Multivariate General Linear Model Research Articles

PSY114 - Age-Related Hospital Utilization Among Patients with Marfan Syndrome

The objective of analysis was to examine age-related hospital utilization in patients diagnosed with Marfan syndrome (MFS), a rare connective tissue disorder affecting multiple organ systems. This non-interventional, retrospective study analyzed MFS-diagnosed patients with hospital visits between October 2015 and September 2017 in the de-identified Vizient health system database. Study cohorts were defined by age (<18, 18-35, 36-50, 51-64, >65). Univariate comparisons were analyzed using Chi-square tests for categorical and ANOVA for continuous variables. Multivariate general linear regression models were used to identify drivers of length of stay (LOS) and cost. The study population included 9,279 visits across 365 facilities. Comorbidity rates increased with age. Hypertension (1.1% vs 52.1%, p<.0001), PVD (11.9% vs 45.3% p<.0001), and CHF (3.0% vs 26.6%, p<.0001) had the largest increases from the <18 to the 65+ cohort. Some disease-related complications such as arrhythmias (1.2% vs 31.6%, p<.0001) and aortic aneurysm (1.6% vs 16.8%, p<.0001) increased between the <18 and 65+ cohorts while others such as aortic ectasia (11.0% vs 2.3%, p<.0001) and scoliosis/kyphosis (11.8% vs 3.5%, p<.0001) decreased. Older patients were more likely to be inpatients (28.6% 65+ vs 5.9% <18, p<.0001) and have higher mortality (1.6% 65+ vs 0.2% <18, p<.0001). Admission type, LOS and cost varied by cohort. The highest LOS (11.2 days) and cost ($49,590) occurred in the <18 cohort after excluding newborns. Room and board, surgery, and diagnostic testing were the largest sources of cost in the <18 cohort. Age was significantly correlated with 14 of 18 disease-related complications and 15 of 16 comorbidities. In multivariate analyses age was not an independent risk factor for increased utilization, however patient comorbidities and disease-related complications did increase utilization. Hospital resource utilization is high in MFS patients, especially those <18 years old. Disease-related complications and patient comorbidities drive resource use.

Effects And Interactions Of Ncaa Di Basketball Participation On Measures Of Reactive Strength

Measures of reactive strength attempt to model the neuromuscular regulation of muscle tissue stress and strain. The specificity of neuromuscular training is important for maximizing the effectiveness of neuromuscular regulation of stress and strain within muscle and tendon tissue. Additionally, failure to regulate stress and strain within the muscle may lead to stresses placed on supporting structures of the body, including ligaments and bones. It is important to understand how sport participation effects neuromuscular reactivity and to develop strategies that maximize neuromuscular reactivity through specific training foci. PURPOSE: The purpose of this study was to evaluate the effects and interactions of sport participation on the Coefficient of Reactivity (CoR), Reactive Strength Index (RSI), and Reactive Strength Kinetic (RSK). METHODS: Fifty-nine young adults from the general community and 21 NCAA Division I basketball players performed five repetitive countermovement jumps (RCM) and a single depth jump from heights of 0.51 m, 0.66 m, and 0.81 m. The CoR, RSI, and the RSK were computed using tri-axial force platform data and two-dimensional videography. A Multivariate General Linear Model Analysis of Variance (GLM ANOVA) was performed on RCM data and another on depth jump data. Condition, sport participation, sex, and age were included as factors in each model. RESULTS: The CoR, RSI, and RSK were 30%, 22%, and 28% greater in males performing depth jumps versus females (p<0.05). The RSI and RSK were 23%, and 21% greater in males performing RCM jumping versus females (p<0.05). Main effects for sport participation were observed for the CoR, RSI, and RSK in depth jumping and for the RSI and RSK in RCM jumping (p<0.05). Sex by sport participation interactions were observed for the RSI and RSK, but not for the CoR. CONCLUSION: All three measures of reactive strength were sensitive to sex. Sex by sport interactions on the RSI and RSK suggest that involvement in NCAA Division I basketball may lead to a divergence in lower extremity neuromuscular reactivity between male and female athletes (males>females). This result makes sense from the perspective that female athletes tend to sustain higher incidence of lower extremity injuries when participating in sport.

Item Parameter Drift in Computer Adaptive Testing Due to Lack of Content Knowledge

This study was conducted to analyze potential item parameter drift (IPD) impact on person ability estimates and classification accuracy when drift affects an examinee subgroup. Using a series of simulations, three factors were manipulated: (a) percentage of IPD items in the CAT exam, (b) percentage of examinees affected by IPD, and (c) item pool targeting. IPD impact on ability estimation was evaluated using bias and root mean square error (RMSE). A multivariate general linear model treating three factors as fixed effects and bias and RMSE as outcome variables are used to investigate both main and interaction effects. The impact on classification accuracy was examined based on number and percentages of misclassifications, their significance, and rank order correlations. The findings revealed that IPD exposed to a sub-group of examinees can affect classification accuracy of those examinees substantially, but IPD impact on average ability estimation was small. The study provides useful information to schools, states, and countries planning to implement or are currently implementing CAT as part of their assessments by emphasizing IPD in subgroups may violate fairness and consistency principles of CAT applications.

Serum folate and cobalamin levels and urinary dimethylarsinic acid in US children and adults

Nutritional status could affect arsenic metabolism and toxicity in the general population chronically exposed to low levels of inorganic arsenic. In this study, we examined the association of serum folate and cobalamin with urinary concentrations of dimethylarsinic acid (DMA), the most abundant metabolite of inorganic arsenic measured in urine, in children and adults who participated in the 2003-2006 US National Health and Nutrition Examination Surveys. A total of 1161 children (aged 6-19years) and 1938 adults (aged 20-85years) were analyzed for the association using multivariate general linear models, adjusting for potential confounders. We observed a positive association between serum levels of folate and cobalamin and creatinine-corrected urinary concentrations of DMA in both children and adults. Furthermore, serum levels of folate and cobalamin were inversely associated with homocysteine (Hcy). These results suggest that dietary intake of folate and cobalamin may exhibit protective functions against arsenic toxicity by increasing arsenic metabolism to the less toxic metabolite DMA and decreasing serum levels of Hcy.

F23. LOW-GRADE INFLAMMATORY PROFILE IN FIRST-EPISODE PSYCHOSIS: RESULTS FROM THE STREAM STUDY IN BRAZIL

BackgroundThe inflammatory hypothesis of schizophrenia suggests that abnormalities in inflammatory factors may contribute to the onset of this disease early in adulthood. Nevertheless, no study has investigated possible effects of shared environment by looking at cytokine levels in healthy siblings of first-episode psychosis patients (FEP). The aim of this study was to investigate inflammatory cytokine (IL-6, IL-10, TNF-a) abnormalities in a sizeable epidemiological-based sample of FEP patients, their healthy siblings and population-based controls.MethodsThis study is part of the epidemiological investigation “Schizophrenia and Other Psychoses Translational Research: Environment and Molecular Biology” (STREAM), conducted in Ribeirão Preto (São Paulo, Brazil) and surrounding area, which is part of the international consortium “European Network of National Schizophrenia Networks Studying Gene-Environment Interactions” (EU-GEI). We recruited a total sample of 507 participants, composed by 166 FEP patients (64% males; mean age: 30.3 ± 12.2), 76 siblings (30.3% males; mean age: 31.5 ± 11.0) and 265 population-based controls (50.2% males; mean age: 31.7 ± 11.2). Plasma cytokines IL-6, TNF-a and IL-10 were analysed by Multiplex Bead Array (Luminex xMap technology). We performed the multivariate general linear model (GLM) analysis with age as covariate, cytokines as dependent variables and diagnostic group and sex as explanatory variables.ResultsWe found significant differences between the three groups [F (6,994) = 10.864; p < 0.001] in the plasma concentration of all the three cytokines (p < 0.001), independent of the sex of the participants (p = 0.115; interaction diagnosis & sex p = 0.115). FEP patients had significantly higher levels of IL-6, TNF-a, and IL-10 when compared to controls (p < 0.001 for all). When compared to their siblings, patients had higher levels of both TNF-a and IL-10 (p < 0.05 for both), and a trend to IL-6 (p = 0.058), whereas siblings did not differ from controls for any of the three cytokines analysed (p > 0.05 for all).DiscussionThis is the first study conducted in the South hemisphere to demonstrate the low-grade inflammatory profile in FEP patients, compared to their siblings and community-based controls. The fact that IL-6, TNF-a and IL-10 are all higher in the FEP group than their healthy siblings and community-based controls suggests the synergism of individual vulnerability factors in the development of this inflammatory profile.

Alcohol binge drinking in early pregnancy and the effect on fetal growth: a cohort study

Alcohol binge drinking is common in early pregnancy and is a well-established risk factor for subsequent child health. Yet, very few studies have investigated the effect on fetal growth. Furthermore, it has been speculated that the timing of binge drinking may be a determining factor for neonatal growth. The objective of this study was to assess the potential effect of binge drinking and different drinking patterns (timing and number of binge drinking episodes) in early pregnancy on fetal growth estimated by birthweight and birth length. From 1 March to 31 August 2000, 1836 pregnant Danish women from Aarhus University Hospital and Fredericia Hospital were included in the study and interviewed around the early second trimester about their drinking habits during their pregnancy. Information on anthropometric measures at birth was obtained from the Danish Medical Birth Registry. The potential effect of binge drinking and different drinking patterns was estimated using a multivariate general linear regression model adjusted for potential confounders that were selected a priori based on the currently available scientific literature. The women who reported any binge drinking gave birth to children with a reduction in birth length of -0.02cm (95% CI -0.23 to 0.18) and an increase in birthweight of 0.2g (95% CI -42.8 to 43.2). The number of binge episodes and the timing of these episodes were also not associated with fetal growth. The study suggests that binge drinking and different drinking patterns in early pregnancy do not affect fetal growth.

The Correlations between Postmortem Brain Pathologies and Cognitive Dysfunction in Aging and Alzheimer's Disease.

The pathological diagnostic criteria for Alzheimer's disease (AD) updated by the National Institute on Aging-Alzheimer's Association (NIA-AA) in 2012 has been widely adopted, but the clinicopathological relevance remained obscure in Chinese population. This study aims to investigate the correlations between the antemortem clinical cognitive performances and the postmortem neuropathological changes in the aging and AD brains collected in a human brain bank in China. A total of 52 human brains with antemortem cognitive status information [Everyday Cognition (ECog)] were collected through the willed donation program by CAMS/PUMC Human Brain Bank. Pathological changes were evaluated with the "ABC" score following the guidelines of NIA-AA. The clinicopathological relationship was analyzed with correlation analysis and general linear multivariate model. The general ABC score has a significant correlation with global ECog score (r=0.37, p=0.014) and most of ECog domains. The CERAD score of neuritic plaques (C score) has a significant correlation with global ECog score (r=0.40, p=0.007) and the majority of ECog domains, such as memory (r=0.50, p=0.001), language (r=0.45, p=0.002), visuospatial functions (r=0.31, p=0.040), planning (r=0.35, p=0.021) and organization (r=0.39, p=0.010). The Braak stage of neurofibrillary tangles (NFTs) (B score) has a moderate correlation with memory (r=0.32, p=0.035). The Thal phases of amyloid-β (Aβ) deposits (A score) present no significant correlation with any of ECog domains. In this study, we verified the correlation of postmortem C and B scores, but not the A score with cognition performance in a collection of samples from the Chinese human brain bank.

A randomized controlled study to evaluate the effect of pharmacist-led educational intervention on glycemic control, self-care activities and disease knowledge among type 2 diabetes patients: A consort compliant study protocol.

Background:Diabetes self-care activities, like, healthy diet, regular exercise, self-monitoring of blood glucose, and rational use of medicines are considered to play a vital role in establishing euglycemia. Health literacy among type 2 diabetes mellitus (T2DM) patients in Pakistan is very low, which is the most likely cause for poor clinical outcomes. This study is designed to investigate the impact of pharmacist-led educational intervention on glycemic control, self-care activities and disease knowledge among T2DM patients in Pakistan.Methods:In this randomized controlled trail, effectiveness of a 6-month pharmacist-led educational intervention will be examined on glycemic control, diabetes self-care activities and disease knowledge of 80 adult T2DM patients (age >30 years) with poorly controlled T2DM (HbA1c> 7%), after randomizing them into intervention and control groups, at diabetes care clinic of Capital Hospital Islamabad, Pakistan.Results:The primary outcome is change in patients’ HbA1c, whereas, changes in self-care activities and patients’ disease knowledge are the secondary outcomes. After baseline assessment of their self-care activities and disease knowledge by using validated Urdu versions of Diabetes Self-management Questionnaire (DSMQ) and Diabetes Knowledge Questionnaire (DKQ), respectively, interventional group patients will be supplemented with a face-to-face pharmacist-led educational intervention, whereas, the control group will receive usual care. Intervention arm patients will be educated successively at their first follow-up visit (12th week) and telephonically after every 4 weeks. All assessments will be made at baseline and end of trail for both intervention and control groups. Multivariate general linear model will be applied to analyze the effects of the intervention.Conclusion:Glycemic control in T2DM patients requires optimum self-care activities. This study is an attempt to improve self-care behaviors among poorly controlled T2DM patients who are at higher risk of diabetes-associated late complications.

Calculating power for the general linear multivariate model with one or more Gaussian covariates

ABSTRACTWe describe a noncentral power approximation for hypotheses about fixed predictors in general linear multivariate models with one or more Gaussian covariates. The results apply to both single and multiple parameter hypotheses. The approach extends power approximations for models with only fixed predictors, and for models with a single Gaussian covariate. The new method approximates the noncentrality parameter under the alternative hypothesis using a Taylor series expansion for the matrix-variate beta distribution of type I. We used a Monte Carlo simulation to evaluate the accuracy of both the novel power approximation, and published power approximations. The simulation study accounted for randomness in both the predictors and the errors. We varied the number of outcomes, the number of parameters in the hypothesis, the per-treatment sample size, and the correlations between the random predictors and the outcomes. We demonstrate that our approximation is more accurate than published methods, both in small and large samples. We show that the run time for a single power calculation with the new method is on the order of milliseconds, compared to an average empirical simulation time of roughly three minutes. Approximate and simulated power can be calculated using the free, open-source rPowerlib package (http://github.com/SampleSizeShop/rPowerlib).

Trait and state anxiety across academic evaluative contexts: development and validation of the MTEA-12 and MSEA-12 scales

ABSTRACTBackground and objectives: Educational measures of anxiety focus heavily on students’ experiences with tests yet overlook other assessment contexts. In this research, two brief multiscale questionnaires were developed and validated to measure trait evaluation anxiety (MTEA-12) and state evaluation anxiety (MSEA-12) for use in various assessment contexts in non-clinical, educational settings.Design: The research included a cross-sectional analysis of self-report data using authentic assessment settings in which evaluation anxiety was measured.Method: Instruments were tested using a validation sample of 241 first-year university students in New Zealand. Scale development included component structures for state and trait scales based on existing theoretical frameworks.Results: Analyses using confirmatory factor analysis and descriptive statistics indicate that the scales are reliable and structurally valid. Multivariate general linear modeling using subscales from the MTEA-12, MSEA-12, and student grades suggest adequate criterion-related validity. Initial predictive validity in which one relevant MTEA-12 factor explained between 21% and 54% of the variance in three MSEA-12 factors.Conclusions: Results document MTEA-12 and MSEA-12 as reliable measures of trait and state dimensions of evaluation anxiety for test and writing contexts. Initial estimates suggest the scales as having promising validity, and recommendations for further validation are outlined.

Development of equations to predict the influence of floor space on average daily gain, average daily feed intake and gain : feed ratio of finishing pigs

Floor space allowance for pigs has substantial effects on pig growth and welfare. Data from 30 papers examining the influence of floor space allowance on the growth of finishing pigs was used in a meta-analysis to develop alternative prediction equations for average daily gain (ADG), average daily feed intake (ADFI) and gain : feed ratio (G : F). Treatment means were compiled in a database that contained 30 papers for ADG and 28 papers for ADFI and G : F. The predictor variables evaluated were floor space (m2/pig), k (floor space/final BW0.67), Initial BW, Final BW, feed space (pigs per feeder hole), water space (pigs per waterer), group size (pigs per pen), gender, floor type and study length (d). Multivariable general linear mixed model regression equations were used. Floor space treatments within each experiment were the observational and experimental unit. The optimum equations to predict ADG, ADFI and G : F were: ADG, g=337.57+(16 468×k)−(237 350×k2)−(3.1209×initial BW (kg))+(2.569×final BW (kg))+(71.6918×k×initial BW (kg)); ADFI, g=833.41+(24 785×k)−(388 998×k2)−(3.0027×initial BW (kg))+(11.246×final BW (kg))+(187.61×k×initial BW (kg)); G : F=predicted ADG/predicted ADFI. Overall, the meta-analysis indicates that BW is an important predictor of ADG and ADFI even after computing the constant coefficient k, which utilizes final BW in its calculation. This suggests including initial and final BW improves the prediction over using k as a predictor alone. In addition, the analysis also indicated that G : F of finishing pigs is influenced by floor space allowance, whereas individual studies have concluded variable results.

Can effective communities of practice enhance stakeholder satisfaction?

Communities of practice (CoP) can influence the perceived customer value. Effective stakeholder related knowledge transfer can help in value creation by building positive relationships between organisations and their stakeholders. CoP are the social tools to connect, engage and share knowledge in organisations. Effective CoP can help the organisation in many ways. This research focuses on understanding the impact of effective CoP interventions on the organisations' abilities to demonstrate learning (DL), take actions on lessons learnt (TALL) and influence business outcomes (BO). Based on a survey of 223 respondents of successful knowledge management (KM) and CoP implementation participants, this study uses a multivariate general linear model to analyse the findings. The findings suggest that effective CoPs are capable of influencing organisations to demonstrate learning, take actions on lessons learned and improve business outcomes. The study discusses the implications of these findings and offers directions for future research.

A low-rank multivariate general linear model for multi-subject fMRI data and a non-convex optimization algorithm for brain response comparison

The focus of this paper is on evaluating brain responses to different stimuli and identifying brain regions with different responses using multi-subject, stimulus-evoked functional magnetic resonance imaging (fMRI) data. To jointly model many brain voxels’ responses to designed stimuli, we present a new low-rank multivariate general linear model (LRMGLM) for stimulus-evoked fMRI data. The new model not only is flexible to characterize variation in hemodynamic response functions (HRFs) across different regions and stimulus types, but also enables information “borrowing” across voxels and uses much fewer parameters than typical nonparametric models for HRFs. To estimate the proposed LRMGLM, we introduce a new penalized optimization function, which leads to temporally and spatially smooth HRF estimates. We develop an efficient optimization algorithm to minimize the optimization function and identify the voxels with different responses to stimuli. We show that the proposed method can outperform several existing voxel-wise methods by achieving both high sensitivity and specificity. We apply the proposed method to the fMRI data collected in an emotion study, and identify anterior dACC to have different responses to a designed threat and control stimuli.

The tick biocontrol agent Metarhizium brunneum (= M. anisopliae) (strain F52) does not reduce non-target arthropods.

Previous studies have found that Met52®, which contains the entomopathogenic fungus Metarhizium brunneum, is effective in reducing the abundance of Ixodes scapularis, the tick vector for the bacterium causing Lyme disease and for other tick-borne pathogens. Given widespread interest in effective, safe methods for controlling ticks, Met52 has the potential to be used at increasing scales. The non-target impacts of Met52, as applied for tick control, have not yet been assessed. A Before-After-Control-Impact experiment was conducted to assess the effects of Met52 on non-target arthropods in lawn and forest habitats typical of residential yards. Ground-dwelling arthropods were collected using bulk sampling of soil and litter, and pitfall sampling. Arthropods were sampled once before and twice after treatment of plots with either Met52 or water (control). Multivariate general linear models were used to jointly model the abundance of arthropod orders. For each sampling method and post-spray sampling occasion, Akaike Information Criterion values were used to compare the fits of two alternative models: one that included effects of period (before vs. after spray), habitat (lawn vs. forest), and treatment (Met52 vs. control), versus a nested null model that included effects of period, and habitat, but no treatment effect. The null model was consistently better supported by the data. Significant effects were found of period and habitat but not treatment. Retrospective power analysis indicated the study had 80% power to detect a 50% reduction in arthropod abundance, as measured by bulk samples taken before versus one week after treatment. The deployment of Met52 in suburban settings is unlikely to cause meaningful reductions in the abundance of non-target arthropods.

The impact of GI events on persistence and adherence to osteoporosis treatment: 3-, 6-, and 12-month findings in the MUSIC-OS study

SummaryThe goal of this multinational, prospective, observational study was to examine the relationship between gastrointestinal (GI) events and self-reported levels of medication adherence and persistence in postmenopausal women. A total of 73.9% of patients remained on their osteoporosis (OP) therapy at month 12, although the presence of a GI event at baseline, month 3, and month 6 significantly reduced month 12 persistence among new users. The odds of a month-12 ADEOS score ≥ 20 were significantly lower among patients who experienced a GI event between baseline and month 6. The occurrence of GI events was observed to be associated with a lower likelihood of patient adherence and persistence to OP medication.IntroductionThis study examines the relationship between gastrointestinal (GI) events and self-reported adherence and persistence with initial osteoporosis (OP) therapy over the course of the first 12 months of treatment.MethodsThe Medication Use Patterns, Treatment Satisfaction, and Inadequate Control of Osteoporosis Study was a multinational, prospective, observational study examining the impact of GI events on OP management in postmenopausal women. Information regarding GI events was collected at the time of enrollment and at months 3, 6, and 12 of follow-up. Patients reported GI events and medication persistence and completed the 12-item Adherence Evaluation of Osteoporosis treatment (ADEOS) questionnaire. Multivariate logistic and general linear models examined the association between GI events at various time points and persistence and adherence at month 12.ResultsThe study enrolled 2943 women; 22.8% were classified as new users of OP therapy and the remainder were considered experienced users. Across all patients, 68.1% reported GI events at baseline; by month 12, over 80% of subjects who completed follow-up reported at least one GI problem. The majority of patients (86.7%) were treated only with bisphosphonates at baseline. At month 12, 73.9% of patients remained on therapy; logistic regression revealed that those with GI problems by month 6 were significantly less likely to persist with treatment, after adjusting for other factors. The odds of a month 12 ADEOS score ≥ 20 (considered predictive of adherence) were significantly lower among patients who experienced a GI event between baseline and month 6.ConclusionsThe occurrence of GI events was associated with a lower likelihood of patient adherence to and persistence with OP medication.

Menstrual cycle characteristics and steroid hormone, prolactin, and growth factor levels in premenopausal women.

Menstrual cycle characteristics are markers of endocrine milieu. However, associations between age at menarche and adulthood sex steroid hormone levels have been inconsistent, and data on menstrual characteristics and non-sex steroid hormones are sparse. We assessed the relations of menstrual characteristics with premenopausal plasma sex steroid hormones, sex hormone binding globulin (SHBG), prolactin, and growth factors among 2,745 premenopausal women (age 32-52) from the Nurses' Health Study II. Geometric means and tests for trend were calculated using multivariable general linear models. Early age at menarche was associated with higher premenopausal early-follicular free estradiol (percent difference < 12 vs. > 13 years = 11%), early-follicular estrone (7%), luteal estrone (7%), and free testosterone (8%) (all p trend < 0.05). Short menstrual cycle length at age 18-22 was associated with higher early-follicular total (< 26 vs. > 39 days = 18%) and free estradiol (16%), early-follicular estrone (9%), SHBG (7%), lower luteal free estradiol (- 14%), total (- 6%), and free testosterone (- 15%) (all p trend < 0.05). Short adult menstrual length was associated with higher early-follicular total estradiol (< 26 vs. > 31 days = 14%), SHBG (10%), lower luteal estrone (- 8%), progesterone (- 9%), total (- 11%) and free testosterone (- 25%), and androstenedione (- 14%) (all p trend < 0.05). Irregularity of menses at 18-22 was associated with lower early-follicular total (irregular vs. very regular = - 14%) and free estradiol (- 14%), and early-follicular estrone (- 8%) (All p trend < 0.05). Irregularity of adult menstrual cycle was associated with lower luteal total estradiol (irregular vs. very regular = - 8%), SHBG (- 3%), higher total (8%), and free testosterone (11%) (all p trend < 0.05). Early-life and adulthood menstrual characteristics are moderately associated with mid-to-late reproductive year's hormone concentrations. These relations of menstrual characteristics with endogenous hormone levels could partially account for associations between menstrual characteristics and reproductive cancers or other chronic diseases.

On additive decompositions of estimators under a multivariate general linear model and its two submodels

Parameters from linear regression models are often estimated by the ordinary least squares estimator (OLSE) or by the best linear unbiased estimator (BLUE). These estimators can be written in analytical form, so that it is not difficult to describe their performances under various model assumptions. In this paper, we study the problem of additive decompositions of OLSEs and BLUEs of parameter spaces in a full multivariate general linear model (MGLM) and in two specific submodels. We establish necessary and sufficient conditions for the validity of various identities involving the OLSEs and BLUEs of whole and partial mean parameter matrices under the MGLM and two smaller MGLMs.

Does intravoxel incoherent motion reliably stage hepatic fibrosis, steatosis, and inflammation?

To investigate the usefulness of intravoxel incoherent motion (IVIM) in determining the severity of hepatic fibrosis, steatosis, and inflammation in patients with chronic liver disease. Forty-nine patients who had liver MRI with IVIM sequence and liver biopsy within three months of MRI were enrolled. A reviewer, blinded to histology, placed regions of interest of 1-2cm2 in the right liver lobe. In addition, the first twenty patients were assessed with a second reviewer. Perfusion fraction (f), pseudodiffusion coefficient (D fast), true diffusion coefficient (D slow), and apparent diffusion coefficient (ADC) were calculated from normalized signal intensities that were fitted into a biexponential model. Errors in the model were minimized with global stochastic optimization using Simulated Annealing. ANOVA with post hoc Tukey-Kramer test and multivariate generalized linear model analysis were performed, using histological findings as the gold standard. The most common etiologies for liver disease were hepatitis C and alcohol, accounting together for 76% (37/49) of patients. Low-grade fibrosis (F0, F1), hepatic steatosis, and inflammation were seen in 24% (12/49), 31% (15/49), and 29% (14/49) of patients, respectively. The interobserver correlation was poor for D fast and D slow (0.105, 0.173) and moderate for f and ADC (0.461, 0.418). ANOVA showed a strong inverse association between D fast and liver fibrosis grade (p=0.001). A weak inverse association was seen between ADC and hepatic steatosis (p=0.059). Multivariate general linear model revealed that the only significant association between IVIM parameters and pathological features was between D fast and fibrosis. On ROC curve analysis, D fast<23.4×10-3 mm2/s had a sensitivity of 82.8% and a specificity of 64.3% in predicting high-grade fibrosis. D fast has the strongest association with hepatic fibrosis but has weak interobserver correlation. IVIM parameters were not significantly associated with hepatic inflammation or steatosis.

Recovery of Motor Nerve Injuries Associated With Displaced, Extension-type Pediatric Supracondylar Humerus Fractures.

Nerve injuries occur in approximately 11% of pediatric extension supracondylar humerus fractures (SCHF), yet there is scarce literature to guide clinicians on management. The primary goal of this study was to report the presentation, treatment, and outcome of motor nerve injuries associated with extension SCHF. Our secondary goal was to determine which injury and treatment factors were associated with prolonged motor nerve recovery. Two hundred forty-four traumatic nerve injuries associated with extension SCHF treated at a single institution between 1996 and 2012 were reviewed. Patients with iatrogenic nerve injuries or subjective paresthesias without motor deficit were excluded. Univariable and multivariable general linear modeling were used to compare recovery times across nerve injury types and to determine the effect of injury and treatment characteristics on recovery time. Patients were a mean age of 6.7 years, with 89% presenting with a single nerve injury and 29% of the cohort experiencing a concurrent vascular injury. The majority of injuries (62%) were to the median nerve. Forty-three (18%) cases had acute nerve decompression at the time of fracture fixation. Five cases required subsequent surgery for poor nerve recovery; none of which underwent initial nerve decompression. Thirty-one patients were lost to follow-up after injury. Median time to nerve recovery was 2.3 months (IQR 1.4 to 3.7 mo); 60% of injuries had nerve recovery by 3 months and 196 (92%) patients had complete nerve recovery at final follow-up. A greater percentage of isolated median nerve (70%) injuries recovered within 3 months compared with radial nerve (42%) injuries (P=0.01). Multivariable analysis demonstrated that multiple nerve injuries took 54% longer to recover than single median nerve injuries (P=0.01), and single radial nerve injuries took 30% longer to recover than single median nerve injuries (P=0.04). The majority of nerve injuries associated with pediatric extension SCHF recover within 6 months without acute nerve decompression. The presence of either an isolated radial nerve injury or multiple nerve injuries is associated with prolonged motor recovery. Level IV.

Maternal Night-Fasting Interval during Pregnancy Is Directly Associated with Neonatal Head Circumference and Adiposity in Girls but Not Boys

Background: Synchrony between daily feeding-fasting signals and circadian rhythms has been shown to improve metabolic health in animals and adult humans, but the potential programming effect on fetal growth is unknown.Objective: We examined the associations of the maternal night-fasting interval during pregnancy with offspring birth size and adiposity.Methods: This was a cross-sectional study of mother-offspring dyads within the Growing Up in Singapore Towards healthy Outcomes (GUSTO) cohort. For 384 mothers aged 30.8 ± 4.8 y (mean ± SD), the night-fasting interval at 26-28 wk of gestation was determined from a 3-d food diary based on the average of the fasting duration at night (1900-0659). Offspring birth weight, length, and head circumference were measured and converted to weight-for-gestational age (GA), length-for-GA, and head circumference-for-GA z scores, respectively, by using local customized percentile charts. The percentage of neonatal total body fat (TBF) was derived by using a validated prediction equation. Multivariable general linear models, stratified by child sex, were performed.Results: The mean ± SD maternal night-fasting interval was 9.9 ± 1.3 h. In infant girls, each 1-h increase in the maternal night-fasting interval was associated with a 0.22-SD (95% CI: 0.05-, 0.40-SD; P = 0.013) increase in birth head circumference-for-GA and a 0.84% (95% CI: 0.19%, 1.49%; P = 0.012) increase in TBF at birth, after adjustment for confounders. In infant boys, no associations were observed between the maternal night-fasting interval and birth size or TBF.Conclusions: An increased maternal night-fasting interval in the late second trimester of pregnancy is associated with increased birth head circumference and TBF in girls but not boys. Our findings are in accordance with previous observations that suggest that there are sex-specific responses in fetal brain growth and adiposity, and raise the possibility of the maternal night-fasting interval as an underlying influence. This trial was registered at clinicaltrials.gov as NCT01174875.