17 resultados para Multivariable logistic regression

em Deakin Research Online - Australia


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This paper adopted logistic regression model to examine the relationship between level of managerial ownership concentration and agency conflict which are proxied by level of risk, firms leverage and firms dividend policy. The study covers a period of 5 years from 1997 through 2001. The study is based on the 100 blue-chip stocks, majority of which are derived from CI components. The findings suggest a positive and significant association between level of level of risk at lower level and managerial ownership while a negative and significant association is also evidenced between risk at higher level and managerial ownership concentration. While debt policy which serves as positive monitoring substitute for agency conflict is found to be positive and significant explaining the level of ownership concentration. Furthermore, dividend policies, which also serve as monitoring, substitute to reduce agency conflict between manager and external shareholders do not appear to have any significant impact on managerial ownership. On the other hand, the level of institutional ownership, which serves as external monitoring force, is found to have inverse impact on level of managerial ownership concentration. This is marginally significant at 10 level (p=.12). The findings, in part explain the argument that the managerial ownership help reduce agency conflict between outside equity holders and managers.

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Aims. Diabetes mellitus is a growing health problem worldwide. This study aimed to describe dysglycaemia and determine the impact of body composition and clinical and lifestyle factors on the risk of progression or regression from impaired fasting glucose (IFG) to diabetes or normoglycaemia in Australian women. Methods. This study included 1167 women, aged 20-94 years, enrolled in the Geelong Osteoporosis Study. Multivariable logistic regression was used to identify predictors for progression to diabetes or regression to normoglycaemia (from IFG), over 10 years of follow-up. Results. At baseline the proportion of women with IFG was 33.8% and 6.5% had diabetes. Those with fasting dysglycaemia had higher obesity-related factors, lower serum HDL cholesterol, and lower physical activity. Over a decade, the incidence of progression from IFG to diabetes was 18.1 per 1,000 person-years (95% CI, 10.7-28.2). Fasting plasma glucose and serum triglycerides were important factors in both progression to diabetes and regression to normoglycaemia. Conclusions. Our results show a transitional process; those with IFG had risk factors intermediate to normoglycaemics and those with diabetes. This investigation may help target interventions to those with IFG at high risk of progression to diabetes and thereby prevent cases of diabetes.

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Malware replicates itself and produces offspring with the same characteristics but different signatures by using code obfuscation techniques. Current generation anti-virus engines employ a signature-template type detection approach where malware can easily evade existing signatures in the database. This reduces the capability of current anti-virus engines in detecting malware. In this paper, we propose a stepwise binary logistic regression-based dimensionality reduction techniques for malware detection using application program interface (API) call statistics. Finding the most significant malware feature using traditional wrapper-based approaches takes an exponential complexity of the dimension (m) of the dataset with a brute-force search strategies and order of (m-1) complexity with a backward elimination filter heuristics. The novelty of the proposed approach is that it finds the worst case computational complexity which is less than order of (m-1). The proposed approach uses multi-linear regression and the p-value of each individual API feature for selection of the most uncorrelated and significant features in order to reduce the dimensionality of the large malware data and to ensure the absence of multi-collinearity. The stepwise logistic regression approach is then employed to test the significance of the individual malware feature based on their corresponding Wald statistic and to construct the binary decision the model. When the selected most significant APIs are used in a decision rule generation systems, this approach not only reduces the tree size but also improves classification performance. Exhaustive experiments on a large malware data set show that the proposed approach clearly exceeds the existing standard decision rule, support vector machine-based template approach with complete data and provides a better statistical fitness.

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Purpose – The workplace is an ideal setting to promote physical activity. The purpose of this study is to examine associations with physical activity at and around the workplace.
Design/methodology/approach – Participants were recruited from a random sample of employed adults (n ¼ 1; 107) in capital cities and major regional centres in Australia. Self-reported barriers and participation in physical activity at and around the workplace were assessed. A multivariable logistic regression model adjusting for age, sex, occupational status, and overall physical activity assessed the odds of being active in this setting.
Findings – Of participants, 61 percent perceived being active in the workplace. Those who perceived their work colleagues and managers to be physically active, and those who indicated that their workplace provides facilities to support them being active had higher odds of being physically active at or around the workplace.
Research limitations/implications – A poor response rate, physically active sample and cross-sectional analysis prevent inferences about the causality of the findings.
Originality/value – The paper provides evidence of the potential for the multiple levels of influence on physical activity at and around the workplace.

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Background : Effective interventions to increase safety and wellbeing of mothers experiencing intimate partner violence (IPV) are scarce. As much attention is focussed on professional intervention, this study aimed to determine the effectiveness of non-professional mentor support in reducing IPV and depression among pregnant and recent mothers experiencing, or at risk of IPV.

Methods :
MOSAIC was a cluster randomised trial in 106 primary care (maternal and child health nurse and general practitioner) clinics in Melbourne, Australia. 63/106 clinics referred 215 eligible culturally and linguistically diverse women between January 2006 and December 2007. 167 in the intervention (I) arm, and 91 in the comparison (C) arm. 174 (80.9%) were recruited. 133 (76.4%) women (90 I and 43 C) completed follow-up at 12 months.

Intervention: 12 months of weekly home visiting from trained and supervised local mothers, (English & Vietnamese speaking) offering non-professional befriending, advocacy, parenting support and referrals.

Main outcome measures: Primary outcomes; IPV (Composite Abuse Scale CAS) and depression (Edinburgh Postnatal Depression Scale EPDS); secondary measures included wellbeing (SF-36), parenting stress (PSI-SF) and social support (MOS-SF) at baseline and follow-up.

Analysis: Intention-to-treat using multivariable logistic regression and propensity scoring.

Results :
There was evidence of a true difference in mean abuse scores at follow-up in the intervention compared with the comparison arm (15.9 vs 21.8, AdjDiff -8.67, CI -16.2 to -1.15). There was weak evidence for other outcomes, but a trend was evident favouring the intervention: proportions of women with CAS scores ≥7, 51/88 (58.4%) vs 27/42 (64.3%) AdjOR 0.47, CI 0.21 to 1.05); depression (EPDS score ≥13) (19/85, 22% (I) vs 14/43, 33% (C); AdjOR 0.42, CI 0.17 to 1.06); physical wellbeing mean scores (PCS-SF36: AdjDiff 2.79; CI -0.40 to 5.99); mental wellbeing mean scores (MCS-SF36: AdjDiff 2.26; CI -1.48 to 6.00). There was no observed effect on parenting stress. 82% of women mentored would recommend mentors to friends in similar situations.

Conclusion :
Non-professional mentor mother support appears promising for improving safety and enhancing physical and mental wellbeing among mothers experiencing intimate partner violence referred from primary care.

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OBJECTIVES: To derive and validate a mortality prediction model from information available at ED triage. METHODS: Multivariable logistic regression of variables from administrative datasets to predict inpatient mortality of patients admitted through an ED. Accuracy of the model was assessed using the receiver operating characteristic area under the curve (ROC-AUC) and calibration using the Hosmer-Lemeshow goodness of fit test. The model was derived, internally validated and externally validated. Derivation and internal validation were in a tertiary referral hospital and external validation was in an urban community hospital. RESULTS: The ROC-AUC for the derivation set was 0.859 (95% CI 0.856-0.865), for the internal validation set was 0.848 (95% CI 0.840-0.856) and for the external validation set was 0.837 (95% CI 0.823-0.851). Calibration assessed by the Hosmer-Lemeshow goodness of fit test was good. CONCLUSIONS: The model successfully predicts inpatient mortality from information available at the point of triage in the ED.

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AIMS: Despite growing recognition of the impact of sleep on diabetes, a clear profile of people with diabetes regarding subjective sleep impairment has yet to be established. This study examines: (1) subjective sleep characteristics in adults with type 1 and type 2 diabetes; (2) the relationship of poor subjective sleep quality with glycaemic control, self-care and daytime functioning; (3) possible risk markers for poor sleep quality. METHODS: In a cross-sectional study, Dutch adults with type 1 (n=267) or type 2 diabetes (n=361) completed an online survey, including the Pittsburgh Sleep Quality Index (PSQI), socio-demographic, clinical, self-care and psychological measures. RESULTS: Poor sleep quality (PSQI-score >5) was reported by 31% of adults with type 1 and 42% of adults with type 2 diabetes. Participants with good and poor sleep quality did not differ in self-reported HbA1c or the frequency of meeting lifestyle recommendations. Poor sleep quality was related to a higher self-care burden and higher levels of daytime sleepiness, fatigue, depressive and anxiety symptoms, and diabetes-specific distress. In multivariable logistic regression analyses examining risk markers, poor sleep quality was associated with depressive symptoms in adults with type 1 (OR=1.39, 95% CI 1.25-1.54) and type 2 diabetes (OR=1.31, 1.16-1.47), and with being female in those with type 2 diabetes (OR=2.72, 1.42-5.20). CONCLUSIONS: Poor subjective sleep quality is prevalent both in adults with type 1 and type 2 diabetes, and is related to poor daytime functioning and higher self-care burden. The temporal relation with depression and merits of therapy should be explored.

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BACKGROUND: It is critical to promote healthy eating early in life. OBJECTIVE: The aim of this study was to examine diet quality and its predictors among Australian preschool-aged children. DESIGN: Diet was assessed at age 3.5 years using multiple 24-hour recalls. Diet quality was assessed using an adapted version of the Revised Children's Diet Quality Index (RC-DQI). Potential predictors of diet quality were from questionnaires at age 3, 9, and 18 months and informed by the ecologic model of childhood overweight. Potential predictors included child's sex, age of introduction to solid foods, breastfeeding status, food acceptance, maternal nutrition knowledge, modeling of healthy eating, self-efficacy, education, and home food availability. PARTICIPANTS: Data from 244 children participating in the Melbourne Infant Feeding, Activity, and Nutrition Trial in 2008-2010 and follow-up data collection in 2011-2013 were examined. MAIN OUTCOME MEASURES: Diet quality at age 3.5 years. STATISTICAL ANALYSES PERFORMED: Bivariate logistic regression was performed to assess the relationship between diet quality and each predictor. A multivariable logistic regression model accounting for influences of covariates, treatment arm, and clustering by group tested associations between diet quality and significant predictors from bivariate analyses. RESULTS: RC-DQI scores had a mean±standard deviation score of 62.8±8.3 points out of a maximum of 85 points. Breastfeeding status (odds ratio [OR] 2.34, 95% CI 1.33 to 4.10) and maternal modeling of healthy eating (OR 1.75, 95% CI 1.01 to 3.03) were positively associated with RC-DQI scores. Both breastfeeding status (OR 3.09, 95% CI 1.63 to 5.85) and modeling (OR 2.01, 95% CI 1.04 to 3.88) remained positively associated with diet quality after adjustment for child age, body mass index z score, energy intake, treatment arm, and clustering. CONCLUSIONS: Breastfeeding status and modeling of healthy eating were independently associated with children's diet quality. Early intervention could assist mothers to practice these behaviors to provide support for improving child diet quality.

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Objective: To investigate sociodemographic and behavioural characteristics associated with weight status among women with children living in socioeconomically disadvantaged neighbourhoods.
Methods and procedures: A total of 1680 women aged 18–46 years, living in socioeconomically disadvantaged neighbourhoods with dependent children (aged 0–18 years), provided self-report data on height and weight and a range of sociodemographic and behavioural (for example, dietary intake, physical activity and time spent sitting) characteristics.
Results: Half of the women were classified as having a healthy weight (body mass index=18.5–25). Bivariable ordinal logistic regression analyses indicated that a healthy weight status was associated with a range of sociodemographic and behavioural characteristics. In a multivariable model, a healthy weight status among women was associated with being younger and unmarried, speaking a language other than English at home, having a medium or high level of education, and a partner with a high level of education, having a high household income, spending more time engaged in leisure-time physical activity and less time spent sitting, and having a lower consumption of soft drink.
Discussion: The present findings highlight that a considerable proportion of women with children living in disadvantaged neighbourhoods manage to maintain a healthy weight. Acknowledging the cross-sectional nature of this study, strategies aimed at helping women with children in socioeconomically disadvantaged areas to maintain their weight should focus on increasing physical activity, and reducing sitting time and soft drink consumption.

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Women living in socioeconomically disadvantaged neighbourhoods are at heightened risk for physical inactivity, but little is known about the correlates of physical activity among this group. Using a social-ecological framework, this study aimed to determine the individual, social and neighbourhood environmental correlates of physical activity amongst women living in such neighbourhoods. During 2007–2008 women (n = 4108) aged 18–45 years randomly selected from urban and rural neighbourhoods of low socioeconomic status in Victoria, Australia completed the International Physical Activity Questionnaire (long). They reported on individual (self-efficacy, enjoyment, intentions, outcome expectancies, skills), social (childcare, social support from family and friends/colleagues, dog ownership) and neighbourhood environmental (neighbourhood cohesion, aesthetics, personal safety, ‘walking environment’) factors. Multinomial logistic regression was used to examine the odds of increasing categories of leisure time physical activity (LTPA) and transport-related physical activity (TRPA) for each individual, social and environmental factor. In partially adjusted analyses, all individual, social and environmental variables were positively associated with LTPA, while all individual factors, family and friend support and the walking environment were positively associated with TRPA. In fully adjusted multivariable models, all individual and social factors remained significantly associated with LTPA, while self-efficacy, enjoyment, intentions, social support, and neighbourhood ‘walking environment’ variables remained significantly associated with TRPA. In conclusion, individual and social factors were most important for LTPA, while individual, social and neighbourhood environmental factors were all associated with TRPA. Acknowledging the cross-sectional design, the findings highlight the importance of different levels of potential influence on physical activity in different domains, which should be considered when developing strategies to promote physical activity amongst women living in socioeconomically disadvantaged neighbourhoods.

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Objective:
To investigate the individual, social and physical environment correlates of preschool children's compliance with Australian/Canadian and American Academy of Pediatrics (AAP) screen recommendations.

Method:
An Ecological Model (EM) was used to identify constructs potentially associated with children's screen time. In 2008–2009, parents in Melbourne, Australia, reported their child's screen time and on a range of potential correlates. Children (n = 935; 54% boys, mean age 4.54 ± 0.70 years) were assessed as meeting or not meeting each of the screen recommendations. Logistic regression assessed bivariable and multivariable associations.

Results:
In total, 15 explanatory variables, across the three domains of the EM were associated with boys' and/or girls' compliance with either Australian/Canadian or AAP recommendations. Correlates varied by sex and recommendation. Maternal television viewing time was the only consistent correlate for both boys' and girls' compliance with both recommendations. No demographic groups were identified as being less likely to comply with screen recommendations.

Conclusion:
Public health programs should take account of the sex-specific nature of correlates of preschool children's screen time. Preschool children across all demographic groups need support to engage in less screen use. Parents may benefit from education and parenting skills to minimize potentially harmful effects of excessive screen time for their child.

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Introduction
Oedematous lesions are a less common but more severe form of Mycobacterium ulcerans disease. Misdiagnosis as bacterial cellulitis can lead to delays in treatment. We report the first comprehensive descriptions of the clinical features and risk factors of patients with oedematous disease from the Bellarine Peninsula of south-eastern Victoria, Australia.

Methods

Data on all confirmed Mycobacterium ulcerans cases managed at Barwon Health, Victoria, were collected from 1/1/1998–31/12/2012. A multivariate logistic regression model was used to assess associations with oedematous forms of Mycobacterium ulcerans disease.

Results

Seventeen of 238 (7%) patients had oedematous Mycobacterium ulcerans lesions. Their median age was 70 years (IQR 17–82 years) and 71% were male. Twenty-one percent of lesions were WHO category one, 35% category two and 41% category three. 16 (94%) patients were initially diagnosed with cellulitis and received a median 14 days (IQR 9–17 days) of antibiotics and 65% required hospitalization prior to Mycobacterium ulcerans diagnosis. Fever was present in 50% and pain in 87% of patients. The WCC, neutrophil count and CRP were elevated in 54%, 62% and 75% of cases respectively. The median duration of antibiotic treatment was 84 days (IQR 67–96) and 94% of cases required surgical intervention. On multivariable analysis, there was an increased likelihood of a lesion being oedematous if on the hand (OR 85.62, 95% CI 13.69–535.70; P<0.001), elbow (OR 7.83, 95% CI 1.39–43.96; p<0.001) or ankle (OR 7.92, 95% CI 1.28–49.16; p<0.001), or if the patient had diabetes mellitus (OR 9.42, 95% CI 1.62–54.74; p = 0.02).

Conclusions

In an Australian population, oedematous Mycobacterium ulcerans lesions present with similar symptoms, signs and investigation results to, and are commonly mistakenly diagnosed for, bacterial limb cellulitis. There is an increased likelihood of oedematous lesions affecting the hand, elbow or ankle, and in patients with diabetes.

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This study was aimed to examine the cross-sectional association of protein, carbohydrate, and fat intake with depressive symptoms among 1794 Japanese male workers aged 18-69 years who participated in a health survey. Dietary intake was assessed with a validated self-administered diet history questionnaire. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale. Odds ratio of depressive symptoms (CES-D scale of ≥16) was estimated by using multiple logistic regression with adjustment for covariates including folate, vitamin B6, vitamin B12, polyunsaturated fatty acid, magnesium, and iron intake. Multivariable-adjusted odds ratio of depressive symptoms for the highest quartile of protein intake was 26%, albeit not statistically significant, lower compared with the lowest. The inverse association was more evident when a cutoff value of CES-D score ≥19 was used. The multivariable-adjusted odds ratios (95% confidence intervals) for the highest through lowest quartile of protein intake were 1.00 (reference), 0.69 (0.47-1.01), 0.69 (0.44-1.09), and 0.58 (0.31-1.06) (P for trend=0.096). Neither carbohydrate nor fat intake was associated with depressive symptoms. Our findings suggest that low protein intake may be associated with higher prevalence of depressive symptoms in Japanese male workers.

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 Background: The Dutch Obesity Intervention in Teenagers (DOiT) programme is an evidence-based obesity prevention programme tailored to adolescents attending the first two years of prevocational education in the Netherlands. The initial programme showed promising results during an effectiveness trial. The programme was adapted and prepared for nationwide dissemination. To gain more insight into the process of translating evidence-based approaches into ‘real world’ (i.e., ‘natural’) conditions, our research aims were to evaluate the impact of the DOiT-implementation programme on adolescents’ adiposity and energy balance-related behaviours during natural dissemination and to explore the mediating and moderating factors underlying the DOiT intervention effects.
Methods: We conducted a cluster-controlled implementation trial with 20 voluntary intervention schools (n=1002 adolescents) and 9 comparable control schools (n = 484 adolescents). We measured adolescents’ body height and weight, skinfold thicknesses, and waist circumference. We assessed adolescents’ dietary and physical activity behaviours by means of self-report. Data were collected at baseline and at 20-months follow-up. We used multivariable multilevel linear or logistic regression analyses to evaluate the intervention effects and to test the hypothesised behavioural mediating factors. We checked for potential effect modification by gender, ethnicity and education level.
Results: We found no significant intervention effects on any of the adiposity measures or behavioural outcomes. Furthermore, we found no mediating effects by any of the hypothesised behavioural mediators. Stratified analyses for gender showed that the intervention was effective in reducing sugar-containing beverage consumption in girls (B = -188.2 ml/day; 95% CI = -344.0; -32.3). In boys, we found a significant positive intervention effect on breakfast frequency (B = 0.29 days/week; 95% CI = 0.01; 0.58). Stratified analyses for education level showed an adverse intervention effect (B = 0.09; 95% CI = 0.02; 0.16) on BMI z-scores for adolescents attending the vocational education track.
Conclusions: Although not successful in changing adolescents’ adiposity, the DOiT-implementation programme had some beneficial effects on specific obesity-related behaviours in subgroups. This study underlines the difficulty of translating intervention effectiveness in controlled settings to real world contexts. Adaptations to the implementation strategy are needed in order to promote implementation as intended by the teachers.

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Background: Implementation of tobacco plain packaging (PP) with larger graphic health warnings (GHWs) in Australia had positive effects on responses reflecting the specific objectives of the PP policy and on follow-up quitting-related cognitions and behaviours. The aim of this study was to examine predictive relationships bewteen these proximal and distal outcomes.
Methods: A nationally representative sample of Australian adult cigarette smokers completed a baseline survey and a 1-month follow-up survey within the first year of policy implementation (n(weighted)=3215). Logistic regression analyses tested whether baseline measures of cigarette appeal, GHW effectiveness, perceived harm and concern/enjoyment predicted each of seven follow-up measures of quitted-related cognitions and behaviours, adjusting for baseline levels of the outcome and covariates.
Results: In multivariable models, we found consistent evidence that several baseline measures of GHW effectiveness positively and significantly predicted the likelihood that smokers at follow-up reported thinking about quitting at least daily, intending to quit, having a firm date to quit, stubbing out cigarettes prematurely, stopping oneself from smoking and having attempted to quit. Two of the quitting-related outcomes were also predicted by feeling more smoking-related concern than enjoyment. A smaller number of the appeal variables were prospectively associated with quitting-related outcomes, while believing that brands do not differ in harmlessness did not positively predict any outcomes.
Conclusions: These findings provide an initial insight into the pathways through which PP with larger GHWs may lead to changes in smoking behaviour. Future research should examine whether the effects are conditional on individual demographic and smoking characteristics.