Gaussian Process-based prediction of memory performance and biomarker status in ageing and Alzheimer's disease-A systematic model evaluation.

Neuroimaging markers based on Magnetic Resonance Imaging (MRI) combined with various other measures (such as genetic covariates, biomarkers, vascular risk factors, neuropsychological tests etc.) might provide useful predictions of clinical outcomes during the progression towards Alzheimer's disease (AD). The use of multiple features in predictive frameworks for clinical outcomes has become increasingly prevalent in AD research. However, many studies do not focus on systematically and accurately evaluating combinations of multiple input features. Hence, the aim of the present work is to explore and assess optimal combinations of various features for MR-based prediction of (1) cognitive status and (2) biomarker positivity with a multi-kernel learning Gaussian process framework. The explored features and parameters included (A) combinations of brain tissues, modulation, smoothing, and image resolution; (B) incorporating demographics & clinical covariates; (C) the impact of the size of the training data set; (D) the influence of dimensionality reduction and the choice of kernel types. The approach was tested in a large German cohort including 959 subjects from the multicentric longitudinal study of cognitive impairment and dementia (DELCODE). Our evaluation suggests the best prediction of memory performance was obtained for a combination of neuroimaging markers, demographics, genetic information (ApoE4) and CSF biomarkers explaining 57% of outcome variance in out-of-sample predictions. The highest performance for Aß42/40 status classification was achieved for a combination of demographics, ApoE4, and a memory score while usage of structural MRI further improved the classification of individual patient's pTau status.

Racial and ethnic minority enrollment in randomized clinical trials of behavioural weight loss utilizing technology: a systematic review.

Many racial and ethnic minority groups (minorities) are disproportionately affected by overweight and obesity; however, minorities are often under-represented in clinical trials of behavioural weight loss (BWL) treatment, potentially limiting the generalizability of these trials' conclusions. Interventions involving technology may be particularly well suited to overcoming the barriers to minority enrollment in BWL trials, such as demanding or unpredictable work schedules, caregiving responsibilities and travel burdens. Thus, this systematic review aimed to describe minority enrollment in trials utilizing technology in interventions, as well as to identify which form(s) of technology yield the highest minority enrollment. Results indicated relatively low enrollment of minorities. Trials integrating smartphone use exhibited significantly greater racial minority enrollment than trials that did not; trials with both smartphone and in-person components exhibited the highest racial minority enrollment. This review is the first to explore how the inclusion of technology in BWL trials relates to minority enrollment and can help address the need to improve minority enrollment in weight loss research.

Personal history of dieting and family history of obesity are unrelated: implications for understanding weight gain proneness.

Identifying predictors of future weight gain is important in obesity prevention efforts. Both family history of obesity and personal dieting history have been established as predictors of future weight gain; however, it is unknown if they are independent or overlapping predictors. The purpose of this study was to examine the degree of overlap between these two predictors using cross-sectional data. Baseline data from four studies were examined separately and in combination for a total of 561 female participants, and analyses were conducted to examine parent anthropometric variables by dieting status within and across studies. All participants were female university students between the ages of 17 and 30. For each study, as well as for the entire sample combined, parent anthropometric variables were examined by dieting status using factorial ANOVAs. No meaningful pattern was found when examining parent anthropometric variables by dieting status, which suggests that the two risk factors are largely independent. This suggests that the processes associated with the development of future weight gain by each variable are different; therefore, future research should use a longitudinal study to test the hypothesis that using both variables to predict future weight gain would account for more variance than using either variable alone.

The mind your health project: a randomized controlled trial of an innovative behavioral treatment for obesity.

OBJECTIVE: To determine whether acceptance-based behavioral treatment (ABT) would result in greater weight loss than standard behavioral treatment (SBT), and whether treatment effects were moderated by interventionist expertise or participants' susceptibility to eating cues. Recent research suggests that poor long-term weight-control outcomes are due to lapses in adherence to weight-control behaviors and that adherence might be improved by enhancing SBT with acceptance-based behavioral strategies. DESIGN AND METHODS: Overweight participants (n = 128) were randomly assigned to 40 weeks of SBT or ABT. RESULTS: Both groups produced significant weight loss, and when administered by experts, weight loss was significantly higher in ABT than SBT at post-treatment (13.17% vs. 7.54%) and 6-month follow-up (10.98% vs. 4.83%). Moreover, 64% of those receiving ABT from experts (vs. 46% for SBT) maintained at least a 10% weight loss by follow-up. Moderation analyses revealed a powerful advantage, at follow-up, of ABT over SBT in those potentially more susceptible to eating cues. For participants with greater baseline depression symptomology, weight loss at follow-up was 11.18% in ABT versus 4.63% in SBT; other comparisons were 10.51% versus 6.00% (emotional eating), 8.29% versus 6.35% (disinhibition), and 9.70% versus 4.46% (responsivity to food cues). Mediation analyses produced partial support for theorized food-related psychological acceptance as a mechanism of action. CONCLUSIONS: Results offer strong support for the incorporation of acceptance-based skills into behavioral weight loss treatments, particularly among those with greater levels of depression, responsivity to the food environment, disinhibition, and emotional eating, and especially when interventions are provided by weight-control experts.

Evidence for prospective associations among depression and obesity in population-based studies.

Obesity may lead to depression or be one of its consequences. We reviewed population-based studies in order to, first, identify the most commonly used research methods, and, second, to evaluate the strength of evidence for prospective associations among obesity and depression. We examined 25 studies, of which 10 tested 'obesity-to-depression' pathways, and 15 tested 'depression-to-obesity' pathways. Descriptive statistics summarized the frequency with which various measurements, designs and data analytic strategies were used. We tallied the number of studies that reported any vs. no statistically significant associations, and report on effect sizes, identified moderating variables within reports, and sought common findings across studies. Results indicated considerable methodological heterogeneity in the literature. Depression was assessed by clinical interview in 44% of studies, weight and height were directly measured in 32%, and only 12% used both. In total, 80% of the studies reported significant obesity-to-depression associations, with odds ratios generally in the range of 1.0 to 2.0, while only 53% of the studies reported significant depression-to-obesity associations. Sex was a common moderating variable. Thus, there was good evidence that obesity is prospectively associated with increased depression, with less consistent evidence that depression leads to obesity. Recommendations for future research regarding study samples, measurement and data analysis are provided.

Attrition from randomized controlled trials of pharmacological weight loss agents: a systematic review and analysis.

Clinical trials of obesity treatments have been limited by substantial dropout. Participant-level variables do not reliably predict attrition, and study-level variables have not yet been examined. We searched MEDLINE and identified 24 large randomized controlled trials of weight loss medications. These trials were comprised of 23 placebo and 32 drug groups. Two authors independently extracted the following for each treatment group: (i) treatment received; (ii) design characteristics (inclusion of a lead-in period, selection of participants with weight-related comorbidities, study location and number of study visits); (iii) sample characteristics (sample size, % female, and mean baseline age and body mass index); and (iv) attrition (total, adverse event [AE]-related and non-AE-related) at 1 year. The primary outcome was total attrition, which was significantly related to treatment (i.e. 34.9%, 28.6%, 28.3% and 35.1% in placebo, orlistat, sibutramine and rimonabant groups, respectively, P < 0.0001). In adjusted multivariable models, total attrition was significantly lower in groups that completed a pre-randomization lead-in period than in those that did not (29.1% vs. 39.9%, P < 0.01). Gender also was significantly related to total attrition; groups with more women had higher dropout (P < 0.01). The pattern was similar for predicting non-AE-related attrition. Findings suggest ways to design studies that maximize retention.

Measurement of laboratory aggression: a new response-choice paradigm.

40 undergraduate student volunteers were tested on a new Response-choice Aggression Paradigm. Men and women were provoked in a reaction time competition by receiving electric shocks and were allowed to respond to a confederate with similar shocks or to refrain from any retaliation. Analysis indicated positive association between a self-report measure of physical aggression and laboratory responses on the paradigm, and positive associations among aggression indices of the task. The results confirm earlier findings of sex differences in aggression and offer new measures of aggression "flashpoint" as a step closer to aggressive behavior in naturalistic settings.

Temperament, hostility, and consequences of alcohol use.

Problems in temperament and hostility have been implicated in alcohol use disorders. This study investigated the relationships among temperament, hostility, and adverse consequences of alcohol consumption in a sample of 180 healthy young social drinkers. Rigid behavior pattern and antagonistic hostility were positively correlated with adverse consequence of drinking.