors and the risk of bipolar disorder in Finland.

PubMed

Chudal, Roshan; Sourander, Andre; Polo-Kantola, Päivi; Hinkka-Yli-Salomäki, Susanna; Lehti, Venla; Sucksdorff, Dan; Gissler, Mika; Brown, Alan S

2014-02-01

Complications during the perinatal period have been associated with neurodevelopmental disorders like schizophrenia and autism. However, similar studies on bipolar disorder (BPD) have been limited and the findings are inconsistent. The aim of this study was to examine the association between perinatal risk factors and BPD. This nested case-control study, based on the Finnish Prenatal Study of Bipolar Disorders (FIPS-B), identified 724 cases and 1419 matched controls from population based registers. Conditional logistic regression was used to examine the associations between perinatal factors and BPD adjusting for potential confounding due to maternal age, psychiatric history and educational level, place of birth, number of previous births and maternal smoking during pregnancy. Children delivered by planned cesarean section had a 2.5-fold increased risk of BPD (95% CI: 1.32-4.78, P<0.01). No association was seen between other examined perinatal risk factors and BPD. The limitations of this study include: the restriction in the sample to treated cases of BPD in the population, and usage of hospital based clinical diagnosis for case ascertainment. In addition, in spite of the large sample size, there was low power to detect associations for certain exposures including the lowest birth weight category and pre-term birth. Birth by planned cesarean section was associated with risk of BPD, but most other perinatal risk factors examined in this study were not associated with BPD. Larger studies with greater statistical power to detect less common exposures and studies utilizing prospective biomarker-based exposures are necessary in the future. © 2013 Published by Elsevier B.V.

Familial confounding of the association between maternal smoking during pregnancy and offspring substance use and problems.

PubMed

D'Onofrio, Brian M; Rickert, Martin E; Langström, Niklas; Donahue, Kelly L; Coyne, Claire A; Larsson, Henrik; Ellingson, Jarrod M; Van Hulle, Carol A; Iliadou, Anastasia N; Rathouz, Paul J; Lahey, Benjamin B; Lichtenstein, Paul

2012-11-01

Previous epidemiological, animal, and human cognitive neuroscience research suggests that maternal smoking during pregnancy (SDP) causes increased risk of substance use/problems in offspring. To determine the extent to which the association between SDP and offspring substance use/problems depends on confounded familial background factors by using a quasi-experimental design. We used 2 separate samples from the United States and Sweden. The analyses prospectively predicted multiple indices of substance use and problems while controlling for statistical covariates and comparing differentially exposed siblings to minimize confounding. Offspring of a representative sample of women in the United States (sample 1) and the total Swedish population born during the period from January 1, 1983, to December 31, 1995 (sample 2). Adolescent offspring of the women in the National Longitudinal Survey of Youth 1979 (n = 6904) and all offspring born in Sweden during the 13-year period (n = 1,187,360). Self-reported adolescent alcohol, cigarette, and marijuana use and early onset (before 14 years of age) of each substance (sample 1) and substance-related convictions and hospitalizations for an alcohol- or other drug-related problem (sample 2). The same pattern emerged for each index of substance use/problems across the 2 samples. At the population level, maternal SDP predicted every measure of offspring substance use/problems in both samples, ranging from adolescent alcohol use (hazard ratio [HR](moderate), 1.32 [95% CI, 1.22-1.43]; HR(high), 1.33 [1.17-1.53]) to a narcotics-related conviction (HR(moderate), 2.23 [2.14-2.31]; HR(high), 2.97 [2.86-3.09]). When comparing differentially exposed siblings to minimize genetic and environmental confounds, however, the association between SDP and each measure of substance use/problems was minimal and not statistically significant. The association between maternal SDP and offspring substance use/problems is likely due to familial background

Use of logistic regression for modelling risk factors: with application to non-melanoma skin cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vitaliano, P.P.

Logistic regression was used to estimate the relative risk of basal and squamous skin cancer for such factors as cumulative lifetime solar exposure, age, complexion, and tannability. In previous reports, a subject's exposure was estimated indirectly, by latitude, or by the number of sun days in a subject's habitat. In contrast, these results are based on interview data gathered for each subject. A relatively new technique was used to estimate relative risk by controlling for confounding and testing for effect modification. A linear effect for the relative risk of cancer versus exposure was found. Tannability was shown to be amore » more important risk factor than complexion. This result is consistent with the work of Silverstone and Searle.« less

Heparanase enhances the generation of activated factor X in the presence of tissue factor and activated factor VII.

PubMed

Nadir, Yona; Brenner, Benjamin; Fux, Liat; Shafat, Itay; Attias, Judith; Vlodavsky, Israel

2010-11-01

Heparanase is an endo-β-D-glucuronidase dominantly involved in tumor metastasis and angiogenesis. Recently, we demonstrated that heparanase is involved in the regulation of the hemostatic system. Our hypothesis was that heparanase is directly involved in activation of the coagulation cascade. Activated factor X and thrombin were studied using chromogenic assays, immunoblotting and thromboelastography. Heparanase levels were measured by enzyme-linked immunosorbent assay. A potential direct interaction between tissue factor and heparanase was studied by co-immunoprecipitation and far-western assays. Interestingly, addition of heparanase to tissue factor and activated factor VII resulted in a 3- to 4-fold increase in activation of the coagulation cascade as shown by increased activated factor X and thrombin production. Culture medium of human embryonic kidney 293 cells over-expressing heparanase and its derivatives increased activated factor X levels in a non-enzymatic manner. When heparanase was added to pooled normal plasma, a 7- to 8-fold increase in activated factor X level was observed. Subsequently, we searched for clinical data supporting this newly identified role of heparanase. Plasma samples from 35 patients with acute leukemia at presentation and 20 healthy donors were studied for heparanase and activated factor X levels. A strong positive correlation was found between plasma heparanase and activated factor X levels (r=0.735, P=0.001). Unfractionated heparin and an inhibitor of activated factor X abolished the effect of heparanase, while tissue factor pathway inhibitor and tissue factor pathway inhibitor-2 only attenuated the procoagulant effect. Using co-immunoprecipitation and far-western analyses it was shown that heparanase interacts directly with tissue factor. Overall, our results support the notion that heparanase is a potential modulator of blood hemostasis, and suggest a novel mechanism by which heparanase increases the generation of activated

Reproductive factors, exogenous estrogen use and risk of Parkinson’s disease

PubMed Central

Simon, Kelly Claire; Chen, Honglei; Gao, Xiang; Schwarzschild, Michael A.; Ascherio, Alberto

2009-01-01

To determine if reproductive factors or exogenous estrogen are associated with risk of Parkinson’s disease (PD), we conducted a prospective study with 22 years of follow-up among post-menopausal participants in the Nurses’ Health Study. Relative risks (RRs) and 95% confidence intervals (CIs) of PD were estimated from a Cox proportional hazards model adjusting for potential confounders. Risk of PD was not significantly associated with any of the reproductive factors measured or exogenous estrogen use. Use of post-menopausal hormones, however, may modify the associations of smoking and caffeine intake with PD risk. The inverse relation between smoking and PD risk was attenuated among ever users of post-menopausal hormones (p for interaction = 0.05). Similar results were obtained for caffeine (p for interaction = 0.09). In exploratory analyses, women using progestin-only hormones were found to have an increased PD risk, but this result was based on a very small number of cases (n=4). In this large longitudinal study, we found no evidence of a beneficial effect of exogenous or endogenous estrogens on risk of PD. The use of post-menopausal hormone use may interact with other risk factors, but findings are preliminary and need confirmation in other populations. PMID:19424986

The association between risk factors and hypertension in perak, malaysia.

PubMed

Loh, K W; Rani, F; Chan, T C; Loh, H Y; Ng, C W; Moy, F M

2013-08-01

Hypertension is a major public health problem in Malaysia. A survey was initiated to examine the association of modifiable and non-modifiable risk factors for hypertension in Perak, Malaysia. A total of 2025 respondents aged 30 years and above were recruited using a multi-stage sampling method. Hypertension was defined as self-reported hypertension and/or average of two blood pressure readings at single occasion with SBP ≥ 140mmHg or DBP ≥ 90 mmHg. Body mass index (BMI) was defined using the Asian criteria and International Physical Activity Questionnaire (IPAQ) was used to evaluate physical activity. Body weight, height and blood pressure were obtained using standard procedures. Univariate analyses were conducted to examine the associations between risk factors and hypertension. Multiple logistic regression was used to examine each significant risk factor on hypertension after adjusted for confounders. In total, 1076 (54.9%) respondents were found to be hypertensive. Significant associations (p <0.001) with hypertension were noted for increasing age, low physical activity, obese BMI, no education background and positive family history of hypertension. After adjusting for age, sex, ethnicity, education background, family history, BMI, physical activity, smoking and diet, respondents who were obese and had positive family history had higher odds for hypertension (OR:2.34; 95% CI:1.84-3.17 and 1.96 (1.59-2.42) respectively. A significant increase (p <0.001) in risk for hypertension was noted for age. Those with moderate physical activities were 1.40 (1.04-1.78) times more of having hypertension than those active. Poor diet score and smoking were not significantly associated with increased risk for hypertension. In conclusion, modifiable risk factors such as BMI and physical activity are important risk factors to target in reducing the risk for hypertension.

Lifetime hormonal factors may predict late-life depression in women

PubMed Central

Ryan, Joanne; Carrière, Isabelle; Scali, Jacqueline; Ritchie, Karen; Ancelin, Marie-Laure

2008-01-01

Background Fluctuating hormone levels are known to influence a woman’s mood and well-being. This study aimed to determine whether lifetime hormonal markers are associated with late-life depression symptoms among elderly community-dwelling women. Method Detailed reproductive histories of 1013 women aged 65 years and over were obtained using questionnaires and depressive symptoms were assessed using the Centre for Epidemiological Studies Depression Scale. Multivariate logistic regression models were generated to determine whether any lifetime endogenous or exogenous hormonal factors were associated with late-life depression. Results The prevalence of depressive symptoms was 17%. Age at menopause was associated with depressive symptoms, but only among women with a lower education level. For these women, an earlier age at menopause increased their risk of late-life depression (linear effect, OR=0.95, 95%CI: 0.91–0.99). The odds of late-life depression were also increased for women who were past (OR=1.6, 95%CI: 1.1–2.5), but not current hormonal replacement users. On the other hand, long-term oral contraceptive use (≥10 years) was protective against depression (OR=0.3, 95%CI: 0.1–0.9). These associations remained significant even after extensive adjustment for a range of potential confounding factors, including socio-demographic factors, mental and physical incapacities, antidepressant use and past depression. The other factors examined, including age at first menses, parity, age at childbirth and surgical menopause, were not associated with late-life depressive symptoms. Conclusions Lifetime hormonal factors that are significantly associated with depression symptoms in later life have been identified. Further work is needed to determine how potential hormonal interventions could be used in the treatment of late-life depression in certain sub-groups of women. PMID:18533067

Risk factors for persistent Aspergillus respiratory isolation in cystic fibrosis.

PubMed

Hong, Gina; Psoter, Kevin J; Jennings, Mark T; Merlo, Christian A; Boyle, Michael P; Hadjiliadis, Denis; Kawut, Steven M; Lechtzin, Noah

2018-02-12

Aspergillus species are increasingly detected in the respiratory tracts of individuals with cystic fibrosis (CF), and chronic Aspergillus fumigatus is associated with more frequent hospitalizations for pulmonary exacerbations. However, patient and clinical factors that may contribute to the acquisition of persistent Aspergillus infection have yet to be identified. The objective of this study was to identify risk factors for development of Aspergillus respiratory isolation in CF. A retrospective cohort study of participants in the CF Foundation Patient Registry between 2006 and 2012 was conducted. Generalized estimating equation models were used to evaluate the association between the development of persistent Aspergillus respiratory isolation and individual level demographic and clinical characteristics. Among 16,095 individuals with CF followed from 2006 to 2012, 1541 (9.6%) subjects developed persistent Aspergillus isolation. White race (Odds Ratio [OR] 1.74, 95% confidence interval 1.23, 2.48, p<0.001) and pancreatic insufficiency (OR 1.50, 95% CI 1.09, 2.06, p<0.001) were found to be risk factors for persistent Aspergillus isolation. Chronic therapies, including inhaled antibiotics (OR 1.33; 95% CI 1.21, 1.46), macrolides (OR 1.23, 95% CI 1.14, 1.32, p<0.001), and inhaled corticosteroids (OR 1.13, 95% CI 1.04, 1.20, p<0.001) were also independently associated with an increased risk for persistent Aspergillus isolation. We identified macrolides and inhaled antibiotics, which individually have been shown to improve CF outcomes, and inhaled corticosteroids as risk factors for developing persistent Aspergillus isolation. Further work is needed to determine whether these associations are causal or due to confounding by other factors. Copyright © 2018 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Sex differences in risk factors for cardiovascular disease: the PERU MIGRANT study.

PubMed

Bernabe-Ortiz, Antonio; Benziger, Catherine Pastorius; Gilman, Robert H; Smeeth, Liam; Miranda, J Jaime

2012-01-01

Although men and women have similar risk factors for cardiovascular disease, many social behaviors in developing countries differ by sex. Rural-to-urban migrants have different cardiovascular risk profiles than rural or urban dwellers. The objective of this study was to evaluate the sex differences with specific cardiovascular risk factors in rural-to-urban migrants. We used the rural-to-urban migrant group of the PERU MIGRANT cross-sectional study to investigate the sex differences in specific cardiovascular risk factors: obesity, hypertension, metabolic syndrome, as well as exposures of socioeconomic status, acculturation surrogates and behavioral characteristics. Logistic regression analysis was used to characterize strength of association between sex and our outcomes adjusting for potential confounders. The sample of migrants was 589 (mean age 46.5 years) and 52.4% were female. In the adjusted models, women were more likely to be obese (OR=5.97; 95%CI: 3.21-11) and have metabolic syndrome (OR=2.22; 95%CI: 1.39-3.55) than men, explaining the greatest variability for obesity and metabolic syndrome but not for hypertension. Our results suggest that interventions for CVD in Peru should be sex-specific and address the unique health needs of migrant populations living in urban shantytowns since the risk factors for obesity and metabolic syndrome differ between males and females.

Comparison of biophysical factors influencing on emphysema quantification with low-dose CT

NASA Astrophysics Data System (ADS)

Heo, Chang Yong; Kim, Jong Hyo

2014-03-01

Emphysema Index(EI) measurements in MDCT is known to be influenced by various biophysical factors such as total lung volume, and body size. We investigated the association of the four biophysical factors with emphysema index in low-dose MDCT. In particular, we attempted to identify a potentially stronger biophysical factor than total lung volume. A total of 400 low-dose MDCT volumes taken at 120kVp, 40mAs, 1mm thickness, and B30f reconstruction kernel were used. The lungs, airways, and pulmonary vessels were automatically segmented, and two Emphysema Indices, relative area below -950HU(RA950) and 15th percentile(Perc15), were extracted from the segmented lungs. The biophysical factors such as total lung volume(TLV), mode of lung attenuation(ModLA), effective body diameter(EBD), and the water equivalent body diameter(WBD) were estimated from the segmented lung and body area. The association of biophysical factors with emphysema indices were evaluated by correlation coefficients. The mean emphysema indices were 8.3±5.5(%) in RA950, and -930±18(HU) in Perc15. The estimates of biophysical factors were 4.7±1.0(L) in TLV, -901±21(HU) in ModLA, 26.9±2.2(cm) in EBD, and 25.9±2.6(cm) in WBD. The correlation coefficients of biophysical factors with RA950 were 0.73 in TLV, 0.94 in ModLA, 0.31 in EBD, and 0.18 WBD, the ones with Perc15 were 0.74 in TLV, 0.98 in ModLA, 0.29 in EBD, and 0.15 WBD. Study results revealed that two biophysical factors, TLV and ModLA, mostly affects the emphysema indices. In particular, the ModLA exhibited strongest correlation of 0.98 with Perc15, which indicating the ModLA is the most significant confounding biophysical factor in emphysema indices measurement.

[Factors influencing the measurement of tear film lipid layer thickness with interferometry].

PubMed

Finis, D; Pischel, N; Borrelli, M; Schrader, S; Geerling, G

2014-06-01

The quantitative measurement of the tear film lipid layer thickness is a relatively new and promising method. However, so far it has not been investigated whether there is a diurnal or a day to day variability and whether certain factors are confounding the measurement of the lipid layer thickness. In three different experimental settings, 10 subjects without known sicca syndrome were examined at three different time points on one day, on three different days and before and after therapeutic expression of the Meibomian glands. As a comparison, the parameters tear film break-up time, tear meniscus height, diagnostic expression of the Meibomian glands and subjective symptoms, determined using the OSDI (ocular surface disease index) questionnaire, were measured. The results of the study showed a smaller variation of the lipid layer thickness measurements during the day and from day to day compared to the tear film break-up time. The expression of the Meibomian glands significantly increased the lipid layer thickness. There was a correlation between the baseline values of tear film break-up time and the lipid layer thickness. Our data showed that the lipid layer thickness as measured with the Lipiview® interferometer appears to be a relatively constant parameter over time. In addition, the expression of the Meibomian glands could be identified as a potential confounding factor. In this study we included only healthy subjects without known sicca syndrome. For the future our findings need to be validated in dry eye patients. Georg Thieme Verlag KG Stuttgart · New York.

Transforming growth factor alpha, Shope fibroma growth factor, and vaccinia growth factor can replace myxoma growth factor in the induction of myxomatosis in rabbits.

PubMed

Opgenorth, A; Nation, N; Graham, K; McFadden, G

1993-02-01

The epidermal growth factor (EGF) homologues encoded by vaccinia virus, myxoma virus, and malignant rabbit fibroma virus have been shown to contribute to the pathogenicity of virus infection upon inoculation of susceptible hosts. However, since the primary structures of these growth factors and the disease profiles induced by different poxvirus genera vary substantially, the degree to which the various EGF homologues perform similar roles in viral pathogenesis remains unclear. In order to determine whether different EGF-like growth factors can perform qualitatively similar functions in the induction of myxomatosis in rabbits, we created recombinant myxoma virus variants in which the native growth factor, myxoma growth factor (MGF), was disrupted and replaced with either vaccinia virus growth factor, Shope fibroma growth factor, or rat transforming growth factor alpha. Unlike the control virus containing an inactivated MGF gene, which caused marked attenuation of the disease syndrome and substantially less proliferation of the epithelial cell layers in the conjunctiva and respiratory tract, the recombinant myxoma virus strains expressing heterologous growth factors produced infections which were both clinically and histopathologically indistinguishable from wild-type myxomatosis. We conclude that these poxviral and cellular EGF-like growth factors, which are diverse with respect to primary structure and origin, have similar biological functions in the context of myxoma virus pathogenesis and are mitogenic for the same target cells.

Bridging the gap between preventive and restorative dentistry: identification of caries risk factors and strategies for minimizing risk.

PubMed

Maragliano-Muniz, Pamela

2013-10-01

Following the introduction of CAMBRA (Caries Management by Risk Assessment) in 2007, a number of recommendations for office protocols were introduced, and many companies have formulated products and procedures for implementing CAMBRA. As a result, the implementation of a caries management program can be confounding and overwhelming to a dental practitioner. Understanding risk factors as they contribute to the caries process can help mitigate confusion and guide the practitioner when selecting materials for their practice. Ultimately, knowing how the risk factors play a role in the progression of dental caries will lead to appropriate risk management and product recommendations. The purpose of this article is to discuss the contribution of risk factors to the caries process and to introduce strategies that restorative dentists can utilize to minimize caries risk.

Is the Association of Subjective SES and Self-Rated Health Confounded by Negative Mood? An Experimental Approach

PubMed Central

Kraus, Michael W.; Adler, Nancy; David Chen, Teh-Way

2012-01-01

Objective Lower subjective socioeconomic status (SSS) consistently shows associations with poorer health with the strongest relationships emerging with global self-rated health. Though often interpreted as reflecting the impact of low SSS on health, the association could also arise from confounding SSS with negative affect. In this research we sought to determine if negative affect confounds, or alternatively, is on the causal pathway linking SSS to self-rated health. Methods 300 adult participants—recruited from throughout the United States—were randomized to experience sadness, shame, or a neutral mood induction wherein they wrote about and visualized a particularly emotionally evocative event. Participants subsequently completed measures of SSS, self-rated health, depression, and negative mood. Results Consistent with predictions, neither SSS scores nor the association of SSS with self-rated health, depression, and chronic negative affect differed by mood induction condition, controlling for demographic factors that covary with SSS (e.g., age, gender, education, income). Moreover, chronic negative affect partially explained the relationship between SSS and self-rated health, independent of manipulated mood. Conclusions These findings support the utility of the measurement of SSS, and provide evidence suggesting that chronic negative affect is a likely mediator of the SSS association with global health rather than a confounder. PMID:22329426

Factors that contribute to biomarker responses in humans including a study in individuals taking Vitamin C supplementation.

PubMed

Anderson, D

2001-09-01

It is possible in many situations to identify humans exposed to potentially toxic materials in the workplace and in the environment. As in most human studies, there tends to be a high degree of interindividual variability in response to chemical insults. Some non-exposed control individuals exhibit as high a level of damage as some exposed individuals and some of these have levels of damage as low as many of the controls. Thus, it is only the mean values of the groups that can substantiate an exposure-related problem; the data on an individual basis are still of limited use. While human lymphocytes remain the most popular cell type for monitoring purposes, sperm, buccal, nasal, epithelial and placental cells are also used. However, for interpretation of responses, the issue of confounding factors must be addressed. There are endogenous confounding factors, such as age, gender, and genetic make-up and exogenous ones, including lifestyle habits (smoking, drinking, etc.) There are biomarkers of exposure, effect/response and susceptibility and the last may be influenced by the genotype and polymorphism genes existing in a population. From our own studies, confounding effects on cytogenetic damage and ras oncoproteins will be considered in relation to workers exposed to vinyl chloride and petroleum emissions and to volunteers taking Vitamin C supplementation. Smoking history, exposure and duration of employment affected the worker studies. For petroleum emissions, so did gender and season of exposure. For the non-smoking volunteer Vitamin C supplementation study, cholesterol levels, plasma Vitamin C levels, lipid peroxidation products and DNA damage in the Comet assay were also measured. Gender affected differences in Vitamin C levels, antioxidant capacity and the number of chromosome aberrations induced by bleomycin challenge in vitro. The results were the same for both high and low cholesterol subjects. The relationship between biomarkers and the various factors which

An exploratory factor analysis of nutritional biomarkers associated with major depression in pregnancy

PubMed Central

Bodnar, Lisa M.; Wisner, Katherine L.; Luther, James F.; Powers, Robert W.; Evans, Rhobert W.; Gallaher, Marcia J.; Newby, P.K.

2011-01-01

Objective Major depressive disorder (MDD) during pregnancy increases the risk of adverse maternal and infant outcomes. Maternal nutritional status may be a modifiable risk factor for antenatal depression. We evaluated the association between patterns in mid-pregnancy nutritional biomarkers and MDD. Design Prospective cohort study Setting Pittsburgh, Pennsylvania, USA Subjects Women who enrolled at ≤20 weeks gestation had a diagnosis of MDD made with the Structured Clinical Interview for DSM-IV at 20-, 30-, and 36-week study visits. A total of 135 women contributed 345 person-visits. Non-fasting blood drawn at enrollment was assayed for red cell essential fatty acids, plasma folate, homocysteine, and ascorbic acid; serum 25-hydroxyvitamin D, retinol, vitamin E, carotenoids, ferritin, and soluble transferrin receptors. Nutritional biomarkers were entered into principal components analysis. Results Three factors emerged: Factor 1, Essential Fatty Acids; Factor 2, Micronutrients; and Factor 3, Carotenoids. MDD was prevalent in 21.5% of women. In longitudinal multivariable logistic models, there was no association between the Essential Fatty Acid or Micronutrient patterns and MDD either before or after adjustment for employment, education, or prepregnancy BMI. In unadjusted analysis, women with Carotenoid factor scores in the middle and upper tertiles were 60% less likely than women in the bottom tertile to have MDD during pregnancy, but after adjustment for confounders, the associations were no longer statistically significant. Conclusions While meaningful patterns were derived using nutritional biomarkers, significant associations with MDD were not observed in multivariable adjusted analyses. Larger, more diverse samples are needed to understand nutrition-depression relationships during pregnancy. PMID:22152590

Host and Environmental Factors Affecting the Intestinal Microbiota in Chickens

PubMed Central

Kers, Jannigje G.; Velkers, Francisca C.; Fischer, Egil A. J.; Hermes, Gerben D. A.; Stegeman, J. A.; Smidt, Hauke

2018-01-01

The initial development of intestinal microbiota in poultry plays an important role in production performance, overall health and resistance against microbial infections. Multiplexed sequencing of 16S ribosomal RNA gene amplicons is often used in studies, such as feed intervention or antimicrobial drug trials, to determine corresponding effects on the composition of intestinal microbiota. However, considerable variation of intestinal microbiota composition has been observed both within and across studies. Such variation may in part be attributed to technical factors, such as sampling procedures, sample storage, DNA extraction, the choice of PCR primers and corresponding region to be sequenced, and the sequencing platforms used. Furthermore, part of this variation in microbiota composition may also be explained by different host characteristics and environmental factors. To facilitate the improvement of design, reproducibility and interpretation of poultry microbiota studies, we have reviewed the literature on confounding factors influencing the observed intestinal microbiota in chickens. First, it has been identified that host-related factors, such as age, sex, and breed, have a large effect on intestinal microbiota. The diversity of chicken intestinal microbiota tends to increase most during the first weeks of life, and corresponding colonization patterns seem to differ between layer- and meat-type chickens. Second, it has been found that environmental factors, such as biosecurity level, housing, litter, feed access and climate also have an effect on the composition of the intestinal microbiota. As microbiota studies have to deal with many of these unknown or hidden host and environmental variables, the choice of study designs can have a great impact on study outcomes and interpretation of the data. Providing details on a broad range of host and environmental factors in articles and sequence data repositories is highly recommended. This creates opportunities to

Host and Environmental Factors Affecting the Intestinal Microbiota in Chickens.

PubMed

Kers, Jannigje G; Velkers, Francisca C; Fischer, Egil A J; Hermes, Gerben D A; Stegeman, J A; Smidt, Hauke

2018-01-01

The initial development of intestinal microbiota in poultry plays an important role in production performance, overall health and resistance against microbial infections. Multiplexed sequencing of 16S ribosomal RNA gene amplicons is often used in studies, such as feed intervention or antimicrobial drug trials, to determine corresponding effects on the composition of intestinal microbiota. However, considerable variation of intestinal microbiota composition has been observed both within and across studies. Such variation may in part be attributed to technical factors, such as sampling procedures, sample storage, DNA extraction, the choice of PCR primers and corresponding region to be sequenced, and the sequencing platforms used. Furthermore, part of this variation in microbiota composition may also be explained by different host characteristics and environmental factors. To facilitate the improvement of design, reproducibility and interpretation of poultry microbiota studies, we have reviewed the literature on confounding factors influencing the observed intestinal microbiota in chickens. First, it has been identified that host-related factors, such as age, sex, and breed, have a large effect on intestinal microbiota. The diversity of chicken intestinal microbiota tends to increase most during the first weeks of life, and corresponding colonization patterns seem to differ between layer- and meat-type chickens. Second, it has been found that environmental factors, such as biosecurity level, housing, litter, feed access and climate also have an effect on the composition of the intestinal microbiota. As microbiota studies have to deal with many of these unknown or hidden host and environmental variables, the choice of study designs can have a great impact on study outcomes and interpretation of the data. Providing details on a broad range of host and environmental factors in articles and sequence data repositories is highly recommended. This creates opportunities to

Vitamin D deficiency and high serum IL-6 concentration as risk factors for tubal factor infertility in Chinese women.

PubMed

Chen, Weiwei; Jiao, Xianting; Zhang, Jun; Wang, Lei; Yu, Xiaodan

2018-05-01

The aim of this study was to investigate the relationship between 25-hydroxyvitamin-D [25(OH)D] and female infertility and to further explore the role of inflammatory cytokines. We recruited 356 infertile women diagnosed with tubal factor infertility (TFI) or polycystic ovary syndrome (PCOS) or endometriosis, as well as 180 fertile women. Serum concentrations of 25(OH)D, interleukin (IL)-6, IL-1 β, and interferon-α were measured. The 25(OH)D concentration in TFI women was the lowest (16.9 ng/mL) and was significantly different from that in the fertile women (19.4 ng/mL; P <0.05)]; whereas women with TFI had higher IL-6 concentrations. After adjusting for confounders, 25(OH)D deficiency presented a risk factor for TFI (odds ratio [OR], 4.2; 95% confidence interval [CI], 1.5-11.3). There was a dose-effect relation between IL-6 tertiles and TFI: the higher the IL-6, the higher the risk for TFI (middle versus low: OR, 3.7; 95% CI, 1.5-9.5; high versus low: OR, 13.2; 95% CI, 4.8-36.4). IL-6 showed a negative correlation with 25(OH)D (r = -0.19). Women with both high IL-6 and low 25(OH)D had the highest risk for TFI (OR, 10.6; 95% CI, 4.2-26.3). Both vitamin D deficiency and high serum IL-6 concentration are risk factors for TFI. Serum 25(OH)D concentration was significantly and negatively correlated with serum IL-6. There was an interaction between IL-6 and 25(OH)D for the risk for TFI-related infertility. We hypothesized that vitamin D might reduce the risk for TFI through suppressing the production of IL-6. Copyright © 2017 Elsevier Inc. All rights reserved.

Systematic evaluation of environmental factors: persistent pollutants and nutrients correlated with serum lipid levels

PubMed Central

Patel, Chirag J; Cullen, Mark R; Ioannidis, John PA; Butte, Atul J

2012-01-01

Background Both genetic and environmental factors contribute to triglyceride, low-density lipoprotein-cholesterol (LDL-C), and high-density lipoprotein-cholesterol (HDL-C) levels. Although genome-wide association studies are currently testing the genetic factors systematically, testing and reporting one or a few factors at a time can lead to fragmented literature for environmental chemical factors. We screened for correlation between environmental factors and lipid levels, utilizing four independent surveys with information on 188 environmental factors from the Centers of Disease Control, National Health and Nutrition Examination Survey, collected between 1999 and 2006. Methods We used linear regression to correlate each environmental chemical factor to triglycerides, LDL-C and HDL-C adjusting for age, age2, sex, ethnicity, socio-economic status and body mass index. Final estimates were adjusted for waist circumference, diabetes status, blood pressure and survey. Multiple comparisons were controlled for by estimating the false discovery rate and significant findings were tentatively validated in an independent survey. Results We identified and validated 29, 9 and 17 environmental factors correlated with triglycerides, LDL-C and HDL-C levels, respectively. Findings include hydrocarbons and nicotine associated with lower HDL-C and vitamin E (γ-tocopherol) associated with unfavourable lipid levels. Higher triglycerides and lower HDL-C were correlated with higher levels of fat-soluble contaminants (e.g. polychlorinated biphenyls and dibenzofurans). Nutrients and vitamin markers (e.g. vitamins B, D and carotenes), were associated with favourable triglyceride and HDL-C levels. Conclusions Our systematic association study has enabled us to postulate about broad environmental correlation to lipid levels. Although subject to confounding and reverse causality bias, these findings merit evaluation in additional cohorts. PMID:22421054

Climate Classification is an Important Factor in ­Assessing Hospital Performance Metrics

NASA Astrophysics Data System (ADS)

Boland, M. R.; Parhi, P.; Gentine, P.; Tatonetti, N. P.

2017-12-01

Context/Purpose: Climate is a known modulator of disease, but its impact on hospital performance metrics remains unstudied. Methods: We assess the relationship between Köppen-Geiger climate classification and hospital performance metrics, specifically 30-day mortality, as reported in Hospital Compare, and collected for the period July 2013 through June 2014 (7/1/2013 - 06/30/2014). A hospital-level multivariate linear regression analysis was performed while controlling for known socioeconomic factors to explore the relationship between all-cause mortality and climate. Hospital performance scores were obtained from 4,524 hospitals belonging to 15 distinct Köppen-Geiger climates and 2,373 unique counties. Results: Model results revealed that hospital performance metrics for mortality showed significant climate dependence (p<0.001) after adjusting for socioeconomic factors. Interpretation: Currently, hospitals are reimbursed by Governmental agencies using 30-day mortality rates along with 30-day readmission rates. These metrics allow Government agencies to rank hospitals according to their `performance' along these metrics. Various socioeconomic factors are taken into consideration when determining individual hospitals performance. However, no climate-based adjustment is made within the existing framework. Our results indicate that climate-based variability in 30-day mortality rates does exist even after socioeconomic confounder adjustment. Use of standardized high-level climate classification systems (such as Koppen-Geiger) would be useful to incorporate in future metrics. Conclusion: Climate is a significant factor in evaluating hospital 30-day mortality rates. These results demonstrate that climate classification is an important factor when comparing hospital performance across the United States.

Obstetric risk factors and autism spectrum disorders in Finland.

PubMed

Polo-Kantola, Päivi; Lampi, Katja M; Hinkka-Yli-Salomäki, Susanna; Gissler, Mika; Brown, Alan S; Sourander, Andre

2014-02-01

To examine the relationship between obstetric risk factors and childhood autism, Asperger syndrome, and other pervasive developmental disorders (PDDs). Registry-based case-control study from all singleton births in Finland from 1990-2005. Cases with childhood autism, Asperger syndrome, or PDD (n = 4713) were identified from the Finnish Hospital Discharge Register. Each case was matched to 4 controls on sex, date of birth, and place of birth. Information on obstetric risk factors was from the Finnish Medical Birth Register. Conditional logistic regression models were used for statistical analyses. When adjusted with confounders, childhood autism was associated with maternal high blood pressure (OR 1.49, 95% CI 1.1-2.1, P = .018), Apgar scores less than 7 (1 minute, OR 1.46, 95% CI 1.1-2.0, P = .021), and neonatal treatment with monitoring (OR 1.40, 95% CI 1.02-1.9, P = .038). PDD was associated with induced labor (OR 1.25 95% CI 1.1-1.5, P = .007), planned cesarean delivery (OR 1.34, 95% CI 1.1-1.7, P = .009), 1-minute Apgar scores 7-8 ( OR 1.22, 95% CI 1.1-1.4, P = .008) and less than 7 (OR 1.34, 95% CI 1.03-1.8, P = .032), and neonatal intensive care unit treatment (OR 1.52, 95% CI 1.2-2.0, P = .003). Asperger syndrome was associated only with 1-minute Apgar scores 7-8 (OR 1.19, 95% CI 1.03-1.4, P = .018). Low Apgar scores as well as conditions requiring neonatal special follow-up are important risk factors for childhood autism and PDD. These findings suggest that fetal distress is a potential risk factor for these disorders, but not for Asperger syndrome. Copyright © 2014 Mosby, Inc. All rights reserved.

Identifying high-risk areas of bacillary dysentery and associated meteorological factors in Wuhan, China

PubMed Central

Li, Zhenjun; Wang, Ligui; Sun, Weige; Hou, Xuexin; Yang, Haiyan; Sun, Lina; Xu, Shuai; Sun, Qiangzheng; Zhang, Jingshan; Song, Hongbin; Lin, Hualiang

2013-01-01

Spatial distribution of bacillary dysentery incidence was mapped at the district level in Wuhan, China. And a generalized additive time series model was used to examine the effect of daily weather factors on bacillary dysentery in the high-risk areas, after controlling for potential confounding factors. Central districts were found to be the high-risk areas. The time series analysis found an acute effect of meteorological factors on bacillary dysentery occurrence. A positive association was found for mean temperature (excess risk (ER) for 1°C increase being 0.94% (95% confidence interval (CI): 0.46% to 1.43% on the lag day 2), while a negative effect was observed for relative humidity and rainfall, the ER for 1% increase in relative humidity was −0.21% (95% CI: −0.34% to −0.08%), and the ER for 1 mm increase in rainfall was −0.23% (95% CI: −0.37% to −0.09%). This study suggests that bacillary dysentery prevention and control strategy should consider local weather variations. PMID:24257434

Associations between toenail arsenic concentration and dietary factors in a New Hampshire population.

PubMed

Gruber, Joann F; Karagas, Margaret R; Gilbert-Diamond, Diane; Bagley, Pamela J; Zens, M Scot; Sayarath, Vicki; Punshon, Tracy; Morris, J Steven; Cottingham, Kathryn L

2012-06-29

Dietary factors such as folate, vitamin B12, protein, and methionine are important for the excretion of arsenic via one-carbon metabolism in undernourished populations exposed to high levels of arsenic via drinking water. However, the effects of dietary factors on toenail arsenic concentrations in well-nourished populations exposed to relatively low levels of water arsenic are unknown. As part of a population-based case-control study of skin and bladder cancer from the USA, we evaluated relationships between consumption of dietary factors and arsenic concentrations in toenail clippings. Consumption of each dietary factor was determined from a validated food frequency questionnaire. We used general linear models to examine the associations between toenail arsenic and each dietary factor, taking into account potentially confounding effects. As expected, we found an inverse association between ln-transformed toenail arsenic and consumption of vitamin B12 (excluding supplements) and animal protein. Unexpectedly, there were also inverse associations with numerous dietary lipids (e.g., total fat, total animal fat, total vegetable fat, total monounsaturated fat, total polyunsaturated fat, and total saturated fat). Finally, increased toenail arsenic concentrations were associated with increased consumption of long chain n-3 fatty acids. In a relatively well-nourished population exposed to relatively low levels of arsenic via water, consumption of certain dietary lipids may decrease toenail arsenic concentration, while long chain n-3 fatty acids may increase toenail arsenic concentration, possibly due to their association with arsenolipids in fish tissue.

Associations between toenail arsenic concentration and dietary factors in a New Hampshire population

PubMed Central

2012-01-01

Background Dietary factors such as folate, vitamin B12, protein, and methionine are important for the excretion of arsenic via one-carbon metabolism in undernourished populations exposed to high levels of arsenic via drinking water. However, the effects of dietary factors on toenail arsenic concentrations in well-nourished populations exposed to relatively low levels of water arsenic are unknown. Methods As part of a population-based case–control study of skin and bladder cancer from the USA, we evaluated relationships between consumption of dietary factors and arsenic concentrations in toenail clippings. Consumption of each dietary factor was determined from a validated food frequency questionnaire. We used general linear models to examine the associations between toenail arsenic and each dietary factor, taking into account potentially confounding effects. Results As expected, we found an inverse association between ln-transformed toenail arsenic and consumption of vitamin B12 (excluding supplements) and animal protein. Unexpectedly, there were also inverse associations with numerous dietary lipids (e.g., total fat, total animal fat, total vegetable fat, total monounsaturated fat, total polyunsaturated fat, and total saturated fat). Finally, increased toenail arsenic concentrations were associated with increased consumption of long chain n-3 fatty acids. Conclusion In a relatively well-nourished population exposed to relatively low levels of arsenic via water, consumption of certain dietary lipids may decrease toenail arsenic concentration, while long chain n-3 fatty acids may increase toenail arsenic concentration, possibly due to their association with arsenolipids in fish tissue. PMID:22747713

Postpartum Depression in Women: A Risk Factor Analysis.

PubMed

Zaidi, Farheen; Nigam, Aruna; Anjum, Ruby; Agarwalla, Rashmi

2017-08-01

Postpartum Depression (PPD) is a known entity affecting not only the women but the whole family. It affects women more harshly and chronically due to their increased stress sensitivity, maladaptive coping strategies and multiple social roles in the community. To estimate the commonly associated risk factors of PPD among the women coming to a tertiary hospital in New Delhi, India. It was a longitudinal study conducted at the antenatal clinic for a period of one year. Total 260 women were screened at > 36 weeks of gestation, of which 149 postnatal women completed the questionnaire for PPD at six weeks of their delivery. The inform consent, demographical data and obstetrical details from each participant was taken before commencing the screening. Various risk factors and their association were determined by odds-ratio and significant association was accepted at < 5% level of error. In order to identify the most important confounding variables, logistic regression analysis was used. PPD is a common mental health problem seen among the postnatal women as it was found in 12.75% (19 out of 149) of subjects at six weeks of their delivery. Moreover, it has significant association with the young maternal age (p-value=0.040), birth of the female child (p-value=0.015), previous stressful life events (p-value= 0.003), low self-esteem and feeling of loneliness (p-value=0.007). This study provides important information regarding the risk factors associated with development of PPD in this region of India. Female sex of the new born and the younger age play an important role in the development of PPD.

Factor VII assay

MedlinePlus

Stable factor; Proconvertin; Autoprothrombin I ... be caused by an abnormally low level of factor VII. ... Decreased factor VII activity may be related to: Deficiency of factor VII Disorder in which the proteins that control ...

Factor V assay

MedlinePlus

Labile factor; Proaccelerin; Ac-globulin ... be caused by an abnormally low level of factor V. ... Decreased factor V activity may be related to: Deficiency of factor V Disorder in which the proteins that control ...

Factor Rotation and Standard Errors in Exploratory Factor Analysis

ERIC Educational Resources Information Center

Zhang, Guangjian; Preacher, Kristopher J.

2015-01-01

In this article, we report a surprising phenomenon: Oblique CF-varimax and oblique CF-quartimax rotation produced similar point estimates for rotated factor loadings and factor correlations but different standard error estimates in an empirical example. Influences of factor rotation on asymptotic standard errors are investigated using a numerical…

On the Confounding Effect of Temperature on Chemical Shift-Encoded Fat Quantification

PubMed Central

Hernando, Diego; Sharma, Samir D.; Kramer, Harald; Reeder, Scott B.

2014-01-01

Purpose To characterize the confounding effect of temperature on chemical shift-encoded (CSE) fat quantification. Methods The proton resonance frequency of water, unlike triglycerides, depends on temperature. This leads to a temperature dependence of the spectral models of fat (relative to water) that are commonly used by CSE-MRI methods. Simulation analysis was performed for 1.5 Tesla CSE fat–water signals at various temperatures and echo time combinations. Oil–water phantoms were constructed and scanned at temperatures between 0 and 40°C using spectroscopy and CSE imaging at three echo time combinations. An explanted human liver, rejected for transplantation due to steatosis, was scanned using spectroscopy and CSE imaging. Fat–water reconstructions were performed using four different techniques: magnitude and complex fitting, with standard or temperature-corrected signal modeling. Results In all experiments, magnitude fitting with standard signal modeling resulted in large fat quantification errors. Errors were largest for echo time combinations near TEinit ≈ 1.3 ms, ΔTE ≈ 2.2 ms. Errors in fat quantification caused by temperature-related frequency shifts were smaller with complex fitting, and were avoided using a temperature-corrected signal model. Conclusion Temperature is a confounding factor for fat quantification. If not accounted for, it can result in large errors in fat quantifications in phantom and ex vivo acquisitions. PMID:24123362

Newborn hearing screening programme in Belgium: a consensus recommendation on risk factors.

PubMed

Vos, Bénédicte; Senterre, Christelle; Lagasse, Raphaël; Levêque, Alain

2015-10-16

Understanding the risk factors for hearing loss is essential for designing the Belgian newborn hearing screening programme. Accordingly, they needed to be updated in accordance with current scientific knowledge. This study aimed to update the recommendations for the clinical management and follow-up of newborns with neonatal risk factors of hearing loss for the newborn screening programme in Belgium. A literature review was performed, and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system assessment method was used to determine the level of evidence quality and strength of the recommendation for each risk factor. The state of scientific knowledge, levels of evidence quality, and graded recommendations were subsequently assessed using a three-round Delphi consensus process (two online questionnaires and one face-to-face meeting). Congenital infections (i.e., cytomegalovirus, toxoplasmosis, and syphilis), a family history of hearing loss, consanguinity in (grand)parents, malformation syndromes, and foetal alcohol syndrome presented a 'high' level of evidence quality as neonatal risk factors for hearing loss. Because of the sensitivity of auditory function to bilirubin toxicity, hyperbilirubinaemia was assessed at a 'moderate' level of evidence quality. In contrast, a very low birth weight, low Apgar score, and hospitalisation in the neonatal intensive care unit ranged from 'very low' to 'low' levels, and ototoxic drugs were evidenced as 'very low'. Possible explanations for these 'very low' and 'low' levels include the improved management of these health conditions or treatments, and methodological weaknesses such as confounding effects, which make it difficult to conclude on individual risk factors. In the recommendation statements, the experts emphasised avoiding unidentified neonatal hearing loss and opted to include risk factors for hearing loss even in cases with weak evidence. The panel also highlighted the cumulative effect

A single factor underlies the metabolic syndrome: a confirmatory factor analysis.

PubMed

Pladevall, Manel; Singal, Bonita; Williams, L Keoki; Brotons, Carlos; Guyer, Heidi; Sadurni, Josep; Falces, Carles; Serrano-Rios, Manuel; Gabriel, Rafael; Shaw, Jonathan E; Zimmet, Paul Z; Haffner, Steven

2006-01-01

Confirmatory factor analysis (CFA) was used to test the hypothesis that the components of the metabolic syndrome are manifestations of a single common factor. Three different datasets were used to test and validate the model. The Spanish and Mauritian studies included 207 men and 203 women and 1,411 men and 1,650 women, respectively. A third analytical dataset including 847 men was obtained from a previously published CFA of a U.S. population. The one-factor model included the metabolic syndrome core components (central obesity, insulin resistance, blood pressure, and lipid measurements). We also tested an expanded one-factor model that included uric acid and leptin levels. Finally, we used CFA to compare the goodness of fit of one-factor models with the fit of two previously published four-factor models. The simplest one-factor model showed the best goodness-of-fit indexes (comparative fit index 1, root mean-square error of approximation 0.00). Comparisons of one-factor with four-factor models in the three datasets favored the one-factor model structure. The selection of variables to represent the different metabolic syndrome components and model specification explained why previous exploratory and confirmatory factor analysis, respectively, failed to identify a single factor for the metabolic syndrome. These analyses support the current clinical definition of the metabolic syndrome, as well as the existence of a single factor that links all of the core components.

Solar radiation increases suicide rate after adjusting for other climate factors in South Korea.

PubMed

Jee, Hee-Jung; Cho, Chul-Hyun; Lee, Yu Jin; Choi, Nari; An, Hyonggin; Lee, Heon-Jeong

2017-03-01

Previous studies have indicated that suicide rates have significant seasonal variations. There is seasonal discordance between temperature and solar radiation due to the monsoon season in South Korea. We investigated the seasonality of suicide and assessed its association with climate variables in South Korea. Suicide rates were obtained from the National Statistical Office of South Korea, and climatic data were obtained from the Korea Meteorological Administration for the period of 1992-2010. We conducted analyses using a generalized additive model (GAM). First, we explored the seasonality of suicide and climate variables such as mean temperature, daily temperature range, solar radiation, and relative humidity. Next, we identified confounding climate variables associated with suicide rate. To estimate the adjusted effect of solar radiation on the suicide rate, we investigated the confounding variables using a multivariable GAM. Suicide rate showed seasonality with a pattern similar to that of solar radiation. We found that the suicide rate increased 1.008 times when solar radiation increased by 1 MJ/m 2 after adjusting for other confounding climate factors (P < 0.001). Solar radiation has a significant linear relationship with suicide after adjusting for region, other climate variables, and time trends. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Risk factors for benign serous and mucinous epithelial ovarian tumors.

PubMed

Jordan, Susan J; Green, Adèle C; Whiteman, David C; Webb, Penelope M

2007-03-01

To investigate the risk factors for benign serous and mucinous epithelial ovarian tumors. Cases were women newly diagnosed with benign serous ovarian tumors (n=230) or benign mucinous tumors (n=133) between 2002 and 2005. Control women were selected at random from the general population (n=752). All participants completed a comprehensive reproductive and lifestyle questionnaire. Multivariable logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) and to simultaneously adjust for potential confounding factors. Current smoking was associated with a three-fold increase in risk of benign mucinous tumors (OR 3.25, 95% CI 1.97-5.34), and there was a trend of increasing risk with increasing amount smoked (P<.001). Both recent obesity (OR 1.93, 95% CI 1.30-2.88) and obesity at age 20 (OR 4.38, 95% CI 1.88-10.20) were associated with increased risk of benign serous ovarian tumors, and having had a hysterectomy was also related to increased risk of serous (OR 2.75, 95% CI 1.90-3.96), but not mucinous tumors. Ever having had a term pregnancy was inversely associated with both tumor types (combined OR 0.65, 95% CI 0.43-0.97), although greater numbers of pregnancies did not decrease risk further. Use of hormonal contraceptives was unrelated to risk. Our results suggest some differences in risk factors between benign serous and mucinous epithelial ovarian tumors and that risk factors for benign serous tumors differ from those well established for ovarian cancer. The results also suggest that there is potential for prevention of these common conditions through avoidance of smoking and obesity. II.

External Factors, Internal Factors and Self-Directed Learning Readiness

ERIC Educational Resources Information Center

Ramli, Nurjannah; Muljono, Pudji; Afendi, Farit M.

2018-01-01

There are many factors which affect the level of self-directed learning readiness. This study aims to investigate the relationship between external factors, internal factors and self-directed learning readiness. This study was carried out by using a census method for fourth year students of medical program of Tadulako University. Data were…

A Pilot Study of Reasons and Risk Factors for "No-Shows" in a Pediatric Neurology Clinic.

PubMed

Guzek, Lindsay M; Fadel, William F; Golomb, Meredith R

2015-09-01

Missed clinic appointments lead to decreased patient access, worse patient outcomes, and increased healthcare costs. The goal of this pilot study was to identify reasons for and risk factors associated with missed pediatric neurology outpatient appointments ("no-shows"). This was a prospective cohort study of patients scheduled for 1 week of clinic. Data on patient clinical and demographic information were collected by record review; data on reasons for missed appointments were collected by phone interviews. Univariate and multivariate analyses were conducted using chi-square tests and multiple logistic regression to assess risk factors for missed appointments. Fifty-nine (25%) of 236 scheduled patients were no-shows. Scheduling conflicts (25.9%) and forgetting (20.4%) were the most common reasons for missed appointments. When controlling for confounding factors in the logistic regression, Medicaid (odds ratio 2.36), distance from clinic, and time since appointment was scheduled were associated with missed appointments. Further work in this area is needed. © The Author(s) 2014.

Risk factors for retained placenta in southwestern Nigeria.

PubMed

Owolabi, A T; Dare, F O; Fasubaa, O B; Ogunlola, I O; Kuti, O; Bisiriyu, L A

2008-07-01

This study aimed to determine the incidence of, and identify independent risk factors to retained placenta in Ile-Ife, southwestern Nigeria. This was a prospective case-control study involving 120 women with retained placenta after vaginal birth at the Obafemi Awolowo University Teaching Hospital, Ile-Ife, southwestern Nigeria over a period of seven years. Two consecutive normal deliveries after each retained placenta served as controls. Following a bivariate analysis, a multivariate logistic regression model was constructed in order to define independent risk factors for retained placenta while controlling for confounding variables. During the study period, there were 120 cases of retained placenta, and the total number of deliveries was 6,160, making the incidence 1.9 percent. Independent risk factors associated with retained placenta include non-use of antenatal care (odds-ratio [OR] 22.71, 95 percent confidence interval [CI] 10.5-49.12, p-value is less than 0.000), previous retained placenta (OR 15.22, 95 percent CI 3.30-70.19, p-value is less than 0.000), previous caesarean section (OR 12.00, 95 percent CI 2.05-70.19, p-value is less than 0.006), maternal age 35 years or more (OR 7.10, 95 percent CI 1.5-32.40, p-values is less than 0.012), grand multiparity (OR 6.63, 95 percent CI 1.88-23.40, p-value is less than 0.003), previous dilatation and curettage (OR 4.44, 95 percent CI 1.69-11.63, p-value is less than 0.002), preterm delivery (OR 3.12, 95 percent CI 1.12-8.68, p-value is less than 0.029) and placenta weight less than 501 g (OR 2.91, 95 percent CI 1.34-6.32, p-value is less than 0.007). Women with identifiable risk factors should be targeted for the prevention of retained placenta. There is a need for the training of birth attendants in the proper conduct of delivery and third stage of labour to prevent placenta retention and postpartum haemorrhage.

Impact of occupational stress and other psychosocial factors on musculoskeletal pain among Chinese offshore oil installation workers

PubMed Central

Chen, W; Yu, I; Wong, T

2005-01-01

Aims: To explore the relation between psychosocial factors and musculoskeletal pain in Chinese offshore oil installation workers. Methods: Half of all offshore workers (being a representative sample) in a Chinese oil company were invited to complete a self-administered questionnaire providing information on sociodemographic characteristics, occupational stressors, type A behaviour, social support, coping style, health related behaviour, past injuries, and musculoskeletal pain. Factor analysis was used to identify the sources of occupational stress and the domains of type A behaviour and coping style. Logistic regression analyses were used to study the relations between psychosocial factors and musculoskeletal pain in each body region. Results: The prevalence of musculoskeletal pain over the previous 12 months varied between 7.5% for elbow pain and 32% for low back pain; 56% workers had at least one complaint. Significant associations were found between various psychosocial factors and musculoskeletal pain in different body regions after adjusting for potential confounding factors. Occupational stressors, in particular stress from safety, physical environment, and ergonomics, were important predictors of musculoskeletal pain, as was coping by eating behaviour. Conclusions: These observations supported the widely accepted biopsychosocial model of musculoskeletal disorders and suggested that in future studies of work related musculoskeletal disorders, psychosocial factors must be given due consideration. PMID:15778258

[Sedentary lifestyle is associated with metabolic and cardiovascular risk factors independent of physical activity].

PubMed

Leiva, Ana María; Martínez, María Adela; Cristi-Montero, Carlos; Salas, Carlos; Ramírez-Campillo, Rodrigo; Díaz Martínez, Ximena; Aguilar-Farías, Nicolás; Celis-Morales, Carlos

2017-04-01

Sedentary behavior is a main risk factor for cardiovascular disease and mortality. To investigate the association between sedentary behavior and metabolic and cardiovascular risk factors. We assessed 322 participants aged between 18 to 65 years. Physical activity and sedentary behavior were measured with accelerometers (Actigraph®). Body mass index (BMI), waist circumference, percentage of body fat, diet and blood markers (glucose, lipid profile, insulin and HOMA-IR) were measured with standardized protocols. Thirty four percent of participants were physically inactive and spent on average 8.7 h/day on sedentary activities. Per one hour increase in sedentary behavior there were significant adverse changes in glucose (4.79 mg/dl), insulin (2.73 pmol/l), HOMA-IR (0.75), BMI (0.69 kg/m²), waist circumference (1.95 cm), fat mass (1.03%), total cholesterol (9.73 mg/dl), HDL-cholesterol (-3.50 mg/dl), LDL-cholesterol (10.7 mg/dl) and triglycerides (12.4 mg/dl). These findings were independent of main confounding factors including total physical activity, dietary factors, BMI and socio-demographics. The detrimental effect of sedentary behaviors on cardiometabolic and obesity-related traits is independent of physical activity levels. Therefore, reducing sedentary time should be targeted in the population apart from increasing their physical activity levels.

Prevalence of abdominal obesity and its association with cardio metabolic risk factors among older adults in Ecuador.

PubMed

Orces, Carlos H; Montalvan, Martha; Tettamanti, Daniel

2017-12-01

To describe the prevalence of abdominal obesity and its association with cardio metabolic risk factors among older adults in Ecuador. The present study used data from the National Survey of Health, Wellbeing, and Aging survey to examine the prevalence of abdominal obesity according to certain demographic, behavioral, and health characteristics of the participants. Logistic regression models adjusted for potential confounders were used to evaluate the association of abdominal obesity with cardio metabolic risk factors. Of 2053 participants aged 60 years and older, the prevalence of abdominal obesity was 65.9% (95% CI; 62.2%, 69.4%) in women and 16.3% (95% CI; 13.8%, 19.2%) in men. Notably, a higher prevalence of abdominal obesity was seen among residents in the urban areas of the country, those who reported their race as black or mulatto, individuals with sedentary lifestyle and obesity, and older adults with greater number of comorbidities. Moreover, after adjustment for potential confounders, women with abdominal obesity were 2.0, 2.8, and 1.6 times more likely to have diabetes, the metabolic syndrome, and hypertriglyceridemia as compared with those without, respectively. Likewise, men with abdominal obesity had 51% and 22% higher rates of hypertension and diabetes than their non-obese counterparts, respectively. the prevalence of abdominal obesity is high among older adults in Ecuador. Moreover, abdominal obesity is significantly associated with cardio metabolic risk factors. Therefore, further research is needed to evaluate sociodemographic and nutritional determinants of this emerging public health burden among older Ecuadorians. Copyright © 2017 Diabetes India. Published by Elsevier Ltd. All rights reserved.

Insulin-Like Growth Factor-1 Bioactivity Plays a Prosurvival Role in Older Participants

PubMed Central

2013-01-01

The aim of this study was to address the intriguing issue of the role of the insulin-like growth factor (IGF)-1 system in longevity looking at the role of different components of IGF system. Vital status was ascertained in 1,197 men and women aged greater than or equal to 65 years from the InCHIANTI study. Hormonal levels were categorized into quartiles, and ratio of IGF-1 to IGF-binding protein (IGFBP)-1 was calculated. The relationship between hormones and mortality was tested by Cox proportional hazard models adjusted for age, sex, and confounders. During the 8-year follow-up period, 240 died and 957 survived. Lowest quartiles of IGF-1 and IGFBP-1 were considered as reference. Compared with the lowest quartiles, IGF-1 in upper quartiles was a negative predictor of mortality independent of age and sex (p = .01) but not independent of IGFBP-1 and other confounders. IGFBP-1 in second–third quartiles was negatively associated and that in the fourth quartiles was positively associated with risk of death. IGF-1/IGFBP-1 ratio in the lowest quartiles was a strong positive predictor of mortality, in age- and sex-adjusted model (p = .005), and independent of additional confounders (p = .037). High IGFBP-1 and low IGF-1/IGFBP-1 ratio are associated with all-cause mortality in older population. PMID:23671288

Insulin-like growth factor-1 bioactivity plays a prosurvival role in older participants.

PubMed

Maggio, Marcello; Cattabiani, Chiara; Lauretani, Fulvio; Bandinelli, Stefania; De Vita, Francesca; Dall'Aglio, Elisabetta; Corsonello, Andrea; Lattanzio, Fabrizia; Paolisso, Giuseppe; Ferrucci, Luigi; Ceda, Gian Paolo

2013-11-01

The aim of this study was to address the intriguing issue of the role of the insulin-like growth factor (IGF)-1 system in longevity looking at the role of different components of IGF system. Vital status was ascertained in 1,197 men and women aged greater than or equal to 65 years from the InCHIANTI study. Hormonal levels were categorized into quartiles, and ratio of IGF-1 to IGF-binding protein (IGFBP)-1 was calculated. The relationship between hormones and mortality was tested by Cox proportional hazard models adjusted for age, sex, and confounders. During the 8-year follow-up period, 240 died and 957 survived. Lowest quartiles of IGF-1 and IGFBP-1 were considered as reference. Compared with the lowest quartiles, IGF-1 in upper quartiles was a negative predictor of mortality independent of age and sex (p = .01) but not independent of IGFBP-1 and other confounders. IGFBP-1 in second-third quartiles was negatively associated and that in the fourth quartiles was positively associated with risk of death. IGF-1/IGFBP-1 ratio in the lowest quartiles was a strong positive predictor of mortality, in age- and sex-adjusted model (p = .005), and independent of additional confounders (p = .037). High IGFBP-1 and low IGF-1/IGFBP-1 ratio are associated with all-cause mortality in older population.

Environmental risk factors by gender associated with attention-deficit/hyperactivity disorder.

PubMed

Silva, Desiree; Colvin, Lyn; Hagemann, Erika; Bower, Carol

2014-01-01

Early environmental risk factors associated with attention-deficit/hyperactivity disorder (ADHD) have been increasingly suggested. Our study investigates the maternal, pregnancy, and newborn risk factors by gender for children prescribed stimulant medication for treatment of ADHD in Western Australia. This is a population-based, record linkage case-control study. The records of all non-Aboriginal children and adolescents born in Western Australia and aged <25 years who were diagnosed with ADHD and prescribed stimulant medication (cases = 12,991) were linked to the Midwives Notification System (MNS) to obtain maternal, pregnancy, and birth information. The control population of 30,071 children was randomly selected from the MNS. Mothers of children with ADHD were significantly more likely to be younger, be single, have smoked in pregnancy, have labor induced, and experience threatened preterm labor, preeclampsia, urinary tract infection in pregnancy, or early term delivery irrespective of the gender of the child, compared with the control group. In the fully adjusted model, a novel finding was of a possible protective effect of oxytocin augmentation in girls. Low birth weight, postterm pregnancy, small for gestational age infant, fetal distress, and low Apgar scores were not identified as risk factors. Smoking in pregnancy, maternal urinary tract infection, being induced, and experiencing threatened preterm labor increase the risk of ADHD, with little gender difference, although oxytocin augmentation of labor appears protective for girls. Early term deliveries marginally increased the risk of ADHD. Studies designed to disentangle possible mechanisms, confounders, or moderators of these risk factors are warranted.

Parental influences on cardiovascular risk factors in Swedish children aged 5-14 years.

PubMed

Khanolkar, Amal R; Byberg, Liisa; Koupil, Ilona

2012-12-01

Precursors of cardiovascular diseases (CVD) originate in childhood. We investigated relationships of children's CVD risk factors with parent's socio-economic position (SEP) and lifestyle and how CVD risk factors correlate within families. We studied 602 families with 2141 individuals comprising two full sibs; aged 5-14 years, and their biological parents (Uppsala Family Study). Parental SEP (occupational class and education) and lifestyle habits [smoking, physical activity (PA), alcohol consumption] were taken from questionnaires. Associations with cholesterol, ApoB/ApoA1, leptin, adiponectin, blood pressure, body mass index (BMI) and overweight/obesity (OW/OB) were analysed by linear/logistic regression. Results were adjusted for child's age, gender, pubertal stage and family clustering. We observed no consistent associations between parental SEP and children's CVD risk factors. Parental lifestyle had stronger effects, independent of parental SEP. Children of smoking fathers had higher BMI (4%, 95% CI 1-7%) and leptin levels (27%, 95% CI 1.00-61.60%). Children of mothers reporting vigorous PA had lower BMI, cholesterol and decreased odds for OW/OB with a possible dose effect. Compared with mothers reporting no vigorous activity, mothers with ≤75 min and 76-150 min/week of vigorous activity had 43% (OR 0.57, 95% CI 0.22-0.89) and 72% (OR 0.28, 95% CI 0.14-0.60) lower risk of having an OW/OB child, respectively, after adjustment for confounders. Independent, consistently stronger and significant associations were found between all studied parents' and children's CVD risk factors. Parental behaviours: smoking, alcohol consumption, low PA are associated with higher levels of CVD risk factors (BMI, OW/OB, cholesterol) in children. Strong correlations in CVD risk factors within families not related to parental SEP/lifestyle suggest a role of genetics in influencing children's CVD risk factors. Public health policies should target families with unhealthy lifestyles.

Perinatal and Family Risk Factors for Hodgkin Lymphoma in Childhood Through Young Adulthood

PubMed Central

Crump, Casey; Sundquist, Kristina; Sieh, Weiva; Winkleby, Marilyn A.; Sundquist, Jan

2012-01-01

The incidence of Hodgkin lymphoma has increased among adolescents and young adults in recent decades, but the relevant risk factors in early life are still unknown. A national cohort study was conducted of 3,571,574 individuals born in Sweden in 1973–2008 and followed up for Hodgkin lymphoma incidence through 2009, to examine perinatal and family risk factors for Hodgkin lymphoma in childhood through young adulthood (ages 0–37 years). There were 943 Hodgkin lymphoma cases identified in 66.3 million person-years of follow-up. High fetal growth was associated with an increased risk of Hodgkin lymphoma after adjustment for gestational age at birth and other potential confounders (Ptrend = 0.005). Family history of Hodgkin lymphoma in a sibling or parent also was strongly associated with an increased risk, with adjusted hazard ratios = 8.83 (95% confidence interval: 3.67, 21.30) and 7.19 (95% confidence interval: 3.58, 14.44), respectively. No association was found between gestational age at birth, birth order, twinning, parental age, or parental education and Hodgkin lymphoma. These findings did not vary by age at Hodgkin lymphoma diagnosis. Similar associations were found for nodular sclerosis and mixed cellularity subtypes. These findings suggest that perinatal factors including possible growth factor pathways may contribute to the risk of Hodgkin lymphoma in childhood through young adulthood. PMID:23171883

Sleep duration, snoring habits, and cardiovascular disease risk factors in an ethnically diverse population.

PubMed

Mosca, Matthew; Aggarwal, Brooke

2012-01-01

Lack of sleep has been associated with an increased risk for cardiovascular disease (CVD) and all-cause mortality, but the mechanisms are not fully understood. Prior research has often been conducted in select populations and has not consistently adjusted for confounders, especially psychosocial factors. The aims of this study were to assess the association between sleep habits and established risk factors for CVD and to evaluate potential interactions by race and gender. Participants were part of a CVD screening and educational outreach program in New York City. Free-living men older than 40 years and women older than 50 years (n = 371, mean age = 60 years, 57% women, 60% racial/ethnic minorities) were systematically assessed for CVD risk (including traditional, lifestyle, and psychosocial risk factors) and completed a standardized questionnaire regarding sleep habits (including sleep duration and snoring). Lipids were analyzed by validated finger-stick technology. Stress at work and at home was assessed using a validated screening tool from the INTERHEART study. Associations between participants' sleep habits and CVD risk factors/demographic factors were assessed using multivariable logistic regression. The proportion of participants who reported sleeping less than 6 hours per night on average was 28%, and 52% of participants reported snoring. Sleeping less than 6 hours per night was significantly (P < .05) associated with female gender, being single, increased stress at home, increased financial stress, and low-density lipoprotein cholesterol (LDL-C) level. Gender modified the association between sleep duration and LDL-C level (P = .04): Sleeping less than 6 hours per night was significantly associated with reduced LDL-C level among women and increased LDL-C level among men. Snoring was significantly associated with low high-density lipoprotein cholesterol (HDL-C) level (<40 mg/dL for men/<50 mg/dL for women), being married, increased stress at work and at home

Factors Associated with Incidence of Induced Abortion in Hamedan, Iran.

PubMed

Hosseini, Hatam; Erfani, Amir; Nojomi, Marzieh

2017-05-01

There is limited reliable information on abortion in Iran, where abortion is illegal and many women of reproductive age seek clandestine abortion to end their unintended pregnancy. This study aims to examine the determinants of induced abortion in the city of Hamedan, Iran. The study utilizes recent data from the 2015 Hamedan Survey of Fertility, conducted in a representative sample of 3,000 married women aged 15-49 years in the city of Hamedan, Iran. Binary logistic regression models are used to examine factors associated with the incidence of abortion. Overall, 3.8% of respondents reported having had an induced abortion in their life. Multivariate results showed that the incidence of abortion was strongly associated with women's education, type of contraceptive and family income level, after controlling for confounding factors. Women using long-acting contraceptive methods, those educated under high school diploma or postsecondary education, and those with high level of income were more likely to report having an induced abortion. The high incidence of abortion among less or more educated women and those with high income level signifies unmet family planning needs among these women, which must be addressed by focused reproductive health and family planning programs.

Acute respiratory distress syndrome without identifiable risk factors: A secondary analysis of the ARDS network trials.

PubMed

Harrington, John S; Schenck, Edward J; Oromendia, Clara; Choi, Augustine M K; Siempos, Ilias I

2018-06-02

We examined whether patients with acute respiratory distress syndrome (ARDS) lacking risk factors are enrolled in therapeutic trials and assessed their clinical characteristics and outcomes. We performed a secondary analysis of patient-level data pooled from the ARMA, ALVEOLI, FACTT, ALTA and EDEN ARDSNet randomized controlled trials obtained from the Biologic Specimen and Data Repository Information Coordinating Center of the National Heart, Lung and Blood Institute. We compared baseline characteristics and clinical outcomes (before and after adjustment using Poisson regression model) of ARDS patients with versus without risk factors. Of 3733 patients with ARDS, 81 (2.2%) did not have an identifiable risk factor. Patients without risk factors were younger, had lower baseline severity of illness, were more likely to have the ARDS resolve rapidly (i.e., within 24 h) (p < 0.001) and they had more ventilator-free days (median 21; p = 0.003), more intensive care unit-free days (18; p = 0.010), and more non-pulmonary organ failure-free days (24; p < 0.001) than comparators (17, 14 and 18, respectively). Differences persisted after adjustment for potential confounders. Patients with ARDS without identifiable risk factors are enrolled in therapeutic trials and may have better outcomes, including a higher proportion of rapidly resolving ARDS, than those with risk factors. Copyright © 2018. Published by Elsevier Inc.

Linking genetic and environmental factors in amphibian disease risk

PubMed Central

Savage, Anna E; Becker, Carlos G; Zamudio, Kelly R

2015-01-01

A central question in evolutionary biology is how interactions between organisms and the environment shape genetic differentiation. The pathogen Batrachochytrium dendrobatidis (Bd) has caused variable population declines in the lowland leopard frog (Lithobates yavapaiensis); thus, disease has potentially shaped, or been shaped by, host genetic diversity. Environmental factors can also influence both amphibian immunity and Bd virulence, confounding our ability to assess the genetic effects on disease dynamics. Here, we used genetics, pathogen dynamics, and environmental data to characterize L. yavapaiensis populations, estimate migration, and determine relative contributions of genetic and environmental factors in predicting Bd dynamics. We found that the two uninfected populations belonged to a single genetic deme, whereas each infected population was genetically unique. We detected an outlier locus that deviated from neutral expectations and was significantly correlated with mortality within populations. Across populations, only environmental variables predicted infection intensity, whereas environment and genetics predicted infection prevalence, and genetic diversity alone predicted mortality. At one locality with geothermally elevated water temperatures, migration estimates revealed source–sink dynamics that have likely prevented local adaptation. We conclude that integrating genetic and environmental variation among populations provides a better understanding of Bd spatial epidemiology, generating more effective conservation management strategies for mitigating amphibian declines. PMID:26136822

[Factors related to urinary iodine in adults from Shanghai].

PubMed

Ren, Tian-hong; Yu, Xiao-dan

2013-12-01

The objective of this study was to analyze the related factors that influencing the level of urinary iodine(UI). 994 adult cases were selected from medical centers. Morning urine was collected and questionnaire including age, sex, family medical history of thyroid disease administered. Information on previous 24-hour consumption of iodine-containing foods was collected. Data was analyzed by Empower(®) software with logistic model. The median UI level was 193.0 µg/L. After adjusting for potential confounders, gender (P = 0.000), family monthly income per capita (P = 0.000), the amount of iodized salt intake (P = 0.041), and eating kelps (P = 0.000)appeared to be associated with the level of UI. Risk regarding the prevalence of excess UI (>300 µg/L)increased with the increasing amount of salt and kelp consumption:salt consumption > 165 g/m (OR = 24.3, 95%CI:1.1-523.8, P < 0.05); kelp consumption (OR = 9.6, 95%CI:2.6 -35.1, P < 0.001). UI was associated with factors as:gender, family monthly income per capita, intake of iodized salt and the amount of kelp consumption. Excessive intake of iodine might be associated with high intake of iodized salt and kelp.

[Coagulation factor VII levels in uremic patients and theirs influence factors].

PubMed

Fang, Jun; Xia, Ling-Hui; Wei, Wen-Ning; Song, Shan-Jun

2004-12-01

This study was aimed to investigate coagulation factor VII level in uremic patients with chronic renal failure and to explore theirs influence factors. The plasma levels of coagulation factor VII were detected in 30 uremic patients with chronic renal failure before and after hemodialysis for 1 month, the factor VII activity (FVII:C) was determined by one-stage coagulation method, while activated factor VII (FVIIa) was measured by one-stage coagulation method using recombinant soluble tissue factor, and factor VII antigen was detected by ELISA. The results showed that: (1) The FVIIa, FVII:C and FVIIAg levels in chronic uremic patients before hemodialysis were 4.00 +/- 0.86 microg/L, (148.5 +/- 40.4)% and (99.8 +/- 21.1)% respectively, which were significantly increased, as compared with healthy controls [2.77 +/- 1.02 microg/L, (113.1 +/- 33.0)% and (73.7 +/- 18.3)% respectively, P < 0.05]. (2) After hemodialysis the FVIIa, FVII:C and FVIIAg levels in uremic patients significantly enhanced to 5.56 +/- 1.45 microg/L, (200.8 +/- 68.7)% and (124.1 +/- 19.3)% respectively (P < 0.05). (3) The abnormal increase of coagulation factor VII was positively correlated with levels of blood uria nitrogen and serum creatinine before hemodialysis but not after hemodialysis. It is concluded that the enhanced levels of coagulation factor VII in chronic uremic patients suggested abnormal activated state, herperactivity and elevated production of factor VII which correlated with renal functional injury. The abnormality of factor VII in uremia may be aggravated by hemodialysis. Coagulation factor (FVII) may be a risk factor for cardiovascular events in uremic patients who especially had been accepted long-term hemodialysis.

An exploratory factor analysis of nutritional biomarkers associated with major depression in pregnancy.

PubMed

Bodnar, Lisa M; Wisner, Katherine L; Luther, James F; Powers, Robert W; Evans, Rhobert W; Gallaher, Marcia J; Newby, P K

2012-06-01

Major depressive disorder (MDD) during pregnancy increases the risk of adverse maternal and infant outcomes. Maternal nutritional status may be a modifiable risk factor for antenatal depression. We evaluated the association between patterns in mid-pregnancy nutritional biomarkers and MDD. Prospective cohort study. Pittsburgh, Pennsylvania, USA. Women who enrolled at ≤20 weeks' gestation and had a diagnosis of MDD made with the Structured Clinical Interview for DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th edition) at 20-, 30- and 36-week study visits. A total of 135 women contributed 345 person-visits. Non-fasting blood drawn at enrolment was assayed for red cell essential fatty acids, plasma folate, homocysteine and ascorbic acid; serum 25-hydroxyvitamin D, retinol, vitamin E, carotenoids, ferritin and soluble transferrin receptors. Nutritional biomarkers were entered into principal components analysis. Three factors emerged: Factor 1, Essential Fatty Acids; Factor 2, Micronutrients; and Factor 3, Carotenoids. MDD was prevalent in 21·5 % of women. In longitudinal multivariable logistic models, there was no association between the Essential Fatty Acids or Micronutrients pattern and MDD either before or after adjustment for employment, education or pre-pregnancy BMI. In unadjusted analysis, women with factor scores for Carotenoids in the middle and upper tertiles were 60 % less likely than women in the bottom tertile to have MDD during pregnancy, but after adjustment for confounders the associations were no longer statistically significant. While meaningful patterns were derived using nutritional biomarkers, significant associations with MDD were not observed in multivariable adjusted analyses. Larger, more diverse samples are needed to understand nutrition-depression relationships during pregnancy.

Risk factors and mortality for nosocomial bloodstream infections in elderly patients.

PubMed

Reunes, S; Rombaut, V; Vogelaers, D; Brusselaers, N; Lizy, C; Cankurtaran, M; Labeau, S; Petrovic, M; Blot, S

2011-10-01

To determine risk factors for nosocomial bloodstream infection (BSI) and associated mortality in geriatric patients in geriatric and internal medicine wards at a university hospital. Single-center retrospective (1992-2007), pairwise-matched (1:1-ratio) cohort study. Geriatric patients with nosocomial BSI were matched with controls without BSI on year of admission and length of hospitalization before onset of BSI. Demographic, microbiological, and clinical data are collected. One-hundred forty-two BSI occurred in 129 patients. Predominant microorganisms were Escherichia coli (23.2%), coagulase-negative Staphylococci (19.4%), Pseudomonas aeruginosa (8.4%), Staphylococcus aureus (7.1%), Klebsiella pneumoniae (5.8%) and Candida spp. (5.8%). Matching was successful for 109 cases. Compared to matched control subjects, cases were more frequently female, suffered more frequently from arthrosis, angina pectoris and pressure ulcers, had worse Activities of Daily Living-scores, had more often an intravenous or bladder catheter, and were more often bedridden. Logistic regression demonstrated presence of an intravenous catheter (odds ratio [OR] 7.5, 95% confidence interval [CI] 2.5-22.9) and being bedridden (OR 2.9, 95% CI 1.6-5.3) as independent risk factors for BSI. In univariate analysis nosocomial BSI was associated with increased mortality (22.0% vs. 11.0%; P=0.029). After adjustment for confounding co-variates, however, nosocomial BSI was not associated with mortality (hazard ratio 1.3, 95% CI 0.6-2.6). Being bedridden and increasing age were independent risk factors for death. Intravenous catheters and being bedridden are the main risk factors for nosocomial BSI. Although associated with higher mortality, this infectious complication seems not to be an independent risk factor for death in geriatric patients. Copyright © 2011 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

A review of factors explaining variability in fentanyl pharmacokinetics; focus on implications for cancer patients

PubMed Central

Zandvliet, Maarten L.; Koolen, Stijn L. W.; Mathijssen, Ron H. J.; van der Rijt, Carin C. D.

2016-01-01

Fentanyl is a strong opioid that is available for various administration routes, and which is widely used to treat cancer‐related pain. Many factors influence the fentanyl pharmacokinetics leading to a wide inter‐ and intrapatient variability. This systematic review summarizes multiple studied factors that potentially influence fentanyl pharmacokinetics with a focus on implications for cancer patients. The use of CYP3A4 inhibitors and inducers, impaired liver function, and heating of the patch potentially influence fentanyl pharmacokinetics in a clinically relevant way. In elderly patients, current data suggest that we should carefully dose fentanyl due to alterations in absorption and metabolism. The influence of BMI and gender on fentanyl pharmacokinetics is questionable, most probably due to a large heterogeneity in the published studies. Pharmacogenetics, e.g. the CYP3A5*3 gene polymorphism, may influence fentanyl pharmacokinetics as well, although further study is warranted. Several other factors have been studied but did not show significant and clinically relevant effects on fentanyl pharmacokinetics. Unfortunately, most of the published papers that studied factors influencing fentanyl pharmacokinetics describe healthy volunteers instead of cancer patients. Results from the studies in volunteers may not be simply extrapolated to cancer patients because of multiple confounding factors. To handle fentanyl treatment in a population of cancer patients, it is essential that physicians recognize factors that influence fentanyl pharmacokinetics, thereby preventing potential side‐effects and increasing its efficacy. PMID:27619152

Confounding factors in using upward feedback to assess the quality of medical training: a systematic review.

PubMed

Zhou, Anli Yue; Baker, Paul

2014-01-01

Upward feedback is becoming more widely used in medical training as a means of quality control. Multiple biases exist, thus the accuracy of upward feedback is debatable. This study aims to identify factors that could influence upward feedback, especially in medical training. A systematic review using a structured search strategy was performed. Thirty-five databases were searched. Results were reviewed and relevant abstracts were shortlisted. All studies in English, both medical and non-medical literature, were included. A simple pro-forma was used initially to identify the pertinent areas of upward feedback, so that a focused pro-forma could be designed for data extraction. A total of 204 articles were reviewed. Most studies on upward feedback bias were evaluative studies and only covered Kirkpatrick level 1-reaction. Most studies evaluated trainers or training, were used for formative purposes and presented quantitative data. Accountability and confidentiality were the most common overt biases, whereas method of feedback was the most commonly implied bias within articles. Although different types of bias do exist, upward feedback does have a role in evaluating medical training. Accountability and confidentiality were the most common biases. Further research is required to evaluate which types of bias are associated with specific survey characteristics and which are potentially modifiable.

Determining Confounding Sensitivities In Eddy Current Thin Film Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gros, Ethan; Udpa, Lalita; Smith, James A.

Determining Confounding Sensitivities In Eddy Current Thin Film Measurements Ethan Gros, Lalita Udpa, Electrical Engineering, Michigan State University, East Lansing MI 48824 James A. Smith, Experiment Analysis, Idaho National Laboratory, Idaho Falls ID 83415 Eddy current (EC) techniques are widely used in industry to measure the thickness of non-conductive films on a metal substrate. This is done using a system whereby a coil carrying a high-frequency alternating current is used to create an alternating magnetic field at the surface of the instrument's probe. When the probe is brought near a conductive surface, the alternating magnetic field will induce ECs inmore » the conductor. The substrate characteristics and the distance of the probe from the substrate (the coating thickness) affect the magnitude of the ECs. The induced currents load the probe coil affecting the terminal impedance of the coil. The measured probe impedance is related to the lift off between coil and conductor as well as conductivity of the test sample. For a known conductivity sample, the probe impedance can be converted into an equivalent film thickness value. The EC measurement can be confounded by a number of measurement parameters. It is the goal of this research to determine which physical properties of the measurement set-up and sample can adversely affect the thickness measurement. The eddy current testing is performed using a commercially available, hand held eddy current probe (ETA3.3H spring loaded eddy probe running at 8 MHz) that comes with a stand to hold the probe. The stand holds the probe and adjusts the probe on the z-axis to help position the probe in the correct area as well as make precise measurements. The signal from the probe is sent to a hand held readout, where the results are recorded directly in terms of liftoff or film thickness. Understanding the effect of certain factors on the measurements of film thickness, will help to evaluate how accurate the ETA3.3H

Risk Factors for Urinary Tract Infection following Mid Urethral Sling Surgery.

PubMed

Vigil, Humberto R; Mallick, Ranjeeta; Nitti, Victor W; Lavallée, Luke T; Breau, Rodney H; Hickling, Duane R

2017-05-01

Mid urethral sling surgery is common. Postoperative urinary tract infection rates vary in the literature and independent risk factors for urinary tract infection are not well defined. We sought to determine the incidence of and risk factors for urinary tract infection following mid urethral sling surgery. A retrospective cohort of females who underwent sling surgery was captured from the 2006 to 2014 NSQIP® (National Surgical Quality Improvement Program®) database. Exclusion criteria included male gender, nonelective surgery, totally dependent functional status, preoperative infection, prior surgery within 30 days, ASA® (American Society of Anesthesiologists®) Physical Status Classification 4 or greater, concomitant procedure and operative time greater than 60 minutes. The primary outcome was the incidence of urinary tract infection within 30 days of mid urethral sling surgery. Risk factors for urinary tract infection were assessed by examining patient demographic, comorbidity and surgical variables. Logistic regression analyses were performed to estimate the ORs of individual risk factors. Multivariable logistic regression was then performed to adjust for confounding. A total of 9,022 mid urethral sling surgeries were identified. The urinary tract infection incidence was 2.6%. Factors independently associated with an increased infection risk included age greater than 65 years (OR 1.54, 95% CI 1.07-2.22), body mass index greater than 40 kg/m 2 (OR 1.89, 95% CI 1.23-2.92) and hospital admission (OR 2.06, 95% CI 1.37-3.11). Mid urethral sling surgery performed by urologists carried a reduced risk of infection compared to the surgery done by gynecologists (OR 0.52, 95% CI 0.40-0.69). The urinary tract infection risk following mid urethral sling surgery in NSQIP associated hospitals is low. Novel patient and surgical factors for postoperative urinary tract infection have been identified and merit further study. Copyright © 2017 American Urological Association

Factor XII (Hageman factor) deficiency

MedlinePlus

... disorders: coagulation factor deficiencies. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine . 25th ed. ... Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by ...

Statin adherence and risk of acute cardiovascular events among women: a cohort study accounting for time-dependent confounding affected by previous adherence.

PubMed

Lavikainen, Piia; Helin-Salmivaara, Arja; Eerola, Mervi; Fang, Gang; Hartikainen, Juha; Huupponen, Risto; Korhonen, Maarit Jaana

2016-06-03

Previous studies on the effect of statin adherence on cardiovascular events in the primary prevention of cardiovascular disease have adjusted for time-dependent confounding, but potentially introduced bias into their estimates as adherence and confounders were measured simultaneously. We aimed to evaluate the effect when accounting for time-dependent confounding affected by previous adherence as well as time sequence between factors. Retrospective cohort study. Finnish healthcare registers. Women aged 45-64 years initiating statin use for primary prevention of cardiovascular disease in 2001-2004 (n=42 807). Acute cardiovascular event defined as a composite of acute coronary syndrome and acute ischaemic stroke was our primary outcome. Low-energy fractures were used as a negative control outcome to evaluate the healthy-adherer effect. During the 3-year follow-up, 474 women experienced the primary outcome event and 557 suffered a low-energy fracture. The causal HR estimated with marginal structural model for acute cardiovascular events for all the women who remained adherent (proportion of days covered ≥80%) to statin therapy during the previous adherence assessment year was 0.78 (95% CI: 0.65 to 0.94) when compared with everybody remaining non-adherent (proportion of days covered <80%). The result was robust against alternative model specifications. Statin adherers had a potentially reduced risk of experiencing low-energy fractures compared with non-adherers (HR 0.90, 95% CI 0.76 to 1.07). Our study, which took into account the time dependence of adherence and confounders, as well as temporal order between these factors, is support for the concept that adherence to statins in women in primary prevention decreases the risk of acute cardiovascular events by about one-fifth in comparison to non-adherence. However, part of the observed effect of statin adherence on acute cardiovascular events may be due to the healthy-adherer effect. Published by the BMJ Publishing

Factoring in Factor VIII With Acute Ischemic Stroke.

PubMed

Siegler, James E; Samai, Alyana; Albright, Karen C; Boehme, Amelia K; Martin-Schild, Sheryl

2015-10-01

There is growing research interest into the etiologies of cryptogenic stroke, in particular as it relates to hypercoagulable states. An elevation in serum levels of the procoagulant factor VIII is recognized as one such culprit of occult cerebral infarctions. It is the objective of the present review to summarize the molecular role of factor VIII in thrombogenesis and its clinical use in the diagnosis and prognosis of acute ischemic stroke. We also discuss the utility of screening for serum factor VIII levels among patients at risk for, or those who have experienced, ischemic stroke. © The Author(s) 2015.

The association of lifetime education with the prevalence of myocardial infarction: an analysis of the 2006 Behavioral Risk Factor Surveillance System.

PubMed

Kelly, Michael J; Weitzen, Sherry

2010-02-01

Socioeconomic status is likely an independent risk factor for coronary heart disease but little research has been done in the United States to study this association in a nationally representative sample. We sought to determine the association between lifetime education and the prevalence of myocardial infarction (MI) among adults over the age of 39 in the US. A cross sectional study was conducted using the 2006 Behavioral Risk Factor Surveillance System (BRFSS). A multivariable logistic regression was performed. The analysis was conducted in 2008. Among respondents aged 40 years and older to the 2006 BRFSS survey those with less than a high school education had 3.09 (95% CI: 2.79-3.43) times the odds of having had an MI compared to college graduates. After adjusting for confounders, respondents with less than a high school education had 1.61 (95% CI: 1.41-1.83) times the odds of having had an MI compared to college graduates. Both those with a high school education and those who completed some college or technical school had 1.22 times the odds of having had an MI compared to college graduates after adjusting for confounders. This study suggests that education is a risk factor for MI. More national prospective studies are needed in the US to better understand the link between socioeconomic status and coronary heart disease.

Clinical risk factors for preeclampsia in the 21st century.

PubMed

Paré, Emmanuelle; Parry, Samuel; McElrath, Thomas F; Pucci, Dominick; Newton, Amy; Lim, Kee-Hak

2014-10-01

We sought to validate several clinical risk factors previously described for preeclampsia in a large contemporary multicenter prospective cohort. We enrolled women from three sites before 15 weeks of gestation. Demographic and clinical risk factors were collected through standardized chart review. The main outcome of preeclampsia was diagnosed using the American College of Obstetricians and Gynecologists definitions from 2002. Multivariable logistic regression was used to control for confounders. Two thousand six hundred thirty-seven women are included in this analysis; 237 (9.0%) developed preeclampsia. In adjusted analysis, chronic hypertension (adjusted odds ratio [OR] 2.72; 95% confidence interval 1.78-4.13), pregestational diabetes (adjusted OR 3.88; 2.08-7.26), multiple gestation (adjusted OR 2.96; 1.74-5.03), African American race (adjusted OR 1.91; 1.35-2.71), prior preeclampsia (adjusted OR 3.63; 2.29-5.73), nulliparity (adjusted OR 1.73; 1.26-2.38), assisted reproductive techniques (adjusted OR: 1.72; 1.10-2.68), and being overweight (adjusted OR for body mass index [BMI, kg/m] greater than 25-30: 1.65; 1.13-2.41) or obese (adjusted OR for BMI greater than 30-35: 2.34, 1.51-3.61; adjusted OR for BMI greater than 35-40: 3.59, 2.13-6.03; adjusted OR for BMI greater than 40: 6.04, 3.56-10.24) were associated with preeclampsia, but advanced maternal age was not. Similar associations were found for severe preeclampsia. A dose-response effect was observed in the relationship between BMI and both preeclampsia and severe preeclampsia. Being overweight or obese was the most important risk factor for both preeclampsia and severe preeclampsia with an attributable risk percent of 64.9% and 64.4%, respectively. In this contemporary cohort, increasingly prevalent and potentially modifiable factors were confirmed as significant risk factors for preeclampsia and severe preeclampsia, the most important being overweight or obese. This information is important to guide

The impact of environmental factors on traffic accidents in Iran.

PubMed

Lankarani, Kamran B; Heydari, Seyed Taghi; Aghabeigi, Mohammad Reza; Moafian, Ghasem; Hoseinzadeh, Amin; Vossoughi, Mehrdad

2014-07-01

Road traffic crashes are the third highest cause of mortality in Iran. The aim of this study was to determine the impact of roadway environmental factors on traffic crash. This cross-sectional study was conducted in Iran between March 21, 2010 and December 30, 2010. The data on road traffic crashes were obtained from the Traffic Police Department records. These records were classified to control for the main confounders related to the type of crash and roadway environmental factors. Roadway environmental factors included crash scene light, weather, place of accident, the defects and geometrics of roadway and road surface. The study included 542,863 traffic crashes. The proportions of road traffic crash which led to injury were 24.44% at sunrise and 27.16% at sunset compared with 5.43% and 1.43% deaths at sunrise and sunset respectively. In regard to day time accidents, the proportions were 20.50% injuries and 0.55% deaths. The statistical analysis of the results showed that the ratio of injuries and deaths were significantly higher at sunrise and sunset than those occurring during daytime (P less than 0.001). The highest rate of death (5.07%) was due to dusty weather compared to 5.07% for other weather conditions (P less than 0.001). The highest mortality rate (3.45%) occurred on oily surfaces (P less than 0.001). The defective traffic signs were responsible for 30,046 injuries and 5.58% deaths, and road narrowing accounted for 22,775 injuries and, 4.23% deaths which indicated that the roadway defects inflict most frequent injuries and deaths. The lowest (0.74 %) and highest (3.09%) proportion of traffic crash- related deaths were due to flat straight and winding uphill/downhill roads respectively (P less than 0.001). Sunrise, sunset, dusty weather, oily road surfaces and winding uphill/downhill road were hazardous environmental factors. This study provides an insight into the potential impacts of environmental factors on road traffic accidents and underlines the

Analysis of vehicle classification data, including monthly and seasonal ADT factors, hourly distribution factors, and lane distribution factors

DOT National Transportation Integrated Search

1998-11-01

This report documents the development of monthly and seasonal average daily traffic (ADT) factors for performing estimating AADTs. It appears that seasonal factors can estimate AADT as well as monthly factors, and it is recommended that seasonal fact...

Kelch-like ECH-associated Protein 1-dependent Nuclear Factor-E2-related Factor 2 Activation in Relation to Antioxidation Induced by Sevoflurane Preconditioning.

PubMed

Cai, Min; Tong, Li; Dong, Beibei; Hou, Wugang; Shi, Likai; Dong, Hailong

2017-03-01

The authors have reported that antioxidative effects play a crucial role in the volatile anesthetic-induced neuroprotection. Accumulated evidence shows that endogenous antioxidation could be up-regulated by nuclear factor-E2-related factor 2 through multiple pathways. However, whether nuclear factor-E2-related factor 2 activation is modulated by sevoflurane preconditioning and, if so, what is the signaling cascade underlying upstream of this activation are still unknown. Sevoflurane preconditioning in mice was performed with sevoflurane (2.5%) 1 h per day for five consecutive days. Focal cerebral ischemia/reperfusion injury was induced by middle cerebral artery occlusion. Expression of nuclear factor-E2-related factor 2, kelch-like ECH-associated protein 1, manganese superoxide dismutase, thioredoxin-1, and nicotinamide adenine dinucleotide phosphate quinolone oxidoreductase-1 was detected (n = 6). The antioxidant activities and oxidative product expression were also examined. To determine the role of kelch-like ECH-associated protein 1 inhibition-dependent nuclear factor-E2-related factor 2 activation in sevoflurane preconditioning-induced neuroprotection, the kelch-like ECH-associated protein 1-nuclear factor-E2-related factor 2 signal was modulated by nuclear factor-E2-related factor 2 knockout, kelch-like ECH-associated protein 1 overexpression lentivirus, and kelch-like ECH-associated protein 1 deficiency small interfering RNA (n = 8). The infarct volume, neurologic scores, and cellular apoptosis were assessed. Sevoflurane preconditioning elicited neuroprotection and increased nuclear factor-E2-related factor 2 nuclear translocation, which in turn up-regulated endogenous antioxidation and reduced oxidative injury. Sevoflurane preconditioning reduced kelch-like ECH-associated protein 1 expression. Nuclear factor-E2-related factor 2 ablation abolished neuroprotection and reversed sevoflurane preconditioning by mediating the up-regulation of antioxidants. Kelch

Reported gum disease as a cardiovascular risk factor in adults with intellectual disabilities.

PubMed

Hsieh, K; Murthy, S; Heller, T; Rimmer, J H; Yen, G

2018-03-01

Several risk factors for cardiovascular disease (CVD) have been identified among adults with intellectual disabilities (ID). Periodontitis has been reported to increase the risk of developing a CVD in the general population. Given that individuals with ID have been reported to have a higher prevalence of poor oral health than the general population, the purpose of this study was to determine whether adults with ID with informant reported gum disease present greater reported CVD than those who do not have reported gum disease and whether gum disease can be considered a risk factor for CVD. Using baseline data from the Longitudinal Health and Intellectual Disability Study from which informant survey data were collected, 128 participants with reported gum disease and 1252 subjects without reported gum disease were identified. A series of univariate logistic regressions was conducted to identify potential confounding factors for a multiple logistic regression. The series of univariate logistic regressions identified age, Down syndrome, hypercholesterolemia, hypertension, reported gum disease, daily consumption of fruits and vegetables and the addition of table salt as significant risk factors for reported CVD. When the significant factors from the univariate logistic regression were included in the multiple logistic analysis, reported gum disease remained as an independent risk factor for reported CVD after adjusting for the remaining risk factors. Compared with the adults with ID without reported gum disease, adults in the gum disease group demonstrated a significantly higher prevalence of reported CVD (19.5% vs. 9.7%; P = .001). After controlling for other risk factors, reported gum disease among adults with ID may be associated with a higher risk of CVD. However, further research that also includes clinical indices of periodontal disease and CVD for this population is needed to determine if there is a causal relationship between gum disease and CVD. © 2017 MENCAP

Sociodemographic factors associated with multiple cardiovascular risk factors among Malaysian adults.

PubMed

Ghazali, Sumarni Mohd; Seman, Zamtira; Cheong, Kee Chee; Hock, Lim Kuang; Manickam, Mala; Kuay, Lim Kuang; Yusoff, Ahmad Faudzi; Mustafa, Feisul Idzwan; Mustafa, Amal Nasir

2015-01-31

To determine the prevalence and sociodemographic correlates of multiple risk factors for cardiovascular disease (CVD) among Malaysian adults. We analysed data on 1044 men and 1528 women, aged 24-64 years, participants in the Non Communicable Disease Surveillance 2005/2006, a nationally representative, population-based, cross-sectional study. Prevalence of obesity, high blood pressure, dyslipidaemia, hyperglycemia, physical inactivity, smoking, risky drinking, low vegetable and fruit intake were determined and multivariable logistic regression was used to identify sociodemographic factors associated with having ≥3 of these cardiovascular disease risk factors. The response rate was 84.6% (2572/3040). Overall, 68.4% (95% CI: 63.2, 73.1) had at least three risk factors. Among men, older age and Indian ethnicity were independently associated with having ≥3 CVD risk factors; while among women, older age, low education, and housewives were more likely to have ≥3 CVD risk factors. The prevalence of cardiovascular risk factors clustering among Malaysian adults is high, raising concerns that cardiovascular disease incidence will rise steeply in the near future if no immediate preventive measures are taken. The current national health education and promotion programmes pertaining to modifiable risk factors can be further improved by taking into account the sociodemographic variation in CVD risk factors clustering.

Using Bayes factors for multi-factor, biometric authentication

NASA Astrophysics Data System (ADS)

Giffin, A.; Skufca, J. D.; Lao, P. A.

2015-01-01

Multi-factor/multi-modal authentication systems are becoming the de facto industry standard. Traditional methods typically use rates that are point estimates and lack a good measure of uncertainty. Additionally, multiple factors are typically fused together in an ad hoc manner. To be consistent, as well as to establish and make proper use of uncertainties, we use a Bayesian method that will update our estimates and uncertainties as new information presents itself. Our algorithm compares competing classes (such as genuine vs. imposter) using Bayes Factors (BF). The importance of this approach is that we not only accept or reject one model (class), but compare it to others to make a decision. We show using a Receiver Operating Characteristic (ROC) curve that using BF for determining class will always perform at least as well as the traditional combining of factors, such as a voting algorithm. As the uncertainty decreases, the BF result continues to exceed the traditional methods result.

Associations between Distal Upper Extremity Job Physical Factors and Psychosocial Measures in a Pooled Study

PubMed Central

2015-01-01

Introduction. There is an increasing body of literature relating musculoskeletal diseases to both job physical exposures and psychosocial outcomes. Relationships between job physical exposure measures and psychosocial factors have not been well examined or quantified. These exploratory analyses evaluate relationships between quantified exposures and psychosocial outcomes. Methods. Individualized quantification of duration, repetition, and force and composite scores of the Strain Index (SI) and the Threshold Limit Value for Hand Activity Level (TLV for HAL) were compared to 10 psychosocial measures. Relationships and predicted probabilities were assessed using ordered logistic regression. Analyses were adjusted for age, BMI, and gender. Results and Discussion. Among 1834 study participants there were multiple statistically significant relationships. In general, as duration, repetition, and force increased, psychosocial factors worsened. However, general health and mental exhaustion improved with increasing job exposures. Depression was most strongly associated with increased repetition, while physical exhaustion was most strongly associated with increased force. SI and TLV for HAL were significantly related to multiple psychosocial factors. These relationships persisted after adjustment for strong confounders. Conclusion. This study quantified multiple associations between job physical exposures and occupational and nonoccupational psychosocial factors. Further research is needed to quantify the impacts on occupational health outcomes. PMID:26557686

Defining the Path Between Social and Economic Factors, Clinical and Lifestyle Determinants, and Cardiovascular Disease.

PubMed

Kastorini, Christina-Maria; Milionis, Haralampos J; Georgousopoulou, Ekavi; Kalantzi, Kallirroi; Nikolaou, Vassilios; Vemmos, Konstantinos N; Goudevenos, John A; Panagiotakos, Demosthenes B

2015-12-01

Low socioeconomic status is associated with poorer cardiovascular health. The aim of the present work was to evaluate how social and economic factors influence modifiable cardiovascular disease risk factors and thus, acute coronary syndrome or ischemic stroke presence. One thousand participants were enrolled; 250 consecutive patients with a first acute coronary syndrome (83% were male, 60 ± 12 years old) and 250 control subjects, as well as 250 consecutive patients with a first ischemic stroke (56% were male, 77 ± 9 years old) and 250 control subjects. The control subjects were population-based and age-sex matched with the patients. Detailed information regarding their medical records, lifestyle characteristics, education level, financial status satisfaction, and type of occupation were recorded. After controlling for potential confounding factors, significant inverse associations were observed regarding financial status satisfaction and sedentary/mental type occupation with acute coronary syndrome or stroke presence, but not with the educational level. Nevertheless, further evaluation using path analysis, revealed quite different results, indicating that the education level influenced the type of occupation and financial satisfaction, hence affecting indirectly the likelihood of developing a cardiovascular disease event. Social and economic parameters interact with modifiable cardiovascular disease risk factors through multiple pathways. Copyright © 2015 World Heart Federation (Geneva). Published by Elsevier B.V. All rights reserved.

Vascular endothelial growth factor and platelet-derived growth factor are potential angiogenic and metastatic factors in human breast cancer.

PubMed

Anan, K; Morisaki, T; Katano, M; Ikubo, A; Kitsuki, H; Uchiyama, A; Kuroki, S; Tanaka, M; Torisu, M

1996-03-01

Angiogenesis is a prerequisite for tumor growth and metastasis. Tumor angiogenesis may be mediated by several angiogenic factors such as vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), transforming growth factor-alpha, and basic fibroblast growth factor. Differential mRNA expressions of VEGF, PDGF (A chain), transforming growth factor-alpha and basic fibroblast growth factor in 32 primary invasive breast tumors were examined by reverse transcriptase-polymerase chain reaction. We analyzed relationships between mRNA expressions of these angiogenic factors and the degree of angiogenesis, tumor size, and metastasis. Quantification of angiogenesis was achieved by the immunohistochemical staining of endothelial cells with antibody to CD31. VEGF and PDGF-A mRNAs were expressed more frequently in breast tumors than in nontumor breast tissues, whereas no difference was found in expression frequency of either transforming growth factor-alpha or basic fibroblast growth factor mRNA. Vascular counts in tumors correlated with each expression frequency of VEGF and PDGF-A mRNA. PDGF-A mRNA was expressed more frequently in tumors with lymph node metastasis than in those without metastasis. Expression of VEGF and PDGF mRNAs detected by reverse transcriptase-polymerase chain reaction in breast tumors correlates with tumor-related characteristics of angiogenesis and metastatic potential. Analysis of these mRNAs by reverse transcriptase-polymerase chain reaction may be useful for assessing the biologic behavior of a breast tumor before surgical treatment.

Gender differences in factors associated with suicidal ideation and depressive symptoms among middle-aged workers in Japan.

PubMed

Sugawara, Norio; Yasui-Furukori, Norio; Sasaki, Giro; Tanaka, Osamu; Umeda, Takashi; Takahashi, Ippei; Danjo, Kazuma; Matsuzaka, Masashi; Kaneko, Sunao; Nakaji, Shigeyuki

2013-01-01

The purpose of this study was to assess middle-aged Japanese workers for possible gender differences in the risk factors associated with depressive symptoms and suicidal ideation. 5,878 workers (40-60 yr of age) (3,631 males and 2,247 females) were recruited from randomly selected companies in northern Japan. Demographic and lifestyle factors, suicidal ideation rate, and the data for the Brief Job Stress Questionnaire (BJSQ) and the Center for Epidemiologic Studies for Depression scale (CES-D) were obtained from the self-report questionnaires. After adjusting for possible confounding variables, marital status, absent of stress reduction technique and low job compatibility were significant independent risk factors for suicidal ideation among males. In females, marital status, feeling of insufficient sleep and absence of stress reduction techniques were significant independent risk factors after adjusting for all variables. Under the same adjustments, temporary employment also showed a protective effect against female suicidal ideation. In conclusion, our results suggest that factors related to suicidal ideation differed by gender. Different approaches for each gender might be useful in the development of suicide prevention programs. However, interpretation of work-related effects, such as temporary employment, interpersonal conflict and transportation industry, was hampered by lack of data concerning personal income, working hours and organizational commitment. Additional studies are needed to examine the longitudinal relationships between the risk factors associated with suicidal ideation and depressive symptoms.

Homophily and Contagion Are Generically Confounded in Observational Social Network Studies

PubMed Central

Shalizi, Cosma Rohilla; Thomas, Andrew C.

2012-01-01

The authors consider processes on social networks that can potentially involve three factors: homophily, or the formation of social ties due to matching individual traits; social contagion, also known as social influence; and the causal effect of an individual’s covariates on his or her behavior or other measurable responses. The authors show that generically, all of these are confounded with each other. Distinguishing them from one another requires strong assumptions on the parametrization of the social process or on the adequacy of the covariates used (or both). In particular the authors demonstrate, with simple examples, that asymmetries in regression coefficients cannot identify causal effects and that very simple models of imitation (a form of social contagion) can produce substantial correlations between an individual’s enduring traits and his or her choices, even when there is no intrinsic affinity between them. The authors also suggest some possible constructive responses to these results. PMID:22523436

Bacterial Sigma Factors and Anti-Sigma Factors: Structure, Function and Distribution

PubMed Central

Paget, Mark S.

2015-01-01

Sigma factors are multi-domain subunits of bacterial RNA polymerase (RNAP) that play critical roles in transcription initiation, including the recognition and opening of promoters as well as the initial steps in RNA synthesis. This review focuses on the structure and function of the major sigma-70 class that includes the housekeeping sigma factor (Group 1) that directs the bulk of transcription during active growth, and structurally-related alternative sigma factors (Groups 2–4) that control a wide variety of adaptive responses such as morphological development and the management of stress. A recurring theme in sigma factor control is their sequestration by anti-sigma factors that occlude their RNAP-binding determinants. Sigma factors are then released through a wide variety of mechanisms, often involving branched signal transduction pathways that allow the integration of distinct signals. Three major strategies for sigma release are discussed: regulated proteolysis, partner-switching, and direct sensing by the anti-sigma factor. PMID:26131973

Mismeasurement and the resonance of strong confounders: uncorrelated errors.

PubMed

Marshall, J R; Hastrup, J L

1996-05-15

Greenland first documented (Am J Epidemiol 1980; 112:564-9) that error in the measurement of a confounder could resonate--that it could bias estimates of other study variables, and that the bias could persist even with statistical adjustment for the confounder as measured. An important question is raised by this finding: can such bias be more than trivial within the bounds of realistic data configurations? The authors examine several situations involving dichotomous and continuous data in which a confounder and a null variable are measured with error, and they assess the extent of resultant bias in estimates of the effect of the null variable. They show that, with continuous variables, measurement error amounting to 40% of observed variance in the confounder could cause the observed impact of the null study variable to appear to alter risk by as much as 30%. Similarly, they show, with dichotomous independent variables, that 15% measurement error in the form of misclassification could lead the null study variable to appear to alter risk by as much as 50%. Such bias would result only from strong confounding. Measurement error would obscure the evidence that strong confounding is a likely problem. These results support the need for every epidemiologic inquiry to include evaluations of measurement error in each variable considered.

Maternal smoking during pregnancy and children's cognitive and physical development: a causal risk factor?

PubMed

Gilman, Stephen E; Gardener, Hannah; Buka, Stephen L

2008-09-01

There remains considerable debate regarding the effects of maternal smoking during pregnancy on children's growth and development. Evidence that exposure to maternal smoking during pregnancy is associated with numerous adverse outcomes is contradicted by research suggesting that these associations are spurious. The authors investigated the relation between maternal smoking during pregnancy and 14 developmental outcomes of children from birth through age 7 years, using data from the Collaborative Perinatal Project (1959-1974; n = 52,919). In addition to adjusting for potential confounders measured contemporaneously with maternal smoking, the authors fitted conditional fixed-effects models among siblings that controlled for unmeasured confounders. Results from the conditional analyses indicated a birth weight difference of -85.63 g associated with smoking of >or=20 cigarettes daily during pregnancy (95% confidence interval: -131.91, -39.34) and 2.73 times' higher odds of being overweight at age 7 years (95% confidence interval: 1.30, 5.71). However, the associations between maternal smoking and 12 other outcomes studied (including Apgar score, intelligence, academic achievement, conduct problems, and asthma) were entirely eliminated after adjustment for measured and unmeasured confounders. The authors conclude that the hypothesized effects of maternal smoking during pregnancy on these outcomes either are not present or are not distinguishable from a broader range of familial factors associated with maternal smoking.

Maternal Smoking during Pregnancy and Children's Cognitive and Physical Development: A Causal Risk Factor?

PubMed Central

Gardener, Hannah; Buka, Stephen L.

2008-01-01

There remains considerable debate regarding the effects of maternal smoking during pregnancy on children's growth and development. Evidence that exposure to maternal smoking during pregnancy is associated with numerous adverse outcomes is contradicted by research suggesting that these associations are spurious. The authors investigated the relation between maternal smoking during pregnancy and 14 developmental outcomes of children from birth through age 7 years, using data from the Collaborative Perinatal Project (1959–1974; n = 52,919). In addition to adjusting for potential confounders measured contemporaneously with maternal smoking, the authors fitted conditional fixed-effects models among siblings that controlled for unmeasured confounders. Results from the conditional analyses indicated a birth weight difference of −85.63 g associated with smoking of ≥20 cigarettes daily during pregnancy (95% confidence interval: −131.91, −39.34) and 2.73 times' higher odds of being overweight at age 7 years (95% confidence interval: 1.30, 5.71). However, the associations between maternal smoking and 12 other outcomes studied (including Apgar score, intelligence, academic achievement, conduct problems, and asthma) were entirely eliminated after adjustment for measured and unmeasured confounders. The authors conclude that the hypothesized effects of maternal smoking during pregnancy on these outcomes either are not present or are not distinguishable from a broader range of familial factors associated with maternal smoking. PMID:18653646

Vaginismus as an independent risk factor for cesarean delivery.

PubMed

Goldsmith, Tomer; Levy, Amalia; Sheiner, Eyal; Goldsmith, Tomer; Levy, Amalia; Sheiner, Eyal

2009-10-01

The present study was aimed to investigate pregnancy outcome of patients with vaginismus, and specifically the relationship between vaginismus and cesarean delivery. A population based study comparing all pregnancies in patients with and without vaginismus was conducted. Patients lacking prenatal care were excluded from the analysis. Deliveries occurred during the years 1988-2007. A multivariate logistic regression model, with backward elimination, was constructed to find independent risk factors associated with vaginismus. During the study period there were 192,954 deliveries, of which 118 occurred in patients with vaginismus. Patients with vaginismus tended to be younger (26.04+/-4.89 vs. 28.61+/-5.83; p < 0.001) and delivered smaller children (3024.2+/-517 g vs. 3160.9+/-576 g; p = 0.01) when compared with patients without vaginismus. Patients with vaginismus had higher rates of infertility treatments (5.9%vs. 2.7%, odds ratio [OR] 2.3; 95% confidence interval [CI] 1.1-4.9; p = 0.04) and labor induction (37.3%vs. 27.4%, OR 1.6; 95% CI 1.1-2.3; p = 0.02), vacuum extraction (9.3%vs. 2.8%, OR 3.6, 95% CI 1.9-6.7; p < 0.001), and cesarean delivery (39.0%vs. 14.5%, OR 3.8; 95% CI 2.6-5.5; p < 0.001) when compared with the comparison group. Even after controlling for possible confounders associated with cesarean delivery such as previous cesarean delivery, pathological presentations, and fetal distress, vaginismus remained as an independent risk factor for cesarean delivery (OR 7.1; 95% CI 4.5-11.1; p < 0.001). Vaginismus is an independent risk factor for cesarean delivery.

Risk factors for carpal tunnel syndrome related to the work organization: a prospective surveillance study in a large working population.

PubMed

Petit, Audrey; Ha, Catherine; Bodin, Julie; Rigouin, Pascal; Descatha, Alexis; Brunet, René; Goldberg, Marcel; Roquelaure, Yves

2015-03-01

The study aimed to determine the risk factors for incident carpal tunnel syndrome (CTS) in a large working population, with a special focus on factors related to work organization. In 2002-2005, 3710 workers were assessed and, in 2007-2010, 1611 were re-examined. At baseline all completed a self-administered questionnaire about personal/medical factors and work exposure. CTS symptoms and physical examination signs were assessed by a standardized medical examination at baseline and follow-up. The risk of "symptomatic CTS" was higher for women (OR = 2.9 [1.7-5.2]) and increased linearly with age (OR = 1.04 [1.00-1.07] for 1-year increment). Two work organizational factors remained in the multivariate risk model after adjustment for the personal/medical and biomechanical factors: payment on a piecework basis (OR = 2.0, 95% CI 1.1-3.5) and work pace dependent on automatic rate (OR = 1.9, 95% CI 0.9-4.1). Several factors related to work organization were associated with incident CTS after adjustment for potential confounders. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Early life course risk factors for childhood obesity: the IDEFICS case-control study.

PubMed

Bammann, Karin; Peplies, Jenny; De Henauw, Stefaan; Hunsberger, Monica; Molnar, Denes; Moreno, Luis A; Tornaritis, Michael; Veidebaum, Toomas; Ahrens, Wolfgang; Siani, Alfonso

2014-01-01

The early life course is assumed to be a critical phase for childhood obesity; however the significance of single factors and their interplay is not well studied in childhood populations. The investigation of pre-, peri- and postpartum risk factors on the risk of obesity at age 2 to 9. A case-control study with 1,024 1:1-matched case-control pairs was nested in the baseline survey (09/2007-05/2008) of the IDEFICS study, a population-based intervention study on childhood obesity carried out in 8 European countries in pre- and primary school settings. Conditional logistic regression was used for identification of risk factors. For many of the investigated risk factors, we found a raw effect in our study. In multivariate models, we could establish an effect for gestational weight gain (adjusted OR = 1.02; 95%CI 1.00-1.04), smoking during pregnancy (adjusted OR = 1.48; 95%CI 1.08-2.01), Caesarian section (adjusted OR = 1.38; 95%CI 1.10-1.74), and breastfeeding 4 to 11 months (adjusted OR = 0.77; 95%CI 0.62-0.96). Birth weight was related to lean mass rather than to fat mass, the effect of smoking was found only in boys, but not in girls. After additional adjustment for parental BMI and parental educational status, only gestational weight gain remained statistically significant. Both, maternal as well as paternal BMI were the strongest risk factors in our study, and they confounded several of the investigated associations. Key risk factors of childhood obesity in our study are parental BMI and gestational weight gain; consequently prevention approaches should target not only children but also adults. The monitoring of gestational weight seems to be of particular importance for early prevention of childhood obesity.

Risk factors for pelvic insufficiency fractures and outcome after conservative therapy.

PubMed

Maier, Gerrit Steffen; Kolbow, Kristina; Lazovic, Djordje; Horas, Konstantin; Roth, Klaus Edgar; Seeger, Jörn Bengt; Maus, Uwe

2016-01-01

The prevalence of osteoporosis has continuously increased over the past decades and it is set to increase substantially as life expectancy rises steadily. Fragility or osteoporotic fractures of the pelvis often occur after low energy falls e.g. from standing, however, some patients present with assumed insufficiency fractures of the pelvis without a previous trauma. Osteoporotic fractures impose a tremendous economic burden and these fractures deserve attention as they lead to a decrease in mobility with an increase in dependency and are associated with a high rate of mortality. To date, little is known about potential risk factors for pelvic insufficiency fractures. Furthermore, information on clinical outcome is scarce. In view of this rather limited knowledge, we aimed to identify potential risk factors for pelvic insufficiency fractures and to collect information on their short- and long-term outcomes. Files of all consecutive patients admitted between January 2010 and December 2013 for a pelvic insufficiency fracture were enrolled in this study. Pelvic fractures that occurred on tumorous bone or after high-energy trauma were excluded. Fractures of the pelvis included all pelvic bones except the coccyx. For all patients, we recorded clinical and biological parameters available from their medical history. For comparison, the same biological and clinical parameters were evaluated in an age matched control group of 1083 patients aged over 70 who were admitted to our orthopaedic department to undergo knee or hip arthroplasty. The statistical analyses used or Fisher test for percentages comparison, 2-tailed t-tests and Mann Whitney for mean comparison. To determine what factors are predictors and what factors are confounders of pelvic insufficiency fractures, multivariate linear regression analysis using the fracture as a continuous variable was performed. Ninety-three patients with a pelvic insufficiency fracture were identified. Following the Rommens and Hofmann

Factors influencing accuracy of cortical thickness in the diagnosis of Alzheimer's disease.

PubMed

Belathur Suresh, Mahanand; Fischl, Bruce; Salat, David H

2018-04-01

There is great value to use of structural neuroimaging in the assessment of Alzheimer's disease (AD). However, to date, predictive value of structural imaging tend to range between 80% and 90% in accuracy and it is unclear why this is the case given that structural imaging should parallel the pathologic processes of AD. There is a possibility that clinical misdiagnosis relative to the gold standard pathologic diagnosis and/or additional brain pathologies are confounding factors contributing to reduced structural imaging classification accuracy. We examined potential factors contributing to misclassification of individuals with clinically diagnosed AD purely from cortical thickness measures. Correctly classified and incorrectly classified groups were compared across a range of demographic, biological, and neuropsychological data including cerebrospinal fluid biomarkers, amyloid imaging, white matter hyperintensity (WMH) volume, cognitive, and genetic factors. Individual subject analyses suggested that at least a portion of the control individuals misclassified as AD from structural imaging additionally harbor substantial AD biomarker pathology and risk, yet are relatively resistant to cognitive symptoms, likely due to "cognitive reserve," and therefore clinically unimpaired. In contrast, certain clinical control individuals misclassified as AD from cortical thickness had increased WMH volume relative to other controls in the sample, suggesting that vascular conditions may contribute to classification accuracy from cortical thickness measures. These results provide examples of factors that contribute to the accuracy of structural imaging in predicting a clinical diagnosis of AD, and provide important information about considerations for future work aimed at optimizing structural based diagnostic classifiers for AD. © 2017 Wiley Periodicals, Inc.

[Analysis of risk factors for dry eye syndrome in visual display terminal workers].

PubMed

Zhu, Yong; Yu, Wen-lan; Xu, Ming; Han, Lei; Cao, Wen-dong; Zhang, Hong-bing; Zhang, Heng-dong

2013-08-01

To analyze the risk factors for dry eye syndrome in visual display terminal (VDT) workers and to provide a scientific basis for protecting the eye health of VDT workers. Questionnaire survey, Schirmer I test, tear break-up time test, and workshop microenvironment evaluation were performed in 185 VDT workers. Multivariate logistic regression analysis was performed to determine the risk factors for dry eye syndrome in VDT workers after adjustment for confounding factors. In the logistic regression model, the regression coefficients of daily mean time of exposure to screen, daily mean time of watching TV, parallel screen-eye angle, upward screen-eye angle, eye-screen distance of less than 20 cm, irregular breaks during screen-exposed work, age, and female gender on the results of Schirmer I test were 0.153, 0.548, 0.400, 0.796, 0.234, 0.516, 0.559, and -0.685, respectively; the regression coefficients of daily mean time of exposure to screen, parallel screen-eye angle, upward screen-eye angle, age, working years, and female gender on tear break-up time were 0.021, 0.625, 2.652, 0.749, 0.403, and 1.481, respectively. Daily mean time of exposure to screen, daily mean time of watching TV, parallel screen-eye angle, upward screen-eye angle, eye-screen distance of less than 20 cm, irregular breaks during screen-exposed work, age, and working years are risk factors for dry eye syndrome in VDT workers.

Crystal-proven Gout and Characteristic Gout Severity Factors are Associated with Cardiovascular Disease.

PubMed

Disveld, Iris J M; Fransen, Jaap; Rongen, Gerard A; Kienhorst, Laura B E; Zoakman, Sahel; Janssens, Hein J E M; Janssen, Matthijs

2018-04-15

Our aim was to examine the prevalence of cardiovascular disease (CVD) in patients with crystal-proven gout compared to arthritis controls. Further, we analyzed the association between characteristic gout severity factors and CVD to provide further support for a pathogenetic relationship between gout and CVD. Patients with arthritis referred for diagnosis were consecutively included in the Gout Arnhem-Liemers cohort. Joint fluid analysis was performed in all referred patients; controls were negative for crystals. Patients' characteristics and different manifestations of CVD and gout severity factors (disease duration, attack frequency, tophi, affected joints, high serum urate acid level, joint damage) were collected. Gout patients were compared with controls for the prevalence of CVD. In addition, the association between characteristic gout severity factors and presence of CVD was analyzed. Data from 700 gout patients and 276 controls were collected. CVD was present in 47% (95% CI 44%-51%) and 24% (95% CI 19%-29%) of gout patients and controls, respectively. Corrected for confounders, gout was still strongly associated with an increased prevalence of CVD compared to controls (OR 3.39, 95% CI 2.37-4.84). In patients with gout, disease duration ≥ 2 years, oligo- or polyarthritis, serum urate acid > 0.55 mmol/l at presentation, and joint damage were independently (p < 0.05) associated with prevalent CVD. Crystal-proven gout was strongly associated with an increased prevalence of CVD. In patients with gout, characteristic gout severity factors were associated with CVD.

A review of genetic, biological, pharmacological, and clinical factors that affect carbohydrate-deficient transferrin levels.

PubMed

Fleming, Michael F; Anton, Raymond F; Spies, Claudia D

2004-09-01

Carbohydrate-deficient transferrin (CDT) is an alcohol biomarker recently approved by the U.S. Food and Drug Administration. This test is increasingly being used to detect and monitor alcohol use in a variety of health care, legal, and industrial settings. The goal of this study is to review the genetic, biological, pharmacological, and clinical factors that may affect CDT levels. A review of the literature identified 95 research articles that met the authors' criteria and reported potential interactions of a variety of factors on percent and total CDT levels. The review established 12 categories of variables that may affect CDT levels. These categories include (1) alcohol use, (2) genetic factors, (3) race, (4) gender, (5) age, (6) liver disease, (7) iron levels, (8) tobacco use, (9) medication such as estrogen and anticonvulsants, (10) metabolic factors such as body mass index and total body water, (11) chronic medical conditions such as rheumatoid arthritis, and (12) surgical patients. There is evidence that %CDT levels are affected by alcohol use, end-stage liver disease, and genetic variants. In addition to these three factors, total CDT levels (CDTect) are also affected by factors that raise transferrin levels such as iron deficiency, chronic illnesses, and menopausal status. Other potential factors such as tobacco and age appear to be confounded by alcohol use. The roles of female gender, low body mass index, chronic inflammatory diseases, and medication on CDT levels require further study. False negatives are associated with female gender, episodic lower level alcohol use, and acute trauma with blood loss. This review suggests that a number of factors are associated with false-positive CDTect and %CDT levels. CDT offers great promise to assist physicians in the care of patients to detect and monitor heavy alcohol use.

Racial disparities in knowledge of stroke and heart attack risk factors and warning signs among Michigan adults.

PubMed

Fussman, Chris; Rafferty, Ann P; Reeves, Mathew J; Zackery, Shannon; Lyon-Callo, Sarah; Anderson, Beth

2009-01-01

To describe the level of knowledge regarding risk factors and warning signs for stroke and heart attack among White and African American adults in Michigan and to quantify racial disparities. Knowledge of stroke and heart attack risk factors and warning signs was assessed by using data from the 2004 Michigan Behavioral Risk Factor Survey. Prevalence estimates of knowledge were generated, and statistical differences in knowledge between Whites and African Americans were assessed. Adequate knowledge was defined as knowing 3 correct warning signs or risk factors. Logistic regression models were used to quantify the racial disparity in knowledge while controlling for potential confounding. Whites had substantially higher levels of adequate knowledge of risk factors (stroke: 31.6% vs 13.8%; heart attack: 52.6% vs 24.3%) and warning signs (stroke: 30.0% vs 17.2%; heart attack: 29.3% vs 13.8%) compared with African Americans (all observed differences were significant at P < .05). The odds of adequate knowledge of risk factors (stroke: adjusted odds ratio [AOR] 2.9; heart attack: AOR 3.4) and warning signs (stroke: AOR 2.0; heart attack: AOR 2.4) were significantly higher for Whites than for African Americans. A strong racial disparity in the knowledge of stroke and heart attack risk factors and warning signs exists among Michigan adults. Communitywide public education programs in conjunction with targeted interventions for at-risk populations are necessary to produce meaningful improvements in the awareness of stroke and heart attack risk factors and warning signs among Michigan adults.

Vascular Endothelial Growth Factor in Eye Disease

PubMed Central

Penn, J.S.; Madan, A.; Caldwell, R.B.; Bartoli, M.; Caldwell, R.W.; Hartnett, M.E.

2012-01-01

Collectively, angiogenic ocular conditions represent the leading cause of irreversible vision loss in developed countries. In the U.S., for example, retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration are the principal causes of blindness in the infant, working age and elderly populations, respectively. Evidence suggests that vascular endothelial growth factor (VEGF), a 40 kDa dimeric glycoprotein, promotes angiogenesis in each of these conditions, making it a highly significant therapeutic target. However, VEGF is pleiotropic, affecting a broad spectrum of endothelial, neuronal and glial behaviors, and confounding the validity of anti-VEGF strategies, particularly under chronic disease conditions. In fact, among other functions VEGF can influence cell proliferation, cell migration, proteolysis, cell survival and vessel permeability in a wide variety of biological contexts. This article will describe the roles played by VEGF in the pathogenesis of retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration. The potential disadvantages of inhibiting VEGF will be discussed, as will the rationales for targeting other VEGF-related modulators of angiogenesis. PMID:18653375

Determination of priority among air pollution factors in preventing COPD in residents of Shanghai City proper

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xuguang, Tao; Chuan-jie, Hong; Shun-zhang, Yu

The purpose of our study is to determine the priority among ambient sulphur dioxide (SO{sub 2}), inhalable particulates (IP), and indoor use of coal for cooking or heating to prevent COPD in residents of Shanghai city proper. We describe spatial and temporal distribution of the concentration of ambient SO{sub 2}, IP, and the proportion of families who use coal (1980-1985) by the trend surface simulating method and other statistics. Stratified by two sets of extreme levels of ambient SO{sub 2}, IP, and the proportion of coal-using families, we selected eight groups with different combinations of exposure levels. We analyzed themore » relationship between air pollution factors and their health effects at levels of mortality (1978-1987, 232,459 person years), prevalence (1987, 12,037 persons), lung function and local immunologic function (1987, 514 women) with logistic and stepwise regression, and ridit analysis. After controlling for possible confounders, e.g., tobacco smoking and occupational exposure, we found that indoor use of coal is a more important risk factor than ambient SO{sub 2} and IP. We then used canonical correlation analysis to evaluate the overall exposure-effect relationship between one set of air pollution and confounding factors and the other set of health effect indices. High correlation is found between the two. The indoor use of coal is more important for the overall health effects than the ambient SO{sub 2} and IP, to change from coal to gas could reduce the environmental exposure canonical variable more readily, with an effect equivalent to a reduction of 0.1839 mg/m{sup 3} for ambient SO{sub 2}, or 0.2806 mg/m{sup 3} for ambient IP in concentration.« less

Comorbidities confounding the outcomes of surgery for third window syndrome: Outlier analysis

PubMed Central

Mackay‐Promitas, Heather T.; Demirel, Shaban; Gianoli, Gerard J.; Gizzi, Martin S.; Carter, Dale M.; Siker, David A.

2017-01-01

Objective Patients with third window syndrome and superior semicircular canal dehiscence (SSCD) symptoms whose surgical outcomes placed them as outliers were systematically studied to determine comorbidities that were responsible for their poor outcomes due to these confounding factors. Study Design Observational analytic case‐control study in a tertiary referral center. Methods Twelve adult patients with clinical SSCD syndrome underwent surgical management and had outcomes that did not resolve all of their subjective symptoms. In addition to one of the neurotologists, 2 neurologists (one specializing in migraine and the other a neuro‐ophthalmologist), and a psychologist clinician‐investigator completed comprehensive evaluations. Neuropsychology test batteries included: the Millon Behavioral Medicine Diagnostic; Patient Health Questionnaire (PHQ‐9) and Generalized Anxiety Disorder Screener (GAD‐7); Adverse Childhood Experiences Scale; the Wide Range Assessment of Memory and Learning, including the 3 domains of verbal memory, visual memory, and attention/concentration; Wechsler Adult Intelligence Scale; and the Delis‐Kaplan Executive Function System. The control cohort was comprised of 17 participants who previously underwent surgery for third window syndrome that resulted in the expected outcomes of resolution of their third window syndrome symptoms and cognitive dysfunction. Results There was a high rate of psychological comorbidity (n = 6) in the outlier cohort; multiple traumatic brain injuries were also a confounding element (n = 10). One patient had elevated cerebrospinal fluid (CSF) pressure requiring ventriculoperitoneal shunting to control the recurrence of dehiscence and one patient with a drug‐induced Parkinson‐like syndrome and idiopathic progressive neurological degenerative process. Conclusions Components of the Millon Behavioral Medicine Diagnostic, PHQ‐9 and GAD‐7 results suggest that these instruments would be useful as

Modifiable and non-modifiable factors associated with employment outcomes following spinal cord injury: A systematic review

PubMed Central

Trenaman, Logan; Miller, William C; Querée, Matthew; Escorpizo, Reuben

2015-01-01

Context Employment rates in individuals with spinal cord injury (SCI) are approximately 35%, which is considerably lower than that of the general population. In order to improve employment outcomes a clear understanding of what factors influence employment outcomes is needed. Objective To systematically review factors that are consistently and independently associated with employment outcomes in individuals with SCI, and to understand the magnitude of their influence. Methods Through an electronic search of MEDLINE/PubMed, EMBASE, CINAHL, PsycINFO, Social Science Abstracts and Social Work databases, we identified studies published between 1952–2014 that investigated factors associated with employment outcomes following SCI. Exclusion criteria included: (1) reviews (2) studies not published in English (3) studies not controlling for potential confounders through a regression analysis, or (4) studies not providing an effect measure in the form of OR, RR, or HR. Data were categorized based on the International Classification of Functioning, Disability and Health framework, with each domain sub-categorized by modifiability. First author, year of publication, sample size, explanatory and outcome variables, and effect measures were extracted. Results Thirty-nine studies met the inclusion criteria. Twenty modifiable and twelve non-modifiable factors have been investigated in the context of employment following SCI. Education, vocational rehabilitation, functional independence, social support, and financial disincentives were modifiable factors that have been consistently and independently associated with employment outcomes. Conclusion A number of key modifiable factors have been identified and can inform interventions aimed at improving employment outcomes for individuals with SCI. Future research should focus on determining which factors have the greatest effect on employment outcomes, in addition to developing and evaluating interventions targeted at these factors

Factors that influence the timing of spontaneous labor at term.

PubMed

Fogleman, Kelly A; Herring, Amy H; Kaczor, Diane; Pusek, Susan N; Jo, Hyejin; Thorp, John M

2007-11-01

Whether pre-term birth culminates as a result of a de novo pathologic process or is more simply early activation of physiologic mechanisms is unknown. Exploration of the onset of labor in term women with classical risk factors for early delivery might provide insights into the mechanisms leading to pre-term birth. This study examines whether sociodemographic factors known to increase the risk of pre-term birth also affect the length of term gestations. From a large prospective cohort composed of women delivering from 1995-2000, a sample was selected of 441 women from Central North Carolina, US, who delivered singletons after 37 weeks gestation. An algorithm was designed to identify induced labors and gestational age was censored at the time of induction. Gestational age was assigned by sonography and menstrual dating. Data were analysed using the Cox proportional hazards model. The main outcome measure was time to spontaneous labor. Women with 12 years of education had longer periods of gestation than women with less than 12 years of education, HR = 0.57 [0.39, 0.84]. Shorter gestational periods were found for women with pre-term premature rupture of membranes (PPROM) in a previous pregnancy, HR = 3.70 [1.60, 8.52], even after adjusting for confounders. Smoking was not associated (p > 0.1) with the timing of labor at term. By studying the timing of spontaneous parturition at term we identified that there is little overlap in risk factors that affect timing of delivery between spontaneous term and pre-term births.

Contemporary Risk Factors and Outcomes of Transfusion-Associated Circulatory Overload.

PubMed

Roubinian, Nareg H; Hendrickson, Jeanne E; Triulzi, Darrell J; Gottschall, Jerome L; Michalkiewicz, Michael; Chowdhury, Dhuly; Kor, Daryl J; Looney, Mark R; Matthay, Michael A; Kleinman, Steven H; Brambilla, Donald; Murphy, Edward L

2018-04-01

Transfusion-associated circulatory overload is characterized by hydrostatic pulmonary edema following blood transfusion. Restrictive transfusion practice may affect the occurrence and severity of transfusion-associated circulatory overload in critically ill patients. We sought to examine contemporary risk factors and outcomes for transfusion-associated circulatory overload. Case-control study. Four tertiary care hospitals. We prospectively enrolled 200 patients with transfusion-associated circulatory overload identified by active surveillance and 405 controls matched by transfusion intensity. None. Among 20,845 transfused patients who received 128,263 blood components from May 2015 until July 2016, transfusion-associated circulatory overload incidence was one case per 100 transfused patients. In addition to cardiovascular comorbidities, multivariable analysis identified the following independent predictors of transfusion-associated circulatory overload: acute kidney injury, emergency surgery, pretransfusion diuretic use, and plasma transfusion-the latter especially in females. Compared with matched controls, transfusion-associated circulatory overload cases were more likely to require mechanical ventilation (71% vs 49%; p < 0.001), experienced longer intensive care and hospital lengths of stay following transfusion, and had higher mortality (21% vs 11%; p = 0.02) even after adjustment for other potentially confounding variables. Despite restrictive transfusion practice, transfusion-associated circulatory overload remains a frequent complication of transfusion and is an independent risk factor for in-hospital morbidity and mortality. In addition to cardiovascular and renal risk factors, plasma transfusion was associated with transfusion-associated circulatory overload after controlling for other covariates. Additional research is needed to examine the benefit of reduced erythrocyte or plasma exposure in patients at high risk for transfusion-associated circulatory

Intrinsic factor

MedlinePlus

Intrinsic factor is a protein that helps your intestines absorb vitamin B12. It is made by cells in the ... Intrinsic factor is a protein that helps your body absorb vitamin B12. Vitamin B12 is needed for red blood ...

Assessment of Confounders in Comparative Effectiveness Studies From Secondary Databases.

PubMed

Franklin, Jessica M; Schneeweiss, Sebastian; Solomon, Daniel H

2017-03-15

Secondary clinical databases are an important and growing source of data for comparative effectiveness research (CER) studies. However, measurement of confounders, such as biomarker values or patient-reported health status, in secondary clinical databases may not align with the initiation of a new treatment. In many published CER analyses of registry data, investigators assessed confounders based on the first questionnaire in which the new exposure was recorded. However, it is known that adjustment for confounders measured after the start of exposure can lead to biased treatment effect estimates. In the present study, we conducted simulations to compare assessment strategies for a dynamic clinical confounder in a registry-based comparative effectiveness study of 2 therapies. As expected, we found that adjustment for the confounder value at the time of the first questionnaire after the start of exposure creates a biased estimate the total effect of exposure choice on outcome when the confounder mediates part of the effect. However, adjustment for the prior value can also be badly biased when measured long before exposure initiation. Thus, investigators should carefully consider the timing of confounder measurements relative to exposure initiation and the rate of change in the confounder in order to choose the most relevant measure for each patient. © The Author 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Biasogram: Visualization of Confounding Technical Bias in Gene Expression Data

PubMed Central

Krzystanek, Marcin; Szallasi, Zoltan; Eklund, Aron C.

2013-01-01

Gene expression profiles of clinical cohorts can be used to identify genes that are correlated with a clinical variable of interest such as patient outcome or response to a particular drug. However, expression measurements are susceptible to technical bias caused by variation in extraneous factors such as RNA quality and array hybridization conditions. If such technical bias is correlated with the clinical variable of interest, the likelihood of identifying false positive genes is increased. Here we describe a method to visualize an expression matrix as a projection of all genes onto a plane defined by a clinical variable and a technical nuisance variable. The resulting plot indicates the extent to which each gene is correlated with the clinical variable or the technical variable. We demonstrate this method by applying it to three clinical trial microarray data sets, one of which identified genes that may have been driven by a confounding technical variable. This approach can be used as a quality control step to identify data sets that are likely to yield false positive results. PMID:23613961

Pathway-based factor analysis of gene expression data produces highly heritable phenotypes that associate with age.

PubMed

Anand Brown, Andrew; Ding, Zhihao; Viñuela, Ana; Glass, Dan; Parts, Leopold; Spector, Tim; Winn, John; Durbin, Richard

2015-03-09

Statistical factor analysis methods have previously been used to remove noise components from high-dimensional data prior to genetic association mapping and, in a guided fashion, to summarize biologically relevant sources of variation. Here, we show how the derived factors summarizing pathway expression can be used to analyze the relationships between expression, heritability, and aging. We used skin gene expression data from 647 twins from the MuTHER Consortium and applied factor analysis to concisely summarize patterns of gene expression to remove broad confounding influences and to produce concise pathway-level phenotypes. We derived 930 "pathway phenotypes" that summarized patterns of variation across 186 KEGG pathways (five phenotypes per pathway). We identified 69 significant associations of age with phenotype from 57 distinct KEGG pathways at a stringent Bonferroni threshold ([Formula: see text]). These phenotypes are more heritable ([Formula: see text]) than gene expression levels. On average, expression levels of 16% of genes within these pathways are associated with age. Several significant pathways relate to metabolizing sugars and fatty acids; others relate to insulin signaling. We have demonstrated that factor analysis methods combined with biological knowledge can produce more reliable phenotypes with less stochastic noise than the individual gene expression levels, which increases our power to discover biologically relevant associations. These phenotypes could also be applied to discover associations with other environmental factors. Copyright © 2015 Brown et al.

Pathway-Based Factor Analysis of Gene Expression Data Produces Highly Heritable Phenotypes That Associate with Age

PubMed Central

Anand Brown, Andrew; Ding, Zhihao; Viñuela, Ana; Glass, Dan; Parts, Leopold; Spector, Tim; Winn, John; Durbin, Richard

2015-01-01

Statistical factor analysis methods have previously been used to remove noise components from high-dimensional data prior to genetic association mapping and, in a guided fashion, to summarize biologically relevant sources of variation. Here, we show how the derived factors summarizing pathway expression can be used to analyze the relationships between expression, heritability, and aging. We used skin gene expression data from 647 twins from the MuTHER Consortium and applied factor analysis to concisely summarize patterns of gene expression to remove broad confounding influences and to produce concise pathway-level phenotypes. We derived 930 “pathway phenotypes” that summarized patterns of variation across 186 KEGG pathways (five phenotypes per pathway). We identified 69 significant associations of age with phenotype from 57 distinct KEGG pathways at a stringent Bonferroni threshold (P<5.38×10−5). These phenotypes are more heritable (h2=0.32) than gene expression levels. On average, expression levels of 16% of genes within these pathways are associated with age. Several significant pathways relate to metabolizing sugars and fatty acids; others relate to insulin signaling. We have demonstrated that factor analysis methods combined with biological knowledge can produce more reliable phenotypes with less stochastic noise than the individual gene expression levels, which increases our power to discover biologically relevant associations. These phenotypes could also be applied to discover associations with other environmental factors. PMID:25758824

Cirrhosis is a risk factor for total hip arthroplasty for avascular necrosis.

PubMed

Deleuran, Thomas; Overgaard, Søren; Vilstrup, Hendrik; Jepsen, Peter

2016-06-01

Background and purpose - There are limited data on risk factors for avascular necrosis of the hip, but cirrhosis has been proposed as a risk factor. We examined the association between cirrhosis and incidence of total hip arthroplasty for avascular necrosis. Methods - We used nationwide healthcare data to identify all Danish residents diagnosed with cirrhosis in 1994-2011, and matched them 1:5 by age and sex to non-cirrhotic reference individuals from the general population. We excluded people with a previous total hip arthroplasty, a previous hip fracture, or a previous diagnosis of avascular necrosis. We used stratified Cox regression to estimate the hazard ratio (HR) for cirrhosis patients relative to reference individuals, adjusting for potential confounders. We used the cumulative incidence function to compute 5-year risks. Results - We included 25,421 cirrhosis patients and 114,052 reference individuals. Their median age was 57 years, and 65% were men. 45 cirrhosis patients and 44 reference individuals underwent total hip arthroplasty for avascular necrosis. Cirrhosis patients' HR for a total hip arthroplasty for avascular necrosis was 10 (95% CI: 6-17), yet their 5-year risk of avascular necrosis was only 0.2%. For the reference individuals, the 5-year risk was 0.02%. Interpretation - Cirrhosis is a strong risk factor for avascular necrosis of the hip, but it is rare even in cirrhosis patients.

Cirrhosis is a risk factor for total hip arthroplasty for avascular necrosis

PubMed Central

Deleuran, Thomas; Overgaard, Søren; Vilstrup, Hendrik; Jepsen, Peter

2016-01-01

Background and purpose There are limited data on risk factors for avascular necrosis of the hip, but cirrhosis has been proposed as a risk factor. We examined the association between cirrhosis and incidence of total hip arthroplasty for avascular necrosis. Methods We used nationwide healthcare data to identify all Danish residents diagnosed with cirrhosis in 1994–2011, and matched them 1:5 by age and sex to non-cirrhotic reference individuals from the general population. We excluded people with a previous total hip arthroplasty, a previous hip fracture, or a previous diagnosis of avascular necrosis. We used stratified Cox regression to estimate the hazard ratio (HR) for cirrhosis patients relative to reference individuals, adjusting for potential confounders. We used the cumulative incidence function to compute 5-year risks. Results We included 25,421 cirrhosis patients and 114,052 reference individuals. Their median age was 57 years, and 65% were men. 45 cirrhosis patients and 44 reference individuals underwent total hip arthroplasty for avascular necrosis. Cirrhosis patients’ HR for a total hip arthroplasty for avascular necrosis was 10 (95% CI: 6–17), yet their 5-year risk of avascular necrosis was only 0.2%. For the reference individuals, the 5-year risk was 0.02%. Interpretation Cirrhosis is a strong risk factor for avascular necrosis of the hip, but it is rare even in cirrhosis patients. PMID:26900635

Cumulative IT Use Is Associated with Psychosocial Stress Factors and Musculoskeletal Symptoms.

PubMed

So, Billy C L; Cheng, Andy S K; Szeto, Grace P Y

2017-12-08

This study aimed to examine the relationship between cumulative use of electronic devices and musculoskeletal symptoms. Smartphones and tablet computers are very popular and people may own or operate several devices at the same time. High prevalence rates of musculoskeletal symptoms associated with intensive computer use have been reported. However, research focusing on mobile devices is only just emerging in recent years. In this study, 285 persons participated including 140 males and 145 females (age range 18-50). The survey consisted of self-reported estimation of daily information technology (IT) exposure hours, tasks performed, psychosocial stress factors and relationship to musculoskeletal discomfort in the past 12 months. Total IT exposure time was an average of 7.38 h (±5.2) per day. The psychosocial factor of "working through pain" showed the most significant association with odds ratio (OR) ranging from 1.078 (95% CI = 1.021-1.138) for elbow discomfort, to 1.111 (95% CI = 1.046-1.180) for shoulder discomfort. Desktop time was also significantly associated with wrist/hand discomfort (OR = 1.103). These findings indicate only a modest relationship but one that is statistically significant with accounting for confounders. It is anticipated that prevalence rates of musculoskeletal disorders would rise in the future with increasing contribution due to psychosocial stress factors.

Heartburn and related factors in general population in Tehran, capital of Iran.

PubMed

Safaee, A; Moghimi-Dehkordi, B; Pourhoseingholi, M Ap; Habibi, M; Qafarnejad, F; Pourhoseingholi, A; Zali, M R

2010-06-01

Heartburn is a highly prevalent disorder and is one of the most common gastrointestinal (GI) symptoms encountered in clinical practice. Despite the increasing importance of the early diagnosis of heartburn, there are few studies available on the prevalence of the disease and its Symptoms. The aim of this study was to estimate the frequency of heartburn in the Iranian adult population and analyze its associations with possible confounding factors. This study was designed as an epidemiological, cross-sectional and population based study that was conducted during May to December 2006 in Firoozkou city of Iran. Participants were interviewed by using a questionnaire which included sociodemographic, health relevant life style and clinical factors and GI symptoms. Statistical analysis was performed by using chi-square test and logistic regression model. The frequency of heartburn was 28% and is different between men and women (P < 0.05). Also there was a relationship between self report tension and anxiety, BMI and depression with heartburn in univariate analysis (p < 0.05), but in multivariate analysis only age, self report tension and anxiety had a significant relationship with heartburn. Heartburn is very frequent in Iranian population and has a considerable impact on everyday life. Many factors that may affect the prevalence of heartburn should be considered for prevention and control of this disease.

Multiple Interacting Risk Factors: On Methods for Allocating Risk Factor Interactions.

PubMed

Price, Bertram; MacNicoll, Michael

2015-05-01

A persistent problem in health risk analysis where it is known that a disease may occur as a consequence of multiple risk factors with interactions is allocating the total risk of the disease among the individual risk factors. This problem, referred to here as risk apportionment, arises in various venues, including: (i) public health management, (ii) government programs for compensating injured individuals, and (iii) litigation. Two methods have been described in the risk analysis and epidemiology literature for allocating total risk among individual risk factors. One method uses weights to allocate interactions among the individual risk factors. The other method is based on risk accounting axioms and finding an optimal and unique allocation that satisfies the axioms using a procedure borrowed from game theory. Where relative risk or attributable risk is the risk measure, we find that the game-theory-determined allocation is the same as the allocation where risk factor interactions are apportioned to individual risk factors using equal weights. Therefore, the apportionment problem becomes one of selecting a meaningful set of weights for allocating interactions among the individual risk factors. Equal weights and weights proportional to the risks of the individual risk factors are discussed. © 2015 Society for Risk Analysis.

Heparin-binding epidermal growth factor-like growth factor promotes neuroblastoma differentiation.

PubMed

Gaviglio, Angela L; Knelson, Erik H; Blobe, Gerard C

2017-05-01

High-risk neuroblastoma is characterized by undifferentiated neuroblasts and low schwannian stroma content. The tumor stroma contributes to the suppression of tumor growth by releasing soluble factors that promote neuroblast differentiation. Here we identify heparin-binding epidermal growth factor-like growth factor (HBEGF) as a potent prodifferentiating factor in neuroblastoma. HBEGF mRNA expression is decreased in human neuroblastoma tumors compared with benign tumors, with loss correlating with decreased survival. HBEGF protein is expressed only in stromal compartments of human neuroblastoma specimens, with tissue from high-stage disease containing very little stroma or HBEGF expression. In 3 human neuroblastoma cell lines (SK-N-AS, SK-N-BE2, and SH-SY5Y), soluble HBEGF is sufficient to promote neuroblast differentiation and decrease proliferation. Heparan sulfate proteoglycans and heparin derivatives further enhance HBEGF-induced differentiation by forming a complex with the epidermal growth factor receptor, leading to activation of the ERK1/2 and STAT3 pathways and up-regulation of the inhibitor of DNA binding transcription factor. These data support a role for loss of HBEGF in the neuroblastoma tumor microenvironment in neuroblastoma pathogenesis.-Gaviglio, A. L., Knelson, E. H., Blobe, G. C. Heparin-binding epidermal growth factor-like growth factor promotes neuroblastoma differentiation. © FASEB.

Tumour Necrosis Factor-alpha and Nuclear Factor-kappa B Gene Variants in Sepsis.

PubMed

Acar, Leyla; Atalan, Nazan; Karagedik, E Hande; Ergen, Arzu

2018-01-20

The humoral system is activated and various cytokines are released due to infections in tissues and traumatic damage. Nuclear factor-kappa B dimers are encoded by nuclear factor-kappa B genes and regulate transcription of several crucial proteins of inflammation such as tumour necrosis factor-alpha. To investigate the possible effect of polymorphisms on tumour necrosis factor-alpha serum levels with clinical and prognostic parameters of sepsis by determining the nuclear factor-kappa B-1-94 ins/del ATTG and tumour necrosis factor-alpha (-308 G/A) gene polymorphisms and tumour necrosis factor-alpha serum levels. Case-control study. Seventy-two patients with sepsis and 104 healthy controls were included in the study. In order to determine the polymorphisms of nuclear factor-kappa B-1-94 ins/del ATTG and tumour necrosis factor-alpha (-308 G/A), polymerase chain reaction-restriction fragment length polymorphism analysis was performed and serum tumour necrosis factor-alpha levels were determined using an enzyme-linked immunosorbent assay. We observed no significant differences in tumour necrosis factor-alpha serum levels between the study groups. In the patient group, an increase in the tumour necrosis factor-alpha serum levels in patients carrying the tumour necrosis factor-alpha (-308 G/A) A allele compared to those without the A allele was found to be statistically significant. Additionally, an increase in the tumour necrosis factor-alpha serum levels in patients carrying tumour necrosis factor-alpha (-308 G/A) AA genotype compared with patients carrying the AG or GG genotypes was statistically significant. No significant differences were found in these 2 polymorphisms between the patient and control groups (p>0.05). Our results showed the AA genotype and the A allele of the tumour necrosis factor-alpha (-308 G/A) polymorphism may be used as a predictor of elevated tumour necrosis factor-alpha levels in patients with sepsis.

Educational gains in cause-specific mortality: Accounting for cognitive ability and family-level confounders using propensity score weighting.

PubMed

Bijwaard, Govert E; Myrskylä, Mikko; Tynelius, Per; Rasmussen, Finn

2017-07-01

A negative educational gradient has been found for many causes of death. This association may be partly explained by confounding factors that affect both educational attainment and mortality. We correct the cause-specific educational gradient for observed individual background and unobserved family factors using an innovative method based on months lost due to a specific cause of death re-weighted by the probability of attaining a higher educational level. We use data on men with brothers from the Swedish Military Conscription Registry (1951-1983), linked to administrative registers. This dataset of some 700,000 men allows us to distinguish between five education levels and many causes of death. The empirical results reveal that raising the educational level from primary to tertiary would result in an additional 20 months of survival between ages 18 and 63. This improvement in mortality is mainly attributable to fewer deaths from external causes. The highly educated gain more than nine months due to the reduction in deaths from external causes, but gain only two months due to the reduction in cancer mortality and four months due to the reduction in cardiovascular mortality. Ignoring confounding would lead to an underestimation of the gains by educational attainment, especially for the less educated. Our results imply that if the education distribution of 50,000 Swedish men from the 1951 cohort were replaced with that of the corresponding 1983 cohort, 22% of the person-years that were lost to death between ages 18 and 63 would have been saved for this cohort. Copyright © 2017 Elsevier Ltd. All rights reserved.

Team versus individual sport participation as a modifying factor in the development of post-concussion syndrome after first concussion: A pilot study.

PubMed

Jeckell, Aaron S; Brett, Benjamin L; Totten, Douglas J; Solomon, Gary S

2018-01-19

Identification of modifying factors that influence the development of post-concussion syndrome (PCS) following sport-related concussion (SRC) has drawn considerable interest. In this pilot study, we investigate the effect of team vs. individual sport participation on the development of PCS in a sample of 136 high school and college student-athletes. Controlling for several confounding variables, we employed a binary logistic regression and chi-squared test. Results of this pilot study indicate that participation in team versus individual sport is not a significant factor in the development of PCS. The identification of other forms of protective mechanisms is discussed.

Risk Factors for Low Back Pain in Childhood and Adolescence: A Systematic Review.

PubMed

Calvo-Muñoz, Inmaculada; Kovacs, Francisco M; Roqué, Marta; Gago Fernández, Inés; Seco Calvo, Jesús

2018-05-01

To identify factors associated with low back pain (LBP) in children and adolescents. A systematic review was conducted (Prospero CRD42016038186). Observational studies analyzing LBP risk factors among participants aged between 9 and 16 were searched for in 13 electronic databases and 8 specialized journals until March 31, 2016, with no language restrictions. In addition, references in the identified studies were manually tracked. All identified studies that included ≥50 participants aged 9 to 16, were reviewed. Their methodological quality was assessed by 2 reviewers separately, using validated tools, which scored, from worst to best, 0 to 100 for cross-sectional and 0 to 12 for cohort studies. A sensitivity analysis only included studies that had adjusted for confounders, had ≥500 participants, and had a methodological score of ≥50%. A total of 5142 citations were screened and 61 studies, including 137,877 participants from 5 continents, were reviewed. Their mean (range) methodological scores were 74.56 (50 to 100) for cross-sectional studies and 7.36 (5 to 9) for cohort studies. The studies had assessed 35 demographic, clinical, biological, family, psychological, ergonomic, and lifestyle risk factors. The mean (range) prevalence of LBP ranged between 15.25% (3.20 to 57.00) for point prevalence and 38.98% (11.60 to 85.56) for lifetime prevalence. Results on the association between LBP and risk factors were inconsistent. In the sensitivity analysis, "older age" and "participation in competitive sports" showed a consistent association with LBP. Future studies should focus on muscle characteristics, the relationship between body and backpack weights, duration of carrying the backpack, characteristics of sport practice, and which are the factors associated with specifically chronic pain.

Physical and psychosocial factors in the prevention of chronic pain in older age.

PubMed

Fancourt, D; Steptoe, A

2018-06-24

Chronic pain is recognised as a major challenge as people age. Yet, despite growing research on chronic pain management, there is little research into chronic pain prevention. So there is a clear need to identify multimodal activities that could be encouraged amongst older adults as part of a healthy lifestyle to reduce the incidence risk of chronic pain. Using data from the English Longitudinal Study of Ageing we tracked 2,631 adults aged 50+ who were free from chronic pain at baseline across a decade and explore whether physical or psychosocial factors reduced the risk of developing chronic pain. In relation to physical factors, engaging in vigorous weekly activity was protective against the development of chronic pain (OR=0.74, SE=0.07, CI=0.62 to 0.89) when controlling for all identified socio-economic, health and social confounders. But no effects were found for moderate weekly activity. In relation to psychosocial factors, cultural engagement was also protective against the development of chronic pain (OR=0.75, SE=0.07, CI=0.63 to 0.91), but community group participation was not. These findings extend previous work showing that physical activity and psychosocial factors such as positive affect are key factors in the long-term success of chronic pain self-management. Future interventional studies for chronic pain are encouraged. Perspective This article explores whether physical and psychosocial activities could reduce the risk of developing chronic pain in older age. These results could potentially help clinicians to recommend multimodal activities as part of a broader healthy lifestyle for those aged 50+ to reduce the incidence rate of chronic pain. Copyright © 2018. Published by Elsevier Inc.

Night-waking trajectories and associated factors in French preschoolers from the EDEN birth-cohort.

PubMed

Reynaud, Eve; Forhan, Anne; Heude, Barbara; de Lauzon-Guillain, Blandine; Charles, Marie-Aline; Plancoulaine, Sabine

Night waking in preschoolers has been associated with adverse health outcomes in cross-sectional studies, but has rarely been analyzed in a longitudinal setting. Therefore, little is known about the evolution of night waking in early childhood. The objectives of the present study were: to identify night-waking trajectories in preschoolers, and to examine the risk factors associated with those trajectories. Analyses were based on the French birth-cohort study EDEN, which recruited 2002 pregnant women between 2003 and 2006. Data on a child's night waking at the ages of two, three, and five, six years, and potential confounders, were collected through parental self-reported questionnaires. Night-waking trajectories were computerized using group-based trajectory modeling on 1346 children. Two distinct developmental patterns were identified: the "2-5 rare night-waking" (77% of the children) and the "2-5 common night-waking" pattern. Logistic regressions were performed to identify the factors associated with the trajectories. Risk factors for belonging to the "2-5 common night-waking" trajectory were: exposure to passive smoking at home, daycare in a collective setting, watching television for extended periods, bottle feeding at night, high emotionality, and low shyness. This approach allowed identification of risk factors associated with night waking during a critical age window, and laid the groundwork for identifying children at higher risk of deleterious sleep patterns. Those risk factors were mainly living habits, which indicated that prevention and intervention programs could be highly beneficial in this population. Copyright © 2016 Elsevier B.V. All rights reserved.

Media composition: growth factors.

PubMed

Hegde, Aparna; Behr, Barry

2012-01-01

Despite the fact that the fundamental principle underlying the most common method of culture media constitution is that of mimicking the natural environment of the preimplantation embryo, one major difference that remains between current embryo culture media and in vivo conditions is the absence of growth factors in vitro. Numerous growth factors are known to be present in the in vivo environment of human and nonhuman preimplantation embryos, often with peak concentrations corresponding to when fertilization and preimplantation embryo growth would occur. Although these growth factors are found in very small concentrations, they have a profound effect on tissue growth and differentiation through attachment to factor-specific receptors on cell surfaces. Receptors for many different growth factors have also been detected in human preimplantation embryos. Preimplantation embryos themselves express many growth factors. The growth factors and receptors are metabolically costly to produce, and thus their presence in the environment of the preimplantation embryo and in the embryo respectively strongly implies that embryos are designed to encounter and respond to the corresponding factors. Studies of embryo coculture also indirectly suggest that growth factors can improve in vitro development. Several animal and human studies attest to a probable beneficial effect of addition of growth factors to culture media. However, there is still ambiguity regarding the exact role of growth factors in embryonic development, the optimal dose of growth factors to be added to culture media, the combinatorial effect and endocrine of growth factors in embryonic development.

EVALUATING THE IMPORTANCE OF FACTORS IN ANY GIVEN ORDER OF FACTORING.

PubMed

Humphreys, L G; Tucker, L R; Dachler, P

1970-04-01

A methodology has been described and illustrated for obtaining an evaluation of the importance of the factors in a particular order of factoring that does not require faotoring beyond that order. For example, one can estimate the intercorrelations of the original measures with the perturbations of the first-order factor held constant or, the reverse, estimate the contribution to the intercorrelations of the originral measures from the first-order factors alone. Similar operations are possible at higher orders.

Effect of maternal and neonatal factors on neonatal thyroid stimulating hormone: Results from a population-based prospective cohort study in China.

PubMed

Zhang, Yixin; Du, Cong; Wang, Wei; Chen, Wen; Shao, Ping; Wang, Chongdan; Leng, Junhong; Shen, Jun; Tan, Long; Zhang, Wanqi

2018-09-01

Neonatal TSH screening is effective in detecting congenital hypothyroidism and estimating iodine status in a given population, but various factors influence TSH levels. The aim of this study was to evaluate the effect of maternal and neonatal factors on neonatal TSH levels. Data were obtained from an ongoing prospective cohort study. A total of 988 pregnant women and their newborn infants participated in the study from April 2015 to May 2017 at Tianjin Maternal and Child Health Center and Tanggu Maternity Hospital in Tianjin, China. Maternal demographic information, including age, height, and parity, was recorded by questionnaire. Fasting blood and urinary samples were collected from all pregnant women. After parturition, information on gestation duration, mode of delivery, neonatal sex, neonatal TSH, neonatal birth weight, and neonatal birth height were recorded. Maternal age, maternal BMI, gestation duration, parity, and neonatal birth weight and height were significantly correlated with neonatal TSH (p < 0.05). Quantile regression revealed that maternal age, TSH, FT 4 , and gestation duration were positively correlated with neonatal TSH level. A logistic regression model identified maternal BMI, TSH, and birth height as risk factors for having neonatal TSH > 5 mIU/L (p < 0.05). Neonatal TSH levels are dynamic and may be affected by several maternal and neonatal factors including maternal age, TSH, FT 4 , and birth weight and height. Identification of these confounders is useful for assessing the status of neonatal thyroid development. STRENGTHS AND LIMITATIONS OF THIS STUDY: (1) Iodine deficiency disorder has generally been eliminated, so the median urinary iodine concentration of pregnancy is higher than 150 μg/L even in mildly or moderately iodine deficient areas. (2) Unlike many other studies, which did not consider the complexity of factors or examined only one or two variables, this study used a multivariate model to analyze the data. (3

Heart disease - risk factors

MedlinePlus

Heart disease - prevention; CVD - risk factors; Cardiovascular disease - risk factors; Coronary artery disease - risk factors; CAD - risk ... a certain health condition. Some risk factors for heart disease you cannot change, but some you can. ...

Factors influencing wound dehiscence.

PubMed

Riou, J P; Cohen, J R; Johnson, H

1992-03-01

Thirty-one abdominal fascial wound dehiscences occurred in 2,761 patients undergoing major abdominal surgery during a 5-year period (1%). Twenty-two specific local and systemic risk factors were analyzed and compared with the risk factors of a control group of 38 patients undergoing similar procedures without dehiscence. Through multivariate analysis, each factor was assessed as an independent statistical variable. Significant factors (p less than 0.05) were found to include age over 65, wound infection, pulmonary disease, hemodynamic instability, and ostomies in the incision. Additional systemic risk factors that were found to be significant included hypoproteinemia, systemic infection, obesity, uremia, hyperalimentation, malignancy, ascites, steroid use, and hypertension. Risk factors not found to be important independent variables included sex, type of incision, type of closure, foreign body in the wound, anemia, jaundice, and diabetes. When dehiscence and control groups were combined, 30% of patients with at least five significant risk factors developed dehiscence, and all the patients with more than eight risk factors developed a wound dehiscence. There was an overall mortality of 29%, which was directly related to the number of significant risk factors. The co-existence of 9 risk factors portended death in one third of the patients, and all the patients with more than 10 risk factors died.

A review of caffeine use as a risk or protective factor for women's health and pregnancy.

PubMed

Peacock, Amy; Mattick, Richard P; Bruno, Raimondo

2017-07-01

To provide a narrative synthesis of recently published studies on caffeine use as a risk or protective factor for health outcomes, with a focus on women's health and pregnancy. Based on predominantly observational studies, moderate caffeine intake has been shown to be a protective factor for liver cancer, certain bowel conditions, colorectal cancer, skin cancer, and regular menstrual cycle function. However, heavy consumption is a risk factor for osteoporosis, urinary incontinence, and poorer birth and child developmental outcomes. Residual confounding and issues surrounding retrospective self-reported intake are cited as key limitations in the majority of these studies. Moderate caffeine intake has been associated with lower risk of cardiovascular disease and metabolic syndrome; however, recent genetic epidemiology studies provide no evidence for a causal relationship. Greater inclusion of female participants in studies, and analysis of sex differences in the relationship between caffeine intake and certain health conditions, is necessary. The current literature suggests caffeine's role as a risk or protective factor differs across health conditions. Often, there are plausible biological mechanisms for this relationship. However, a continued precautionary stance is recommended until direct causal pathways are established. Review of recently published studies does not suggest that current intake guidelines for adults and for pregnant woman need to be modified.

Vitamin D in endometriosis: a causative or confounding factor?

PubMed

Sayegh, Lamia; Fuleihan, Ghada El-Hajj; Nassar, Anwar H

2014-01-01

The aim of this paper is to review the evidence from studies that evaluated the relationship between vitamin D and endometriosis. Comprehensive review. Systematic literature search in Medline for relevant publications from 1946 until June 2013. Endometriosis risk may be influenced by dietary vitamin D intake and plasma hydroxyvitamin D concentration. Vitamin D receptor and vitamin D metabolizing enzymes, 24-hydroxylase and 1-α hydroxylase, are found in the normal cycling endometrium and also in the eutopic and ectopic endometrium of women with endometriosis. The endometrium is a target of 1, 25 dihydroxyvitamin D actions through regulation of specific genes and via immunomodulation. The endometrium in endometriosis expresses dysregulation of some vitamin D enzymes and receptors. If vitamin D and its metabolites are implicated in endometriosis-associated infertility, it is likely through interference with HOXA10 gene expression. The Gc2 phenotype of vitamin D binding protein is prevalent in women with endometriosis and may be implicated in its pathogenesis. In a mouse model, Elocalcitol, a VDR-agonist was shown to reduce the development of endometriotic lesions and recurrence. A biological plausibility for a role of vitamin D, as an immunomodulator and anti-inflammatory agent, in the pathogenesis and treatment of endometriosis is suggested in this article, but is difficult to illustrate due to sparse evidence from human studies limited primarily to case-control studies. A significant knowledge gap precludes the establishment of a clear cause-effect relationship. The intriguing leads presented herein need to be investigated further with placebo-controlled supplementation trials. © 2013.

Pain as a confounding factor in postnatal depression screening.

PubMed

Jardri, Renaud; Maron, Michel; Delion, Pierre; Thomas, Pierre

2010-12-01

Postnatal depression (PND) is one of the most serious complications following delivery in developed countries today. Thus, early screening strategies by first-line healthcare workers are of primary importance. Pain following childbirth has been proposed as a possible risk-marker for later depressive disorder. We tested this assumption and explored the possible link between pain and overestimation of PND risk in routine clinical screenings. We assessed 320 women between the third and fifth day after delivery as well as at 8 weeks post-partum (PP). Midwives were asked to evaluate the risk of later PND upon discharge from the maternity unit; additionally, pain measurements were obtained using the Visual Analogic Scale (VAS) over the same time period. A stepwise logistic regression analysis was performed to identify the risk markers linked to a positive depressive disorder diagnosis (according to the MINI-DSM-IV) at 8 weeks PP. Multivariate risk analysis showed no statistical link between physical pain shortly after childbirth and subsequent PND diagnosis at 8 weeks PP. However, VAS measurements for pain were significantly higher for women that the midwives estimated to be at risk for PND (|Z| = 2.78, p = 0.005), suggesting the routine clinical screening for PND is susceptible for false-positives. Psychiatrists should encourage midwives to have an empathetic approach, to increase the detection as well as treatment of mental and physical suffering in early postpartum. At the same time, adequate education programmes for early PND screening should be proposed to non-psychiatric staffs to demonstrate that women at risk of PND often show minimal physical symptoms.

Confounding factors in diagnosing brain death: a case report

PubMed Central

Burns, Jeffrey M; Login, Ivan S

2002-01-01

Background Brain death is strictly defined medically and legally. This diagnosis depends on three cardinal neurological features: coma, absent brainstem reflexes, and apnea. The diagnosis can only be made, however, in the absence of intoxication, hypothermia, or certain medical illnesses. Case presentation A patient with severe hypoxic-ischemic brain injury met the three cardinal neurological features of brain death but concurrent profound hypothyroidism precluded the diagnosis. Our clinical and ethical decisions were further challenged by another facet of this complex case. Although her brain damage indicated a hopeless prognosis, we could not discontinue care based on futility because the only known surrogate was mentally retarded and unable to participate in medical planning. Conclusion The presence of certain medical conditions prohibits a diagnosis of brain death, which is a medicolegal diagnosis of death, not a prediction or forecast of future outcome. While prognostication is important in deciding to withdraw care, it is not a component in diagnosing brain death. PMID:12097152

Confounding factors in diagnosing brain death: a case report.

PubMed

Burns, Jeffrey M; Login, Ivan S

2002-06-26

Brain death is strictly defined medically and legally. This diagnosis depends on three cardinal neurological features: coma, absent brainstem reflexes, and apnea. The diagnosis can only be made, however, in the absence of intoxication, hypothermia, or certain medical illnesses. A patient with severe hypoxic-ischemic brain injury met the three cardinal neurological features of brain death but concurrent profound hypothyroidism precluded the diagnosis. Our clinical and ethical decisions were further challenged by another facet of this complex case. Although her brain damage indicated a hopeless prognosis, we could not discontinue care based on futility because the only known surrogate was mentally retarded and unable to participate in medical planning. The presence of certain medical conditions prohibits a diagnosis of brain death, which is a medicolegal diagnosis of death, not a prediction or forecast of future outcome. While prognostication is important in deciding to withdraw care, it is not a component in diagnosing brain death.

General Factors of the Korean Exposure Factors Handbook

PubMed Central

Kim, So-Yeon; Kim, Sun-Ja; Lee, Kyung-Eun; Cheong, Hae-Kwan; Kim, Eun-Hye; Choi, Kyung-Ho; Kim, Young-Hee

2014-01-01

Risk assessment considers the situations and characteristics of the exposure environment and host. Various physiological variables of the human body reflects the characteristics of the population that can directly influence risk exposure. Therefore, identification of exposure factors based on the Korean population is required for appropriate risk assessment. It is expected that a handbook about general exposure factors will be used by professionals in many fields as well as the risk assessors of the health department. The process of developing the exposure factors handbook for the Korean population will be introduced in this article, with a specific focus on the general exposure factors including life expectancy, body weight, surface area, inhalation rates, amount of water intake, and soil ingestion targeting the Korean population. The researchers used national databases including the Life Table and the 2005 Time Use Survey from the National Statistical Office. The anthropometric study of size in Korea used the resources provided by the Korean Agency for Technology and Standards. In addition, direct measurement and questionnaire surveys of representative samples were performed to calculate the inhalation rate, drinking water intake, and soil ingestion. PMID:24570802

Block LU factorization

NASA Technical Reports Server (NTRS)

Demmel, James W.; Higham, Nicholas J.; Schreiber, Robert S.

1992-01-01

Many of the currently popular 'block algorithms' are scalar algorithms in which the operations have been grouped and reordered into matrix operations. One genuine block algorithm in practical use is block LU factorization, and this has recently been shown by Demmel and Higham to be unstable in general. It is shown here that block LU factorization is stable if A is block diagonally dominant by columns. Moreover, for a general matrix the level of instability in block LU factorization can be founded in terms of the condition number kappa(A) and the growth factor for Gaussian elimination without pivoting. A consequence is that block LU factorization is stable for a matrix A that is symmetric positive definite or point diagonally dominant by rows or columns as long as A is well-conditioned.

Association of Sociodemographic and Perceived Environmental Factors with Public Bicycle Use among Taiwanese Urban Adults.

PubMed

Liao, Yung

2016-03-19

This study examined the sociodemographic and perceived environmental factors associated with public bicycle use among Taiwanese urban adults. A random-digit-dialing telephone-based cross-sectional survey was administered to Taiwanese urban adults aged 20-64 years in 2015. Data on sociodemographic variables, perceived environmental factors (for attributes identified in the International Physical Activity Questionnaire-Environmental Module), and public bicycle use were obtained from 1002 adults in three cities. Adjusted logistic regression was used. After adjustment for potential confounders, the results showed that adults aged 20-29 years (odds ratio (OR) = 4.42) with a university degree or higher (OR = 2.03) were more likely to use public bicycles. In addition, adults living in Kaohsiung City were less likely to use public bicycles (OR = 0.24). Adults who saw people being active (OR = 1.76; 95% CI: 1.05-2.86) and had positive aesthetic experiences of their environment (OR = 1.69) were more likely to use public bicycles. Our findings suggest that seeing physically active people and positive aesthetic perceptions of the environment are key factors for developing transportation policies and intervention strategies for promoting public bicycle use among Taiwanese urban adults.

Ocular Angiogenesis: Vascular Endothelial Growth Factor and Other Factors.

PubMed

Rubio, Roman G; Adamis, Anthony P

2016-01-01

Systematic study of the mechanisms underlying pathological ocular neovascularization has yielded a wealth of knowledge about pro- and anti-angiogenic factors that modulate diseases such as neovascular age-related macular degeneration. The evidence implicating vascular endothelial growth factor (VEGF) in particular has led to the development of a number of approved anti-VEGF therapies. Additional proangiogenic targets that have emerged as potential mediators of ocular neovascularization include hypoxia-inducible factor-1, angiopoietin-2, platelet-derived growth factor-B and components of the alternative complement pathway. As for VEGF, knowledge of these factors has led to a product pipeline of many more novel agents that are in various stages of clinical development in the setting of ocular neovascularization. These agents are represented by a range of drug classes and, in addition to novel small- and large-molecule VEGF inhibitors, include gene therapies, small interfering RNA agents and tyrosine kinase inhibitors. In addition, combination therapy is beginning to emerge as a strategy to improve the efficacy of individual therapies. Thus, a variety of agents, whether administered alone or as adjunctive therapy with agents targeting VEGF, offer the promise of expanding the range of treatments for ocular neovascular diseases. © 2016 S. Karger AG, Basel.

Violent behavior and aggression in schizophrenia: Prevalence and risk factors. A multicentric study from three Latin-America countries.

PubMed

Caqueo-Urízar, Alejandra; Fond, Guillaume; Urzúa, Alfonso; Boyer, Laurent; Williams, David R

2016-12-01

The aim of the present study was (i) to assess the prevalence of Violent Behavior in Schizophrenia (VBS) in a sample of community-dwelling outpatients in three middle-income countries of Latin America and (ii) to determine the clinical and socio-demographical risk factors associated with VBS and aggression level. The study included 253 stabilized outpatients with schizophrenia and their principal caregivers from 3 public ambulatory psychiatric care centers in Bolivia (N=83), Chile (N=85), and Peru (N=85). VBS was defined according to the Overt Aggression Scale (OAS) score and the aggression level was measured by the aggression subscore of the Agitated Behavior Scale of Corrigan. We collected socio-demographic information and clinical data. Multiple linear and logistic regressions were performed to determine which variables were associated with VBS and aggression level. The prevalence of VBS differed statistically between the three countries (p<0.001) with 3.5% in Chile, 14.6% in Peru and 55.4% in Bolivia. After adjustment for confounding factors, VBS was associated with a younger age, a more severe psychotic symptomatology, a lower family income and unemployment. After adjustment for confounding factors, aggression level was associated with a more severe psychotic symptomatology, a lower family income, a younger age at illness onset and higher number of hospitalizations in the last 3years. These results may guide future health policies to specifically provide social support and rehabilitation care to VBS patients in middle-income countries, including psychoeducation and a more integrated work between the treating medical team and the social workers. Copyright © 2016 Elsevier B.V. All rights reserved.

Role of carbohydrate in multimeric structure of factor VIII/von Willebrand factor protein.

PubMed Central

Gralnick, H R; Williams, S B; Rick, M E

1983-01-01

The carbohydrate moiety of the factor VIII/von Willebrand (vW) factor protein is important in the expression of vW factor activity and the intravascular survival of the protein. Studies of normal human factor VIII/vW factor protein indicate that there is a requirement of a full complement of penultimate galactose for the maintenance of a normal multimeric structure. Release of penultimate galactose by beta-galactosidase or modification by galactose oxidase results in loss of the largest molecular weight multimers and increased numbers of intermediate and smaller multimers. In contrast, terminal galactose on the factor VIII/vW factor protein does not appear to play a significant role in the maintenance of the multimer organization. The abnormalities in multimeric structure and molecular size were demonstrated by NaDodSO4/polyacrylamide/agarose gel electrophoresis, NaDodSO4/glyoxyl-agarose electrophoresis, and sucrose density ultracentrifugation. These studies indicate that the penultimate galactose plays a role in the maintenance of the largest multimers of the factor VIII/vW factor protein. This may explain why, in some patients with variant forms of vW disease, a carbohydrate abnormality also may affect the multimeric structure of the plasma factor VIII/vW factor protein. Images PMID:6601805

Methods to control for unmeasured confounding in pharmacoepidemiology: an overview.

PubMed

Uddin, Md Jamal; Groenwold, Rolf H H; Ali, Mohammed Sanni; de Boer, Anthonius; Roes, Kit C B; Chowdhury, Muhammad A B; Klungel, Olaf H

2016-06-01

Background Unmeasured confounding is one of the principal problems in pharmacoepidemiologic studies. Several methods have been proposed to detect or control for unmeasured confounding either at the study design phase or the data analysis phase. Aim of the Review To provide an overview of commonly used methods to detect or control for unmeasured confounding and to provide recommendations for proper application in pharmacoepidemiology. Methods/Results Methods to control for unmeasured confounding in the design phase of a study are case only designs (e.g., case-crossover, case-time control, self-controlled case series) and the prior event rate ratio adjustment method. Methods that can be applied in the data analysis phase include, negative control method, perturbation variable method, instrumental variable methods, sensitivity analysis, and ecological analysis. A separate group of methods are those in which additional information on confounders is collected from a substudy. The latter group includes external adjustment, propensity score calibration, two-stage sampling, and multiple imputation. Conclusion As the performance and application of the methods to handle unmeasured confounding may differ across studies and across databases, we stress the importance of using both statistical evidence and substantial clinical knowledge for interpretation of the study results.

The Impact of System Factors on Quality and Safety in Arterial Surgery: A Systematic Review.

PubMed

Lear, R; Godfrey, A D; Riga, C; Norton, C; Vincent, C; Bicknell, C D

2017-07-01

A systems approach to patient safety proposes that a wide range of factors contribute to surgical outcome, yet the impact of team, work environment, and organisational factors, is not fully understood in arterial surgery. The aim of this systematic review is to summarize and discuss what is already known about the impact of system factors on quality and safety in arterial surgery. A systematic review of original research papers in English using MEDLINE, Embase, PsycINFO, and Cochrane databases, was performed according to PRISMA guidelines. Independent reviewers selected papers according to strict inclusion and exclusion criteria, and using predefined data fields, extracted relevant data on team, work environment, and organisational factors, and measures of quality and/or safety, in arterial procedures. Twelve papers met the selection criteria. Study endpoints were not consistent between papers, and most failed to report their clinical significance. A variety of tools were used to measure team skills in five papers; only one paper measured the relationship between team factors and patient outcomes. Two papers reported that equipment failures were common and had a significant impact on operating room efficiency. The influence of hospital characteristics on failure-to-rescue rates was tested in one large study, although their conclusions were limited to the American Medicare population. Five papers implemented changes in the patient pathway, but most studies failed to account for potential confounding variables. A small number of heterogenous studies have evaluated the relationship between system factors and quality or safety in arterial surgery. There is some evidence of an association between system factors and patient outcomes, but there is more work to be done to fully understand this relationship. Future research would benefit from consistency in definitions, the use of validated assessment tools, measurement of clinically relevant endpoints, and adherence to

Perceived environmental and personal factors associated with walking and cycling for transportation in Taiwanese adults.

PubMed

Liao, Yung; Wang, I-Ting; Hsu, Hsiu-Hua; Chang, Shao-Hsi

2015-02-13

This study examined perceived environmental and personal factors associated with walking and cycling as means of transportation for Taiwanese adults. A random-digit-dialing telephone-based cross-sectional survey was conducted with Taiwanese adults aged 20 to 64 years. Data on time spent walking and cycling for transportation and perceptions of neighborhood environment and personal characteristics were obtained from 1065 adults by using the International Physical Activity Questionnaire-long version and its environmental module. Adjusted binary logistic regression was performed. The results showed that, after adjusting potential confounders, common and different personal and perceived environmental factors were associated with walking and cycling for transportation. For common personal factors, adults who had employment were less likely to engage in 150 min of walking per week (odds ratio [OR] = 0.41; 95% confidence interval (CI): 0.27-0.62) and to use cycling as a means of transportation (OR = 0.51; 95% CI: 0.32-0.79). For common perceived environmental factors, adults who perceived good connectivity of streets were more likely to walk (OR = 1.95; 95% CI: 1.20-3.16) and cycle (OR = 2.02; 95% CI: 1.16-3.54) for transportation. Targeting employed adults and improving the connectivity of streets should be a priority for developing transport policies and intervention strategies to promote active transportation.

Factors associated with the development of cardiac allograft vasculopathy--a systematic review of observational studies.

PubMed

Braga, J R; Santos, I S O; McDonald, M; Shah, P S; Ross, H J

2012-01-01

Cardiac allograft vasculopathy (CAV) is a significant factor impacting outcomes after heart transplant. We performed a systematic review of risk factors for the development of CAV. A search of electronic databases was performed. The eligibility criteria included cohort and case-control studies with more than 50 adult patients submitted to a heart transplant. The outcome should be CAV diagnosed by angiography and/or intravascular ultrasound (IVUS). Two reviewers performed study selection, data abstraction, and quality assessment. Of 2514 citations, 66 articles were included--46 had 200 participants or less; 61 were single-center; and 44 were retrospective cohorts. The most used definition of CAV using angiography was the detection of any degree of abnormality (21 studies of 58). In studies using IVUS, an intimal thickness ≥0.5 mm was the most used definition (five of eight studies). Quality assessment revealed an inadequate description of patient selection, attrition, and accounting of potential confounders. Donor age, recipient age, recipient gender, etiology of heart failure, ischemic time, human leukocyte antigen matching, cytomegalovirus, lipid profile, and rejection episodes were the most studied factors. Our review indicates that the current evidence is not consistent across different studies. The definite contribution of risk factors for the development of CAV is still to be determined. © 2011 John Wiley & Sons A/S.

Perceived Environmental and Personal Factors Associated with Walking and Cycling for Transportation in Taiwanese Adults

PubMed Central

Liao, Yung; Wang, I-Ting; Hsu, Hsiu-Hua; Chang, Shao-Hsi

2015-01-01

This study examined perceived environmental and personal factors associated with walking and cycling as means of transportation for Taiwanese adults. A random-digit-dialing telephone-based cross-sectional survey was conducted with Taiwanese adults aged 20 to 64 years. Data on time spent walking and cycling for transportation and perceptions of neighborhood environment and personal characteristics were obtained from 1065 adults by using the International Physical Activity Questionnaire-long version and its environmental module. Adjusted binary logistic regression was performed. The results showed that, after adjusting potential confounders, common and different personal and perceived environmental factors were associated with walking and cycling for transportation. For common personal factors, adults who had employment were less likely to engage in 150 min of walking per week (odds ratio [OR] = 0.41; 95% confidence interval (CI): 0.27–0.62) and to use cycling as a means of transportation (OR = 0.51; 95% CI: 0.32–0.79). For common perceived environmental factors, adults who perceived good connectivity of streets were more likely to walk (OR = 1.95; 95% CI: 1.20–3.16) and cycle (OR = 2.02; 95% CI: 1.16–3.54) for transportation. Targeting employed adults and improving the connectivity of streets should be a priority for developing transport policies and intervention strategies to promote active transportation. PMID:25689349

Heparin-binding epidermal growth factor-like growth factor promotes neuroblastoma differentiation

PubMed Central

Gaviglio, Angela L.; Knelson, Erik H.; Blobe, Gerard C.

2017-01-01

High-risk neuroblastoma is characterized by undifferentiated neuroblasts and low schwannian stroma content. The tumor stroma contributes to the suppression of tumor growth by releasing soluble factors that promote neuroblast differentiation. Here we identify heparin-binding epidermal growth factor–like growth factor (HBEGF) as a potent prodifferentiating factor in neuroblastoma. HBEGF mRNA expression is decreased in human neuroblastoma tumors compared with benign tumors, with loss correlating with decreased survival. HBEGF protein is expressed only in stromal compartments of human neuroblastoma specimens, with tissue from high-stage disease containing very little stroma or HBEGF expression. In 3 human neuroblastoma cell lines (SK-N-AS, SK-N-BE2, and SH-SY5Y), soluble HBEGF is sufficient to promote neuroblast differentiation and decrease proliferation. Heparan sulfate proteoglycans and heparin derivatives further enhance HBEGF-induced differentiation by forming a complex with the epidermal growth factor receptor, leading to activation of the ERK1/2 and STAT3 pathways and up-regulation of the inhibitor of DNA binding transcription factor. These data support a role for loss of HBEGF in the neuroblastoma tumor microenvironment in neuroblastoma pathogenesis.—Gaviglio, A. L., Knelson, E. H., Blobe, G. C. Heparin-binding epidermal growth factor-like growth factor promotes neuroblastoma differentiation. PMID:28174207

The pattern space factor and quality factor of cylindrical source antennas

NASA Astrophysics Data System (ADS)

Jarem, John M.

1982-09-01

For the first time the quality factor of cylindrical source antennas is derived by a plane wave expansion. The evanescent energy (and therefore the quality factor) as defined by a plane wave expansion is shown to be different from Collin and Rothschild's [IEEE Trans. Antennas Propagation AP-12, 23 (1964)] quality factor.

Association of Helicobacter pylori and Chlamydia pneumoniae infections with coronary heart disease and cardiovascular risk factors.

PubMed Central

Patel, P.; Mendall, M. A.; Carrington, D.; Strachan, D. P.; Leatham, E.; Molineaux, N.; Levy, J.; Blakeston, C.; Seymour, C. A.; Camm, A. J.

1995-01-01

OBJECTIVE--To investigate the relation between seropositivity to chronic infections with Helicobacter pylori and Chlamydia pneumoniae and both coronary heart disease and cardiovascular risk factors. DESIGN--Cross sectional study of a population based random sample of men. Coronary heart disease was assessed by electrocardiography, Rose angina questionnaire, and a history of myocardial infarction; serum antibody levels to H pylori and C pneumoniae were measured, risk factor levels determined, and a questionnaire administered. SETTING--General practices in Merton, Sutton, and Wandsworth, south London. SUBJECTS--388 white south London men aged 50-69. MAIN OUTCOME MEASURES--Evidence of coronary risk factors and infection with H pylori or C pneumoniae. RESULTS--47 men (12.1%) had electrocardiographic evidence of ischaemia or infarction. 36 (76.6%) and 18 (38.3%) were seropositive for H pylori and C pneumoniae, respectively, compared with 155 (45.5%) and 62 (18.2%) men with normal electrocardiograms. Odds ratios for abnormal electrocardiograms were 3.82 (95% confidence interval 1.60 to 9.10) and 3.06 (1.33 to 7.01) in men seropositive for H pylori and C pneumoniae, respectively, after adjustment for a range of socioeconomic indicators and risk factors for coronary heart disease. Cardiovascular risk factors that were independently associated with seropositivity to H pylori included fibrinogen concentration and total leucocyte count. Seropositivity to C pneumoniae was independently associated with raised fibrinogen and malondialdehyde concentrations. CONCLUSIONS--Both H pylori and C pneumoniae infectins are associated with coronary heart disease. These relations are not explained by a wide range of confounding factors. Possible mechanisms include an increase in risk factor levels due to a low grade chronic inflammatory response. PMID:7549683

Differences in cardiovascular disease risk factor management in primary care by sex of physician and patient.

PubMed

Tabenkin, Hava; Eaton, Charles B; Roberts, Mary B; Parker, Donna R; McMurray, Jerome H; Borkan, Jeffrey

2010-01-01

The purpose of this study was to evaluate differences in the management of cardiovascular disease (CVD) risk factors based upon the sex of the patient and physician and their interaction in primary care practice. We evaluated CVD risk factor management in 4,195 patients cared for by 39 male and 16 female primary care physicians in 30 practices in southeastern New England. Many of the sex-based differences in CVD risk factor management on crude analysis are lost once adjusted for confounding factors found at the level of the patient, physician, and practice. In multilevel adjusted analyses, styles of CVD risk factor management differed by the sex of the physician, with more female physicians documenting diet and weight loss counseling for hypertension (odds ratio [OR] = 2.22; 95% confidence interval [CI], 1.12-4.40) and obesity (OR = 2.14; 95% CI, 1.30-3.51) and more physical activity counseling for obesity (OR = 2.03; 95% CI, 1.30-3.18) and diabetes (OR = 6.55; 95% CI, 2.01-21.33). Diabetes management differed by the sex of the patient, with fewer women receiving glucose-lowering medications (OR = 0.49; 95% CI, 0.25-0.94), angiotensin-converting enzyme inhibitor therapy (OR = 0.39; 95% CI, 0.22-0.72), and aspirin prophylaxis (OR = 0.30; 95% CI, 0.15-0.58). Quality of care as measured by patients meeting CVD risk factors treatment goals was similar regardless of the sex of the patient or physician. Selected differences were found in the style of CVD risk factor management by sex of physician and patient.

Traditional risk factors as the underlying cause of racial disparities in stroke: lessons from the half-full (empty?) glass.

PubMed

Howard, George; Cushman, Mary; Kissela, Brett M; Kleindorfer, Dawn O; McClure, Leslie A; Safford, Monika M; Rhodes, J David; Soliman, Elsayed Z; Moy, Claudia S; Judd, Suzanne E; Howard, Virginia J

2011-12-01

Black/white disparities in stroke incidence are well documented, but few studies have assessed the contributions to the disparity. Here we assess the contribution of "traditional" risk factors. A total of 25 714 black and white men and women, aged≥45 years and stroke-free at baseline, were followed for an average of 4.4 years to detect stroke. Mediation analysis using proportional hazards analysis assessed the contribution of traditional risk factors to racial disparities. At age 45 years, incident stroke risk was 2.90 (95% CI: 1.72-4.89) times more likely in blacks than in whites and 1.66 (95% CI: 1.34-2.07) times at age 65 years. Adjustment for risk factors attenuated these excesses by 40% and 45%, respectively, resulting in relative risks of 2.14 (95% CI: 1.25-3.67) and 1.35 (95% CI: 1.08-1.71). Approximately one half of this mediation is attributable to systolic blood pressure. Further adjustment for socioeconomic factors resulted in total mediation of 47% and 53% to relative risks of 2.01 (95% CI: 1.16-3.47) and 1.30 (1.03-1.65), respectively. Between ages 45 to 65 years, approximately half of the racial disparity in stroke risk is attributable to traditional risk factors (primarily systolic blood pressure) and socioeconomic factors, suggesting a critical need to understand the disparity in the development of these traditional risk factors. Because half of the excess stroke risk in blacks is not attributable to traditional risk factors and socioeconomic factors, differential impact of risk factors, residual confounding, or nontraditional risk factors may also play a role.

Risk Factors for Internet Gaming Disorder: Psychological Factors and Internet Gaming Characteristics.

PubMed

Rho, Mi Jung; Lee, Hyeseon; Lee, Taek-Ho; Cho, Hyun; Jung, Dong Jin; Kim, Dai-Jin; Choi, In Young

2017-12-27

Background : Understanding the risk factors associated with Internet gaming disorder (IGD) is important to predict and diagnose the condition. The purpose of this study is to identify risk factors that predict IGD based on psychological factors and Internet gaming characteristics; Methods : Online surveys were conducted between 26 November and 26 December 2014. There were 3568 Korean Internet game users among a total of 5003 respondents. We identified 481 IGD gamers and 3087 normal Internet gamers, based on Diagnostic and Statistical Manual for Mental Disorders (DSM-5) criteria. Logistic regression analysis was applied to identify significant risk factors for IGD; Results : The following eight risk factors were found to be significantly associated with IGD: functional and dysfunctional impulsivity (odds ratio: 1.138), belief self-control (1.034), anxiety (1.086), pursuit of desired appetitive goals (1.105), money spent on gaming (1.005), weekday game time (1.081), offline community meeting attendance (2.060), and game community membership (1.393; p < 0.05 for all eight risk factors); Conclusions : These risk factors allow for the prediction and diagnosis of IGD. In the future, these risk factors could also be used to inform clinical services for IGD diagnosis and treatment.

Prenatal and perinatal risk factors and testicular cancer: a hospital-based case-control study.

PubMed

Sonke, Gabe S; Chang, Shine; Strom, Sara S; Sweeney, Anne M; Annegers, J Fred; Sigurdson, Alice J

2007-01-01

Some evidence exists to support the hypothesis that elevated levels of circulating maternal estrogens during early pregnancy may increase risk of testicular germ cell cancer. However, the results from studies evaluating maternal factors have been mixed. We evaluated maternal factors, particularly those associated with excess estrogen levels, as risk factors for testicular cancer. We conducted a hospital-based case-control study at The University of Texas M. D. Anderson Cancer Center in Houston, Texas of 144 testicular cancer patients diagnosed between 1990 and 1996 and 86 friend controls matched to cases on age, race, and state of residence. Risk factor data about the mother, the son, and the pregnancy were obtained from the mothers by telephone interviews and from the sons by self-administered questionnaires. Extreme nausea during the first trimester of pregnancy was associated with an elevated risk of testicular cancer [odds ratio (OR) = 2.0; 95% confidence interval (CI) = 1.0-3.9]. Adjustment for potential confounders slightly lowered this risk (OR = 1.8; 95% CI = 0.9-3.8). Risks were modestly increased for other factors that are proxy measures for maternal estrogens, including preterm delivery (OR = 2.2; 95% CI = 0.4-12.9), birth weight <3000 g (OR = 2.4: 95% CI = 0.7-8.1), and birth weight >4000 g (OR = 1.7; 95% CI = 0.9-3.2), albeit nonsignificantly so. Our finding that severe nausea was associated with increased testicular cancer risk adds evidence to support the in utero estrogen exposure hypothesis because nausea early in pregnancy is related to rising levels of circulating estrogens. For other factors, which are less direct measures of maternal estrogens, the modest associations found indicate a suggestive pattern in support of the excess estrogen hypothesis.

Family-Environmental Factors Associated with Attention Deficit Hyperactivity Disorder in Chinese Children: A Case-Control Study

PubMed Central

du Prel Carroll, Xianming; Yi, Honggang; Liang, Yuezhu; Pang, Ke; Leeper-Woodford, Sandra; Riccardi, Patrizia; Liang, Xianhong

2012-01-01

Background Attention deficit hyperactivity disorder (ADHD) is one of the most common psychiatric disorders, affecting an estimated 5 to 12% of school-aged children worldwide. From 15 to 19 million Chinese children suffer from ADHD. The aim of this study was to investigate the association between family-environmental factors and ADHD in a sample of Chinese children. Methods A pair-matched, case-control study was conducted with 161 ADHD children and 161 non-ADHD children of matching age and sex, all from 5–18 years of age. The ADHD subjects and the normal controls were all evaluated via structured diagnostic interviews. We examined the association between family-environmental factors and ADHD using the conditional multiple logistic regression with backward stepwise selection to predict the associated factors of ADHD. Results Having experienced emotional abuse and being a single child were both significant factors associated with children diagnosed with ADHD. ADHD subjects were more likely to have suffered from emotional abuse (OR = 11.09, 95% CI = 2.15–57.29, P = 0.004) and have been a single child in the family (OR = 6.32, 95% CI = 2.09–19.14, P = 0.001) when compared to normal controls. The results were not modified by other confounding factors. Conclusion Our findings provide evidence that family-environmental factors are associated with ADHD among children in China. These findings, if confirmed by future research, may help to decrease ADHD by increasing the awareness of the effects of childhood emotional abuse. PMID:23209774

Synergistic effect of factor VII gene polymorphisms causing mild factor VII deficiency in a case of severe factor X deficiency.

PubMed

Deshpande, Rutuja; Ghosh, Kanjaksha; Shetty, Shrimati

2017-01-01

Congenital combined deficiency of coagulation factors VII and X are mainly attributed to large deletions involving both the genes in chromosome 13 or occasionally due to the coincidental occurrence of independently occurring mutations. We report the molecular basis of congenital combined deficiency of factors VII and X in a 6-year-old female child. Direct DNA sequencing of both factor VII (F7) and factor X (F10) genes showed a novel homozygous missense mutation p.Cys90Tyr (c.307G>A) in exon 4 of F10. No mutations were detected in F7; however, the patient was homozygous for three polymorphic alleles known to be associated with reduced factor VII levels. The present case illustrates the synergistic effect of multiple polymorphisms resulting in phenotypic factor VII deficiency in the absence of a pathogenic mutation.

Management strategies, early results, benefits, and risk factors of laparoscopic repair of perforated peptic ulcer.

PubMed

Lunevicius, Raimundas; Morkevicius, Matas

2005-10-01

The primary goal of this study was to describe epidemiology and management strategies of the perforated duodenal ulcer, as well as the most common methods of laparoscopic perforated duodenal ulcer repair. The secondary goal was to demonstrate the value of prospective and retrospective studies regarding the early results of surgery and the risk factors. The tertiary goal was to emphasize the benefits of this operation, and the fourth goal was to clarify the possible risk factors associated with laparoscopic repair of the duodenal ulcer. The Medline/Pubmed database was used. Review was done after evaluation of 96 retrieved full-text articles. Thirteen prospective and twelve retrospective studies were selected, grouped, and summarized. The spectrum of the retrospective studies' results are as follows: median overall morbidity rate 10.5 %, median conversion rate 7%, median hospital stay 7 days, and median postoperative mortality rate 0%. The following is the spectrum of results of the prospective studies: median overall morbidity rate was slightly less (6%); the median conversion rate was higher (15%); the median hospital stay was shorter (5 days) and the postoperative mortality was higher (3%). The risk factors identified were the same. Shock, delayed presentation (> 24 hours), confounding medical condition, age > 70 years, poor laparoscopic expertise, ASA III-IV, and Boey score should be considered preoperative laparoscopic repair risk factors. Each of these factors independently should qualify as a criterion for open repair due to higher intraoperative risks as well as postoperative morbidity. Inadequate ulcer localization, large perforation size (defined by some as > 6 mm diameter, and by others as > 10 mm), and ulcers with friable edges are also considered as conversion risk factors.

Relationship between stress-related psychosocial work factors and suboptimal health among Chinese medical staff: a cross-sectional study

PubMed Central

Meng, Shi-Jiao; Zhang, Jie; Wu, Li-Juan; Yan, Yu-Xiang

2018-01-01

Objectives The study aimed to develop and validate a model to measure psychosocial factors at work among medical staff in China based on confirmatory factor analysis (CFA). The second aim of the current study was to clarify the association between stress-related psychosocial work factors and suboptimal health status. Design The cross-sectional study was conducted using clustered sampling method. Setting Xuanwu Hospital, a 3A grade hospital in Beijing. Participants Nine hundred and fourteen medical staff aged over 40 years were sampled. Seven hundred and ninety-seven valid questionnaires were collected and used for further analyses. The sample included 94% of the Han population. Main outcome measures The Copenhagen Psychosocial Questionnaire (COPSOQ) and the Suboptimal Health Status Questionnaires-25 were used to assess the psychosocial factors at work and suboptimal health status, respectively. CFA was conducted to establish the evaluating method of COPSOQ. A multivariate logistic regression model was used to estimate the relationship between suboptimal health status and stress-related psychosocial work factors among Chinese medical staff. Results There was a strong correlation among the five dimensions of COPSOQ based on the first-order factor model. Then, we established two second-order factors including negative and positive psychosocial work stress factors to evaluate psychosocial factors at work, and the second-order factor model fit well. The high score in negative (OR (95% CI)=1.47 (1.34 to 1.62), P<0.001) and positive (OR (95% CI)=0.96 (0.94 to 0.98), P<0.001) psychosocial work factors increased and decreased the risk of suboptimal health, respectively. This relationship remained statistically significant after adjusting for confounders and when using different cut-offs of suboptimal health status. Conclusions Among medical staff, the second-order factor model was a suitable method to evaluate the COPSOQ. The negative and positive psychosocial work

ISS Payload Human Factors

NASA Technical Reports Server (NTRS)

Ellenberger, Richard; Duvall, Laura; Dory, Jonathan

2016-01-01

The ISS Payload Human Factors Implementation Team (HFIT) is the Payload Developer's resource for Human Factors. HFIT is the interface between Payload Developers and ISS Payload Human Factors requirements in SSP 57000. ? HFIT provides recommendations on how to meet the Human Factors requirements and guidelines early in the design process. HFIT coordinates with the Payload Developer and Astronaut Office to find low cost solutions to Human Factors challenges for hardware operability issues.

Constructivism, Factoring, and Beliefs.

ERIC Educational Resources Information Center

Rauff, James V.

1994-01-01

Discusses errors made by remedial intermediate algebra students in factoring polynomials in light of student definitions of factoring. Found certain beliefs about factoring to logically imply many of the errors made. Suggests that belief-based teaching can be successful in teaching factoring. (16 references) (Author/MKR)

Factors affecting microbial adhesion to stainless steel and other materials used in medical devices.

PubMed

Verran, J; Whitehead, K

2005-11-01

The role of biofilm in medical device associated infections is well documented. Biofilms are more resistant to antibiotics than planktonic cells, these are extremely difficult to treat. Prevention strategies include efforts to insert implants under stringent aseptic conditions, and also encompass the development of novel materials which interfere with the initial attachment of microorganisms to the surface of the device. Microbial cells also attach onto hygienic surfaces in the hospital setting, and thereby pose a cross-infection problem. In this case, vigorous cleaning and sanitizing regimes may be employed in addition to any surface modifications. Many factors affect the initial attachment of organisms to inert substrata, and their subsequent retention or removal/detachment, including the physical and chemical nature and location of the substratum, the type of organic material and microorganisms potentially fouling the surface, and the nature of the interface (solid-liquid in the body; solid-air on environmental surfaces). Focusing on one factor, surface topography, it is apparent that many further variables need to be defined in order to fully understand the interactions occurring between the cell and surface. It is therefore important when modifying one substratum surface property in order to reduce adhesion, to also consider other potentially confounding factors.

Resting-state FMRI confounds and cleanup

PubMed Central

Murphy, Kevin; Birn, Rasmus M.; Bandettini, Peter A.

2013-01-01

The goal of resting-state functional magnetic resonance imaging (FMRI) is to investigate the brain’s functional connections by using the temporal similarity between blood oxygenation level dependent (BOLD) signals in different regions of the brain “at rest” as an indicator of synchronous neural activity. Since this measure relies on the temporal correlation of FMRI signal changes between different parts of the brain, any non-neural activity-related process that affects the signals will influence the measure of functional connectivity, yielding spurious results. To understand the sources of these resting-state FMRI confounds, this article describes the origins of the BOLD signal in terms of MR physics and cerebral physiology. Potential confounds arising from motion, cardiac and respiratory cycles, arterial CO2 concentration, blood pressure/cerebral autoregulation, and vasomotion are discussed. Two classes of techniques to remove confounds from resting-state BOLD time series are reviewed: 1) those utilising external recordings of physiology and 2) data-based cleanup methods that only use the resting-state FMRI data itself. Further methods that remove noise from functional connectivity measures at a group level are also discussed. For successful interpretation of resting-state FMRI comparisons and results, noise cleanup is an often over-looked but essential step in the analysis pipeline. PMID:23571418

[Prevalence of cardiovascular risk factors in the Spanish working population].

PubMed

Sánchez-Chaparro, Miguel A; Román-García, Javier; Calvo-Bonacho, Eva; Gómez-Larios, Tomás; Fernández-Meseguer, Ana; Sáinz-Gutiérrez, Juan C; Cabrera-Sierra, Martha; García-García, Angel; Rueda-Vicente, Juan; Gálvez-Moraleda, Adolfo; González-Quintela, Arturo

2006-05-01

The routine medical check-up provides a good opportunity for screening workers early for cardiovascular risk factors. The aim of the present study was to investigate the prevalence of cardiovascular risk factors in the Spanish working population. The study included 216 914 working people (mean age 36.4 years, range 16-74 years, 73.1% male) undergoing routine medical check-up, which involved a structured questionnaire, physical examination, and standard serum biochemical analysis. Cardiovascular disease had been diagnosed previously in 0.7% of workers, hypertension in 6.2%, diabetes in 1.2%, and dyslipidemia in 8.9%. Routine check-up showed that 49.3% (51.3% of males and 43.8% of females) were smokers, 22.1% (27.0% of males and 8.8% of females) had high blood pressure (< or =140/90 mm Hg), 15.5% (18.3% of males and 13.3% of females) were obese (body mass index > or =30), 6.2% (7.8% of males and 1.9% of females) were hyperglycemic (blood glucose >110 mg/dL), and 64.2% had dyslipidemia (total cholesterol > or =200 mg/dL, LDL cholesterol > or =160 mg/dL, triglycerides > or =200 mg/dL, or HDL cholesterol < 40 mg/dL in males or < 50 mg/dL in females). When compared with workers in the service sector and after adjustment for potential confounders, workers in manufacturing, and particularly those in construction, had higher prevalences of both high blood pressure and smoking. The prevalence of cardiovascular risk factors in the Spanish working population is high, particularly in males and in certain types of employment.

Factors Affecting Dental Caries of Preschool Children in Shiraz, 2014

PubMed Central

Shaghaghian, Soheila; Abolvardi, Masoud; Akhlaghian, Marzieh

2018-01-01

Statement of the Problem: Dental caries, the most common infectious disease, can lead to several consequences, including inflammation and bleeding of the gum, abscess formation, tooth loss, and subsequently loss of available space in the arch. Purpose: This study was designed to determine dental caries status of Shiraz preschool children and its related factors. Materials and Method: This cross-sectional study was conducted on the children registered in Shiraz kindergartens in 2014. The study recruited 453 children by randomized cluster sampling. We evaluated the children’s demographic and oral hygiene factors, and their dental caries status using decayed, missed, and filled tooth (dmft) index and prevalence of the children with untreated dental caries. Relationship between the children’s characteristics and their dental caries status was evaluated. Results: Only 119 children (30.1%) were caries-free. The children’s mean dmft index was 3.88(±3.9). After controlling the effect of confounding factors, the children’s dental caries status was significantly associated with variables indicating their socioeconomic status such as fathers’ job, mothers’ education, and number of children in the family. Furthermore, there was a significant association between the children’s dental caries status and their oral hygiene habits such as frequency of tooth brushing. Conclusion: The dental caries status of the studied preschool children was not desirable which could be indicative of the inadequacy of the current preventive programs. To improve this issue, interventional preventive programs such as tooth brushing are recommended. The programs are more necessary for the children of low socioeconomic families and those with poor oral hygiene habits. PMID:29854883

Risk Factors for Internet Gaming Disorder: Psychological Factors and Internet Gaming Characteristics

PubMed Central

Lee, Hyeseon; Lee, Taek-Ho; Cho, Hyun; Kim, Dai-Jin; Choi, In Young

2017-01-01

Background: Understanding the risk factors associated with Internet gaming disorder (IGD) is important to predict and diagnose the condition. The purpose of this study is to identify risk factors that predict IGD based on psychological factors and Internet gaming characteristics; Methods: Online surveys were conducted between 26 November and 26 December 2014. There were 3568 Korean Internet game users among a total of 5003 respondents. We identified 481 IGD gamers and 3087 normal Internet gamers, based on Diagnostic and Statistical Manual for Mental Disorders (DSM-5) criteria. Logistic regression analysis was applied to identify significant risk factors for IGD; Results: The following eight risk factors were found to be significantly associated with IGD: functional and dysfunctional impulsivity (odds ratio: 1.138), belief self-control (1.034), anxiety (1.086), pursuit of desired appetitive goals (1.105), money spent on gaming (1.005), weekday game time (1.081), offline community meeting attendance (2.060), and game community membership (1.393; p < 0.05 for all eight risk factors); Conclusions: These risk factors allow for the prediction and diagnosis of IGD. In the future, these risk factors could also be used to inform clinical services for IGD diagnosis and treatment. PMID:29280953

Recombinant factor VIIa treatment for asymptomatic factor VII deficient patients going through major surgery.

PubMed

Livnat, Tami; Shenkman, Boris; Spectre, Galia; Tamarin, Ilia; Dardik, Rima; Israeli, Amnon; Rivkind, Avraham; Shabtai, Moshe; Marinowitz, Uri; Salomon, Ophira

2012-07-01

Factor VII deficiency is the most common among the rare autosomal recessive coagulation disorders worldwide. In factor VII deficient patients, the severity and clinical manifestations cannot be reliably determined by factor VII levels. Severe bleeding tends to occur in individuals with factor VII activity levels of 2% or less of normal. Patients with 2-10% factor VII vary between asymptomatic to severe life threatening haemorrhages behaviour. Recombinant factor VIIa (rFVIIa) is the most common replacement therapy for congenital factor VII deficiency. However, unlike haemophilia patients for whom treatment protocols are straight forward, in asymptomatic factor VII deficiency patients it is still debatable. In this study, we demonstrate that a single and very low dose of recombinant factor VIIa enabled asymptomatic patients with factor VII deficiency to go through major surgery safely. This suggestion was also supported by thrombin generation, as well as by thromboelastometry.

Association between Epicondylitis and Cardiovascular Risk Factors in Pooled Occupational Cohorts.

PubMed

Hegmann, Kurt T; Thiese, Matthew S; Kapellusch, Jay; Merryweather, Andrew; Bao, Stephen; Silverstein, Barbara; Wood, Eric M; Kendall, Richard; Foster, James; Drury, David L; Garg, Arun

2017-05-30

The pathophysiology of lateral epicondylitis (LE) is unclear. Recent evidence suggests some common musculoskeletal disorders may have a basis in cardiovascular disease (CVD) risk factors. Thus, we examined CVD risks as potential LE risks. Workers (n = 1824) were enrolled in two large prospective studies and underwent structured interviews and physical examinations at baseline. Analysis of pooled baseline data assessed the relationships separately between a modified Framingham Heart Study CVD risk score and three prevalence outcomes of: 1) lateral elbow pain, 2) positive resisted wrist or middle finger extension, and 3) a combination of both symptoms and at least one resisted maneuver. Quantified job exposures, personal and psychosocial confounders were statistically controlled. Odds ratios (ORs) and 95% Confidence Intervals (CIs) were calculated. There was a strong relationship between CVD risk score and lateral elbow symptoms, resisted wrist or middle finger extension and LE after adjustment for confounders. The adjusted ORs for symptoms were as high as 3.81 (95% CI 2.11, 6.85), for positive examination with adjusted odds ratios as high as 2.85 (95% CI 1.59, 5.12) and for combined symptoms and physical examination 6.20 (95% CI 2.04, 18.82). Relationships trended higher with higher CVD risk scores. These data suggest a potentially modifiable disease mechanism for LE.

Psychosocial, environmental and behavioral factors associated with bone health in middle-school girls

PubMed Central

Sharma, Shreela V.; Hoelscher, Deanna M.; Kelder, Steven H.; Day, R. Sue; Hergenroeder, Albert

2009-01-01

The purpose of this study was to identify the psychosocial, environmental and behavioral factors associated with calcium intake, physical activity and bone health in a cohort of adolescent girls. Baseline data (N = 718 girls, mean age: 11.6 ±0.4 years) from the Incorporating More Physical Activity and Calcium in Teens (IMPACT) study conducted in Texas, 2001–03, were utilized for the analyses. Hierarchical linear regression was used to examine the associations of interest. Confounders adjusted for included ethnicity, menarchal status, body mass index and lactose intolerance. Several psychosocial and behavioral factors were significantly associated with bone quality. These included knowledge of calcium content of foods (β = 0.08, P = 0.016), self-efficacy toward consuming calcium-rich foods (β = 0.16, P = 0.047), physical activity self-efficacy (β = 0.20, P = 0.002), physical activity outcome expectations (β = 0.5, P = 0.004), family encouragement to do physical activity (β = 0.96, P = 0.027), friend engagement in physical activity (β = 1.3, P = 0.001) and participation in sports teams (β = 1.7, P < 0.001). Self-efficacy, social support and participation in sports teams appear to be strongly associated with bone health in adolescent girls. Future health education/health promotion programs need to address these factors for effective primary prevention of osteoporosis in this population. PMID:18359949

Breast-feeding and cardiovascular risk factors and outcomes in later life: evidence from epidemiological studies.

PubMed

Owen, Christopher G; Whincup, Peter H; Cook, Derek G

2011-11-01

This paper considers the body of observational evidence examining the association of being breast-fed to cardiovascular risk factors and outcomes in later life, and whether any potentially advantageous findings are causal. Early cardiovascular consequences/correlates of breast-feeding, compared to being formula fed, include markedly higher levels of total blood cholesterol, lower levels of pre-prandial blood glucose and insulin and lower levels of adiposity. However, a key issue is whether these early differences at a period of rapid development programme/influence cardiovascular risk factors and outcomes in later life. Evidence of long-term effects of early feeding, largely from observational studies, has shown that those breast-fed have lower levels of blood total cholesterol, lower risk of type-2 diabetes and marginally lower levels of adiposity and blood pressure in adult life. There is no strong evidence to suggest effects of early feeding on adult levels of blood glucose, blood insulin and CHD outcomes, although further data are needed. However, the influence of confounding factors, such as maternal body size, maternal smoking and socio-demographic factors, and exclusivity of early feeding on these potentially beneficial associations needs to be considered before inferring any causal effects. Moreover, fewer studies have examined whether duration of exclusive breast-feeding has a graded influence on these risk factors and outcomes; such data would help further in deciding upon causal associations. While strong observational evidence suggests nutritional programming of adult cholesterol levels, associations with other markers of cardiometabolic risk and their consequences in later life need to be confirmed in well-conducted observational and experimental studies.

Physician trust and depression influence adherence to factor replacement: a single-centre cross-sectional study.

PubMed

Tran, D Q; Barry, V; Antun, A; Ribeiro, M; Stein, S; Kempton, C L

2017-01-01

Poor adherence to factor replacement therapy among patients with haemophilia can lead to joint bleeding and eventual disability. The aim of this study was to determine patient-related characteristics associated with adherence to factor replacement in adults with haemophilia. Adults with haemophilia were recruited to participate in this cross-sectional study. Adherence was measured using either the Validated Hemophilia Regimen Treatment Adherence Scale (VERITAS)-Pro or the VERITAS-PRN questionnaire. Simple and multiple regression analyses that controlled for confounding were performed to determine the association between patient-related characteristics and adherence to factor replacement therapy. Of the 99 subjects enrolled, all were men; 91% had haemophilia A and 78% had severe disease. Age ranged from 18 to 62 years. Most (95%) had functional health literacy; but only 23% were numerate. Mean adherence scores were 45.6 (SD 18) and 51.0 (SD 15) for those on a prophylactic and those on an episodic regimen, respectively, with a lower score indicating better adherence. On multivariable analysis, being on any chronic medication, longer duration followed at our haemophilia treatment centre, higher physician trust and better quality of life were associated with higher adherence. A history of depression was associated with lower adherence. Two potentially modifiable characteristics, physician trust and depression, were identified as motivator and barrier to adherence to factor replacement therapy. Promoting a high level of trust between the patient and the healthcare team as well as identifying and treating depression may impact adherence to factor replacement therapy and accordingly reduce joint destruction. © 2016 John Wiley & Sons Ltd.

Personal and workplace psychosocial risk factors for carpal tunnel syndrome: a pooled study cohort.

PubMed

Harris-Adamson, Carisa; Eisen, Ellen A; Dale, Ann Marie; Evanoff, Bradley; Hegmann, Kurt T; Thiese, Matthew S; Kapellusch, Jay M; Garg, Arun; Burt, Susan; Bao, Stephen; Silverstein, Barbara; Gerr, Fred; Merlino, Linda; Rempel, David

2013-08-01

Between 2001 and 2010, six research groups conducted coordinated multiyear, prospective studies of carpal tunnel syndrome (CTS) incidence in US workers from various industries and collected detailed subject-level exposure information with follow-up symptom, physical examination, electrophysiological measures and job changes. This analysis of the pooled cohort examined the incidence of dominant-hand CTS in relation to demographic characteristics and estimated associations with occupational psychosocial factors and years worked, adjusting for confounding by personal risk factors. 3515 participants, without baseline CTS, were followed-up to 7 years. Case criteria included symptoms and an electrodiagnostic study consistent with CTS. Adjusted HRs were estimated in Cox proportional hazard models. Workplace biomechanical factors were collected but not evaluated in this analysis. Women were at elevated risk for CTS (HR=1.30; 95% CI 0.98 to 1.72), and the incidence of CTS increased linearly with both age and body mass index (BMI) over most of the observed range. High job strain increased risk (HR=1.86; 95% CI 1.11 to 3.14), and social support was protective (HR=0.54; 95% CI 0.31 to 0.95). There was an inverse relationship with years worked among recent hires with the highest incidence in the first 3.5 years of work (HR=3.08; 95% CI 1.55 to 6.12). Personal factors associated with an increased risk of developing CTS were BMI, age and being a woman. Workplace risk factors were high job strain, while social support was protective. The inverse relationship between CTS incidence and years worked among recent hires suggests the presence of a healthy worker survivor effect in the cohort.

The burden of anaemia and associated factors in HIV positive Nigerian women.

PubMed

Ezechi, O C; Kalejaiye, O O; Gab-Okafor, C V; Oladele, D A; Oke, B; Ekama, S O; Odunukwe, N N; Ujah, I A O

2013-02-01

Anaemia is the most common complication of pregnancy and a predictor of poor maternal and foetal outcomes. HIV infection is now recognized as one of the major contributors to anaemia in pregnancy. It is therefore important to determine the burden and risk factors of anaemia in maternal HIV infection in others to plan effective prevention strategies as well as optimize management outcomes. To determine the prevalence and risk factors of anaemia in pregnant HIV positive Nigerians. The prevalence and possible risk factors of anaemia were investigated in HIV positive pregnant Nigerian women at a large HIV treatment clinic in southwestern Nigeria using a cross-sectional design between January 2006 and December 2011. Nine hundred and eighty-five (42.5 %) women of 2,318 HIV positive pregnant women seen during the period were anaemic by WHO standard defined by haemoglobin <11 g/dl. Majority were of mild to moderate severity (97.9 %). Short inter birth interval (p = 0.002), presence of opportunistic infections (OIs), (p = 0.001), use of zidovudine containing regimen (p = 0.0005) and CD4 cell count <200 cells/mm(3) (p = 0.001) were found to be independently associated with anaemia in HIV positive pregnant women after controlling for confounding variables. Anaemia was found to be high at 42.5 % among the HIV positive women studied and was found to be independently associated with short inter birth interval, presence of OIs, advanced HIV disease and use of zidovudine containing HAART regimen.

Environmental risk factors associated with bovine tuberculosis among cattle in high-risk areas

PubMed Central

Winkler, B.; Mathews, F.

2015-01-01

Our research shows that environmental features are important predictors of bovine tuberculosis (bTB) in British cattle herds in high-prevalence regions. Data from 503 case and 808 control farms included in the randomized badger culling trial (RBCT) were analysed. bTB risk increased in larger herds and on farms with greater areas of maize, deciduous woodland and marsh, whereas a higher percentage of boundaries composed of hedgerows decreased the risk. The model was tested on another case–control study outside RBCT areas, and here it had a much smaller predictive power. This suggests that different infection dynamics operate outside high-risk areas, although it is possible that unknown confounding factors may also have played a role. PMID:26559511

Oversimplifying quantum factoring.

PubMed

Smolin, John A; Smith, Graeme; Vargo, Alexander

2013-07-11

Shor's quantum factoring algorithm exponentially outperforms known classical methods. Previous experimental implementations have used simplifications dependent on knowing the factors in advance. However, as we show here, all composite numbers admit simplification of the algorithm to a circuit equivalent to flipping coins. The difficulty of a particular experiment therefore depends on the level of simplification chosen, not the size of the number factored. Valid implementations should not make use of the answer sought.

Elevated plasma factor VIII enhances venous thrombus formation in rabbits: contribution of factor XI, von Willebrand factor and tissue factor.

PubMed

Sugita, Chihiro; Yamashita, Atsushi; Matsuura, Yunosuke; Iwakiri, Takashi; Okuyama, Nozomi; Matsuda, Shuntaro; Matsumoto, Tomoko; Inoue, Osamu; Harada, Aya; Kitazawa, Takehisa; Hattori, Kunihiro; Shima, Midori; Asada, Yujiro

2013-07-01

Elevated plasma levels of factor VIII (FVIII) are associated with increased risk of deep venous thrombosis. The aim of this study is to elucidate how elevated FVIII levels affect venous thrombus formation and propagation in vivo. We examined rabbit plasma FVIII activity, plasma thrombin generation, whole blood coagulation, platelet aggregation and venous wall thrombogenicity before and one hour after an intravenous infusion of recombinant human FVIII (rFVIII). Venous thrombus induced by the endothelial denudation of rabbit jugular veins was histologically assessed. Thrombus propagation was evaluated as indocyanine green fluorescence intensity. Argatroban, a thrombin inhibitor, and neutralised antibodies for tissue factor (TF), factor XI (FXI), and von Willebrand factor (VWF) were infused before or after thrombus induction to investigate their effects on venous thrombus formation or propagation. Recombinant FVIII (100 IU/kg) increased rabbit plasma FVIII activity two-fold and significantly enhanced whole blood coagulation and total plasma thrombin generation, but did not affect initial thrombin generation time, platelet aggregation and venous wall thrombogenicity. The rFVIII infusion also increased the size of venous thrombus 1 hour after thrombus induction. Argatroban and the antibodies for TF, FXI or VWF inhibited such enhanced thrombus formation and all except TF suppressed thrombus propagation. In conclusion, elevated plasma FVIII levels enhance venous thrombus formation and propagation. Excess thrombin generation by FXI and VWF-mediated FVIII recruitment appear to contribute to the growth of FVIII-driven venous thrombus.

Factor Structure of the Penn State Worry Questionnaire: Examination of a Method Factor

ERIC Educational Resources Information Center

Hazlett-Stevens, Holly; Ullman, Jodie B.; Craske, Michelle G.

2004-01-01

The Penn State Worry Questionnaire (PSWQ) was originally designed as a unifactorial measure of pathological trait worry. However, recent studies supported a two-factor solution with positively worded items loading on the first factor and reverse-scored items loading on a second factor. The current study compared this two-factor model to a negative…

Fresh fruit intake and asthma symptoms in young British adults: confounding or effect modification by smoking?

PubMed

Butland, B K; Strachan, D P; Anderson, H R

1999-04-01

Antioxidant vitamins have been postulated as a protective factor in asthma. The associations between the frequency of fresh fruit consumption in summer, and the prevalence of self-reported asthma symptoms were investigated. The analysis was based on 5,582 males and 5,770 females, born in England, Wales and Scotland between March 3-9, 1958 and aged 33 yrs at the time of survey. The 12-month period prevalence of wheeze and frequent wheeze were inversely associated with frequent intakes of fresh fruit and salad/raw vegetables and positively associated with smoking and lower social class. After adjustment for mutual confounding and sex, associations with smoking persisted, but those with social class and salad/raw vegetable consumption lost significance. The frequency of fresh fruit intake was no longer associated with wheeze after adjustment, but was inversely associated with frequent wheeze and speech-limiting attacks. The association with frequent wheeze differed significantly between smoking groups (never, former, current) and appeared to be confined to exsmokers and current smokers. These findings support postulated associations between infrequent fresh fruit consumption and the prevalence of frequent or severe asthma symptoms in adults. Associations appeared to be restricted to smokers, with effect modification as a more likely explanation of this pattern than residual confounding by smoking.

Eating behaviour, insulin resistance and cluster of metabolic risk factors in European adolescents. The HELENA study.

PubMed

Sesé, Maria A; Jiménez-Pavón, David; Gilbert, Chantal C; González-Gross, Marcela; Gottrand, Frédéric; de Henauw, Stefaan; Breidenassel, Christina; Wärnberg, Julia; Widhalm, Kurt; Molnar, Dénes; Manios, Yannis; Cuenca-García, Magdalena; Kafatos, Anthony; Moreno, Luis A

2012-08-01

The present study examined the associations of food behaviours and preferences with markers of insulin resistance and clustered metabolic risk factors score after controlling for potential confounders, including body fat in European adolescents. A cross-sectional study "Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study" of 3546 European adolescents aged 12.5-17.5 years was conducted, using a complete dataset on at least glucose, insulin and "Food Choice Questionnaire". Results indicated skipping breakfast, as well as the preference of some foods such as nuts, chocolate, burgers and pizzas, soft drinks or juices, explain part of homeostasis model assessment index variance. In addition, snacking regularly during school day is associated with higher metabolic risk score in females. In conclusion, the present findings suggest that intervention studies aimed to prevent insulin resistance and metabolic risk factors in youth should focus not only in influencing food and drink preferences, but also to ensure healthy food behaviour in adolescents. The harmful consequences in the choice of certain foods or drinks and food habits can be countered with proper planning and intervention programs to prevent insulin resistance and metabolic risk factors. Copyright © 2012 Elsevier Ltd. All rights reserved.

Independent association of clustered metabolic risk factors with cardiorespiratory fitness in youth aged 11-17 years.

PubMed

Machado-Rodrigues, Aristides M; Leite, Neiva; Coelho-e-Silva, Manuel J; Martins, Raul A; Valente-dos-Santos, João; Mascarenhas, Luís P G; Boguszewski, Margaret C S; Padez, Cristina; Malina, Robert M

2014-01-01

Although the prevalence of metabolic syndrome (MetS) has increased in youth, the potential independent contribution of cardiorespiratory fitness (CRF) to the clustering of metabolic risk factors has received relatively little attention. This study evaluated associations between the clustering of metabolic risk factors and CRF in a sample of youth. Height, weight, BMI, fasting glucose, insulin, HDL-cholesterol, triglycerides and blood pressures were measured in a cross-sectional sample of 924 youth (402 males, 522 females) of 11-17 years. CRF was assessed using the 20-metre shuttle run test. Physical activity (PA) was measured with a 3-day diary. Outcome variables were statistically normalized and expressed as Z-scores. A MetS risk score was computed as the mean of the Z-scores. Multiple linear regression was used to test associations between CRF and metabolic risk, adjusted for age, sex, BMI, PA and parental education. CRF was inversely associated with MetS after adjustment for potential confounders. After adjusting for BMI, the relationship between CRF and metabolic risk has substantially improved. CRF was independently associated with the clustering of metabolic risk factors in youth of 11-17 years of age.

Factors associated with the choice of general medicine as a career among Japanese medical students

PubMed Central

Kawamoto, Ryuichi; Ninomiya, Daisuke; Kasai, Yoshihisa; Kusunoki, Tomo; Ohtsuka, Nobuyuki; Kumagi, Teru; Abe, Masanori

2016-01-01

Background In Japan, there is a shortage of young physicians in various specialties; the present situation of general medicine or family medicine (GM/FM) in particular is risky. The factors influencing the career choice of Japanese medical students are poorly understood. This study aims to identify factors related to choosing GM/FM as a career. Methods The study was designed as a cross-sectional survey. Students at one medical school in Japan filled out a questionnaire. Students were asked to state their intended medical specialty, and they rated the importance of specific individual and occupational aspects using a 4-point likert scale. Factor analysis was performed on the variables. Reliability of the factor scores was estimated using Cronbach‘s alpha coefficients; biserial correlations between the factors and career choices were calculated. Furthermore, multiple linear regression analysis was performed using career choice (GM/FM vs. others) as the criterion variable and the factors plus demographic characteristics as confounding variables. Results Factor analysis produced six factors that explained future career plans. Medical students in this study had a positive and realistic idea about GM/FM, but only 18.8% of them chose GM/FM first as a career. The significant variables associated with choosing GM/FM first as a career were: ‘Admission from hometown’ (β=0.189, P=0.001), ‘Student preparing for the entrance exam’ (β=0.172; P=0.001), ‘Intent for rural practice’ (β=0.123, P=0.016), and ‘Work–life balance’ (β=0.126, P=0.013). While significant variables that were negatively associated with choosing GM/FM were ‘Presence of medical relatives’ (β=−0.107, P=0.037) and ‘Scientific orientation’ (β=−0.125, P=0.013). Conclusions Strategies have been suggested, such as recruiting medical students with significant variables that were associated with choosing GM/FM first as a career. By engaging students early in their choice of career

Factors associated with the choice of general medicine as a career among Japanese medical students.

PubMed

Kawamoto, Ryuichi; Ninomiya, Daisuke; Kasai, Yoshihisa; Kusunoki, Tomo; Ohtsuka, Nobuyuki; Kumagi, Teru; Abe, Masanori

2016-01-01

Background In Japan, there is a shortage of young physicians in various specialties; the present situation of general medicine or family medicine (GM/FM) in particular is risky. The factors influencing the career choice of Japanese medical students are poorly understood. This study aims to identify factors related to choosing GM/FM as a career. Methods The study was designed as a cross-sectional survey. Students at one medical school in Japan filled out a questionnaire. Students were asked to state their intended medical specialty, and they rated the importance of specific individual and occupational aspects using a 4-point likert scale. Factor analysis was performed on the variables. Reliability of the factor scores was estimated using Cronbach's alpha coefficients; biserial correlations between the factors and career choices were calculated. Furthermore, multiple linear regression analysis was performed using career choice (GM/FM vs. others) as the criterion variable and the factors plus demographic characteristics as confounding variables. Results Factor analysis produced six factors that explained future career plans. Medical students in this study had a positive and realistic idea about GM/FM, but only 18.8% of them chose GM/FM first as a career. The significant variables associated with choosing GM/FM first as a career were: 'Admission from hometown' (β=0.189, P=0.001), 'Student preparing for the entrance exam' (β=0.172; P=0.001), 'Intent for rural practice' (β=0.123, P=0.016), and 'Work-life balance' (β=0.126, P=0.013). While significant variables that were negatively associated with choosing GM/FM were 'Presence of medical relatives' (β=-0.107, P=0.037) and 'Scientific orientation' (β=-0.125, P=0.013). Conclusions Strategies have been suggested, such as recruiting medical students with significant variables that were associated with choosing GM/FM first as a career. By engaging students early in their choice of career, we may be able to increase

Factors associated with the choice of general medicine as a career among Japanese medical students.

PubMed

Kawamoto, Ryuichi; Ninomiya, Daisuke; Kasai, Yoshihisa; Kusunoki, Tomo; Ohtsuka, Nobuyuki; Kumagi, Teru; Abe, Masanori

2016-01-01

In Japan, there is a shortage of young physicians in various specialties; the present situation of general medicine or family medicine (GM/FM) in particular is risky. The factors influencing the career choice of Japanese medical students are poorly understood. This study aims to identify factors related to choosing GM/FM as a career. The study was designed as a cross-sectional survey. Students at one medical school in Japan filled out a questionnaire. Students were asked to state their intended medical specialty, and they rated the importance of specific individual and occupational aspects using a 4-point likert scale. Factor analysis was performed on the variables. Reliability of the factor scores was estimated using Cronbach's alpha coefficients; biserial correlations between the factors and career choices were calculated. Furthermore, multiple linear regression analysis was performed using career choice (GM/FM vs. others) as the criterion variable and the factors plus demographic characteristics as confounding variables. Factor analysis produced six factors that explained future career plans. Medical students in this study had a positive and realistic idea about GM/FM, but only 18.8% of them chose GM/FM first as a career. The significant variables associated with choosing GM/FM first as a career were: 'Admission from hometown' (β=0.189, P=0.001), 'Student preparing for the entrance exam' (β=0.172; P=0.001), 'Intent for rural practice' (β=0.123, P=0.016), and 'Work-life balance' (β=0.126, P=0.013). While significant variables that were negatively associated with choosing GM/FM were 'Presence of medical relatives' (β=-0.107, P=0.037) and 'Scientific orientation' (β=-0.125, P=0.013). Strategies have been suggested, such as recruiting medical students with significant variables that were associated with choosing GM/FM first as a career. By engaging students early in their choice of career, we may be able to increase enthusiasm for this specialty.

Environmental risk factors for autism: an evidence-based review of systematic reviews and meta-analyses.

PubMed

Modabbernia, Amirhossein; Velthorst, Eva; Reichenberg, Abraham

2017-01-01

According to recent evidence, up to 40-50% of variance in autism spectrum disorder (ASD) liability might be determined by environmental factors. In the present paper, we conducted a review of systematic reviews and meta-analyses of environmental risk factors for ASD. We assessed each review for quality of evidence and provided a brief overview of putative mechanisms of environmental risk factors for ASD. Current evidence suggests that several environmental factors including vaccination, maternal smoking, thimerosal exposure, and most likely assisted reproductive technologies are unrelated to risk of ASD. On the contrary, advanced parental age is associated with higher risk of ASD. Birth complications that are associated with trauma or ischemia and hypoxia have also shown strong links to ASD, whereas other pregnancy-related factors such as maternal obesity, maternal diabetes, and caesarian section have shown a less strong (but significant) association with risk of ASD. The reviews on nutritional elements have been inconclusive about the detrimental effects of deficiency in folic acid and omega 3, but vitamin D seems to be deficient in patients with ASD. The studies on toxic elements have been largely limited by their design, but there is enough evidence for the association between some heavy metals (most important inorganic mercury and lead) and ASD that warrants further investigation. Mechanisms of the association between environmental factors and ASD are debated but might include non-causative association (including confounding), gene-related effect, oxidative stress, inflammation, hypoxia/ischemia, endocrine disruption, neurotransmitter alterations, and interference with signaling pathways. Compared to genetic studies of ASD, studies of environmental risk factors are in their infancy and have significant methodological limitations. Future studies of ASD risk factors would benefit from a developmental psychopathology approach, prospective design, precise exposure

Traditional risk factors as the underlying cause of racial disparities in stroke: lessons from the half full (empty?) glass

PubMed Central

Howard, George; Cushman, Mary; Kissela, Brett M.; Kleindorfer, Dawn O.; McClure, Leslie A.; Safford, Monika M.; Rhodes, J. David; Soliman, Elsayed Z.; Moy, Claudia S.; Judd, Suzanne E.; Howard, Virginia J.

2011-01-01

Background and Purpose Black/white disparities in stroke incidence are well-documented, but few studies have assessed the contributions to the disparity. Here we assess the contribution of “traditional” risk factors. Methods 25,714 black and white men and women, aged 45+ and stroke-free at baseline were followed for an average of 4.4 years to detect stroke. Mediation analysis employing proportional hazards analysis assessed the contribution of “traditional” risk factors to racial disparities. Results At age 45, incident stroke risk was 2.90 (95% CI: 1.72 – 4.89) times more likely in blacks than whites, and 1.66 (95% CI: 1.34 – 2.07) times at age 65. Adjustment for risk factors attenuated these excesses by 40% and 45%, respectively, resulting in relative risks of 2.14 (95% CI: 1.25 – 3.67) and 1.35 (95% CI: 1.08 – 1.71). Approximately one-half of this mediation is attributable to systolic blood pressure. Further adjustment for socioeconomic factors resulted in total mediation of 47% and 53% to relative risks of 2.01 (95% CI: 1.16 – 3.47) and 1.30 (1.03 – 1.65) respectively. Conclusions Between ages 45 to 65 years, approximately half of the racial disparity in stroke risk is attributable to traditional risk factors (primarily systolic blood pressure) and socioeconomic factors, suggesting a critical need to understand the disparity in the development of these traditional risk factors. Because half of the excess stroke risk in blacks is not attributable to traditional risk factors and socioeconomic factors, differential racial susceptibility to risk factors, residual confounding or non-traditional risk factors may also play a role. PMID:21960581

What Are Rare Clotting Factor Deficiencies?

MedlinePlus

... Deficiency Factor V Deficiency Combined FV & FVIII Deficiencies Factor VII Deficiency Factor X Deficiency Factor XI Deficiency Factor ... Deficiency Factor V Deficiency Combined FV & FVIII Deficiencies Factor VII Deficiency Factor X Deficiency Factor XI Deficiency Factor ...

Bayesian Exploratory Factor Analysis

PubMed Central

Conti, Gabriella; Frühwirth-Schnatter, Sylvia; Heckman, James J.; Piatek, Rémi

2014-01-01

This paper develops and applies a Bayesian approach to Exploratory Factor Analysis that improves on ad hoc classical approaches. Our framework relies on dedicated factor models and simultaneously determines the number of factors, the allocation of each measurement to a unique factor, and the corresponding factor loadings. Classical identification criteria are applied and integrated into our Bayesian procedure to generate models that are stable and clearly interpretable. A Monte Carlo study confirms the validity of the approach. The method is used to produce interpretable low dimensional aggregates from a high dimensional set of psychological measurements. PMID:25431517

Risk Factors for Scleroderma

MedlinePlus

... You are here: Home For Patients Risk Factors Risk Factors for Scleroderma The cause of scleroderma is ... what biological factors contribute to scleroderma pathogenesis. Genetic Risk Scleroderma does not tend to run in families ...

Incidence and Predicted Risk Factors of Pressure Ulcers in Surgical Patients: Experience at a Medical Center in Taipei, Taiwan

PubMed Central

Fu Shaw, Ling; Chang, Pao-Chu; Lee, Jung-Fen; Kung, Huei-Yu

2014-01-01

Purpose. To explore the context of incidence of and associated risk factors for pressure ulcers amongst the population of surgical patients. Methods. The initial study cohort was conducted with a total of 297 patients admitted to a teaching hospital for a surgical operation from November 14th to 27th 2006 in Taipei, Taiwan. The Braden scale, pressure ulcers record sheet, and perioperative patient outcomes free from signs and symptoms of injury related to positioning and related nursing interventions and activities were collected. Results. The incidence of immediate and thirty-minute-later pressure ulcers is 9.8% (29/297) and 5.1% (15/297), respectively. Using logistic regression model, the statistically significantly associated risk factors related to immediate and thirty-minute-later pressure ulcers include operation age, type of anesthesia, type of operation position, type of surgery, admission Braden score, and number of nursing intervention after adjustment for confounding factors. Conclusion. Admission Braden score and number of nursing intervention are well-established protected factors for the development of pressure ulcers. Our study shows that older operation age, type of anesthesia, type of operation position, and type of surgery are also associated with the development of pressure ulcers. PMID:25057484

Domestic Violence as a Risk Factor for Attempted Suicide in Married Women.

PubMed

Indu, Pankajakshan Vijayanthi; Remadevi, Sivaraman; Vidhukumar, Karunakaran; Shah Navas, Peer Mohammed; Anilkumar, Thekkethayyil Viswanathan; Subha, Nanoo

2017-08-01

High rates of suicide attempts and domestic violence (DV) in women of reproductive age group have been reported from South India, but the association between them was not studied. Hence, this study was undertaken to assess whether DV is a risk factor for attempted suicide in married women of reproductive age group. A hospital-based case-control study with 77 incident cases of attempted suicide in married women of the age group of 18 to 45 years and 153 controls belonging to the same age group, without history of suicide attempt, was undertaken over a period of 6 months. Univariate and multivariate analyses were done. The crude odds ratio (cOR) for DV was found to be 6.15 (95% confidence interval [95% CI] = [2.95, 12.82], p value = .0001). Other statistically significant risk factors included younger age group (below 30 years); gross family income > Rs. 5,000; higher occupational status of spouse; having poor social support; having a family history of psychiatric disorders, substance use disorders, and suicide/suicide attempt; higher impulsiveness scores; having higher scores of stressful life events over the past 12 months, and alcohol use disorder in husband. Islamic faith was found to be a significant protective factor. On logistic regression, DV was found to be an independent risk factor for attempted suicide in this study population (adjusted OR = 3.79, 95% CI = [1.35, 10.62], p value = .011). Age groups, stressful life events, impulsiveness, and alcohol use disorder in husband were the confounders adjusted for in logistic regression along with other significant risk and protective factors. Significant dose-response relationship was also observed between DV and attempted suicide. In accordance with the stress-diathesis model for suicidal behavior, DV is found to be a stressor which precipitates suicide attempt in those with diathesis like family history of psychiatric disorders. Clinical, research, and policy implications of the findings are discussed.

Maternal and family factors and child eating pathology: risk and protective relationships

PubMed Central

2014-01-01

Background Previous studies have found associations between maternal and family factors and child eating disorder symptoms. However, it is not clear whether family factors predict eating disorder symptoms specifically, or relate to more general child psychopathology, of which eating disorder symptoms may be one component. This study aimed to identify maternal and family factors that may predict increases or decreases in child eating disorder symptoms over time, accounting for children’s body mass index z-scores and levels of general psychological distress. Methods Participants were 221 mother-child dyads from the Childhood Growth and Development Study, a prospective cohort study in Western Australia. Participants were assessed at baseline, 1-year follow-up and 2-year follow-up using interview and self-report measures. Children had a mean age of 10 years at baseline and 46% were male. Linear mixed models and generalised estimating equations were used to identify predictors of children’s eating disorder symptoms, with outcome variables including a global index of eating disorder psychopathology, levels of dietary restraint, levels of emotional eating, and the presence of loss of control (‘binge’) eating. Results Children of mothers with a current or past eating disorder reported significantly higher levels of global eating disorder symptoms and emotional eating than other children, and mothers with a current or past eating disorder reported significantly more concern about their children’s weight than other mothers. Maternal concern about child weight, rather than maternal eating disorder symptoms, was significant in predicting child eating disorder symptoms over time. Family exposure to stress and low maternal education were additional risk factors for eating disorder symptoms, whilst child-reported family satisfaction was a protective factor. Conclusions After adjusting for relevant confounding variables, maternal concern about child weight, children�

Coagulation Factor Tests

MedlinePlus

... your coagulation factors. Coagulation factors are known by Roman numerals (I, II VIII, etc.) or by name ( ... need this test if you have a family history of bleeding disorders. Most bleeding disorders are inherited . ...

Socioeconomic factors and the risk for sarcoma.

PubMed

Hampras, Shalaka S; Moysich, Kirsten B; Marimuthu, Sathiya P; Ravi, Vinod; Jayaprakash, Vijayvel

2014-11-01

Sarcomas are a heterogeneous group of rare malignancies arising from mesenchymal tissue. Although several occupational exposures have been evaluated in association with sarcoma, little is known about the role of socioeconomic indicators such as education. Socioeconomic status has been found to be associated with risk of development of several types of cancers, primarily lung, gastric, and cervical cancers. We conducted a hospital-based case-control study to evaluate the association of socioeconomic level with the risk for sarcoma. A total of 371 incident cases of sarcoma were matched in terms of age, sex, and year of enrollment in the study with 742 cancer-free controls. Education and income levels were evaluated as the indicators of socioeconomic status. Higher education (college level) was associated with a significantly lower risk for sarcoma [odds ratio (OR)=0.48, 95% confidence interval (CI)=0.29-0.80], even after adjusting for important confounders. After stratifying by sex, significantly lower risk for sarcoma was observed among men who had college level education compared with men with a level of education of eighth grade or lower (OR=0.38, 95% CI=0.19-0.74). A significant association between education and the risk for sarcoma remained after stratifying by income (OR=0.49, 95% CI=0.28-0.86, among the low income group). When analyzed as a composite exposure, individuals with high education and high income status had significantly lower risk for sarcoma compared with those with low income and low education status (OR=0.41, 95% CI=0.23-0.71). Thus, socioeconomic factors may play a significant role in determining the risk for sarcoma and should be explored further to elucidate the underlying factors that may explain these sociodemographic inequalities related to sarcoma.

IVI human factors strategy

DOT National Transportation Integrated Search

1999-11-01

This document focuses on human factors research that supports the Intelligent Vehicle Initiative (IVI). The status of the problem areas within categories used often by the human factors community to organize human factors process is discussed. A simi...

Factor Analysis and Counseling Research

ERIC Educational Resources Information Center

Weiss, David J.

1970-01-01

Topics discussed include factor analysis versus cluster analysis, analysis of Q correlation matrices, ipsativity and factor analysis, and tests for the significance of a correlation matrix prior to application of factor analytic techniques. Techniques for factor extraction discussed include principal components, canonical factor analysis, alpha…

Anatomical, chemical, and ecological factors affecting tree species choice in dendrochemistry studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cutter, B.E.; Guyette, R.P.

1993-07-01

Recently, element concentrations in tree rings have been used to monitor metal contamination, fertilization, and the effects of acid precipitation on soils. This has stimulated interest in which tree species may be suitable for use in studies of long-term trends in environmental chemistry. Potential radial translocation of elements across living boundaries can be a confounding factor in assessing environmental change. The selection of species which minimizes radial translocation of elements can be critical to the success of dendrochemical research. Criteria for selection of species with characteristics favorable for dendrochemical analysis are categorized into (1) habitat-based factors, (2) xylem-based factors, andmore » (3) element-based factors. A wide geographic range and ecological amplitude provide an advantage in calibration and better controls on the effects of soil chemistry. The most important xylem-based criteria are heartwood moisture content, permeability, and the nature of the sapwood-heartwood transition. The element of interest is important in determining suitable tree species because all elements are not equally mobile or detectable in the xylem. Ideally, the tree species selected for dendrochemical study will be long-lived, grow on a wide range of sites over a large geographic distribution, have a distinct heartwood with a low number of rings in the sapwood, a low heartwood moisture content, and have low radial permeability. Recommended temperate zone North American species include white oak (Quercus alba L.), post oak (Q. stellate Wangenh.), eastern redcedar (funiperus virginiana L.), old-growth Douglas-fir [Pseudoaugu menziesii (Mirb.) Franco] and big sagebrush (Artemisia tridentata Nutt.). In addition, species such as bristlecone pine (Pinus aristata Engelm. syn. longaeva), old-growth redwood [Sequoia sempervirens (D. Don) Endl.], and giant sequoia [S. gigantea (Lindl.) Deene] may be suitable for local purposes. 118 refs., 2 tabs.« less

Risk factors for mercury exposure of children in a rural mining town in northern Chile.

PubMed

Ohlander, Johan; Huber, Stella Maria; Schomaker, Michael; Heumann, Christian; Schierl, Rudolf; Michalke, Bernhard; Jenni, Oskar G; Caflisch, Jon; Muñoz, Daniel Moraga; von Ehrenstein, Ondine S; Radon, Katja

2013-01-01

Traditional gold mining is associated with mercury exposure. Especially vulnerable to its neurotoxic effects is the developing nervous system of a child. We aimed to investigate risk factors of mercury exposure among children in a rural mining town in Chile. Using a validated questionnaire distributed to the parents of the children, a priori mercury risk factors, potential exposure pathways and demographics of the children were obtained. Mercury levels were measured through analyzing fingernail samples. Logistic regression modeling the effect of risk factors on mercury levels above the 75(th) percentile were made, adjusted for potential confounders. The 288 children had a mean age of 9.6 years (SD = 1.9). The mean mercury level in the study population was 0.13 µg/g (SD 0.11, median 0.10, range 0.001-0.86 µg/g). The strongest risk factor for children's odds of high mercury levels (>75(th) percentile, 0.165 µg/g) was to play inside a house where a family member worked with mercury (OR adjusted 3.49 95% CI 1.23-9.89). Additionally, children whose parents worked in industrial gold mining had higher odds of high mercury levels than children whose parents worked in industrial copper mining or outside mining activities. Mercury exposure through small-scale gold mining might affect children in their home environments. These results may further help to convince the local population of banning mercury burning inside the households.

Early life risk factors and their cumulative effects as predictors of overweight in Spanish children.

PubMed

Iguacel, Isabel; Escartín, Laura; Fernández-Alvira, Juan M; Iglesia, Iris; Labayen, Idoia; Moreno, Luis A; Samper, María Pilar; Rodríguez, Gerardo

2018-05-01

To explore early life risk factors of overweight/obesity at age 6 years and their cumulative effects on overweight/obesity at ages 2, 4 and 6 years. Altogether 1031 Spanish children were evaluated at birth and during a 6-year follow-up. Early life risk factors included: parental overweight/obesity, parental origin/ethnicity, maternal smoking during pregnancy, gestational weight gain, gestational age, birth weight, caesarean section, breastfeeding practices and rapid infant weight gain collected via hospital records. Cumulative effects were assessed by adding up those early risk factors that significantly increased the risk of overweight/obesity. We conducted binary logistic regression models. Rapid infant weight gain (OR 2.29, 99% CI 1.54-3.42), maternal overweight/obesity (OR 1.93, 99% CI 1.27-2.92), paternal overweight/obesity (OR 2.17, 99% CI 1.44-3.28), Latin American/Roma origin (OR 3.20, 99% CI 1.60-6.39) and smoking during pregnancy (OR 1.61, 99% CI 1.01-2.59) remained significant after adjusting for confounders. A higher number of early life risk factors accumulated was associated with overweight/obesity at age 6 years but not at age 2 and 4 years. Rapid infant weight gain, parental overweight/obesity, maternal smoking and origin/ethnicity predict childhood overweight/obesity and present cumulative effects. Monitoring children with rapid weight gain and supporting a healthy parental weight are important for childhood obesity prevention.

American Visceral Leishmaniasis: Factors Associated with Lethality in the State of São Paulo, Brazil

PubMed Central

Madalosso, Geraldine; Fortaleza, Carlos Magno; Ribeiro, Ana Freitas; Cruz, Lisete Lage; Nogueira, Péricles Alves; Lindoso, José Angelo Lauletta

2012-01-01

Objectives. To identify factors associated with death in visceral leishmaniasis (VL) cases. Patients and Methodology. We evaluated prognostic factors for death from VL in São Paulo state, Brazil, from 1999 to 2005. A prognostic study nested in a clinical cohort was carried out by data analysis of 376 medical files. A comparison between VL fatal cases and survivors was performed for clinical, laboratory, and biological features. Association between variables and death was assessed by univariate analysis, and the multiple logistic regression model was used to determine adjusted odds ratio for death, controlling confounding factors. Results. Data analysis identified 53 fatal cases out of 376 patients, between 1999 and 2005 in São Paulo state. Lethality was 14.1% (53/376), being higher in patients older than fifty years. The main causes of death were sepsis, bleeding, liver failure, and cardiotoxicity due to treatment. Variables significantly associated with death were severe anemia, bleeding, heart failure, jaundice, diarrhea, fever for more than sixty days, age older than fifty years, and antibiotic use. Conclusion. Educational health measures are needed for the general population and continuing education programs for health professionals working in the affected areas with the purpose of identifying and treating early cases, thus preventing the disease evolution towards death. PMID:23024661

Identification of factors involved in medication compliance: incorrect inhaler technique of asthma treatment leads to poor compliance

PubMed Central

Darbà, Josep; Ramírez, Gabriela; Sicras, Antoni; García-Bujalance, Laura; Torvinen, Saku; Sánchez-de la Rosa, Rainel

2016-01-01

Objective To identify the impact of delivery device of inhaled corticosteroids and long-acting β2-agonist (ICS/LABA) on asthma medication compliance, and investigate other factors associated with compliance. Materials and methods We conducted a retrospective and multicenter study based on a review of medical registries of asthmatic patients treated with ICS/LABA combinations (n=2,213) whose medical devices were either dry powder inhalers (DPIs, such as Accuhaler®, Turbuhaler®, and NEXThaler®) or pressurized metered-dose inhalers (pMDI). Medication compliance included persistence outcomes through 18 months and medication possession ratios. Data on potential confounders of treatment compliance such as asthma exacerbations, comorbidities, demographic characteristics, and health care resource utilization were also explored. Results The probability of asthma medication compliance in case of DPIs was lower compared to pMDIs, which suggests that inhaler devices influence inhalation therapies. There were additional confounding factors that were considered as explanatory variables of compliance. A worse measure of airflow obstruction (forced expiration volume in 1 second), comorbidities and general practitioner (GP) consultations more than once per month decreased the probability of compliance. Within comorbidities, alcoholism was positively associated with compliance. Patients of 29–39, 40–50, and 51–61 age groups or suffering from more than two exacerbations during the study period were more likely to comply with their medication regime. The effects of DPIs toward compliance varied with the different DPIs. For instance, Accuhaler® had a greater negative effect on compliance compared to Turbuhaler® and Nexthaler® in cases of patients who suffered exacerbations. We found that GP consultations reduced the probability of medication compliance for patients treated with formoterol/budesonide combination. For retired patients, visiting the GP increased the

Success Providing Postpartum Intrauterine Devices in Private-Sector Health Care Facilities in Nigeria: Factors Associated With Uptake.

PubMed

Eluwa, George Ie; Atamewalen, Ronke; Odogwu, Kingsley; Ahonsi, Babatunde

2016-06-20

Use of modern contraceptive methods in Nigeria remained at 10% between 2008 and 2013 despite substantive investments in family planning services. Many women in their first postpartum year, in particular, have an unmet need for family planning. We evaluated use of postpartum intrauterine device (IUD) insertion and determined factors associated with its uptake in Nigeria. Data were collected between May 2014 and February 2015 from 11 private health care facilities in 6 southern Nigerian states. Women attending antenatal care in participating facilities were counseled on all available contraceptive methods including the postpartum IUD. Data were abstracted from participating facility records and evaluated using a cross-sectional analysis. Categorical variables were calculated as proportions while continuous variables were calculated as medians with the associated interquartile range (IQR). Multivariate logistic regression analysis was used to identify factors associated with uptake of the postpartum IUD while controlling for potential confounding factors, including age, educational attainment, marital status, parity, number of living children, and previous use of contraception. During the study period, 728 women delivered in the 11 facilities. The median age was 28 years, and most women were educated (73% had completed at least the secondary level). The majority (96%) of the women reported they were married, and the median number of living children was 3 (IQR, 2-4). Uptake of the postpartum IUD was 41% (n = 300), with 8% (n = 25) of the acceptors experiencing expulsion of the IUD within 6 weeks post-insertion. After controlling for potential confounding factors, several characteristics were associated with greater likelihood of choosing the postpartum IUD, including lower education, having a higher number of living children, and being single. Women who had used contraceptives previously were less likely to choose the postpartum IUD than women who had not

Success Providing Postpartum Intrauterine Devices in Private-Sector Health Care Facilities in Nigeria: Factors Associated With Uptake

PubMed Central

Eluwa, George IE; Atamewalen, Ronke; Odogwu, Kingsley; Ahonsi, Babatunde

2016-01-01

ABSTRACT Background: Use of modern contraceptive methods in Nigeria remained at 10% between 2008 and 2013 despite substantive investments in family planning services. Many women in their first postpartum year, in particular, have an unmet need for family planning. We evaluated use of postpartum intrauterine device (IUD) insertion and determined factors associated with its uptake in Nigeria. Methods: Data were collected between May 2014 and February 2015 from 11 private health care facilities in 6 southern Nigerian states. Women attending antenatal care in participating facilities were counseled on all available contraceptive methods including the postpartum IUD. Data were abstracted from participating facility records and evaluated using a cross-sectional analysis. Categorical variables were calculated as proportions while continuous variables were calculated as medians with the associated interquartile range (IQR). Multivariate logistic regression analysis was used to identify factors associated with uptake of the postpartum IUD while controlling for potential confounding factors, including age, educational attainment, marital status, parity, number of living children, and previous use of contraception. Results: During the study period, 728 women delivered in the 11 facilities. The median age was 28 years, and most women were educated (73% had completed at least the secondary level). The majority (96%) of the women reported they were married, and the median number of living children was 3 (IQR, 2–4). Uptake of the postpartum IUD was 41% (n = 300), with 8% (n = 25) of the acceptors experiencing expulsion of the IUD within 6 weeks post-insertion. After controlling for potential confounding factors, several characteristics were associated with greater likelihood of choosing the postpartum IUD, including lower education, having a higher number of living children, and being single. Women who had used contraceptives previously were less likely to choose the

FACTOR FINDER CD-ROM

EPA Science Inventory

The Factor Finder CD-ROM is a user-friendly, searchable tool used to locate exposure factors and sociodemographic data for user-defined populations. Factor Finder improves the exposure assessors and risk assessors (etc.) ability to efficiently locate exposure-related informatio...

Human Factors Job Aid

DOT National Transportation Integrated Search

1996-12-09

The purpose of this Human Factors Job Aid is to serve as a desk reference for : human factors integration during system acquisition. The first chapter contains : an overview of the FAA human factors process in system acquisitions. The : remaining eig...

Risk factors for Clostridium difficile infections - an overview of the evidence base and challenges in data synthesis.

PubMed

Eze, Paul; Balsells, Evelyn; Kyaw, Moe H; Nair, Harish

2017-06-01

Recognition of a broad spectrum of disease and development of Clostridium difficile infection (CDI) and recurrent CDI (rCDI) in populations previously considered to be at low risk has renewed attention on differences in the risk profile of patients. In the absence of primary prevention for CDI and limited treatment options, it is important to achieve a deep understanding of the multiple factors that influence the risk of developing CDI and rCDI. We conducted a review of systematic reviews and meta-analyses on risk factors for CDI and rCDI published between 1990 and October 2016. 22 systematic reviews assessing risk factors for CDI (n = 19) and rCDI (n = 6) were included. Meta-analyses were conducted in 17 of the systematic reviews. Over 40 risk factors have been associated with CDI and rCDI and can be classified into three categories: pharmacological risk factors, host-related risk factors, and clinical characteristics or interventions. Most systematic reviews and meta-analyses have focused on antibiotic use (n = 8 for CDI, 3 for rCDI), proton pump inhibitors (n = 8 for CDI, 4 for rCDI), and histamine 2 receptor antagonists (n = 4 for CDI) and chronic kidney disease (n = 4 for rCDI). However, other risk factors have been assessed. We discuss the state of the evidence, methods, and challenges for data synthesis. Several studies, synthesized in different systematic review, provide valuable insights into the role of different risk factors for CDI. Meta-analytic evidence of association has been reported for factors such as antibiotics, gastric acid suppressants, non-selective NSAID, and some co-morbidities. However, despite statistical significance, issues of high heterogeneity, bias and confounding remain to be addressed effectively to improve overall risk estimates. Large, prospective primary studies on risk factors for CDI with standardised case definitions and stratified analyses are required to develop more accurate and robust estimates of

Psychiatric symptoms are not an independent mortality risk factor in community-living elderly people.

PubMed

Benabarre, Sergio; Olivera, Javier; Lorente, Teófilo; Rodriguez, Mariano; Barros-Loscertales, Alfonso; Pelegrín, Carmelo; Claver, Paula; Galindo, Izarbe; Labarta, María; Rodriguez, Jara

2014-06-01

Mortality risk factors have attracted great research interest in recent years. Physical illness is strongly associated with mortality risk in elderly people. Furthermore, a relationship between mortality risk and psychiatric disease in the elderly has gained research interest. This is a prospective longitudinal multicenter study. A sample of 324 participants was selected as a representative sample of community members aged 65 years and older and living in Huesca (Spain). The following information was collected: affiliation data, severity of physical illness, psychosocial, and psychiatric factors. Statistical analyses were completed with a multivariate analysis in order to control possible confounding variables related to mortality. Of the initially selected sample, 293 participants were assessed. Sixty-four participants died (21.8%, 95% CI [16.9%, 26.7%]), 5.3% annual rate, and 46.1% showed symptomatology of mental disorders. Older people have eight times greater risk of mortality. The risk increased 53 times in patients affected by several physical illness. No relationship between cognitive dysfunction and depressive symptomatology was observed. In fact, physical condition was associated with depression, and the percentage of participants with depressive symptoms increased according to the severity of physical illness. Severity of physical illness and age are independently and directly associated with mortality in the elderly people. Therefore, severity of physical illness seems to be a crucial factor in the bi-directional association between mortality and depression, acting as a risk factor independently for both. So the relationship between depression and mortality can be affected by the severity of physical illness.

Synergistic and Non-synergistic Associations for Cigarette Smoking and Non-tobacco Risk Factors for Cardiovascular Disease Incidence in the Atherosclerosis Risk In Communities (ARIC) Study.

PubMed

Lubin, Jay H; Couper, David; Lutsey, Pamela L; Yatsuya, Hiroshi

2017-07-01

Cigarette smoking, various metabolic and lipid-related factors and hypertension are well-recognized cardiovascular disease (CVD) risk factors. Since smoking affects many of these factors, use of a single imprecise smoking metric, for example, ever or never smoked, may allow residual confounding and explain inconsistencies in current assessments of interactions. Using a comprehensive model in pack-years and cigarettes/day for the complex smoking-related relative risk (RR) of CVD to reduce residual confounding, we evaluated interactions with non-tobacco risk factors, including additive (non-synergistic) and multiplicative (synergistic) forms. Data were from the prospective Atherosclerosis Risk in Communities (ARIC) Study from four areas of the United States recruited in 1987-1989 with follow-up through 2008. Analyses included 14 127 participants, 207 693 person-years and 2857 CVD events. Analyses revealed distinct interactions with smoking: including statistical consistency with additive (body mass index [BMI], waist to hip ratio [WHR], diabetes mellitus [DM], glucose, insulin, high density lipoproteins [HDL] and HDL(2)); and multiplicative (hypertension, total cholesterol [TC], low density lipoproteins [LDLs], apolipoprotein B [apoB], TC to HDL ratio and HDL(3)) associations, as well as indeterminate (apolipoprotein A-I [apoA-I] and triglycerides) associations. The forms of the interactions were revealing but require confirmation. Improved understanding of joint associations may help clarify the public health burden of smoking for CVD, links between etiologic factors and biological mechanisms, and the consequences of joint exposures, whereby synergistic associations highlight joint effects and non-synergistic associations suggest distinct contributions. Joint associations for cigarette smoking and non-tobacco risk factors were distinct, revealing synergistic/multiplicative (hypertension, TC, LDL, apoB, TC/HDL, HDL(3)), non-synergistic/additive (BMI, WHR, DM, glucose

Modifiable risk factors for schizophrenia and autism--shared risk factors impacting on brain development.

PubMed

Hamlyn, Jess; Duhig, Michael; McGrath, John; Scott, James

2013-05-01

Schizophrenia and autism are two poorly understood clinical syndromes that differ in age of onset and clinical profile. However, recent genetic and epidemiological research suggests that these two neurodevelopmental disorders share certain risk factors. The aims of this review are to describe modifiable risk factors that have been identified in both disorders, and, where available, collate salient systematic reviews and meta-analyses that have examined shared risk factors. Based on searches of Medline, Embase and PsycINFO, inspection of review articles and expert opinion, we first compiled a set of candidate modifiable risk factors associated with autism. Where available, we next collated systematic-reviews (with or without meta-analyses) related to modifiable risk factors associated with both autism and schizophrenia. We identified three modifiable risk factors that have been examined in systematic reviews for both autism and schizophrenia. Advanced paternal age was reported as a risk factor for schizophrenia in a single meta-analysis and as a risk factor in two meta-analyses for autism. With respect to pregnancy and birth complications, for autism one meta-analysis identified maternal diabetes and bleeding during pregnancy as risks factors for autism whilst a meta-analysis of eight studies identified obstetric complications as a risk factor for schizophrenia. Migrant status was identified as a risk factor for both autism and schizophrenia. Two separate meta-analyses were identified for each disorder. Despite distinct clinical phenotypes, the evidence suggests that at least some non-genetic risk factors are shared between these two syndromes. In particular, exposure to drugs, nutritional excesses or deficiencies and infectious agents lend themselves to public health interventions. Studies are now needed to quantify any increase in risk of either autism or schizophrenia that is associated with these modifiable environmental factors. Copyright © 2012 Elsevier Inc

Women's Career Success: A Factor Analytic Study of Contributing Factors.

ERIC Educational Resources Information Center

Gaskill, LuAnn Ricketts

1991-01-01

A survey of 466 women employed in retailing received 205 responses identifying (1) factors influencing the success and advancement of women in retailing and (2) how those factors differ for women in upper versus middle positions. Upper-level executives placed more importance on ambition and abilities; midlevel executives credited opportunity and…

Critical Success Factors for E-Learning Acceptance: Confirmatory Factor Models

ERIC Educational Resources Information Center

Selim, Hassan M.

2007-01-01

E-learning, one of the tools emerged from information technology, has been integrated in many university programs. There are several factors that need to be considered while developing or implementing university curriculums that offer e-learning based courses. This paper is intended to specify e-learning critical success factors (CSFs) as…

Mortality risk and associated factors in HIV-exposed, uninfected children.

PubMed

Arikawa, Shino; Rollins, Nigel; Newell, Marie-Louise; Becquet, Renaud

2016-06-01

With increasing maternal antiretroviral treatment (ART), the number of children newly infected with HIV has declined. However, the possible increased mortality in the large number of HIV-exposed, uninfected (HEU) children may be of concern. We quantified mortality risks among HEU children and reviewed associated factors. Systematic search of electronic databases (PubMed, Scopus). We included all studies reporting mortality of HEU children to age 60 months and associated factors. Relative risk of mortality between HEU and HIV-unexposed, uninfected (HUU) children was extracted where relevant. Inverse variance methods were used to adjust for study size. Random-effects models were fitted to obtain pooled estimates. A total of 14 studies were included in the meta-analysis and 13 in the review of associated factors. The pooled cumulative mortality in HEU children was 5.5% (95% CI: 4.0-7.2; I(2) = 94%) at 12 months (11 studies) and 11.0% (95% CI: 7.6-15.0; I(2) = 93%) at 24 months (four studies). The pooled risk ratios for the mortality in HEU children compared to HUU children in the same setting were 1.9 (95% CI: 0.9-3.8; I(2) = 93%) at 12 months (four studies) and 2.4 (95% CI: 1.1-5.1; I(2) = 93%) at 24 months (three studies). Compared to HUU children, mortality risk in HEU children was about double at both age points, although the association was not statistically significant at 12 months. Interpretation of the pooled estimates is confounded by considerable heterogeneity between studies. Further research is needed to characterise the impact of maternal death and breastfeeding on the survival of HEU infants in the context of maternal ART, where current evidence is limited. © 2016 The Authors. Tropical Medicine & International Health Published by John Wiley & Sons Ltd.

Factors affecting work ability in day and shift-working nurses.

PubMed

Camerino, Donatella; Conway, Paul Maurice; Sartori, Samantha; Campanini, Paolo; Estryn-Béhar, Madeleine; van der Heijden, Beatrice Isabella Johanna Maria; Costa, Giovanni

2008-04-01

Satisfactory work ability is sustained and promoted by good physical and mental health and by favorable working conditions. This study examined whether favorable and rewarding work-related factors increased the work ability among European nurses. The study sample was drawn from the Nurses' Early Exit Study and consisted of 7,516 nursing staff from seven European countries working in state-owned and private hospitals. In all, 10.8% were day, 4.2% were permanent night, 20.9% were shift without night shift, and 64.1% were shift workers with night shifts. Participants were administered a composite questionnaire at baseline (Time 0) and 1 yr later (Time 1). The Work Ability Index (WAI) at Time 1 was used as the outcome measure, while work schedule, sleep, rewards (esteem and career), satisfaction with pay, work involvement and motivation, and satisfaction with working hours at Time 0 were included as potential determinants of work ability. Univariate and multivariate analyses were conducted after adjusting for a number of confounders (i.e., country, age, sex, type of employment, family status, and other job opportunities in the same area). Work schedule was not related to Time 1 changes in WAI. Higher sleep quality and quantity and more favorable psychosocial factors significantly increased work ability levels. Higher sleep quality and quantity did not mediate the effect of work schedule on work ability. No relevant interaction effects on work ability were observed between work schedule and the other factors considered at Time 0. As a whole, sleep and satisfaction with working time were gradually reduced from day work to permanent night work. However, scores on work involvement, motivation, and satisfaction with pay and rewards were the highest in permanent night workers and the lowest in rotating shift workers that included night shifts.

Growth factors in porcine full and partial thickness burn repair. Differing targets and effects of keratinocyte growth factor, platelet-derived growth factor-BB, epidermal growth factor, and neu differentiation factor.

PubMed Central

Danilenko, D. M.; Ring, B. D.; Tarpley, J. E.; Morris, B.; Van, G. Y.; Morawiecki, A.; Callahan, W.; Goldenberg, M.; Hershenson, S.; Pierce, G. F.

1995-01-01

The topical application of recombinant growth factors such as epidermal growth factor, platelet-derived growth factor-BB homodimer (rPDGF-BB), keratinocyte growth factor (rKGF), and neu differentiation factor has resulted in significant acceleration of healing in several animal models of wound repair. In this study, we established highly reproducible and quantifiable full and deep partial thickness porcine burn models in which burns were escharectomized 4 or 5 days postburn and covered with an occlusive dressing to replicate the standard treatment in human burn patients. We then applied these growth factors to assess their efficacy on several parameters of wound repair: extracellular matrix and granulation tissue production, percent reepithelialization, and new epithelial area. In full thickness burns, only rPDGF-BB and the combination of rPDGF-BB and rKGF induced significant changes in burn repair. rPDGF-BB induced marked extracellular matrix and granulation tissue production (P = 0.013) such that the burn defect was filled within several days of escharectomy, but had no effect on new epithelial area or reepithelialization. The combination of rPDGF-BB and rKGF in full thickness burns resulted in a highly significant increase in extracellular matrix and granulation tissue area (P = 0.0009) and a significant increase in new epithelial area (P = 0.007), but had no effect on reepithelialization. In deep partial thickness burns, rKGF induced the most consistent changes. Daily application of rKGF induced a highly significant increase in new epithelial area (P < 0.0001) but induced only a modest increase in reepithelialization (83.7% rKGF-treated versus 70.2% control; P = 0.016) 12 days postburn. rKGF also doubled the number of fully reepithelialized burns (P = 0.02) at 13 days postburn, at least partially because of marked stimulation of both epidermal and follicular proliferation as assessed by proliferating cell nuclear antigen expression. In situ hybridization for

Causes and risk factors for male-factor infertility in Nigeria: a review.

PubMed

Abarikwu, Sunny O

2013-12-01

In recent times there has been a decline in the semen quality of young healthy men worldwide, with similar findings being reported in Nigeria. Although little is known about what is responsible for the decline in male sperm count worldwide, significant associations have been reported between impaired semen quality including sperm count, motility as well as morphology and exposures to heavy metals such as cadmium and lead, mycotoxins such as aflatoxins, pesticides, industrial chemicals and endocrine factors. In Nigeria, the problem is further compounded by a variety of factors such as sexually transmitted infections, genito-urinary tract infections/inflammations and deficiencies of dietary antioxidant nutrients, thereby increasing male-factor contribution to infertility in the population. In this article, we analyze data from different sources and present evidence of the possible etiology and risk factors for male-factor infertility in Nigeria.

Randomized placebo-controlled double-blind clinical trial of cannabis-based medicinal product (Sativex) in painful diabetic neuropathy: depression is a major confounding factor.

PubMed

Selvarajah, Dinesh; Gandhi, Rajiv; Emery, Celia J; Tesfaye, Solomon

2010-01-01

To assess the efficacy of Sativex, a cannabis-based medicinal extract, as adjuvant treatment in painful diabetic peripheral neuropathy (DPN). In this randomized controlled trial, 30 subjects with painful DPN received daily Sativex or placebo. The primary outcome measure was change in mean daily pain scores, and secondary outcome measures included quality-of-life assessments. There was significant improvement in pain scores in both groups, but mean change between groups was not significant. There were no significant differences in secondary outcome measures. Patients with depression had significantly greater baseline pain scores that improved regardless of intervention. This first-ever trial assessing the efficacy of cannabis has shown it to be no more efficacious than placebo in painful DPN. Depression was a major confounder and may have important implications for future trials on painful DPN.

Mismatch of Posttraumatic Stress Disorder (PTSD) Symptoms and DSM-IV Symptom Clusters in a Cancer Sample: Exploratory Factor Analysis of the PTSD Checklist-Civilian Version

PubMed Central

Shelby, Rebecca A.; Golden-Kreutz, Deanna M.; Andersen, Barbara L.

2007-01-01

The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV; American Psychiatric Association, 1994a) conceptualization of posttraumatic stress disorder (PTSD) includes three symptom clusters: reexperiencing, avoidance/numbing, and arousal. The PTSD Checklist-Civilian Version (PCL-C) corresponds to the DSM-IV PTSD symptoms. In the current study, we conducted exploratory factor analysis (EFA) of the PCL-C with two aims: (a) to examine whether the PCL-C evidenced the three-factor solution implied by the DSM-IV symptom clusters, and (b) to identify a factor solution for the PCL-C in a cancer sample. Women (N = 148) with Stage II or III breast cancer completed the PCL-C after completion of cancer treatment. We extracted two-, three-, four-, and five-factor solutions using EFA. Our data did not support the DSM-IV PTSD symptom clusters. Instead, EFA identified a four-factor solution including reexperiencing, avoidance, numbing, and arousal factors. Four symptom items, which may be confounded with illness and cancer treatment-related symptoms, exhibited poor factor loadings. Using these symptom items in cancer samples may lead to overdiagnosis of PTSD and inflated rates of PTSD symptoms. PMID:16281232

Relationship between stress-related psychosocial work factors and suboptimal health among Chinese medical staff: a cross-sectional study.

PubMed

Liang, Ying-Zhi; Chu, Xi; Meng, Shi-Jiao; Zhang, Jie; Wu, Li-Juan; Yan, Yu-Xiang

2018-03-06

The study aimed to develop and validate a model to measure psychosocial factors at work among medical staff in China based on confirmatory factor analysis (CFA). The second aim of the current study was to clarify the association between stress-related psychosocial work factors and suboptimal health status. The cross-sectional study was conducted using clustered sampling method. Xuanwu Hospital, a 3A grade hospital in Beijing. Nine hundred and fourteen medical staff aged over 40 years were sampled. Seven hundred and ninety-seven valid questionnaires were collected and used for further analyses. The sample included 94% of the Han population. The Copenhagen Psychosocial Questionnaire (COPSOQ) and the Suboptimal Health Status Questionnaires-25 were used to assess the psychosocial factors at work and suboptimal health status, respectively. CFA was conducted to establish the evaluating method of COPSOQ. A multivariate logistic regression model was used to estimate the relationship between suboptimal health status and stress-related psychosocial work factors among Chinese medical staff. There was a strong correlation among the five dimensions of COPSOQ based on the first-order factor model. Then, we established two second-order factors including negative and positive psychosocial work stress factors to evaluate psychosocial factors at work, and the second-order factor model fit well. The high score in negative (OR (95% CI)=1.47 (1.34 to 1.62), P<0.001) and positive (OR (95% CI)=0.96 (0.94 to 0.98), P<0.001) psychosocial work factors increased and decreased the risk of suboptimal health, respectively. This relationship remained statistically significant after adjusting for confounders and when using different cut-offs of suboptimal health status. Among medical staff, the second-order factor model was a suitable method to evaluate the COPSOQ. The negative and positive psychosocial work stress factors might be the risk and protective factors of suboptimal health

Personal and workplace psychosocial risk factors for carpal tunnel syndrome: a pooled study cohort

PubMed Central

Harris-Adamson, Carisa; Eisen, Ellen A; Dale, Ann Marie; Evanoff, Bradley; Hegmann, Kurt T; Thiese, Matthew S; Kapellusch, Jay M; Garg, Arun; Burt, Susan; Bao, Stephen; Silverstein, Barbara; Gerr, Fred; Merlino, Linda; Rempel, David

2015-01-01

Background Between 2001 and 2010, six research groups conducted coordinated multiyear, prospective studies of carpal tunnel syndrome (CTS) incidence in US workers from various industries and collected detailed subject-level exposure information with follow-up symptom, physical examination, electrophysiological measures and job changes. Objective This analysis of the pooled cohort examined the incidence of dominant-hand CTS in relation to demographic characteristics and estimated associations with occupational psychosocial factors and years worked, adjusting for confounding by personal risk factors. Methods 3515 participants, without baseline CTS, were followed-up to 7 years. Case criteria included symptoms and an electrodiagnostic study consistent with CTS. Adjusted HRs were estimated in Cox proportional hazard models. Workplace biomechanical factors were collected but not evaluated in this analysis. Results Women were at elevated risk for CTS (HR=1.30; 95% CI 0.98 to 1.72), and the incidence of CTS increased linearly with both age and body mass index (BMI) over most of the observed range. High job strain increased risk (HR=1.86; 95% CI 1.11 to 3.14), and social support was protective (HR=0.54; 95% CI 0.31 to 0.95). There was an inverse relationship with years worked among recent hires with the highest incidence in the first 3.5 years of work (HR=3.08; 95% CI 1.55 to 6.12). Conclusions Personal factors associated with an increased risk of developing CTS were BMI, age and being a woman. Workplace risk factors were high job strain, while social support was protective. The inverse relationship between CTS incidence and years worked among recent hires suggests the presence of a healthy worker survivor effect in the cohort. PMID:23645610

Periodontitis as a Modifiable Risk Factor for Dementia: A Nationwide Population-Based Cohort Study.

PubMed

Lee, Yao-Tung; Lee, Hsin-Chien; Hu, Chaur-Jongh; Huang, Li-Kai; Chao, Shu-Ping; Lin, Chia-Pei; Su, Emily Chia-Yu; Lee, Yi-Chen; Chen, Chu-Chieh

2017-02-01

To determine whether periodontitis is a modifiable risk factor for dementia. Prospective cohort study. National Health Insurance Research Database in Taiwan. Individuals aged 65 and older with periodontitis (n = 3,028) and an age- and sex-matched control group (n = 3,028). Individuals with periodontitis were compared age- and sex-matched controls with for incidence density and hazard ratio (HR) of new-onset dementia. Periodontitis was defined according to International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes 523.3-5 diagnosed by dentists. To ensure diagnostic validity, only those who had concurrently received antibiotic therapies, periodontal treatment other than scaling, or scaling more than twice per year performed by certified dentists were included. Dementia was defined according to ICD-9-CM codes 290.0-290.4, 294.1, 331.0-331.2. After adjustment for confounding factors, the risk of developing dementia was calculated to be higher for participants with periodontitis (HR = 1.16, 95% confidence interval = 1.01-1.32, P = .03) than for those without. Periodontitis is associated with greater risk of developing dementia. Periodontal infection is treatable, so it might be a modifiable risk factor for dementia. Clinicians must devote greater attention to this potential association in an effort to develop new preventive and therapeutic strategies for dementia. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

Factors associated with numbers of remaining teeth among type 2 diabetes: a cross-sectional study.

PubMed

Huang, Jui-Chu; Peng, Yun-Shing; Fan, Jun-Yu; Jane, Sui-Whi; Tu, Liang-Tse; Chang, Chang-Cheng; Chen, Mei-Yen

2013-07-01

To explore the factors associated with the numbers of remaining teeth among type 2 diabetes community residents. Promoting oral health is an important nursing role for patients with diabetes, especially in disadvantaged areas. However, limited research has been carried out on the relationship between numbers of remaining teeth, diabetes-related biomarkers and personal oral hygiene among diabetic rural residents. A cross-sectional, descriptive design with a simple random sample was used. This study was part of a longitudinal cohort study of health promotion for preventing diabetic foot among rural community diabetic residents. It was carried out in 18 western coastal and inland districts of Chiayi County in central Taiwan. In total, 703 participants were enrolled in this study. The findings indicated that a high percentage of the participants (26%) had no remaining natural teeth. Nearly three quarters (74%) had fewer than 20 natural teeth. After controlling for the potential confounding factors, multivariate analysis demonstrated that the factors determining numbers of remaining teeth were age (p < 0.001), education (p < 0.001), using dental floss (p = 0.003), ankle brachial pressure index (p = 0.028), waist circumference (p = 0.024) and HbA1C (p = 0.033). Except for some unmodifiable factors, the factors most significantly associated with numbers of remaining teeth were less tooth-brushing with dental floss, abnormal ankle brachial pressure and poor glycemic control. This study highlights the importance of nursing intervention in oral hygiene for patients with type 2 diabetes. It is necessary to initiate oral health promotion activities when diabetes is first diagnosed, especially for older diabetic residents of rural or coastal areas who are poorly educated. © 2013 John Wiley & Sons Ltd.

Environmental Factors in Autism

PubMed Central

Grabrucker, Andreas M.

2013-01-01

Autism is a neurodevelopmental disorders characterized by impairments in communication and social behavior, and by repetitive behaviors. Although genetic factors might be largely responsible for the occurrence of autism they cannot fully account for all cases and it is likely that in addition to a certain combination of autism-related genes, specific environmental factors might act as risk factors triggering the development of autism. Thus, the role of environmental factors in autism is an important area of research and recent data will be discussed in this review. Interestingly, the results show that many environmental risk factors are interrelated and their identification and comparison might unveil a common scheme of alterations on a contextual as well as molecular level. For example, both, disruption in the immune system and in zinc homeostasis may affect synaptic transmission in autism. Thus, here, a model is proposed that interconnects the most important and scientifically recognized environmental factors. Moreover, similarities in how these risk factors impact synapse function are discussed and a possible influence on an already well described genetic pathway leading to the development of autism via zinc homeostasis is proposed. PMID:23346059

Recruitment factors which affect the outcome of a seasonal allergic rhinitis trial.

PubMed

Sharma, Shilpy; Vasnani, Raj; De Tineo, Marcella; Du, Gaixin; Pinto, Jayant M; Baroody, Fuad M; Naclerio, Robert M

2011-01-01

Although intranasal corticosteroids (INSs) are the first-line treatment for seasonal allergic rhinitis (SAR), some patients do not respond adequately, reflecting biological heterogeneity or confounding conditions. The objective of this study was to determine what recruitment factors identify SAR subjects who will be unresponsive to mometasone furoate (MF). We performed a 2-week, double-blind, placebo-controlled, parallel study on 40 subjects with SAR. Each subject underwent a decongestant test using oxymetazoline. Baseline nasal symptoms, nasal peak inspiratory flow (NPIF) and Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) scores were recorded. Next, subjects were randomized to either 200 μg of MF or placebo. Symptom diaries and NPIF measurements were completed twice daily. After 2 weeks, subjects repeated the RQLQ and the global assessment of symptoms. There was a significant reduction in symptoms in the MF group compared with placebo (p ≤ 0.05) in patients with baseline total symptom scores of ≥6. Multivariate analysis showed that treatment (MF versus placebo; p = 0.049) and amount of decongestion (percent change in NPIF after oxymetazoline; p = 0.008) predicted the improvement in total nasal symptoms. In clinical trials, SAR subjects must report multiple symptoms to be responsive to treatment with INSs. Our results also support the use of the decongestant test for choice of appropriate study volunteers, both to ensure participation of potentially responsive subjects and to eliminate those with confounding issues.

Spatial patterns in community response to aircraft noise associated with non-noise factors

NASA Astrophysics Data System (ADS)

Hall, F. L.; Taylor, S. M.; Birnie, S. E.

1980-08-01

Non-noise aspects of airport operations may affect individuals' responses to aircraft noise. Fear of crashes, other forms of pollution, and proximity to the flight path are three such non-noise aspects which have spatial patterns that are closely related to the pattern of noise contours around an airport. If these variables affect response to aircraft noise, they may therefore confound attempts to understand relationships between noise level and community response. Analyses based on data from 673 individuals around Toronto International Airport suggest that these factors do affect annoyance responses, but do not affect reported activity interference. Hence it may prove fruitful, in aggregate analyses of community response data, to control for these variables in order to better understand the noise-annoyance relationships.

Environmental risk factors contributing to traffic accidents in children: a case-control study.

PubMed

Jamshidi, Ensiyeh; Moradi, Ali; Majdzadeh, Reza

2017-09-01

The aim of this study is to identify environmental risk factors related to road accidents in children of Tehran. This case-control study was performed in 2013. The cases were injured pedestrians aged 5-15 who were admitted to major hospitals supervised by Tehran University of Medical Sciences. The sample size for the cases was 273 and for the control group was 546. For the completeness of the clusters, 7 extra persons in case (total = 280) and 14 persons (total = 560) in control group were included. The interference of confounding variables assessed through forward conditional logistic regression. Result shows occurrence of traffic accidents was significantly associate with the width of the alleys or (<5 m: OR = 8.4, 95% CI: 3.3-21.5; 5-8 m: OR = 4.7, 95% CI: 1.8-12.2), distance from home to school((<100 m: OR = 1.7, 95% CI: 1.0-2.8), existence of parking lot (OR = 1.5, 95% CI: 1.0-2.3), traffic congestion (OR = 4.1, 95% CI: 2.6-6.4), traffic speed (OR = 2.1, 95% CI: 1.3-3.2) and existence of pedestrian bridges(OR = 4.2, 95% CI: 2.6-6.8). In the light of the important role of environmental factors in the occurrence of child traffic accidents, alleviating structural risk factors in addition to education and enforcement need more systematic efforts and planning by policymakers and urban planners to attain pedestrian safety goals.

On the Likelihood Ratio Test for the Number of Factors in Exploratory Factor Analysis

ERIC Educational Resources Information Center

Hayashi, Kentaro; Bentler, Peter M.; Yuan, Ke-Hai

2007-01-01

In the exploratory factor analysis, when the number of factors exceeds the true number of factors, the likelihood ratio test statistic no longer follows the chi-square distribution due to a problem of rank deficiency and nonidentifiability of model parameters. As a result, decisions regarding the number of factors may be incorrect. Several…

Taking the Error Term of the Factor Model into Account: The Factor Score Predictor Interval

ERIC Educational Resources Information Center

Beauducel, Andre

2013-01-01

The problem of factor score indeterminacy implies that the factor and the error scores cannot be completely disentangled in the factor model. It is therefore proposed to compute Harman's factor score predictor that contains an additive combination of factor and error variance. This additive combination is discussed in the framework of classical…

Analyzing the risk factors influencing surgical site infections: the site of environmental factors.

PubMed

Alfonso-Sanchez, Jose L; Martinez, Isabel M; Martín-Moreno, Jose M; González, Ricardo S; Botía, Francisco

2017-06-01

Addressing surgical site infection (SSI) is accomplished, in part, through studies that attempt to clarify the nature of many essential factors in the control of SSI. We sought to examine the link between multiple risk factors, including environmental factors, and SSI for prevention management. We conducted a longitudinal prospective study to identify SSIs in all patients who underwent interventions in 2014 in 8 selected hospitals on the Mediterranean coast of Spain. Risk factors related to the operating theatre included level of fungi and bacterial contamination, temperature and humidity, air renewal and differential air pressure. Patient-related variables included age, sex, comorbidity, nutrition level and transfusion. Other factors were antibiotic prophylaxis, electric versus manual shaving, American Society of Anaesthesiologists physical status classification, type of intervention, duration of the intervention and preoperative stay. Superficial SSI was most often associated with environmental factors, such as environmental contamination by fungi (from 2 colony-forming units) and bacteria as well as surface contamination. When there was no contamination in the operating room, no SSI was detected. Factors that determined deep and organ/space SSI were more often associated with patient characteristics (age, sex, transfusion, nasogastric feeding and nutrition, as measured by the level of albumin in the blood), type of intervention and preoperative stay. Antibiotic prophylaxis and shaving with electric razor were protective factors for both types of infection, whereas the duration of the intervention and the classification of the intervention as "dirty" were shared risk factors. Our results suggest the importance of environmental and surface contamination control to prevent SSI.

The presence of advanced lesions and associating risk factors for advanced cervical carcinoma in patients with atypical sguamous cells of undetermined significance.

PubMed

Sun, L L; Chen, W; Fan, Y Y; Wang, M L; Wang, L N

2015-01-01

To characterize histopathological status, high-risk human papillomavirus (hr-HPV) infection status, and associated risk factors in patients with atypical squamous cells of undetermined significance (ASCUS). Cervical biopsies obtained from 130 ASCUS patients were subjected to histopathological examination and hr-HPV testing. Associations between advanced lesions and hr-HPV load or age were analyzed, and the confounding factors for high-grade cervical lesions were identified. Cervical biopsies from ASCUS patients had a wide range of pathological states, ranging from normal to invasive cervical carcinoma. High-risk HPV infection was significantly associated with advanced cervical lesions in ASCUS patients; hr-HPV infection and the number of gestations were risk factors for developing advanced cervical disease. A significant portion of ASCUS patients harbor advanced cervical lesions. The number of gestations and hr-HPV infection can increase the risk of developing advanced cervical lesions in ASCUS patients.

Determining confounding sensitivities in eddy current thin film measurements

NASA Astrophysics Data System (ADS)

Gros, Ethan; Udpa, Lalita; Smith, James A.; Wachs, Katelyn

2017-02-01

Eddy current (EC) techniques are widely used in industry to measure the thickness of non-conductive films on a metal substrate. This is done by using a system whereby a coil carrying a high-frequency alternating current is used to create an alternating magnetic field at the surface of the instrument's probe. When the probe is brought near a conductive surface, the alternating magnetic field will induce ECs in the conductor. The substrate characteristics and the distance of the probe from the substrate (the coating thickness) affect the magnitude of the ECs. The induced currents load the probe coil affecting the terminal impedance of the coil. The measured probe impedance is related to the lift off between coil and conductor as well as conductivity of the test sample. For a known conductivity sample, the probe impedance can be converted into an equivalent film thickness value. The EC measurement can be confounded by a number of measurement parameters. It was the goal of this research to determine which physical properties of the measurement set-up and sample can adversely affect the thickness measurement. The eddy-current testing was performed using a commercially available, hand-held eddy-current probe (ETA3.3H spring-loaded eddy probe running at 8 MHz) that comes with a stand to hold the probe. The stand holds the probe and adjusts the probe on the z-axis to help position the probe in the correct area as well as make precise measurements. The signal from the probe was sent to a hand-held readout, where the results are recorded directly in terms of liftoff or film thickness. Understanding the effect of certain factors on the measurements of film thickness, will help to evaluate how accurate the ETA3.3H spring-loaded eddy probe was at measuring film thickness under varying experimental conditions. This research studied the effects of a number of factors such as i) conductivity, ii) edge effect, iii) surface finish of base material and iv) cable condition.

Psychosocial job factors and biological cardiovascular risk factors in Mexican workers.

PubMed

Garcia-Rojas, Isabel Judith; Choi, BongKyoo; Krause, Niklas

2015-03-01

Psychosocial job factors (PJF) have been implicated in the development of cardiovascular disease. The paucity of data from developing economies including Mexico hampers the development of worksite intervention efforts in those regions. This cross-sectional study of 2,330 Mexican workers assessed PJF (job strain [JS], social support [SS], and job insecurity [JI]) and biological cardiovascular disease risk factors [CVDRF] by questionnaire and on-site physical examinations. Alternative formulations of the JS scales were developed based on factor analysis and literature review. Associations between both traditional and alternative job factor scales with CVDRF were examined in multiple regression models, adjusting for physical workload, and socio-demographic factors. Alternative formulations of the job demand and control scales resulted in substantial changes in effect sizes or statistical significance when compared with the original scales. JS and JI showed hypothesized associations with most CVDRF, but they were inversely associated with diastolic blood pressure and some adiposity measures. SS was mainly protective against CVDRF. Among Mexican workers, alternative PJF scales predicted health outcomes better than traditional scales, and psychosocial stressors were associated with most CVDRF. © 2015 Wiley Periodicals, Inc.

Detection rates of geckos in visual surveys: Turning confounding variables into useful knowledge

USGS Publications Warehouse

Lardner, Bjorn; Rodda, Gordon H.; Yackel Adams, Amy A.; Savidge, Julie A.; Reed, Robert N.

2016-01-01

Transect surveys without some means of estimating detection probabilities generate population size indices prone to bias because survey conditions differ in time and space. Knowing what causes such bias can help guide the collection of relevant survey covariates, correct the survey data, anticipate situations where bias might be unacceptably large, and elucidate the ecology of target species. We used negative binomial regression to evaluate confounding variables for gecko (primarily Hemidactylus frenatus and Lepidodactylus lugubris) counts on 220-m-long transects surveyed at night, primarily for snakes, on 9,475 occasions. Searchers differed in gecko detection rates by up to a factor of six. The worst and best headlamps differed by a factor of at least two. Strong winds had a negative effect potentially as large as those of searchers or headlamps. More geckos were seen during wet weather conditions, but the effect size was small. Compared with a detection nadir during waxing gibbous (nearly full) moons above the horizon, we saw 28% more geckos during waning crescent moons below the horizon. A sine function suggested that we saw 24% more geckos at the end of the wet season than at the end of the dry season. Fluctuations on a longer timescale also were verified. Disturbingly, corrected data exhibited strong short-term fluctuations that covariates apparently failed to capture. Although some biases can be addressed with measured covariates, others will be difficult to eliminate as a significant source of error in longterm monitoring programs.

"A Bayesian sensitivity analysis to evaluate the impact of unmeasured confounding with external data: a real world comparative effectiveness study in osteoporosis".

PubMed

Zhang, Xiang; Faries, Douglas E; Boytsov, Natalie; Stamey, James D; Seaman, John W

2016-09-01

Observational studies are frequently used to assess the effectiveness of medical interventions in routine clinical practice. However, the use of observational data for comparative effectiveness is challenged by selection bias and the potential of unmeasured confounding. This is especially problematic for analyses using a health care administrative database, in which key clinical measures are often not available. This paper provides an approach to conducting a sensitivity analyses to investigate the impact of unmeasured confounding in observational studies. In a real world osteoporosis comparative effectiveness study, the bone mineral density (BMD) score, an important predictor of fracture risk and a factor in the selection of osteoporosis treatments, is unavailable in the data base and lack of baseline BMD could potentially lead to significant selection bias. We implemented Bayesian twin-regression models, which simultaneously model both the observed outcome and the unobserved unmeasured confounder, using information from external sources. A sensitivity analysis was also conducted to assess the robustness of our conclusions to changes in such external data. The use of Bayesian modeling in this study suggests that the lack of baseline BMD did have a strong impact on the analysis, reversing the direction of the estimated effect (odds ratio of fracture incidence at 24 months: 0.40 vs. 1.36, with/without adjusting for unmeasured baseline BMD). The Bayesian twin-regression models provide a flexible sensitivity analysis tool to quantitatively assess the impact of unmeasured confounding in observational studies. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Using Horn's Parallel Analysis Method in Exploratory Factor Analysis for Determining the Number of Factors

ERIC Educational Resources Information Center

Çokluk, Ömay; Koçak, Duygu

2016-01-01

In this study, the number of factors obtained from parallel analysis, a method used for determining the number of factors in exploratory factor analysis, was compared to that of the factors obtained from eigenvalue and scree plot--two traditional methods for determining the number of factors--in terms of consistency. Parallel analysis is based on…

Total insulinlike growth factor 1 and insulinlike growth factor binding protein levels, functional status, and mortality in older adults.

PubMed

Kaplan, Robert C; McGinn, Aileen P; Pollak, Michael N; Kuller, Lewis; Strickler, Howard D; Rohan, Thomas E; Xue, XiaoNan; Kritchevsky, Stephen B; Newman, Anne B; Psaty, Bruce M

2008-04-01

To assess the association between total insulinlike growth factor (IGF)-1, IGF binding protein-1 (IGFBP-1), and IGFBP-3 levels and functioning and mortality in older adults. Cohort study. One thousand one hundred twenty-two individuals aged 65 and older without prior cardiovascular disease events participating in the Cardiovascular Health Study. Baseline fasting plasma levels of IGF-1, IGFBP-1, and IGFBP-3 (defined as tertiles, T1-T3) were examined in relationship to handgrip strength, time to walk 15 feet, development of new difficulties with activities of daily living (ADLs), and mortality. Higher IGFBP-1 predicted worse handgrip strength (P-trend(T1-T3)<.01) and slower walking speed (P-trend(T1-T3)=.03), lower IGF-1 had a borderline significant association with worse handgrip strength (P-trend(T1-T3)=.06), and better grip strength was observed in the middle IGFBP-3 tertile than in the low or high tertiles (P=.03). Adjusted for age, sex, and race, high IGFBP-1 predicted greater mortality (P-trend(T1-T3)<.001, hazard ratio (HR)(T3vsT1)=1.48, 95% confidence interval (CI)=1.15-1.90); this association was borderline significant after additional confounder adjustment (P-trend(T1-T3)=.05, HR(T3vsT1)=1.35, 95% CI=0.98-1.87). High IGFBP-1 was associated with greater risk of incident ADL difficulties after adjustment for age, sex, race, and other confounders (P-trend(T1-T3)=.04, HR(T3vsT1)=1.40, CI=1.01-1.94). Neither IGF-1 nor IGFBP-3 level predicted mortality or incident ADL difficulties. In adults aged 65 and older, high IGFBP-1 levels were associated with greater risk of mortality and poorer functional ability, whereas IGF-1 and IGFBP-3 had little association with these outcomes.

Factor VIII-bypassing activity of bovine tissue factor using the canine hemophilic model.

PubMed Central

O'Brien, D P; Giles, A R; Tate, K M; Vehar, G A

1988-01-01

The bleeding disorder of hemophilia A currently treated by replacement therapy of the missing coagulation factor, factor VIII, is frequently complicated by the development of neutralizing antibodies. The therapeutic potential of attenuated forms of the lipid-associated glycoprotein tissue factor, a known initiator of coagulation, was investigated as a factor VIII-by-passing activity. The protein moiety of tissue factor (Apo-TF) was partially purified and exhibited minimal procoagulant activity before relipidation in vitro. In pilot studies, Apo-TF injection into rabbits previously anticoagulated with an antibody to factor VIII was found to have a procoagulant effect. The efficacy of the material was further demonstrated when injection of Apo-TF in hemophilic dogs resulted in a normalization of the cuticle bleeding time. Little or no change in the blood parameters associated with disseminated intravascular coagulation was observed at lower doses, although mild to moderate effects were seen at higher doses. These data suggest a novel role for Apo-TF preparations as a potential therapeutic agent for hemophiliacs with antibodies to factor VIII once the potential thrombogenicity of such materials is evaluated. Images PMID:3134399

Multi-factor authentication using quantum communication

DOEpatents

Hughes, Richard John; Peterson, Charles Glen; Thrasher, James T.; Nordholt, Jane E.; Yard, Jon T.; Newell, Raymond Thorson; Somma, Rolando D.

2018-02-06

Multi-factor authentication using quantum communication ("QC") includes stages for enrollment and identification. For example, a user enrolls for multi-factor authentication that uses QC with a trusted authority. The trusted authority transmits device factor information associated with a user device (such as a hash function) and user factor information associated with the user (such as an encrypted version of a user password). The user device receives and stores the device factor information and user factor information. For multi-factor authentication that uses QC, the user device retrieves its stored device factor information and user factor information, then transmits the user factor information to the trusted authority, which also retrieves its stored device factor information. The user device and trusted authority use the device factor information and user factor information (more specifically, information such as a user password that is the basis of the user factor information) in multi-factor authentication that uses QC.

Model of a ternary complex between activated factor VII, tissue factor and factor IX.

PubMed

Chen, Shu-wen W; Pellequer, Jean-Luc; Schved, Jean-François; Giansily-Blaizot, Muriel

2002-07-01

Upon binding to tissue factor, FVIIa triggers coagulation by activating vitamin K-dependent zymogens, factor IX (FIX) and factor X (FX). To understand recognition mechanisms in the initiation step of the coagulation cascade, we present a three-dimensional model of the ternary complex between FVIIa:TF:FIX. This model was built using a full-space search algorithm in combination with computational graphics. With the known crystallographic complex FVIIa:TF kept fixed, the FIX docking was performed first with FIX Gla-EGF1 domains, followed by the FIX protease/EGF2 domains. Because the FIXa crystal structure lacks electron density for the Gla domain, we constructed a chimeric FIX molecule that contains the Gla-EGF1 domains of FVIIa and the EGF2-protease domains of FIXa. The FVIIa:TF:FIX complex has been extensively challenged against experimental data including site-directed mutagenesis, inhibitory peptide data, haemophilia B database mutations, inhibitor antibodies and a novel exosite binding inhibitor peptide. This FVIIa:TF:FIX complex provides a powerful tool to study the regulation of FVIIa production and presents new avenues for developing therapeutic inhibitory compounds of FVIIa:TF:substrate complex.

A case-control study to identify risk factors for totally implantable central venous port-related bloodstream infection.

PubMed

Lee, Guk Jin; Hong, Sook Hee; Roh, Sang Young; Park, Sa Rah; Lee, Myung Ah; Chun, Hoo Geun; Hong, Young Seon; Kang, Jin Hyoung; Kim, Sang Il; Kim, Youn Jeong; Chun, Ho Jong; Oh, Jung Suk

2014-07-01

To date, the risk factors for central venous port-related bloodstream infection (CVPBSI) in solid cancer patients have not been fully elucidated. We conducted this study in order to determine the risk factors for CVP-BSI in patients with solid cancer. A total of 1,642 patients with solid cancer received an implantable central venous port for delivery of chemotherapy between October 2008 and December 2011 in a single center. CVP-BSI was diagnosed in 66 patients (4%). We selected a control group of 130 patients, who were individually matched with respect to age, sex, and catheter insertion time. CVP-BSI occurred most frequently between September and November (37.9%). The most common pathogen was gram-positive cocci (n=35, 53.0%), followed by fungus (n=14, 21.2%). Multivariate analysis identified monthly catheter-stay as a risk factor for CVP-BSI (p=0.000), however, its risk was lower in primary gastrointestinal cancer than in other cancer (p=0.002). Initial metastatic disease and long catheter-stay were statistically significant factors affecting catheter life span (p=0.005 and p=0.000). Results of multivariate analysis showed that recent transfusion was a risk factor for mortality in patients with CVP-BSI (p=0.047). In analysis of the results with respect to risk factors, prolonged catheter-stay should be avoided as much as possible. It is necessary to be cautious of CVP-BSI in metastatic solid cancer, especially non-gastrointestinal cancer. In addition, avoidance of unnecessary transfusion is essential in order to reduce the mortality of CVP-BSI. Finally, considering the fact that confounding factors may have affected the results, conduct of a well-designed prospective controlled study is warranted.

TauFactor: An open-source application for calculating tortuosity factors from tomographic data

NASA Astrophysics Data System (ADS)

Cooper, S. J.; Bertei, A.; Shearing, P. R.; Kilner, J. A.; Brandon, N. P.

TauFactor is a MatLab application for efficiently calculating the tortuosity factor, as well as volume fractions, surface areas and triple phase boundary densities, from image based microstructural data. The tortuosity factor quantifies the apparent decrease in diffusive transport resulting from convolutions of the flow paths through porous media. TauFactor was originally developed to improve the understanding of electrode microstructures for batteries and fuel cells; however, the tortuosity factor has been of interest to a wide range of disciplines for over a century, including geoscience, biology and optics. It is still common practice to use correlations, such as that developed by Bruggeman, to approximate the tortuosity factor, but in recent years the increasing availability of 3D imaging techniques has spurred interest in calculating this quantity more directly. This tool provides a fast and accurate computational platform applicable to the big datasets (>108 voxels) typical of modern tomography, without requiring high computational power.

Non-genetic risk factors in haemophilia A inhibitor management - the danger theory and the use of animal models.

PubMed

Lövgren, K M; Søndergaard, H; Skov, S; Wiinberg, B

2016-09-01

In haemophilia A (HA) management, antidrug antibodies, or inhibitors, are a serious complication that renders factor VIII (FVIII) replacement therapy ineffective, increases morbidity and reduces quality of life for affected patients. Inhibitor development aetiology is multifactorial and covers both genetic and therapy related risk factors. Many therapy-related risk factors have proven difficult to confirm due to several confounding factors and the small study populations available. However, clinical studies indicate that e.g. on-demand treatment and surgery affect inhibitor development, and explanations for this association are being investigated. A potential explanation is the danger signal effect, where the immune response is activated by endogenous or exogenous danger or damage signals present at the time and site of FVIII administration. The danger theory explains how alarm signals from stressed, injured or dying cells can activate an immune reaction, without the involvement of foreign antigens. Bleeds, trauma, surgery or concomitant infection could be events initiating danger signalling in HA patients, resulting in an immune reaction towards administered FVIII that otherwise would pass unnoticed. This role of danger in HA inhibitor formation has previously been suggested, but a thorough discussion of this subject is lacking. The present review will discuss the potential role of danger signals in haemophilia and inhibitor development, with focus on treatment related risk factors with a suspected danger signal aetiology; on-demand treatment, treatment during major bleeds or surgery, and treatment during infection or vaccination. Clinical studies as well as animal experiments addressing these factors will be reviewed. © 2016 John Wiley & Sons Ltd.

Risk factors for stress fractures.

PubMed

Bennell, K; Matheson, G; Meeuwisse, W; Brukner, P

1999-08-01

Preventing stress fractures requires knowledge of the risk factors that predispose to this injury. The aetiology of stress fractures is multifactorial, but methodological limitations and expediency often lead to research study designs that evaluate individual risk factors. Intrinsic risk factors include mechanical factors such as bone density, skeletal alignment and body size and composition, physiological factors such as bone turnover rate, flexibility, and muscular strength and endurance, as well as hormonal and nutritional factors. Extrinsic risk factors include mechanical factors such as surface, footwear and external loading as well as physical training parameters. Psychological traits may also play a role in increasing stress fracture risk. Equally important to these types of analyses of individual risk factors is the integration of information to produce a composite picture of risk. The purpose of this paper is to critically appraise the existing literature by evaluating study design and quality, in order to provide a current synopsis of the known scientific information related to stress fracture risk factors. The literature is not fully complete with well conducted studies on this topic, but a great deal of information has accumulated over the past 20 years. Although stress fractures result from repeated loading, the exact contribution of training factors (volume, intensity, surface) has not been clearly established. From what we do know, menstrual disturbances, caloric restriction, lower bone density, muscle weakness and leg length differences are risk factors for stress fracture. Other time-honoured risk factors such as lower extremity alignment have not been shown to be causative even though anecdotal evidence indicates they are likely to play an important role in stress fracture pathogenesis.

Factors associated with second trimester abortion in rural Maharashtra and Rajasthan, India.

PubMed

Zavier, A J Francis; Jejeebhoy, Shireen; Kalyanwala, Shveta

2012-01-01

Many married women in India experience abortion in their second trimester of pregnancy. While there is an impression that second trimester abortions are now overwhelmingly used for sex selection, little is known about the extent to which second trimester abortions are indeed associated with son preference and sex selection motives, relative to other factors. Using data from a community-based study in rural Maharashtra and Rajasthan, research highlights the role of limited access in explaining second trimester abortion. While women with a single child who was a daughter were indeed more likely than other women to have terminated a pregnancy carrying a female foetus in the second trimester, more strikingly, exclusion from abortion-related decision-making, unsuccessful prior attempts to terminate the pregnancy, and distance from the facility in which their abortion was performed, were significantly associated with second trimester abortion, even after controlling for confounding factors. The study calls for greater efficiency in implementing the PCPNDT Act and addressing deep-rooted son preference. At the same time, findings that poverty and limited access to facilities are as, if not more, important drivers of second trimester abortion, highlight the need to meet commitments to ensure accessible abortion facilities for poor rural women.

Tae-Eum Type as an Independent Risk Factor for Obstructive Sleep Apnea

PubMed Central

Lee, Seung Ku; Yoon, Dae Wui; Yi, Hyeryeon; Lee, Si Woo; Kim, Jong Yeol; Shin, Chol

2013-01-01

Obstructive sleep apnea (OSA) is prevalent and associated with several kinds of chronic diseases. There has been evidence that a specific type of Sasang constitution is a risk factor for metabolic and cardiovascular diseases that can be found in patients with OSA, but there are no studies that address the association between the Sasang constitution type (SCT) and OSA. The purpose of this study was to investigate the association between the SCT and OSA. A total of 652 participants were included. All participants were examined for demographic information, medical history, and completed an interviewer-administered questionnaire on life style and sleep-related variables. Biochemical analyses were performed to determine the glucose and lipid profiles. An objective recording of OSA was done with an unattended home PSG using an Embla portable device. The apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) were significantly higher in the Tae-eum (TE) type as compared to the So-eum (SE) and the So-yang (SY) types. Even after adjusting for confounding variables, the TE type still had a 2.34-fold (95% CI, 1.11–4.94; P = 0.0262) increased risk for OSA. This population-based cohort study found that the TE constitutional type is an independent risk factor for the development of OSA. PMID:23554836

WRKY transcription factors.

PubMed

Rushton, Paul J; Somssich, Imre E; Ringler, Patricia; Shen, Qingxi J

2010-05-01

WRKY transcription factors are one of the largest families of transcriptional regulators in plants and form integral parts of signalling webs that modulate many plant processes. Here, we review recent significant progress in WRKY transcription factor research. New findings illustrate that WRKY proteins often act as repressors as well as activators, and that members of the family play roles in both the repression and de-repression of important plant processes. Furthermore, it is becoming clear that a single WRKY transcription factor might be involved in regulating several seemingly disparate processes. Mechanisms of signalling and transcriptional regulation are being dissected, uncovering WRKY protein functions via interactions with a diverse array of protein partners, including MAP kinases, MAP kinase kinases, 14-3-3 proteins, calmodulin, histone deacetylases, resistance proteins and other WRKY transcription factors. WRKY genes exhibit extensive autoregulation and cross-regulation that facilitates transcriptional reprogramming in a dynamic web with built-in redundancy. 2010 Elsevier Ltd. All rights reserved.

Threshold factorization redux

NASA Astrophysics Data System (ADS)

Chay, Junegone; Kim, Chul

2018-05-01

We reanalyze the factorization theorems for the Drell-Yan process and for deep inelastic scattering near threshold, as constructed in the framework of the soft-collinear effective theory (SCET), from a new, consistent perspective. In order to formulate the factorization near threshold in SCET, we should include an additional degree of freedom with small energy, collinear to the beam direction. The corresponding collinear-soft mode is included to describe the parton distribution function (PDF) near threshold. The soft function is modified by subtracting the contribution of the collinear-soft modes in order to avoid double counting on the overlap region. As a result, the proper soft function becomes infrared finite, and all the factorized parts are free of rapidity divergence. Furthermore, the separation of the relevant scales in each factorized part becomes manifest. We apply the same idea to the dihadron production in e+e- annihilation near threshold, and show that the resultant soft function is also free of infrared and rapidity divergences.

Aerospace Human Factors

NASA Technical Reports Server (NTRS)

Jordan, Kevin

1999-01-01

The following contains the final report on the activities related to the Cooperative Agreement between the human factors research group at NASA Ames Research Center and the Psychology Department at San Jose State University. The participating NASA Ames division has been, as the organization has changed, the Aerospace Human Factors Research Division (ASHFRD and Code FL), the Flight Management and Human Factors Research Division (Code AF), and the Human Factors Research and Technology Division (Code IH). The inclusive dates for the report are November 1, 1984 to January 31, 1999. Throughout the years, approximately 170 persons worked on the cooperative agreements in one capacity or another. The Cooperative Agreement provided for research personnel to collaborate with senior scientists in ongoing NASA ARC research. Finally, many post-MA/MS and post-doctoral personnel contributed to the projects. It is worth noting that 10 former cooperative agreement personnel were hired into civil service positions directly from the agreements.

Risk factors for ischemic stroke and its subtypes in Chinese vs. Caucasians: Systematic review and meta-analysis.

PubMed

Tsai, Chung-Fen; Anderson, Niall; Thomas, Brenda; Sudlow, Cathie L M

2015-06-01

Chinese populations are reported to have a different distribution of ischemic stroke subtypes compared with Caucasians. To understand this better, we aimed to evaluate the differences in prevalence of risk factors in ischemic stroke and their distributions among ischemic stroke subtypes in Chinese vs. Caucasians. We systematically sought studies conducted since 1990 with data on frequency of risk factors among ischemic stroke subtypes in Chinese or Caucasians. For each risk factor, we calculated study-specific and random effects pooled estimates in Chinese and Caucasians separately for: prevalence among ischemic stroke; odds ratios, comparing prevalence for each ischemic stroke subtype vs. all others. We included seven studies among 16,199 Chinese, and eleven among 16,189 Caucasian ischemic stroke patients. Risk factors studied were hypertension, diabetes, atrial fibrillation, ischemic heart disease, hypercholesterolemia, smoking and alcohol. Chinese ischemic stroke patients had younger onset of stroke than Caucasians, similar prevalence of hypertension, diabetes, smoking and alcohol, and significantly lower prevalence of atrial fibrillation, ischemic heart disease and hypercholesterolemia. Risk factor associations with ischemic stroke subtypes were mostly similar among Chinese and Caucasian ischemic stroke patients. Compared with all other ischemic subtypes, diabetes was more common in large artery stroke, atrial fibrillation and ischemic heart disease in cardioembolic stroke, and hypertension and diabetes in lacunar stroke. Our study showed a lower prevalence of atrial fibrillation, ischemic heart disease and hypercholesterolemia in Chinese, and mostly similar risk factor associations in Chinese and Caucasian ischemic stroke patients. Further analyses of individual patient data to allow adjustment for confounders are needed to confirm and extend these findings. © 2015 World Stroke Organization.

Severe edentulism is a major risk factor influencing stroke incidence in rural Ecuador (The Atahualpa Project).

PubMed

Del Brutto, Oscar H; Mera, Robertino M; Zambrano, Mauricio; Del Brutto, Victor J

2017-02-01

Background There is no information on stroke incidence in rural areas of Latin America, where living conditions and cardiovascular risk factors are different from urban centers. Aim Using a population-based prospective cohort study design, we aimed to assess risk factors influencing stroke incidence in community-dwelling adults living in rural Ecuador. Methods First-ever strokes occurring from 1 June 2012 to 31 May 2016, in Atahualpa residents aged ≥40 years, were identified from yearly door-to-door surveys and other overlapping sources. Poisson regression models adjusted for demographics, cardiovascular risk factors, edentulism and the length of observation time per subject were used to estimate stroke incidence rate ratio as well as factors influencing such incidence. Results Of 807 stroke-free individuals prospectively enrolled in the Atahualpa Project, follow-up was achieved in 718 (89%), contributing 2,499 years of follow-up (average 3.48 ± 0.95 years). Overall stroke incidence rate was 2.97 per 100 person-years of follow-up (95% CI: 1.73-4.2), which increased to 4.77 (95% CI: 1.61-14.1) when only persons aged ≥57 years were considered. Poisson regression models, adjusted for relevant confounders, showed that high blood pressure (IRR: 5.24; 95% CI: 2.55-7.93) and severe edentulism (IRR: 5.06; 95% CI: 2.28-7.85) were the factors independently increasing stroke incidence. Conclusions Stroke incidence in this rural setting is comparable to that reported from the developed world. Besides age and high blood pressure, severe edentulism is a major factor independently predicting incident strokes. Public awareness of the consequences of poor dental care might reduce stroke incidence in rural settings.

Is the Factor Observed in Investigations on the Item-Position Effect Actually the Difficulty Factor?

PubMed

Schweizer, Karl; Troche, Stefan

2018-02-01

In confirmatory factor analysis quite similar models of measurement serve the detection of the difficulty factor and the factor due to the item-position effect. The item-position effect refers to the increasing dependency among the responses to successively presented items of a test whereas the difficulty factor is ascribed to the wide range of item difficulties. The similarity of the models of measurement hampers the dissociation of these factors. Since the item-position effect should theoretically be independent of the item difficulties, the statistical ex post manipulation of the difficulties should enable the discrimination of the two types of factors. This method was investigated in two studies. In the first study, Advanced Progressive Matrices (APM) data of 300 participants were investigated. As expected, the factor thought to be due to the item-position effect was observed. In the second study, using data simulated to show the major characteristics of the APM data, the wide range of items with various difficulties was set to zero to reduce the likelihood of detecting the difficulty factor. Despite this reduction, however, the factor now identified as item-position factor, was observed in virtually all simulated datasets.

Psychosocial factors at work and self reported health: comparative results of cross sectional and prospective analyses of the French GAZEL cohort

PubMed Central

Niedhammer, I; Chea, M

2003-01-01

Background: Psychosocial factors at work have been found to be significant contributors to health, especially cardiovascular health. Aims: To explore the relation between psychosocial factors at work and self reported health, using cross sectional and prospective analyses for a large occupational cohort of men and women. Methods: Psychosocial factors at work were evaluated using the Karasek questionnaire, designed to measure psychological demands, decision latitude, social support, and physical demands. Self reported health was used as health outcome. Covariates included chronic diseases, and sociodemographic, occupational, and behavioural factors. The cross sectional and prospective analyses concerned respectively 11 447 and 7664 workers. Men and women were analysed separately. Results: Cross sectional analysis revealed significant associations between psychological demands, decision latitude, social support, and physical demands, and self reported health for both men and women. Prospective analysis showed that high psychological demands for both genders, low decision authority for men, and low social support and high physical demands for women were predictive of poor self reported health. These results were independent of potential confounding variables. Conclusions: Results highlight the predictive effects of psychosocial factors at work on self reported health in a one year follow up study. They also underline the need for longitudinal study design and separate analyses for men and women in the field of psychosocial factors at work. PMID:12819285

Factors, fiction and endothelium-derived hyperpolarizing factor.

PubMed

Sandow, Shaun L

2004-09-01

1. The principal mediators of vascular tone are neural, endothelial and physical stimuli that result in the initiation of dilator and constrictor responses to facilitate the control of blood pressure. Two primary vasodilatory stimuli produced by the endothelium are nitric oxide (NO) and prostaglandins. An additional endothelium-dependent vasodilatory mechanism is characterized as the hyperpolarization-mediated relaxation that remains after the inhibition of the synthesis of NO and prostaglandins. This mechanism is due to the action of a so-called endothelium-derived hyperpolarizing factor (EDHF) and is dependent on either the release of diffusible factor(s) and/or to a direct contact-mediated mechanism. 2. Most evidence supports the concept that 'EDHF' activity is dependent on contact-mediated mechanisms. This involves the transfer of an endothelium-derived electrical current, as an endothelium-derived hyperpolarization (EDH), through direct heterocellular coupling of endothelial cells and smooth muscle cells via myoendothelial gap junctions (MEGJ). However, there is a lack of consensus with regard to the nature and mechanism of action of EDHF/EDH (EDH(F)), which has been shown to vary within and between vascular beds, as well as among species, strains, sex and during development, ageing and disease. 3. In addition to actual heterogeneity in EDH(F), further heterogeneity has resulted from the less-than-optimal design, analysis and interpretation of data in some key papers in the EDHF literature; with such views being perpetuated in the subsequent literature. 4. The focus of the present brief review is to examine what factors are proposed as EDH(F) and highlight the correlative structural and functional studies from our laboratory that demonstrate an integral role for MEGJ in the conduction of EDH, which account for the heterogeneity in EDH(F), while incorporating the reported diffusible mechanisms in the regulation of this activity. Furthermore, in addition to the

Factors potentially associated with the decision of admission to the intensive care unit in a middle-income country: a survey of Brazilian physicians.

PubMed

Ramos, João Gabriel Rosa; Passos, Rogerio da Hora; Baptista, Paulo Benigno Pena; Forte, Daniel Neves

2017-01-01

To evaluate the factors potentially associated with the decision of admission to the intensive care unit in Brazil. An electronic survey of Brazilian physicians working in intensive care units. Fourteen variables that were potentially associated with the decision of admission to the intensive care unit were rated as important (from 1 to 5) by the respondents and were later grouped as "patient-related," "scarcity-related" and "administrative-related" factors. The workplace and physician characteristics were evaluated for correlation with the factor ratings. During the study period, 125 physicians completed the survey. The scores on patient-related factors were rated higher on their potential to affect decisions than scarcity-related or administrative-related factors, with a mean ± SD of 3.42 ± 0.7, 2.75 ± 0.7 and 2.87 ± 0.7, respectively (p < 0.001). The patient's underlying illness prognosis was rated by 64.5% of the physicians as always or frequently affecting decisions, followed by acute illness prognosis (57%), number of intensive care unit beds available (56%) and patient's wishes (53%). After controlling for confounders, receiving specific training on intensive care unit triage was associated with higher ratings of the patient-related factors and scarcity-related factors, while working in a public intensive care unit (as opposed to a private intensive care unit) was associated with higher ratings of the scarcity-related factors. Patient-related factors were more frequently rated as potentially affecting intensive care unit admission decisions than scarcity-related or administrative-related factors. Physician and workplace characteristics were associated with different factor ratings.

A review on environmental factors regulating arsenic methylation in humans.

PubMed

Tseng, Chin-Hsiao

2009-03-15

Subjects exposed to arsenic show significant inter-individual variation in urinary patterns of arsenic metabolites but insignificant day-to-day intra-individual variation. The inter-individual variation in arsenic methylation can be partly responsible for the variation in susceptibility to arsenic toxicity. Wide inter-ethnic variation and family correlation in urinary arsenic profile suggest a genetic effect on arsenic metabolism. In this paper the environmental factors affecting arsenic metabolism are reviewed. Methylation capacity might reduce with increasing dosage of arsenic exposure. Furthermore, women, especially at pregnancy, have better methylation capacity than their men counterparts, probably due to the effect of estrogen. Children might have better methylation capacity than adults and age shows inconsistent relevance in adults. Smoking and alcohol consumption might be associated with a poorer methylation capacity. Nutritional status is important in the methylation capacity and folate may facilitate the methylation and excretion of arsenic. Besides, general health conditions and medications might influence the arsenic methylation capacity; and technical problems can cause biased estimates. The consumption of seafood, seaweed, rice and other food with high arsenic contents and the extent of cooking and arsenic-containing water used in food preparation may also interfere with the presentation of the urinary arsenic profile. Future studies are necessary to clarify the effects of the various arsenic metabolites including the trivalent methylated forms on the development of arsenic-induced human diseases with the consideration of the effects of confounding factors and the interactions with other effect modifiers.

Factors associated with furry pet ownership among patients with asthma.

PubMed

Downes, Martin J; Roy, Angkana; McGinn, Thomas G; Wisnivesky, Juan P

2010-09-01

Exposure to indoor allergens is an established risk factor for poor asthma control. Current guidelines recommend removing pets from the home of patients with asthma. This cross-sectional study was conducted to determine the prevalence of furry pet ownership in asthmatics compared to non-asthmatics and to identify factors associated with furry pet ownership among those with asthma. Secondary analysis assessed characteristics among asthmatics that might be associated with allowing a furry pet into the bedroom. Using data from The National Asthma Survey collected from 2003 to 2004, we carried out univariate and multiple regression analyses, in 2009, to identify independent predictors of furry pet ownership in asthma sufferers after controlling for potential confounders. Overall, asthmatics were more likely to own a furry pet than nonasthmatic individuals in the general population (49.9% versus 44.8%, p < .001). Multivariate analysis showed that female sex, older age, white race, and high income were independent predictors of furry pet ownership among asthmatics. Additionally, 68.7% of patients with asthma who own a furry pet allowed them into their bedroom. Higher income and carrying out < or =2 environmental control practices in the home were associated with increased likelihood of allowing a furry pet into the bedroom. Furry pet ownership is equally or more common among asthmatics compared to those without asthma. The majority of asthmatics with furry pets allow them into the bedroom. Recognizing and addressing these problems may help decrease asthma morbidity.

Assessing risk factors for dental caries: a statistical modeling approach.

PubMed

Trottini, Mario; Bossù, Maurizio; Corridore, Denise; Ierardo, Gaetano; Luzzi, Valeria; Saccucci, Matteo; Polimeni, Antonella

2015-01-01

The problem of identifying potential determinants and predictors of dental caries is of key importance in caries research and it has received considerable attention in the scientific literature. From the methodological side, a broad range of statistical models is currently available to analyze dental caries indices (DMFT, dmfs, etc.). These models have been applied in several studies to investigate the impact of different risk factors on the cumulative severity of dental caries experience. However, in most of the cases (i) these studies focus on a very specific subset of risk factors; and (ii) in the statistical modeling only few candidate models are considered and model selection is at best only marginally addressed. As a result, our understanding of the robustness of the statistical inferences with respect to the choice of the model is very limited; the richness of the set of statistical models available for analysis in only marginally exploited; and inferences could be biased due the omission of potentially important confounding variables in the model's specification. In this paper we argue that these limitations can be overcome considering a general class of candidate models and carefully exploring the model space using standard model selection criteria and measures of global fit and predictive performance of the candidate models. Strengths and limitations of the proposed approach are illustrated with a real data set. In our illustration the model space contains more than 2.6 million models, which require inferences to be adjusted for 'optimism'.

Confounding and Statistical Significance of Indirect Effects: Childhood Adversity, Education, Smoking, and Anxious and Depressive Symptomatology.

PubMed

Sheikh, Mashhood Ahmed

2017-01-01

The life course perspective, the risky families model, and stress-and-coping models provide the rationale for assessing the role of smoking as a mediator in the association between childhood adversity and anxious and depressive symptomatology (ADS) in adulthood. However, no previous study has assessed the independent mediating role of smoking in the association between childhood adversity and ADS in adulthood. Moreover, the importance of mediator-response confounding variables has rarely been demonstrated empirically in social and psychiatric epidemiology. The aim of this paper was to (i) assess the mediating role of smoking in adulthood in the association between childhood adversity and ADS in adulthood, and (ii) assess the change in estimates due to different mediator-response confounding factors (education, alcohol intake, and social support). The present analysis used data collected from 1994 to 2008 within the framework of the Tromsø Study ( N = 4,530), a representative prospective cohort study of men and women. Seven childhood adversities (low mother's education, low father's education, low financial conditions, exposure to passive smoke, psychological abuse, physical abuse, and substance abuse distress) were used to create a childhood adversity score. Smoking status was measured at a mean age of 54.7 years (Tromsø IV), and ADS in adulthood was measured at a mean age of 61.7 years (Tromsø V). Mediation analysis was used to assess the indirect effect and the proportion of mediated effect (%) of childhood adversity on ADS in adulthood via smoking in adulthood. The test-retest reliability of smoking was good (Kappa: 0.67, 95% CI: 0.63; 0.71) in this sample. Childhood adversity was associated with a 10% increased risk of smoking in adulthood (Relative risk: 1.10, 95% CI: 1.03; 1.18), and both childhood adversity and smoking in adulthood were associated with greater levels of ADS in adulthood ( p < 0.001). Smoking in adulthood did not significantly mediate the

Confounding and Statistical Significance of Indirect Effects: Childhood Adversity, Education, Smoking, and Anxious and Depressive Symptomatology

PubMed Central

Sheikh, Mashhood Ahmed

2017-01-01

The life course perspective, the risky families model, and stress-and-coping models provide the rationale for assessing the role of smoking as a mediator in the association between childhood adversity and anxious and depressive symptomatology (ADS) in adulthood. However, no previous study has assessed the independent mediating role of smoking in the association between childhood adversity and ADS in adulthood. Moreover, the importance of mediator-response confounding variables has rarely been demonstrated empirically in social and psychiatric epidemiology. The aim of this paper was to (i) assess the mediating role of smoking in adulthood in the association between childhood adversity and ADS in adulthood, and (ii) assess the change in estimates due to different mediator-response confounding factors (education, alcohol intake, and social support). The present analysis used data collected from 1994 to 2008 within the framework of the Tromsø Study (N = 4,530), a representative prospective cohort study of men and women. Seven childhood adversities (low mother's education, low father's education, low financial conditions, exposure to passive smoke, psychological abuse, physical abuse, and substance abuse distress) were used to create a childhood adversity score. Smoking status was measured at a mean age of 54.7 years (Tromsø IV), and ADS in adulthood was measured at a mean age of 61.7 years (Tromsø V). Mediation analysis was used to assess the indirect effect and the proportion of mediated effect (%) of childhood adversity on ADS in adulthood via smoking in adulthood. The test-retest reliability of smoking was good (Kappa: 0.67, 95% CI: 0.63; 0.71) in this sample. Childhood adversity was associated with a 10% increased risk of smoking in adulthood (Relative risk: 1.10, 95% CI: 1.03; 1.18), and both childhood adversity and smoking in adulthood were associated with greater levels of ADS in adulthood (p < 0.001). Smoking in adulthood did not significantly mediate the

The Secondary Structure of Human Hageman Factor (Factor XII) and its Alteration by Activating Agents

PubMed Central

McMillin, Carl R.; Saito, Hidehiko; Ratnoff, Oscar D.; Walton, Alan G.

1974-01-01

Hageman factor (factor XII) is activated by exposure to surfaces such as glass or by solutions of certain compounds, notably ellagic acid. Changes in the structure of Hageman factor accompanying activation have been examined in this study by circular dichroism spectroscopy. The spectrum of unactivated Hageman factor in aqueous solutions suggests that its conformation is mainly aperiodic. Various perturbants altered the conformation of Hageman factor in differing ways, demonstrating the sensitivity of Hageman factor to its environment. After activation of Hageman factor with solutions of ellagic acid, a negative trough appeared in the region of the circular dichroism spectrum commonly assigned to tyrosine residues, along with other minor changes in the peptide spectral region. Some of these changes are similar to changes that occurred upon partial neutralization of the basic residues at alkali pH. Activation of Hageman factor by adsorption to quartz surfaces (in an aqueous environment) also produced changes similar to those in the ellagic acid-activated Hageman factor, including the negative ellipticity in the tyrosine region. These observations suggest that the activation process may be related to a change in status of some of the basic amino acid residues, coupled with a specific change in the environment of some tyrosine residues. The importance of these changes during the activation process remains to be determined. The sensitivity of Hageman factor to its environment is consistent with the view that the initiation of clotting by exposure of plasma to appropriate agents is brought about by alterations in the conformation of Hageman factor that occur in the apparent absence of Fletcher factor or other recognized clotting factors. Images PMID:4373492

Maternal Risk Factors and Periodontal Disease: A Cross-sectional Study among Postpartum Mothers in Tamil Nadu.

PubMed

Govindasamy, Rohini; Dhanasekaran, Manikandan; Varghese, Sheeja S; Balaji, V R; Karthikeyan, B; Christopher, Ananthi

2017-11-01

It is inconclusive that periodontitis is an independent risk factor for adverse pregnancy outcomes. This study aims to investigate the association between maternal periodontitis and preterm and/or low birth weight babies. This was a prospective cross-sectional study. After prior informed consent, 3500 postpartum mothers were selected from various hospitals in Tamil Nadu and categorized into the following groups: group-1 - Normal term normal birth weight ( n = 1100); Group-2 - Preterm normal birth weight ( n = 400); Group-3 - preterm low birth weight (PTLBW) ( n = 1000); and Group-4 - Normal term low birth weight ( n = 1000). Periodontal examination was done, and risk factors were ascertained by means of questionnaire and medical records. Comparison between case groups and control groups were done, odds ratio (OR) was calculated, and statistical significance were assessed by Chi-square tests. To control for the possible confounders, all variables with P < 0.05 were selected and entered into multivariate regression model, and OR and 95% confidence limits were again estimated. SPSS-15 software was used. Periodontitis was diagnosed in 54.8%, 52.3%, 53.8%, 59.4%, respectively. On comparison between the groups, none of periodontal parameters showed significant association except for the crude association observed in Group-4 for mild periodontitis (OR - 1.561; P = 0.000) and PTLBW. Periodontitis is not a significant independent risk factor, and obstetric factors contribute a major risk for preterm and/or low birth weight babies.

Prospective cohort study of factors influencing the relative weights of the placenta and the newborn infant.

PubMed

Williams, L A; Evans, S F; Newnham, J P

1997-06-28

To determine the demographic, environmental, and medical factors that influence the relative weights of the newborn infant and the placenta and compare this ratio with other factors known to predispose to adult ill health. Prospective cohort study. The tertiary referral centre for perinatal care in Perth, Western Australia. 2507 pregnant women who delivered a single live infant at term. Placental weight, birth weight, and the ratio of placental weight to birth weight. By multiple regression analysis the placental weight to birthweight ratio was significantly and positively associated with gestational age, female sex, Asian parentage, increasing maternal body mass index, increased maternal weight at booking, lower socioeconomic status, maternal anaemia, and increasing number of cigarettes smoked daily. There were no consistent relations between the placental weight to birthweight ratio and measures of newborn size. The ratio of placental weight to birth weight is not an accurate marker of fetal growth. In its role as a predictor of adult disease the ratio may be acting as a surrogate for other factors which are already known to influence health and may act before or after birth. Determining the role that relative growth rates of the fetus and placenta have in predisposing to adult disease requires prospective study to account for the many confounding variables which complicate this hypothesis.

Testing alternative factor models of PTSD and the robustness of the dysphoria factor.

PubMed

Elklit, Ask; Armour, Cherie; Shevlin, Mark

2010-01-01

This study first aimed to examine the structure of self-reported posttraumatic stress disorder (PTSD) symptoms using three different samples. The second aim of the paper was to test the robustness of the factor analytic model when depression scores were controlled for. Based on previous factor analytic findings and the DSM-IV formulation, six confirmatory factor models were specified and estimated that reflected different symptom clusters. The best fitting model was subsequently re-fitted to the data after including a depression variable. The analyses were based on responses from 973 participants across three samples. Sample 1 consisted of 633 parents who were members of 'The National Association of Infant Death' and who had lost a child. Sample 2 consisted of 227 victims of rape, who completed a questionnaire within 4 weeks of the rape. Each respondent had been in contact with the Centre for Rape Victims (CRV) at the Aarhus University Hospital, Denmark. Sample 3 consisted of 113 refugees resident in Denmark. All participants had been referred to a treatment centre which focused on rehabilitating refugees through treatment for psychosocial integration problems (RRCF: Rehabliterings og Revliderings Centre for Flygtninge). In total 500 participants received a diagnosis of PTSD/sub-clinical PTSD (Sample 1, N=214; 2, N=176; 3, N=110). A correlated four-factor model with re-experiencing, avoidance, dysphoria, and arousal factors provided the best fit to the sample data. The average attenuation in the factor loadings was highest for the dysphoria factor (M=-.26, SD=.11) compared to the re-experiencing (M=-.14, SD=.18), avoidance (M=-.10, SD=.21), and arousal (M=-.09, SD=.13) factors. With regards to the best fitting factor model these results concur with previous research findings using different trauma populations but do not reflect the current DSM-IV symptom groupings. The attenuation of dysphoria factor loadings suggests that dysphoria is a non-specific component of

Adding Salt to Meals as a Risk Factor of Type 2 Diabetes Mellitus: A Case-Control Study.

PubMed

Radzeviciene, Lina; Ostrauskas, Rytas

2017-01-13

Type 2 diabetes mellitus (T2DM) is thought to arise from the complex interplay between genetic and environmental factors. It is important to identify modifiable risk factors that may help to reduce the risk of diabetes. Data on salt intake and the risk of type 2 diabetes are limited. The aim of this study was to assess the relationship between adding salt to prepared meals and the risk of type 2 diabetes. In a case-control study, we included 234 cases, all of whom were patients aged 35-86 years with a newly confirmed diagnosis of T2DM, and 468 controls that were free of the disease. Cases and controls (ratio 1:2) were matched by gender and age (±5 years). A questionnaire was used to collect information on possible risk factors for diabetes. Adding salt to prepared meals was assessed according to: Never, when there was not enough, or almost every time without tasting. The odds ratios (OR), and 95% confidence intervals (CI) for type 2 diabetes was calculated using a conditional logistic regression. The cases had a higher body mass index and a significantly lower education level compared to the controls. Variables such as waist circumference, body mass index, eating speed, smoking, family history of diabetes, arterial hypertension, plasma triglycerides, educational level, occupational status, morning exercise, marital status, daily urine sodium excretion, and daily energy intake were retained in the models as confounders. After adjusting for possible confounders, an approximately two-fold increased risk of type 2 diabetes was determined in subjects who add salt to prepared meals when "it is not enough" or "almost every time without tasting" (1.82; 95% CI 1.19-2.78; p = 0.006) compared with never adding salt. Presented data suggest the possible relationship between additional adding of salt to prepared meals and an increased risk of type 2 diabetes.

Reading Behind the Lines: The Factors Affecting the Text Reception Threshold in Hearing Aid Users.

PubMed

Zekveld, Adriana A; Pronk, Marieke; Danielsson, Henrik; Rönnberg, Jerker

2018-03-15

The visual Text Reception Threshold (TRT) test (Zekveld et al., 2007) has been designed to assess modality-general factors relevant for speech perception in noise. In the last decade, the test has been adopted in audiology labs worldwide. The 1st aim of this study was to examine which factors best predict interindividual differences in the TRT. Second, we aimed to assess the relationships between the TRT and the speech reception thresholds (SRTs) estimated in various conditions. First, we reviewed studies reporting relationships between the TRT and the auditory and/or cognitive factors and formulated specific hypotheses regarding the TRT predictors. These hypotheses were tested using a prediction model applied to a rich data set of 180 hearing aid users. In separate association models, we tested the relationships between the TRT and the various SRTs and subjective hearing difficulties, while taking into account potential confounding variables. The results of the prediction model indicate that the TRT is predicted by the ability to fill in missing words in incomplete sentences, by lexical access speed, and by working memory capacity. Furthermore, in line with previous studies, a moderate association between higher age, poorer pure-tone hearing acuity, and poorer TRTs was observed. Better TRTs were associated with better SRTs for the correct perception of 50% of Hagerman matrix sentences in a 4-talker babble, as well as with better subjective ratings of speech perception. Age and pure-tone hearing thresholds significantly confounded these associations. The associations of the TRT with SRTs estimated in other conditions and with subjective qualities of hearing were not statistically significant when adjusting for age and pure-tone average. We conclude that the abilities tapped into by the TRT test include processes relevant for speeded lexical decision making when completing partly masked sentences and that these processes require working memory capacity. Furthermore

Associations of unhealthy lifestyle factors with sexual inactivity and sexual dysfunctions in Denmark.

PubMed

Christensen, Birgitte S; Grønbaek, Morten; Pedersen, Bo V; Graugaard, Christian; Frisch, Morten

2011-07-01

Studies have linked obesity, a sedentary lifestyle, and tobacco smoking to erectile dysfunction, but the evidence linking unhealthy lifestyle factors to other sexual dysfunctions or to sexual inactivity is conflicting. To examine associations between unhealthy lifestyle factors and sexual inactivity with a partner and four specific sexual dysfunctions in each sex. We used nationally representative survey data from 5,552 Danish men and women aged 16-97 years in 2005. Cross-sectional associations of lifestyle factors with sexual inactivity and sexual dysfunctions were estimated by logistic regression-derived, confounder-adjusted odds ratios (ORs). We calculated ORs for sexual inactivity with a partner and for sexual dysfunction and sexual difficulties overall in both sexes, for erectile dysfunction, anorgasmia, premature ejaculation, and dyspareunia in men, and for lubrication insufficiency, anorgasmia, dyspareunia, and vaginismus in women. Obesity (body mass index [BMI]≥30 kg/m(2) ) or a substantially increased waist circumference (men ≥102 cm; women ≥88 cm), physical inactivity, and, among women, tobacco smoking were each significantly associated with sexual inactivity in the last year. Among sexually active men, both underweight (BMI <20 kg/m(2) ) and obesity, a substantially increased waist circumference, physical inactivity in leisure time, high alcohol consumption (>21 alcoholic beverages/week), tobacco smoking, and use of hard drugs were each significantly positively associated with one or more sexual dysfunctions (ORs between 1.71 and 22.0). Among sexually active women, the only significant positive association between an unhealthy lifestyle factor and sexual dysfunction was between hashish use and anorgasmia (OR 2.85). In both sexes, several unhealthy lifestyle factors were associated with sexual inactivity with a partner in the last year. Additionally, among sexually active participants, men with unhealthy lifestyles were significantly more likely to

Laparoscopic repair of giant paraesophageal hernia: are there factors associated with anatomic recurrence?

PubMed

Antiporda, Michael; Veenstra, Benjamin; Jackson, Chloe; Kandel, Pujan; Daniel Smith, C; Bowers, Steven P

2018-02-01

Repair of giant paraesophageal hernia (PEH) is associated with a favorably high rate of symptom improvement; however, rates of recurrence by objective measures remain high. Herein we analyze our experience with laparoscopic giant PEH repair to determine what factors if any can predict anatomic recurrence. We prospectively collected data on PEH characteristics, variations in operative techniques, and surgeon factors for 595 patients undergoing laparoscopic PEH repair from 2008 to 2015. Upper GI study was performed at 6 months postoperatively and selectively thereafter-any supra-diaphragmatic stomach was considered hiatal hernia recurrence. Exclusion criteria included revisional operation (22.4%), size <5 cm (17.6%), inadequate follow-up (17.8%), and confounding concurrent operations (6.9%). Inclusion criteria were met by 202 patients (31% male, median age 71 years, and median BMI 28.7). At a median follow-up of 6 months (IQR 6-12), overall anatomic recurrence rate was 34.2%. Symptom recurrence rate was 9.9% and revisional operation was required in ten patients (4.9%). Neither patient demographics nor PEH characteristics (size, presence of Cameron erosions, esophagitis, or Barrett's) correlated with anatomic recurrence. Technical factors at operation (mobilized intra-abdominal length of esophagus, Collis gastroplasty, number of anterior/posterior stitches, use of crural buttress, use of pledgeted or mattress sutures, or gastrostomy) were also not correlated with recurrence. Regarding surgeon factors, annual volume of fewer than ten cases per year was associated with increased risk of anatomic failure (54 vs 33%, P = 0.02). Multivariate analysis identified surgeon experience (<10 cases per year) as an independent factor associated with early hiatal hernia recurrence (OR 3.7, 95% CI 1.34-10.9). Laparoscopic repair of giant PEH is associated with high anatomic recurrence rate but excellent symptom control. PEH characteristics and technical operative variables do

[Pathological gambling: risk factors].

PubMed

Bouju, G; Grall-Bronnec, M; Landreat-Guillou, M; Venisse, J-L

2011-09-01

In France, consumption of gambling games increased by 148% between 1960 and 2005. In 2004, gamblers lost approximately 0.9% of household income, compared to 0.4% in 1960. This represents approximately 134 Euros per year and per head. In spite of this important increase, the level remains lower than the European average (1%). However, gambling practices may continue to escalate in France in the next few years, particularly with the recent announce of the legalisation of online games and sports betting. With the spread of legalised gambling, pathological gambling rates may increase in France in the next years, in response to more widely available and more attractive gambling opportunities. In this context, there is a need for better understanding of the risk factors that are implicated in the development and maintenance of pathological gambling. This paper briefly describes the major risk factors for pathological gambling by examining the recent published literature available during the first quarter of 2008. This documentary basis was collected by Inserm for the collective expert report procedure on Gambling (contexts and addictions). Seventy-two articles focusing on risk factors for pathological gambling were considered in this review. Only 47 of them were taken into account for analysis. The selection of these 47 publications was based on the guide on literature analysis established by the French National Agency for Accreditation and Assessment in Health (ANAES, 2000). Some publications from more recent literature have also been added, mostly about Internet gambling. We identify three major types of risk factors implicated in gambling problems: some of them are related to the subject (individual factors), others are related to the object of the addiction, here the gambling activity by itself (structural factors), and the last are related to environment (contextual or situational factors). Thus, the development and maintenance of pathological gambling seems to be

Rare coagulation disorders: fibrinogen, factor VII and factor XIII.

PubMed

de Moerloose, P; Schved, J-F; Nugent, D

2016-07-01

Rare coagulation disorders (RCDs) include the inherited deficiencies of fibrinogen, factor (F) II, FV, combined FV and VIII, FVII, FX, combined FVII and X, FXI, FXIII and combined congenital deficiency of vitamin K-dependent factors (VKCFDs). Despite their rarity, a deep comprehension of all these disorders is essential to really understand haemostasis. Indeed, even if they share some common features each RCD has some particularity which makes it unique. In this review, we focus on three disorders: fibrinogen, FVII and FXIII. © 2016 John Wiley & Sons Ltd.

Preanalytical Confounding Factors in the Analysis of Cerebrospinal Fluid Biomarkers for Alzheimer’s Disease: The Issue of Diurnal Variation

PubMed Central

Cicognola, Claudia; Chiasserini, Davide; Parnetti, Lucilla

2015-01-01

Given the growing use of cerebrospinal fluid (CSF) beta-amyloid (Aβ) and tau as biomarkers for early diagnosis of Alzheimer’s disease (AD), it is essential that the diagnostic procedures are standardized and the results comparable across different laboratories. Preanalytical factors are reported to be the cause of at least 50% of the total variability. Among them, diurnal variability is a key issue and may have an impact on the comparability of the values obtained. The available studies on this issue are not conclusive so far. Fluctuations of CSF biomarkers in young healthy volunteers have been previously reported, while subsequent studies have not confirmed those observations in older subjects, the ones most likely to receive this test. The observed differences in circadian rhythms need to be further assessed not only in classical CSF biomarkers but also in novel forthcoming biomarkers. In this review, the existing data on the issue of diurnal variations of CSF classical biomarkers for AD will be analyzed, also evaluating the available data on new possible biomarkers. PMID:26175714

Examining the role of unmeasured confounding in mediation analysis with genetic and genomic applications.

PubMed

Lutz, Sharon M; Thwing, Annie; Schmiege, Sarah; Kroehl, Miranda; Baker, Christopher D; Starling, Anne P; Hokanson, John E; Ghosh, Debashis

2017-07-19

In mediation analysis if unmeasured confounding is present, the estimates for the direct and mediated effects may be over or under estimated. Most methods for the sensitivity analysis of unmeasured confounding in mediation have focused on the mediator-outcome relationship. The Umediation R package enables the user to simulate unmeasured confounding of the exposure-mediator, exposure-outcome, and mediator-outcome relationships in order to see how the results of the mediation analysis would change in the presence of unmeasured confounding. We apply the Umediation package to the Genetic Epidemiology of Chronic Obstructive Pulmonary Disease (COPDGene) study to examine the role of unmeasured confounding due to population stratification on the effect of a single nucleotide polymorphism (SNP) in the CHRNA5/3/B4 locus on pulmonary function decline as mediated by cigarette smoking. Umediation is a flexible R package that examines the role of unmeasured confounding in mediation analysis allowing for normally distributed or Bernoulli distributed exposures, outcomes, mediators, measured confounders, and unmeasured confounders. Umediation also accommodates multiple measured confounders, multiple unmeasured confounders, and allows for a mediator-exposure interaction on the outcome. Umediation is available as an R package at https://github.com/SharonLutz/Umediation A tutorial on how to install and use the Umediation package is available in the Additional file 1.

Factors associated with different hygiene practices in the homes of 15 month old infants

PubMed Central

Sherriff, A; Golding, J; The, A

2002-01-01

Background: Improved hygiene in Westernised regions of the world may be partly responsible for the increased prevalence of diseases of the immune system, such as asthma and atopy. There is a paucity of data on cleanliness norms in young children in the UK and there has been no attempt to identify factors that influence the adoption of particular hygiene practices in the home. Aims: To examine levels of hygiene in a contemporary cohort of children and identify social and lifestyle factors influencing hygiene practices in the home. Methods: The sample under study are participants in the Avon Longitudinal Study of Parents and Children (ALSPAC). Parental self completion questionnaires provided data on hygiene levels in children at 15 months of age, and a hygiene score was derived from these responses. Multivariable logistic regression models investigated associations between high hygiene scores (top quintile) and a number of perinatal, maternal, social, and environmental factors. Results: Maternal smoking during pregnancy, low maternal educational achievement, and living in local authority housing were factors independently associated with high hygiene scores, as was increased use of chemical household products. High hygiene scores were inversely related to living in damp housing and attendance at day care. There were no gender or ethnic differences in hygiene score. Conclusion: Important data on cleanliness norms for infants have been presented. The adoption of hygiene practices is influenced to some degree by social, lifestyle, and environmental factors—with higher hygiene scores occurring in more socially disadvantaged groups. Increased use of chemical household products in the more socially disadvantaged groups within ALSPAC has emerged as an important confounder in any study of hygiene and ill health. PMID:12089118

[Environmental factors of longevity].

PubMed

Christen, Yves

2003-03-01

A PROBABLE ROLE: The great increase in life expectancy over the past decades and too short a time lapse for any major genetic mutations to intervene, are arguments in favour of the intervention of environmental factors in longevity. A FAIRLY LONG LIST: Various environmental factors can be envisaged: prenatal environment, pollution, radiation and oncogenic agents, notably tobacco, food (quantitatively and qualitatively), medicinal products, stress, education and socio-professional life style, isolation, number of children and sexual activity, sports and exercising, etc. It is highly likely that all these factors, or at least some of them, have a real effect on longevity, although this is difficult to demonstrate directly. A COMBINED EFFECT: The basic idea of this paper is that these environmental factors should be seen as agents, the effects of which would be combined with those of genetic factors, considered as agents of radically different nature. We suggest that, in order to have any real effect, these environmental factors have to work on the same cell mechanisms as those that affect the genetic process, notably the mechanisms related to oxidative stress and genetic expression.

The Development of the General Factor of Psychopathology 'p Factor' Through Childhood and Adolescence.

PubMed

Murray, Aja Louise; Eisner, Manuel; Ribeaud, Denis

2016-11-01

Recent studies have suggested that the structure of psychopathology may be usefully represented in terms of a general factor of psychopathology (p-factor) capturing variance common to a broad range of symptoms transcending diagnostic domains in addition to specific factors capturing variance common to smaller subsets of more closely related symptoms. Little is known about how the general co-morbidity captured by this p-factor develops and whether general co-morbidity increases or decreases over childhood and adolescence. We evaluated two competing hypotheses: 1) dynamic mutualism which predicts growth in general co-morbidity and associated p-factor strength over time and 2) p-differentiation which predicts that manifestations of liabilities towards psychopathology become increasingly specific over time. Data came from the Zurich Project on the Social Development of Children and Youths (z-proso), a longitudinal study of a normative sample (approx. 50 % male) measured at 8 time points from ages 7 to 15. We operationalised general co-morbidity as p-factor strength in a bi-factor model and used omega hierarchical to track how this changed over development. In contrast to the predictions of both dynamic mutualism and p-differentiation, p-factor strength remained relatively constant over the studied period suggesting that such processes do not govern the interplay between psychopathological symptoms during this phase of development. Future research should focus on earlier phases of development and on factors that maintain the consistency of symptom-general covariation across this period.

Exposure Factors Handbook Chapter 19

EPA Pesticide Factsheets

Exposure Factors Handbook: 2011 Edition. The Exposure Factors Handbook provides information on various physiological and behavioral factors commonly used in assessing exposure to environmental chemicals.