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Potential Confounding Variables (potential + confounding_variable)
Selected AbstractsThe rationale for early intervention in schizophrenia and related disordersEARLY INTERVENTION IN PSYCHIATRY, Issue 2009Merete Nordentoft Abstract Aim: To examine the rationale and evidence supporting an early intervention approach in schizophrenia. Methods: A selective literature review was conducted. Results: During the onset of schizophrenia, there is often a significant delay between the emergence of psychotic symptoms and the initiation of treatment. The average duration of untreated psychosis is around 1,2 years. During this period, brain function may continue to deteriorate and social networks can be irreversibly damaged. Studies have consistently linked longer duration of untreated psychosis with poorer outcomes and this relationship holds even after controlling for the potential confounding variable of premorbid functioning. In Norway, the early Treatment and Intervention in PSychosis study demonstrated that duration of untreated psychosis is amenable to intervention with the combination of educational campaigns and specialized early detection units substantially decreasing the period from onset of symptoms to treatment initiation. Furthermore, recent evidence from the randomized controlled OPUS and the Lambeth Early Onset trial studies have linked phase-specific early interventions to improved outcomes spanning symptoms, adherence to treatment, comorbid drug abuse, relapse and readmission. Some benefits persist after cessation of the intervention. Conclusions: Early intervention in schizophrenia is justified to reduce the negative personal and social impact of prolonged periods of untreated symptoms. Furthermore, phase-specific interventions are associated with improved outcomes, at least in the short term. Further research is needed to establish the optimum duration of such programmes. [source] Nutritional relevance of trans isomeric fatty acids in human milkACTA PAEDIATRICA, Issue 12 2003T Decsi Trans isomeric fatty acids amount to about 2% of the fatty acid composition of human milk in Europe, whereas lower values were seen in Africa, and higher values were reported for North-America. At least five human studies indicate that trans fatty acids may interfere with the metabolism of long-chain polyunsaturated fatty acids. Conclusion: Trans isomeric fatty acids in human milk should be regarded as a potential confounding variable in studies investigating the role of long-chain polyunsaturated fatty acids in the development of breastfed infants. [source] The incidence of anxiety and depression among employees,the role of psychosocial work characteristicsDEPRESSION AND ANXIETY, Issue 11 2009Helene Andrea Ph.D. Abstract Background: Anxiety and depression are prevalent among employees and are associated with functional disability and work impairment. To date, little is known about the incidence and possible risk factors for developing anxiety and depression in the working population. Study aims were to (a) determine the incidence of subclinical anxiety and depression in a general working population and (b) identify the psychosocial work characteristics associated with the onset of subclinical anxiety and depression. Methods: This prospective study is based on 3,707 employees participating in the Maastricht Cohort Study on Fatigue at Work. Psychosocial work characteristics were measured in May 2000; anxiety and depression were measured with the Hospital Anxiety and Depression Scale in April 2002. Results: The cumulative 23-month incidence for subclinical anxiety and depression was 4.6 and 3.3%, respectively. High psychological job demands increased the risk for both subsequent anxiety and depression. Moreover, low social support was predictive for the onset of anxiety, whereas job insecurity increased the risk for the onset of depression. These prospective associations were independent of potential confounding variables and the other psychosocial work characteristics. Conclusions: Adverse psychosocial work characteristics are significant predictors for the onset of subclinical anxiety and depression in the general working population. These findings encourage intervention studies testing whether modifying the psychosocial work environment reduces both anxiety and depressive symptoms among employees. Depression and Anxiety 26:1040,1048, 2009. © 2009 Wiley-Liss, Inc. [source] The Use of Scripting at Triage and Its Impact on ElopementsACADEMIC EMERGENCY MEDICINE, Issue 5 2010Daniel A. Handel MD Abstract Objectives:, The objective of this study was to measure the effect of scripting language at triage on the likelihood of elopements, controlling for patient volume and other potential confounding variables. Methods:, This was a pre- and postintervention cohort study using the same 5-month period (November 2007,March 2008 and November 2008,March 2009, respectively) that included in the analysis all patients 21 years of age and older, who presented to the triage window in the emergency department (ED) waiting room (not by ambulance). As part of the scripting, triage nurses informed patients of the longest waiting time (at that point in time) for any patients still waiting to be brought back from the waiting room into the ED. Rates of elopement were compared between patients who did and did not receive the scripting, controlling for individual and daily ED variables. Results:, A total of 24,390 ED visits were included in this analysis. The elopement rate was 4.4% among ED patients in the prescripting period, compared to 2.3% in the postscripting period. In a multivariate logistic regression model, the use of scripting was significantly associated with decreased odds of elopement, compared to the nonscripting group (odds ratio [OR] = 0.61, 95% confidence interval [CI] = 0.46 to 0.80). Conclusions:, The use of triage scripting was found to significantly reduce elopement rates in patients placed in the ED waiting room, even after controlling for other confounding variables. Scripting is a simple and underutilized technique that can have a positive effect for patients and the ED. ACADEMIC EMERGENCY MEDICINE 2010; 17:495,500 © 2010 by the Society for Academic Emergency Medicine [source] Genotoxicity in wood mice (Apodemus sylvaticus) along a pollution gradient: Exposure-, age-, and gender-related effectsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2006Jan Scheirs Abstract We investigated the effects of environmental pollution on genetic damage in wood mice (Apodemus sylvaticus) by means of the comet assay, with special attention to the role of age and gender as potential confounding variables. The present study was carried out at four sites along a pollution gradient in the vicinity of Antwerp (Belgium), with a nonferrous smelter as the main pollution source. We measured the concentration of heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Pb, and Zn) in mouse liver and kidney and the concentration of organochlorine compounds (polychlorinated biphenyls and 1,1-dichloro-2,2-bis(p -chlorophenyl)ethylene) in mouse muscle tissue to assess individual exposure. Cadmium exposure was very high at the sites closest to the smelter, and exposure to this metal decreased with increasing distance from the smelter. Exposure to the other pollutants was low to moderate at the different sites. Genetic damage was higher in mice from populations in the vicinity of the nonferrous smelter compared with that in the control populations. A significant increase in genetic damage with age was observed at the most polluted sites, but not at the control sites. Genetic damage was higher in male mice than in female mice at the most polluted site, but not at the other areas. Yet, no obvious relationship was found between individual pollutant levels and individual genetic damage levels. We conclude that the comet assay can be used to compare genotoxicity at the population level if the confounding variables of gender and age are taken into account. However, its use for individual health risk assessment remains questionable. [source] Issues in the epidemiological investigation of dry mouthGERODONTOLOGY, Issue 2 2005W. Murray Thomson Despite decades of research, much remains unanswered about the epidemiology of dry mouth. This review aims to provide an overview of the condition's epidemiology and the issues to consider when planning an epidemiological study of dry mouth. The latter can be broadly grouped into: study design; sampling and statistical power considerations; the measurement of dry mouth; and the selection, nature and measurement of relevant exposure measures, including medications and potential confounding variables. Each of these is discussed, in order to provide guidance for prospective researchers based on experience with past research. Finally, an agenda for further epidemiological research into dry mouth is proposed. [source] Cognition following bilateral deep brain stimulation surgery of the subthalamic nucleus for Parkinson's diseaseINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 5 2009Casey H. Halpern Abstract Objective Parkinson's disease (PD) is a neurodegenerative disorder characterized by significant motor dysfunction and various non-motor disturbances, including cognitive alterations. Deep brain stimulation (DBS) is an increasingly utilized therapeutic option for patients with PD that yields remarkable success in alleviating disabling motor symptoms. DBS has additionally been associated with changes in cognition, yet the evidence is not consistent across studies. The following review sought to provide a clearer understanding of the various cognitive sequelae of bilateral subthalamic nucleus (STN) DBS while taking into account corresponding neuroanatomy and potential confounding variables. Design A literature search was performed using the following inclusion criteria: (1) at least five subjects followed for a mean of at least 3 months after surgery; (2) pre- and postoperative cognitive data using at least one standardized measure; (3) adequate report of study results using means and standard deviations. Results Two recent meta-analyses found mild post-operative impairments in verbal learning and executive function in patients who underwent DBS surgery. However, studies have revealed improved working memory and psychomotor speed in the ,on' vs ,off' stimulation state. A deficit in language may be a consequence of the surgical procedure. Conclusions While cognitive decline has been observed in some domains, our review of the data suggests that STN DBS is a worthwhile and safe method to treat PD. Copyright © 2008 John Wiley & Sons, Ltd. [source] Methylxanthines and sensorineural outcome at 14 years in children < 1501 g birthweightJOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 1 2000PG Davis Objectives: Methylxanthines, including theophylline, have been used extensively and successfully to treat apnoea in preterm infants. However, long-term consequences of such therapy are largely unknown. The aim of this study was to determine the relationship between theophylline therapy and outcome at 14 years of age in surviving preterm children of birthweight < 1501 g. Methodology: The subjects of this study were 154 consecutive survivors with birthweights < 1501 g born from 1 October 1980 to 31 March 1982; 130 (84.4%) were assessed at 14 years of age. Outcomes included motor function, psychological test scores, and growth. Results: Of the 130 children assessed, 69 (53.1%) had been exposed to theophylline; 13.0% had cerebral palsy, significantly higher than 1.6% in the 61 children not exposed to theophylline (P < 0.02). This difference remained statistically significant after adjusting for potential confounding variables including the presence of cerebroventricular haemorrhage. In contrast, after adjusting for known confounding variables, children who had received theophylline achieved higher psychological test scores. There was no association between theophylline therapy and growth. Conclusions: Theophylline therapy in the newborn period is associated with some evidence of harmful, but also helpful sensorineural effects at 14 years of age. [source] Non-stress-related factors associated with maternal corticotrophin-releasing hormone (CRH) concentrationPAEDIATRIC & PERINATAL EPIDEMIOLOGY, Issue 4 2010Michael S. Kramer Summary Kramer MS, Lydon J, Séguin L, Goulet L, Kahn SR, McNamara H, Genest J, Sharma S, Meaney MJ, Libman M, Dahhou M, Platt RW. Non-stress-related factors associated with maternal corticotrophin-releasing hormone (CRH) concentration. Paediatric and Perinatal Epidemiology 2010. During pregnancy, most maternal corticotrophin-releasing hormone (CRH) is secreted by the placenta, not the hypothalamus. Second trimester maternal CRH concentration is robustly associated with the subsequent risk of preterm birth, and it is often assumed that physiological and/or psychological stress stimulates placental CRH release. Evidence supporting the latter assumption is weak, however, and other factors affecting maternal CRH have received little attention from investigators. We carried out a case,control study nested within a large, multicentre prospective cohort of pregnant women to examine potential ,upstream' factors associated with maternal CRH concentration measured at 24,26 weeks of gestation. The predictors studied included maternal age, parity, birthplace (as a proxy for ethnic origin), pre-pregnancy body mass index, height, smoking, bacterial vaginosis and vaginal fetal fibronectin (FFN) concentration. Women with high (above the median) plasma CRH concentration were significantly less likely to have been born in Sub-Saharan Africa or the Caribbean, less likely to be overweight or obese, and more likely to be smokers. Associations with maternal birthplace and BMI persisted in logistic regression analyses controlling for potential confounding variables and when restricted to term controls. A strong (but imprecise and statistically non-significant) association was also observed with high vaginal FFN concentration. Further studies are indicated both in animal models and human populations to better understand the biochemical and physiological pathways to CRH secretion and their aetiological role, if any, in preterm birth. [source] A multivitamin supplementation and education intervention as an effective means of increasing multivitamin use among postpartum women of Mexican originPAEDIATRIC & PERINATAL EPIDEMIOLOGY, Issue 3 2007Kathleen M. O'Rourke Summary Postpartum Hispanic women in the USA are at elevated risk for neural tube defects in subsequent pregnancies from the combined effects of ethnicity, folate depletion from the prior pregnancy and lactation, and high parity rates with short inter-birth intervals. This study evaluated an education programme and distribution of a 3-month starter package of multivitamins among Hispanic women attending nutrition clinics for low-income women in El Paso, Texas. At 1,6 weeks postpartum, 329 subjects were selected to receive education only, multivitamins only, education and multivitamins, or no intervention. Multivariable regression obtained odds ratios (OR) and 95% confidence intervals [CI] to measure the association between intervention status and self-reported multivitamin use at least four times per week at 6 and 12 months postpartum, while controlling for potential confounding variables. Multivitamin distribution was related to consumption at both 6 months (OR = 3.5 [95% CI 1.1, 11.2]) and 12 months (OR = 6.5 [95% CI 1.5, 28.3]). Multivitamins plus education was most effective in increasing multivitamin use at both periods: 6 months (OR = 4.0 [95% CI 1.53, 11.7]) and 12 months (OR = 6.4 [95% CI 1.7, 24.2]). At enrolment, 66% of women regularly took vitamins, and approximately 35% took them at both 6 and 12 months postpartum. The education intervention alone was not associated with multivitamin use at either 6 months (OR = 0.79 [95% CI 0.3, 2.4]) or 12 months (OR = 3.1 [95% CI 0.8, 12.1]). Multivitamin use declines precipitously during postpartum at the time Hispanic women may be susceptible to a subsequent pregnancy. This study provides evidence that multivitamin starter packs sustain multivitamin usage up to 1 year postpartum for a specific high-risk group, but the effect of educational intervention alone should be further studied. [source] The influence of maternal respiratory infections during pregnancy on infant lung function,PEDIATRIC PULMONOLOGY, Issue 10 2007Nienke Van Putte-Katier MD Abstract Introduction We studied whether maternal respiratory infections during pregnancy adversely influence lung growth and development of the offspring, resulting in poor early life lung function. Methods Infants were participants of the Wheezing Illnesses Study Leidsche Rijn (WHISTLER). Lung function measurements (single occlusion technique) were performed during natural sleep. Questionnaire data were used to obtain information on maternal respiratory infections during pregnancy. Multivariate analysis was conducted to assess the relationship between maternal respiratory infections during pregnancy and resistance and compliance of the respiratory system, adjusting for potential confounding variables. Results Lower values of compliance (Crs) were found in infants of mothers with respiratory infections during pregnancy; Crs fell by 5.5% (P,=,0.031). The difference in Crs between infants of mothers with and without respiratory infections during pregnancy remained unchanged and statistically significant after adjusting for potential confounding variables. The more respiratory infections the mother experienced during pregnancy, the lower the value of Crs was in her offspring (P for trend,=,0.016). Using Crs corrected for body weight the relationship with maternal infections was non-significant, however still showing a trend. Conclusions The results of this study may indicate that mothers who experience respiratory infections during pregnancy have newborns with lower compliance of the respiratory system. Pediatr Pulmonol. 2007; 42:945,951. © 2007 Wiley-Liss, Inc. [source] Oral anticoagulants and the risk of osteoporotic fractures among elderly,,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 5 2004Danielle Pilon MD Abstract Purpose Coumadin-based oral anticoagulants are associated with a decrease in bone mass density, but their role in fracture risk is equivocal. Because the use of oral anticoagulants is prevalent among the elderly, as is the risk and morbidity of osteoporotic fractures, the association between osteoporotic fractures and oral anticoagulants needs to be clarified. Method We conducted a case-control study on a 10% random sample of subjects aged 70 years and older enrolled in the Quebec universal health insurance plan between 1992 and 1994. Incident cases of a first osteoporotic fracture were identified by International Classification of Diseases, Ninth Revision codes. Exposure was defined as one or more prescriptions of oral anticoagulants dispensed before the osteoporotic fracture. Ten controls for each case, matched by age and date of osteoporotic fracture, were identified. Results Among 1523 cases, 48 (3.2%) were ever exposed to oral anticoagulants; among 15,205 controls, 461 (3.0%) were ever exposed (crude odds ratio: 1.0: 95% confidence interval: 0.7,1.5). These negative results persisted after adjusting for potential confounding variables and stratifying exposure into cumulative dose and treatment duration. Conclusions Coumadin-based oral anticoagulants are not significantly associated with osteoporotic fractures among the elderly, providing reassurance for elderly patients on long-term oral anticoagulants. Copyright © 2003 John Wiley & Sons, Ltd. [source] Moral Reasoning Effects on Political ParticipationPOLITICAL PSYCHOLOGY, Issue 4 2000Peter Muhlberger In this study, respondents who agreed to participate in a computer-administered interview were presented with information and questions about public interest groups, followed by the Defining Issues Test of moral reasoning (DIT). Respondents with high DIT scores stressed morally central over morally peripheral considerations in deciding whether to participate in public interest groups. Less sophisticated reasoners showed the opposite pattern. Morally central considerations also had a much greater impact on the probability that sophisticated respondents would attempt to participate in public interest groups after completing the interview. The analysis included controls for potential confounding variables such as cognitive ability, education, prior political participation, and gender. The findings imply motivational differences between advantaged and disadvantaged population groups. Such differences may help to account for the differing strategies and successes of political organizations mobilizing these groups. [source] Gender Differences in the Across-Time Associations of the Job Demands-Control-Support Model and Depressive Symptoms: A Three-Wave StudyAPPLIED PSYCHOLOGY: HEALTH AND WELL-BEING, Issue 1 2010Galit Armon We used a full-panel longitudinal design to investigate, separately for women and men, the hypotheses that changes in the components of the Job Demands-Control-Support (JDC-S) model predict changes in depression symptoms levels over time and that the reversed prediction would also be found. Our study was conducted on a multi-occupational sample of apparently healthy employees (N = 692, 68% men) using three waves of data gathering, replicating our tests on two time lags of 18 months and 3 years on average. We controlled for neuroticism and other potential confounding variables. For both time lags, support for our hypotheses was found for the men only. We did not find systematic differences between the time lags, nor did we find a predominance of one of the unidirectional effects examined. We outline the theoretical and practical implications of our findings, including their relevance for efforts to combat depressive symptoms by changing job characteristics. [source] Trends in mode of delivery during 1984,2003: can they be explained by pregnancy and delivery complications?BJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 7 2007CM O'Leary Objectives, To describe trends in mode of delivery, to identify significant factors which affected mode of delivery, and to describe how these factors and their impact have changed over time. Design, Total population birth cohort. Setting, Western Australia 1984,2003. Participants, The analysis was restricted to all singleton infants delivered at 37,42 weeks of gestation with a cephalic presentation (n= 432 327). Methods, Logistic regression analyses were undertaken to estimate significant independent risk factors separately for elective and emergency caesarean sections compared with vaginal delivery (spontaneous and instrumental), adjusting for potential confounding variables. Main outcome measures, Trends in mode of delivery, demographic factors, and pregnancy and delivery complications. Estimated likelihood of elective caesarean section compared with vaginal delivery and emergency caesarean section compared with vaginal delivery. Results, Between 1984,88 and 1999,2003, the likelihood of women having an elective caesarean section increased by a factor of 2.35 times (95% CI 2.28,2.42) and the likelihood of an emergency caesarean section increased 1.89 times (95% CI 1.83,1.96). These caesarean section rate increases remained even after adjustment for their strong associations with many sociodemographic factors, obstetric risk factors, and obstetric complications. Rates of caesarean section were higher in older mothers, especially those older than 40 years of age (elective caesarean section, OR 5.42 [95% CI 4.88,6.01]; emergency caesarean section, OR 2.67 [95% CI 2.39,2.97]), and in nulliparous women (elective caesarean section, OR 1.54 [95% CI 1.47,1.61]; emergency caesarean section, OR 3.61 [95% CI 3.47,3.76]). Conclusions, Our data show significant changes in mode of delivery in Western Australia from 1984,2003, with an increasing trend in both elective and emergency caesarean section rates that do not appear to be explained by increased risk or indication. [source] High incidence of obstetric interventions after successful external cephalic versionBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 6 2002Louis Yik-Si Chan Objective To investigate the delivery outcome after successful external cephalic version (ECV). Design Case,control study. Setting University teaching hospital. Population The study group consisted of 279 consecutive singleton deliveries at term over a six-year period, all of which had had successful ECV performed. The control group included 28,447 singleton term deliveries during the same six-year period. Methods Between group differences were compared with the Mann,Whitney U test or Student's t test where appropriate. Odds ratio and 95% confidence interval (CI) were calculated for categorical variables. Main outcome measures Incidence of and indications for obstetric interventions. Results The risk of instrumental delivery and emergency caesarean section was higher in the ECV group (14.3%vs 12.8%; OR 1.4; 95% CI 1.0,2.0, and 23.3%vs 9.4%; OR 3.1; 95% CI 2.3,4.1, respectively). The higher caesarean rate was due to an increase in all major indications, namely, suspected fetal distress, failure to progress in labour and failed induction. The higher incidence of instrumental delivery was mainly due to an increase in prolonged second stage. The odds ratio for operative delivery remained significant after controlling for potential confounding variables. There were also significantly greater frequencies of labour induction (24.0%vs 13.4%; OR 2.0; 95% CI 1.5,2.7) and use of epidural analgesia (20.4%vs 12.4%; OR 1.8; 95% CI 1.4,2.4) by women in the ECV group. The higher induction rate is mainly due to induction for post term, abnormal cardiotocography (CTG) and antepartum haemorrhage (APH) of unknown origin. Conclusion The incidence of operative delivery and other obstetric interventions are higher in pregnancies after successful ECV. Women undergoing ECV should be informed about this higher risk of interventions. [source] | ||||||||||||||||||||||