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Results for “Logistic Models”

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PubMed2004

Serum vitamin levels and the risk of asthma in children.

Dietary intake, especially of antioxidant vitamins A, C, E, and the carotenoids, has been linked with the presence and severity of asthma. From the Third National Health and Nutrition Examination Survey (NHANES III), conducted in the United States between 1988 and 1994, the authors selected 4,093 children (aged 6-17 years) for whom relevant medical, socioeconomic, and anthropometric data were complete. The children were 50.6% female, and 9.7% reported a diagnosis of asthma. Bivariate analyses showed that asthma diagnosis was associated with lower levels of serum vitamin C, alpha-carotene, beta-carotene, and beta-cryptoxanthin. However, antioxidant levels may be surrogate markers for socioeconomic variables such as race, poverty, tobacco exposure, or general nutritional status. In logistic models that included age, body mass index, socioeconomic variables, antioxidant levels, parental asthma, and household smoking, the only antioxidants significantly associated with asthma were vitamin C (odds ratio = 0.72 per mg/dl, 95% confidence interval = 0.55, 0.95) and alpha-carotene (odds ratio = 0.95 per micro g/dl, 95% confidence interval = 0.90, 0.99). The odds ratio for asthma in the highest quintile of serum vitamin C relative to the lowest was 0.65 (p < 0.05), whereas it was 0.74 for alpha-carotene (p = 0.066). The authors concluded that low vitamin C and alpha-carotene intakes are associated with asthma risk in children.

Adolescent↗

PubMed1996

Predicting stroke inpatient rehabilitation outcome: the prominent role of neuropsychological disorders.

This study was designed to determine the role of demographic, medical and cognitive factors in the results of rehabilitation in first stroke patients. In a prospective study on 273 consecutive patients admitted to a rehabilitation hospital for sequelae of first stroke, we used multiple regressions to assess the relationship between 11 independent variables and a battery of outcome measures: mortality, length of hospital stay, Barthel Index (BI) and Rivermead Mobility Index (RMI) scores at discharge and their effectiveness. Severity of stroke at admission and hemineglect were the strongest prognostic factors. In a logistic model, cognitive impairment was a significant independent predictor (OR = 4.10) also after adjusting for age and severity of stroke. Patients with hemineglect had a significantly higher relative risk of poor autonomy [RR = 7.30, 95% confidence interval (CI) 4.04-13.18] and impaired mobility (RR = 9.25, CI 4.63-18.45). Global aphasic patients had similar risks for both autonomy (RR = 4.51, CI 2.74-7.41) and mobility (RR = 4.71, CI 2.79-7.97). This study underlines the crucial role of cognitive disorders as predictors of poor functional outcome in stroke survivors and confirms the need for early neuropsychological screening.

Activities of Daily Living↗

PubMed1991

Statistical analysis of outcomes from repeated pregnancies: effects of HLA sharing on fetal loss rates.

As part of our ongoing studies of genetic markers of reproductive outcome in the Hutterites, we have been analyzing potential risk factors for pregnancy outcomes. In particular, we are interested in the effects of HLA sharing between parents on fetal loss rates. Pregnancy outcome data such as these have two characteristics that create statistical challenges, i.e., repeated observations per couple and between-couple heterogeneity in risk. We critically examine four approaches based on the logistic model for the analysis of this and similar data: 1) unconditional likelihood analysis with and without fixed cluster effects; 2) conditional likelihood analysis; 3) mixed-effects analysis with random cluster effects; and 4) the robust generalized estimating equation (GEE) procedure. Of these approaches, the GEE method of Liang and Zeger would be best suited for the analysis of our data when the question of interest concerns a variable that is constant over all pregnancies, such as HLA sharing. If the question concerns a couple's risk associated with a changing variable such as maternal age, the mixed-effects analysis is the more appropriate.

Cluster Analysis↗

PubMed2005

Risk factors for cerebral palsy in preterm infants.

OBJECTIVE: To identify crucial factors that precipitate cerebral palsy by controlling confounding factors in logistic regression analyses. DESIGN AND PATIENTS: We retrospectively investigated a cohort of all 922 infants with gestational ages of less than 34 weeks (22-33 weeks), who were admitted to our neonatal intensive care unit between 1990 and 1998. Thirty (3.7%) were diagnosed to have cerebral palsy. We analyzed the prenatal and postnatal clinical variables of the cerebral palsy cases and compared them with 150 randomly selected controls. RESULTS: Risk factors for cerebral palsy identified in univariate analysis were: twin pregnancy, long-term ritodrine tocolysis, respiratory distress syndrome, air leak, surfactant administration, intermittent mandatory ventilation, high frequency oscillation, lowest PaCO2 levels, prolonged hypocarbia during the first 72 h of life, and postnatal steroid therapy. In a conditional multiple logistic model, long-term ritodrine tocolysis, prolonged hypocarbia and postnatal steroid therapy remained associated with an increased risk of cerebral palsy after adjustment for other antenatal and postnatal variables (OR [Odds Ratio] = 8.62, 95% CI [Confidence Interval], 2.18-33.97; OR = 7.81, 95% CI, 1.42-42.92; OR = 21.37, 95% CI, 2.01-227.29, respectively). CONCLUSIONS: Our results suggest that long-term ritodrine tocolysis underlines the development of cerebral palsy. Further assessments of the effect of ritodrine on fetal circulation and nervous system are required. Moreover, possible alternatives to systemic postnatal steroids are needed, and carbon dioxide levels should be more strictly controlled.

Cerebral Palsy↗

PubMed2000

Tone abnormalities are associated with maternal cigarette smoking during pregnancy in in utero cocaine-exposed infants.

OBJECTIVE: Maternal cigarette smoking, alcohol use, and other factors confound studies of in utero cocaine exposure. Our goal was to determine whether in utero cocaine exposure is associated with an abnormal neurologic examination in infants, while controlling for concomitant cigarette smoke exposure and other confounding variables. DESIGN: Healthy newborns with birth weights > or =2000 g were prospectively enrolled into a race-matched study of cocaine-exposed and cocaine-unexposed infants. Urine and meconium samples were analyzed for illicit drugs, the cocaine metabolite, benzoylecgonine, and the nicotine metabolite, cotinine. A detailed neurological examination was performed at approximately 6 weeks of age by an examiner blinded to history. RESULTS: At 6 weeks of age, 40 cocaine-exposed infants and 56 cocaine-unexposed infants were examined. Tone abnormalities were the only neurologic abnormalities discovered, predominantly generalized hypertonia. Logistic models found that maternal urine cotinine levels were predictive of an abnormal neurologic examination, whereas cocaine exposure or benzoylecgonine levels were not. No interaction was found between maternal cigarette smoking and cocaine exposure. Race, ethanol exposure, prenatal care, homelessness, and head circumference were not predictive of an abnormal tone examination. The odds ratio for an abnormal examination was 2.9 (95% confidence interval: 1.04-8.25), if the maternal urine cotinine level was >200 ng/mL. CONCLUSION: Our findings suggest that maternal cigarette smoking may be the major predictor of tone abnormalities reported in cocaine-exposed infants.

Cocaine↗

PubMed1997

Risk factors for colonization of salivary lactobacilli and Candida in children.

We analyzed the occurrence of salivary lactobacilli and Candida in a sample of 166 children aged 1-4 years (mean, 2.5 years) in relation to possible risk factors for colonization of the microbes. The risk factors examined were sucking habits, feeding habits, symptoms of respiratory infections, and antibiotic therapy at the time of sampling. Lactobacilli occurred in 18% of the children's saliva, and Candida in 24%. In the logistic modeling the variables most strongly associated with the occurrence of lactobacilli were pacifier-sucking (relative risk (RR), 2.9; 95% confidence interval (CI), 1.1-7.0; P = 0.01) and antibiotic therapy (RR, 4.6; CI, 1.2-16.9; P = 0.01). The association between positive Candida test and use of a pacifier was also significant (RR, 4.8; CI, 2.1-10.7; P = 0.0001). The results of the study suggest that the use of a pacifier increases the occurrence of both salivary lactobacilli and Candida. It could therefore be a factor influencing caries susceptibility and activity in children.

Anti-Bacterial Agents↗

PubMed2000

Premorbid risk factors for alcohol dependence in antisocial personality disorder.

BACKGROUND: Many, but not all, types of antisocial personality disorders (ASP) are complicated by alcohol dependence. Therefore, some additional risk factors may exist for alcohol dependence co-occurring with ASP. We studied whether severe childhood conduct disorder and a family history of alcohol dependence are possible risk factors for the development of alcohol dependence in ASP. METHODS: The subjects were 81 male Japanese criminals diagnosed with DSM-III-R ASP. Relative risks of alcohol dependence for severe conduct disorder and for a positive family history were estimated by using a multiple logistic model. RESULTS: Forty-three subjects (53.0%) met criteria for DSM-III-R alcohol dependence. The relative risk of alcohol dependence for severe conduct disorder (n = 44), compared with mild conduct disorder, was 4.1; whereas the relative risk for a positive family history (n = 31), relative to a negative family history, was 1.9. Severe childhood conduct disorder was also associated with severe adulthood antisocial behavior and an earlier onset of alcohol dependence. CONCLUSIONS: The results suggest that severe childhood conduct disorder and a positive family history of alcohol dependence are independent premorbid risk factors for developing alcohol dependence among persons with ASP.

Adult↗

PubMed1989

A sixteen-factor personality test for predicting automobile driving accidents of young drivers.

The predictive value of the Cattell 16-factor personality test on the occurrence of automobile accidents among conscripts during their 11-month military service in a transportation section of Finnish Defense Forces was examined. Automobile driving experience before and during the follow-up as well as the occurrence of traffic accidents and penalties before and during the follow-up period were investigated. Complete data on personality, mileage, and traffic accidents plus penalties were obtained for 597 conscripts. In this population, altogether 91 automobile accidents were recorded for 82 conscripts. A logistic model showed that impulsivity and adventurousness (high score in factor H), naivete and excessive trustfulness (low score in factor L), and poor self-control (low score in factor Q3) predicted significantly, and guilt proneness and depression (high score in factor O) almost significantly the subsequent occurrence of motor vehicle accidents. Factors L and Q3 remained significant when only accidents of which the subject was found guilty were being predicted. All these personality factors are related to the control of emotions. The results indicate that the 16-factor personality test is valuable when selecting safe drivers in a population of young male adults with little previous driving experience.

Accidents, Traffic↗

PubMed1992

Risk factors for septic shock in the early management of bacteremia.

PURPOSE: Aggressive treatment of bacteremia in patients at high risk of septic shock may prove to be beneficial and cost-effective since these patients account for 50% of the mortality. The purpose of this study was to identify risk factors for septic shock in bacteremic patients. PATIENTS AND METHODS: We retrospectively collected clinical, biologic, and radiologic data from medical records of patients who experienced one episode of bacteremia between March 1 and December 31, 1990, at the University Hospital of Dijon, France. Statistical analysis was univariate and multivariate (logistic regression). RESULTS: During the survey, 331 patients experienced one episode of bacteremia. Bacteremia due to gram-negative species was more frequently found in surgical units. Septic shocks were equally attributed to gram-negative and gram-positive bacteria. The do-not-resuscitate order was associated with nearly half of the deaths secondary to underlying diseases or poor general condition. Neither hospital-acquired bacteremia nor underlying diseases were associated with a high risk of septic shock. Multivariate analysis showed the following to be risk factors for septic shock: male gender and age older than 75 years (odds ratio = 2.91), creatinine level greater than 20 mg/L (odds ratio = 4.52), prothrombin time less than 60% (odds ratio = 4.86), and presence of an interstitial pattern on the chest radiograph involving more than half of both lung fields (odds ratio = 4.1). Our logistic model with these selected parameters allowed an overall classification of 77% of the studied patients, with a positive predictive value of 55% and a negative predictive value of 89%. CONCLUSION: Our results provide a positive predictive value that is similar to that of the clinical scores of severity proposed by other authors in selected populations. Our classification, in conjunction with a clinical classification, would allow improvement in the prognosis of patients with bacteremia by early treatment of those at high risk for developing septic shock. Validation of these results with further studies involving a larger population that includes patients with suspected infections, as well as bacteremic patients, is needed.

Adolescent↗

PubMed2003

Comparison between two common methods for measuring Giardia lamblia susceptibility to antiparasitic drugs in vitro.

In this study a comparison between two different methods for measuring the susceptibility of Giardia lamblia trophozoites to metronidazole and albendazole is performed. Modifications of Meloni's method, based on the loss of adherence of parasites to surfaces, and the Hill method, based on the loss of parasite division capacity, are compared. A logistic model was used to calculate the inhibitory concentrations IC(10), IC(50) and IC(90) that were further compared using the respective standard errors. The results obtained, after contact of parasites with the antiparasitic drugs for 24h, show that the adherence method is more sensitive than the multiplication method for low and moderate inhibitory concentrations of albendazole. Conversely for metronidazole the multiplication method seems to be more sensitive for high inhibitory concentrations of the drug. For screening the IC(50), both methods seem to be effective, however, the inhibition of adherence method have even better performance for the benzimidazole like drugs.

Albendazole↗

PubMed2003

Social class, family, and life-style factors associated with overweight and obesity among adults in Peruvian cities.

BACKGROUND: Overweight and obesity have reached epidemic proportions in Latin America. OBJECTIVE: The purpose of this study was to explore social and behavioral factors associated with obesity in Peruvian cities. DESIGN: Between 1998 and 2000 health examination surveys were conducted among adults in 1176 families identified in six cities. Stratified by social class, multistaged random sampling was used. Using body mass index (weight (kg)/height (m)(2)), men and women were classified into normal weight (BMI <25), overweight (BMI 25-29), or obese (BMI > or =30); abdominal circumference (> or =94 cm in men and > or =84 cm in women) further identified morbidity risk. Several demographic, social, and behavioral variables were collected following standardized procedures. RESULTS: Adjusting for age, 37% of women were categorized as normal weight, 40% overweight, and 23% obese; corresponding figures for men were 40, 44, and 16%. More developed cities, e.g., Lima, Arequipa, and Ica, had the largest prevalence of overweight and obesity for both men and women. Adjusted logistic models showed that BMI > or =25 was positively correlated with age; whereas, education was negatively associated, only among women. Other significant associated factors of overweight included city of residence, television viewing > or =4 h daily in women, and underestimation of body weight status. CONCLUSIONS: The study showed elevated rates of overweight across the income level spectrum. Factors such as urban development stage, income, education, and gender posed differential relationships with the risk of overweight and must be considered in designing future public health interventions. Underestimation of body weight status and sedentary behavior may also constitute specific areas of intervention.

Adult↗

PubMed1994

Factors potentiating the smoking-related risk of fetal growth retardation.

OBJECTIVE: To estimate the risk of fetal growth retardation resulting from the interaction between maternal smoking during pregnancy and other recognized risk factors. DESIGN: Case-control study of prospectively recorded data. SETTING: Department of Obstetrics and Gynaecology, University of Pavia, Italy. SUBJECTS: Three hundred and forty-seven singleton pregnancies with diagnosis of fetal growth retardation and 694 control pregnancies with appropriately grown fetuses. RESULTS: The overall odds ratio for fetal growth retardation associated with maternal smoking was 2.87 (95% confidence interval, 2.17-3.80). In logistic models the factors which independently increased the smoking-related risk of fetal growth retardation were a male fetus, nulliparity, maternal age 20 years or less, a history of first trimester haemorrhage and low (less than 50 kg) pre-pregnancy weight. The combined effect of smoking and caffeine consumption on the risk of fetal growth retardation was found to be additive rather than multiplicative. CONCLUSIONS: Several factors can affect the risk of fetal growth retardation associated with maternal smoking. The prenatal identification of these factors could help detect subgroups of women at high risk of fetal growth retardation.

Adult↗

PubMed1999

Association of hyperdense middle cerebral artery sign with clinical outcome in patients treated with tissue plasminogen activator.

BACKGROUND AND PURPOSE: The hyperdense middle cerebral artery sign (HMCAS) is a marker of thrombus in the middle cerebral artery. The aim of our study was to find out the frequency of the HMCAS, its association with initial neurological severity and early parenchymal ischemic changes on CT, its relevance to clinical outcome, and the efficacy of intravenous recombinant tissue plasminogen activator (rtPA) in patients with the HMCAS. METHODS: Secondary analysis of the data from 620 patients who received either rtPA or placebo in the European Cooperative Acute Stroke Study I (ECASS I), a double-blind, randomized, multicenter trial. The baseline CT scans were obtained within 6 hours from the onset of symptoms. Functional and neurological outcomes were assessed using the modified Rankin Scale and the Scandinavian Stroke Scale at day 90. RESULTS: We found an HMCAS in 107 patients(17.7%). The initial neurological deficit was more severe in patients with the HMCAS than in those lacking this sign (P<0.0001). Early cerebral edema and mass effect were also more common in patients with the HMCAS (P<0.0001). The HMCAS was related to the risk of poor functional outcome (grade of 3 to 6 on the modified Rankin Scale) on univariate analysis: 90 patients (84%) with the HMCAS and 310 patients (62%) lacking this sign were dependent or dead at day 90 (P<0.0001). However, this association was no longer significant in a logistic model accounting for the effect of age, sex, treatment with rtPA, initial severity of neurological deficit and early parenchymal ischemic changes on CT. Patients with the HMCAS who were given rtPA had better neurological recovery than those who received placebo (P=0.0297). CONCLUSIONS: The HMCAS is associated with severe brain ischemia and poor functional outcome. However, it has no significant independent prognostic value when accounting for the effect of initial severity of neurological deficit and of early parenchymal ischemic changes on CT. Patients with the HMCAS may benefit from intravenous rtPA.

Acute Disease↗

PubMed2006

Familial and sociopsychopathological risk factors for suicide attempt in bulimic and in depressed women: prospective study.

OBJECTIVE: This study was carried out to examine sociopsychopathological predictors of prospective observed suicide attempts in bulimic women purging type without comorbid major depression (BNG) at the time of study entry and in woman with major depression without comorbid eating disorder at the time of study entry (MDG). METHODS: Data from 28 BNG (age 23.5 +/- 3.6) and 126 MDG women (age 33.4 +/- 5.1) who had attempted suicide during 12 months' monitoring were compared. RESULTS: A univariate comparison of the two groups revealed various differences. Analysis of risk factors for suicide attempts using stepwise logistic regression was conducted separately for each group. The derived logistic models showed that patients from the BNG group had a history of higher incidence of sexual abuse in childhood, as well as abuse of laxatives and illicit drugs; they also lacked orientation in life, felt lonely despite family and friends, tended to direct their anger outward, and were unable to relax. CONCLUSIONS: Sociopsychopathological risk factors for suicide attempts in the BNG and MDG appear to vary.

Adolescent↗

PubMed2001

Associations between self-reported and objective physical environmental factors and use of a community rail-trail.

BACKGROUND: To effectively promote physical activIty, researchers and policy makers have advocated for greater use of environmental approaches, such as the construction of community paths and trails. However, research on the use of these facilities is limited. METHODS: In this cross-sectional community study, we examined associations between self-reported and objective physical environmental variables and use of the Minuteman Bikeway (Arlington, MA) in a random sample of 413 adults. Sociodemographic and perceived environmental variables were measured with a mail survey during September 1998. Geographic information system (GIS) data were used to geocode survey respondents' homes and create three objective environmental variables: distance to the Bikeway, steep hill barrier, and a busy street barrier. RESULTS: In logistic models, age and female gender showed statistically significant inverse associations with Bikeway use over the previous 4-week period. Increases in self-reported (OR = 0.65) and GIS distance (OR = 0.57) were associated with decreased likelihood of Bikeway use. Absence of self-reported busy street (OR = 2.01) and GIS steep hill barriers (OR = 1.84) were associated with Bikeway use. CONCLUSIONS: Environmental barriers such as travel distance and hilly terrain should be considered when planning community trails. A better understanding of such factors may lead to more effective promotion of trail use.

Adult↗

PubMed2001

Work-related stress and early atherosclerosis.

The purpose of this study was to examine the link between work-related stress and early atherosclerosis as measured by common carotid artery intima-media thickness and focal lesions in the common carotid artery and bifurcation. Four hundred sixty-seven members of an occupational cohort (total N = 573) were examined via questionnaires and B-mode ultrasound. We used multiple linear and logistic models to regress lesion risk and intima-media thickness on work-related stress scores from a questionnaire administered at an 18-month follow-up examination. In an age-adjusted model, the prevalence of carotid lesions among men scoring in the highest stress quintile was 36% compared with 21% among men in the lowest quintile. We also observed an increase in intima-media thickness in the highest quintile relative to the lowest (difference = 0.048 +/- 0.025 mm) among men. Among women, stress was not related to the prevalence of lesions or intima-media thickness. These findings suggest that men with greater work-related stress are at increased risk for atherosclerotic disease. Women in this age group may be protected from such effects, or current work-place questionnaires may not accurately assess stress in women.

Adult↗

PubMed1999

Workplace-violence investigations by the California Division of Occupational Safety and Health, 1993-1996.

In response to the growing recognition of violence in the workplace, government agencies who oversee workplace safety are beginning to incorporate security issues into comprehensive safety plans. The California Division of Occupational Safety and Health began conducting inspections for violent events in 1993, and information from these security inspections was collected from January 1993 through January 1997. The inspections were examined by initiating source, industry, type of event, and citations issued and compared with distributions of known victimizations. The factors predicting whether a citation was issued were determined through logistic models. Over 200 inspections were conducted in 11 industries, with retail and health care establishments inspected most frequently. Employee complaints initiated 50.6% of events and accident reports initiated 40.1%. One third of inspections were initiated because of a fatal event, and 27.4% were initiated in response to a physical assault. Citations for security hazards were issued to 23.6% of businesses. Inspections initiated by employee complaints, in response to customer-related security issues, and involving non-fatal assaults were the most frequently cited reasons for inspection. The California Division of Occupational Safety and Health conducted security inspections in a large range of industries and for diverse issues, even though no specific security codes exist.

Accidents, Occupational↗

PubMed2002

A solution to the problem of separation in logistic regression.

The phenomenon of separation or monotone likelihood is observed in the fitting process of a logistic model if the likelihood converges while at least one parameter estimate diverges to +/- infinity. Separation primarily occurs in small samples with several unbalanced and highly predictive risk factors. A procedure by Firth originally developed to reduce the bias of maximum likelihood estimates is shown to provide an ideal solution to separation. It produces finite parameter estimates by means of penalized maximum likelihood estimation. Corresponding Wald tests and confidence intervals are available but it is shown that penalized likelihood ratio tests and profile penalized likelihood confidence intervals are often preferable. The clear advantage of the procedure over previous options of analysis is impressively demonstrated by the statistical analysis of two cancer studies.

Breast Neoplasms↗