Transparency in Cognitive Training Meta-analyses: A Meta-review

Meta-analyses often present flexibility regarding their inclusion criteria, outcomes of interest, statistical analyses, and assessments of the primary studies. For this reason, it is necessary to transparently report all the information that could impact the results. In this meta-review, we aimed to assess the transparency of meta-analyses that examined the benefits of cognitive training, given the ongoing controversy that exists in this field. Ninety-seven meta-analytic reviews were included, which examined a wide range of populations with different clinical conditions and ages. Regarding the reporting, information about the search of the studies, screening procedure, or data collection was detailed by most reviews. However, authors usually failed to report other aspects such as the specific meta-analytic parameters, the formula used to compute the effect sizes, or the data from primary studies that were used to compute the effect sizes. Although some of these practices have improved over the years, others remained the same. Moreover, examining the eligibility criteria of the reviews revealed a great heterogeneity in aspects such as the training duration, age cut-offs, or study designs that were considered. Preregistered meta-analyses often specified poorly how they would deal with the multiplicity of data or assess publication bias in their protocols, and some contained non-disclosed deviations in their eligibility criteria or outcomes of interests. The findings shown here, although they do not question the benefits of cognitive training, illustrate important aspects that future reviews must consider.

Perfectionism and binge eating association: a systematic review and meta-analysis

BACKGROUND

Perfectionism is considered a vulnerability factor for eating disorders. However, the role of perfectionism in binge eating needs clarification due to notably inconsistencies between studies. The purpose to this study was to conduct a systematic review and meta-analysis to estimate the perfectionism-binge eating association.

METHOD

Systematic review was performed according to the PRISMA 2020 statement. Four databases (Web of Science, Scopus, PsycINFO and Psicodoc) were searched to identify studies published until September 2022. The literature search yielded 30 published articles (N = 9392) that provided 33 independent estimations of the correlation between the two variables.

RESULTS

Random-effects meta-analysis revealed a small-to-moderate positive average effect size between general perfectionism and binge eating (r₊ = .17) with a large heterogeneity. Perfectionistic Concerns showed a significant small-to-moderate relationship with binge eating (r₊ = .27), whereas Perfectionistic Strivings presented a negligible relationship with binge eating (r₊ = .07). Moderator analyses showed that the age, the type of the sample, the study design, and the tools for assessing both variables were statistically associated with the perfectionism-binge eating effect sizes.

CONCLUSIONS

Our findings suggest that Perfectionism Concerns are closely associated with binge eating symptomatology. This relationship might be moderated by certain variables, especially by the clinical or non-clinical nature of the sample and the instrument employed to assess binge eating.

Heterogeneity estimation in meta-analysis of standardized mean differences when the distribution of random effects departs from normal: A Monte Carlo simulation study

BACKGROUND

Advantages of meta-analysis depend on the assumptions underlying the statistical procedures used being met. One of the main assumptions that is usually taken for granted is the normality underlying the population of true effects in a random-effects model, even though the available evidence suggests that this assumption is often not met. This paper examines how 21 frequentist and 24 Bayesian methods, including several novel procedures, for computing a point estimate of the heterogeneity parameter ([Formula: see text]) perform when the distribution of random effects departs from normality compared to normal scenarios in meta-analysis of standardized mean differences.

METHODS

A Monte Carlo simulation was carried out using the R software, generating data for meta-analyses using the standardized mean difference. The simulation factors were the number and average sample size of primary studies, the amount of heterogeneity, as well as the shape of the random-effects distribution. The point estimators were compared in terms of absolute bias and variance, although results regarding mean squared error were also discussed.

RESULTS

Although not all the estimators were affected to the same extent, there was a general tendency to obtain lower and more variable [Formula: see text] estimates as the random-effects distribution departed from normality. However, the estimators ranking in terms of their absolute bias and variance did not change: Those estimators that obtained lower bias also showed greater variance. Finally, a large number and sample size of primary studies acted as a bias-protective factor against a lack of normality for several procedures, whereas only a high number of studies was a variance-protective factor for most of the estimators analyzed.

CONCLUSIONS

Although the estimation and inference of the combined effect have proven to be sufficiently robust, our work highlights the role that the deviation from normality may be playing in the meta-analytic conclusions from the simulation results and the numerical examples included in this work. With the aim to exercise caution in the interpretation of the results obtained from random-effects models, the tau2() R function is made available for obtaining the range of [Formula: see text] values computed from the 45 estimators analyzed in this work, as well as to assess how the pooled effect, its confidence and prediction intervals vary according to the estimator chosen.

Florida Obsessive-Compulsive Inventory and Children's Florida Obsessive Compulsive Inventory: A reliability generalization meta-analysis

BACKGROUND

The Florida Obsessive Compulsive Inventory (FOCI) and its pediatric version, the Children's Florida Obsessive Compulsive Inventory (C-FOCI), are instruments for evaluating obsessive-compulsive symptomatology.

METHOD

A reliability generalization meta-analysis was conducted to estimate an average reliability of the scores and to identify study characteristics that explained the heterogeneity among scores. Using Kuder-Richardson 20 (KR-20) and Cronbach's α, a total of 23 and 20 independent samples were included in the meta-analysis for the FOCI and C-FOCI.

RESULTS

We found an average KR-20 of 0.826 for the FOCI's Symptom Checklist and an α of 0.882 FOCI's Symptom Severity. An average KR-20 of 0.740 was found for the C-FOCI's Symptom Checklist, while an average α of 0.794 was found for the C-FOCI's Symptom Severity. Moderator analyses showed that the source of the coefficients (i.e., whether they were reported by the authors of the primary study or estimated by the meta-analysts) was an important variable for the FOCI Symptom Severity, and that the focus of the study (i.e., whether it was psychometric or applied) and the sample size were relevant for the C-FOCI Symptom Checklist.

CONCLUSIONS

Considering that the FOCI and C-FOCI are scales characterized by their brevity and ease of use, and the reliabilities obtained here, both scales are well suited for screening purposes.

The Adult Prosocialness Behavior Scale: A reliability generalization meta-analysis

The Adult Prosocialness Behavior Scale (APBS) is most often used to measure adult prosociality. We conducted a reliability generalization meta-analysis to compute the average APBS reliability and examine the heterogeneity among reliability estimations and the influence of moderator variables. An exhaustive search identified 74 articles that applied the APBS with 16 items assessed on a 5-point Likert-type scale. Of these, 58 had reliability coefficients with the current data, and 76 reliability estimates were provided. Random- and mixed-effects models were used. The average reliability coefficient was .903 for Cronbach’s alpha, .896 for McDonald’s omega, and .674 for test–retest. Moderator analyses were used to create a predictive model in which the target population and study language accounted for 48.7% of the total variability among Cronbach’s alpha coefficients. Although the APBS has shown satisfactory internal consistency, it can vary as a function of several factors.

Cognitive-Behavioral Therapy and Anxiety and Depression Level in Pediatric Obsessive-Compulsive Disorder: A Systematic Review and Meta-Analysis

BACKGROUND

Although some meta-analyses have identified potential moderators associated with treatment outcomes for pediatric obsessive-compulsive disorder (OCD), there is as yet no consensus regarding the influence of anxiety and depression symptoms on the recovery from pediatric OCD. A meta-analysis was conducted to investigate the effects of depression and anxiety symptoms and their comorbidities on the efficacy of CBT in pediatric OCD, as well as other potential moderators that may be associated with outcomes.

METHOD

An exhaustive literature search from 1983 to March 2021 located 22 published articles that applied cognitive-behavioral therapy (CBT) to pediatric OCD, producing a total of 26 treatment groups. Some of the moderator variables analyzed included age, gender, comorbidity baseline in anxiety, depression and obsession, and methodological quality.

RESULTS

Results showed that the psychological treatment of OCD achieves clinically significant effectiveness, both for measures of obsessions and compulsions ( d + = 2.030), and for anxiety ( d + = 0.613) and depression ( d + = 0.451). An explanatory model for the CY-BOCS effect sizes showed that three moderator variables were statistically related: the mean of the CY-BOCS (Children´s Yale Brown Obsessive Compulsive Scale) in pretest, the effect size for anxiety, and the mean age of the sample.

CONCLUSIONS

CBT reduced obsessive-compulsive symptoms and, to a lesser extent, anxiety and depression symptoms. Since anxiety symptoms are reduced with the same therapy, resources would be saved compared to other treatments.

Overviews of Reviews: Concept and Development

BACKGROUND

In the last years, overviews of systematic reviews, or umbrella reviews, have seen a dramatic increase in their use. An overview aims to provide a summary of the included reviews and will often examine research questions beyond those addressed in the systematic reviews being synthesised. The purpose of this article is to provide some recommendations on how overviews should be conducted and reported.

METHOD

A literature review was performed to identify relevant papers on both methodological and applied overviews.

RESULTS

The current literature recommends carrying out overviews by following similar steps to those of systematic reviews: (a) Defining the overview research question; (b) inclusion and exclusion criteria; (c) literature search; (d) data extraction; (e) assessment of risk of bias and reporting quality; (f) overview results; and (g) reporting the overview. Of special interest is how to address dependencies between the systematic reviews.

CONCLUSIONS

Overviews allow evidence to be efficiently combined from multiple systematic reviews. This offers the possibility of translating and summarizing large amounts of information. As in primary studies and systematic reviews, conducting and reporting of overviews must meet appropriate quality standards.

A Reliability Generalization Meta-analysis of the Padua Inventory-Revised (PI-R)

Background/Objective: The Padua Inventory-Revised (PI-R) is a widely applied instrument to measure obsessive-compulsive symptoms in clinical and nonclinical samples. We conducted a reliability generalization meta-analysis on the PI-R. Method: An exhaustive literature search yielded 118 empirical studies that had applied the PI-R, from which 30 studies (33 samples) reported an original reliability estimate. Results: Assuming a random-effects model, the average internal consistency reliability (Cronbach's alpha) was .92 (95% CI [.91, .93]) for the total scores, and ranged from .74 to .89 for the subscales. Assuming mixed-effects models, moderator analyses showed a positive statistically significant association between the standard deviation of the total scores and the reliability coefficients (p = .002; R² = .38). Conclusions: In terms of reliability, the PI-R scale was found to be adequate for both research and clinical purposes, although exhibiting large heterogeneity across studies. Future empirical studies using the PI-R should be required to provide at least one reliability estimate based on their own data.

The association of telomere length with substance use disorders: a systematic review and meta-analysis of observational studies

BACKGROUND AND AIMS

Several recent studies have investigated the relationship between telomere length and substance use disorders with inconsistent results. We aimed to assess this association and to identify moderators of the relationship.

METHODS

Systematic review and meta-analysis. Selection criteria were observational studies reporting telomere length in people with a substance use disorder compared with a control group. Studies focused solely on nicotine addiction, employing other study designs, and non-human studies were excluded. Study selection and data extraction were independently conducted by two researchers following a standardized protocol and included studies until December 2019. Standardized mean differences were used as the effect size index [d; 95% confidence interval (CI)] and random-effects models were used for the meta-analysis. Cochran's Q-statistic, I² index, visual inspection of the forest plot and a 95% prediction interval were applied to verify study heterogeneity. Subgroup analyses and meta-regressions were conducted to explore heterogeneity. Small study effects were examined using the 'funnel plot', the Egger test, Duval & Tweedie's trim-and-fill method and the precision-effect test-precision-effect estimate with standard error (PET-PEESE) method. The risk of bias and the quality of evidence were assessed.

RESULTS

Ten studies (12 analysis units with 2671 cases and 4532 controls) met the selection criteria. An overall effect size of moderate magnitude was found (d₊  = -0.63; 95% CI = -1.00 and -0.26; P = 0.0008). A potential small study effect was detected, as well as large heterogeneity between studies (Q-statistic P < 0.001, I²  = 97.3%). Selection of controls, reporting laboratory quality control procedures and total sample size significantly affected the effect size. The quality of the evidence was very low, based on risk of bias analysis and the grading of recommendations assessment, development and evaluation (GRADE) system.

CONCLUSIONS

People with substance use disorders appear to have shorter telomere length than controls; however, this finding should be interpreted with caution due to the poor quality of the evidence.

Concentrations of bisphenol-A in adults from the general population: A systematic review and meta-analysis

BACKGROUND

Human bisphenol-A (BPA) exposure has been linked to adverse health effects even at low doses, which may be of potential public health concern.

OBJECTIVE

To summarize BPA concentrations in general human population and their variability according to sex, geographic area, and analytical method.

METHODS

Systematic review and meta-analysis of studies reporting BPA concentrations in adult human populations. Separate meta-analyses of median values were carried out for BPA in serum, creatinine-adjusted urinary BPA, and unadjusted urinary BPA concentrations using a random-effects model. Cochran's Q-statistic, I² index, 95% prediction intervals (PIs), between-studies standard deviation (τ), and forest plots were applied to verify study heterogeneity. Sensitivity and subgroup analyses and weighted ANOVAs and meta-regressions were conducted. Funnel plots and Egger's tests were used to examine publication bias.

RESULTS

Fifteen studies were included in the meta-analysis, totaling 28,353 participants. BPA was detected in over 90% of participants. The pooled creatinine-adjusted urinary BPA concentration was 1.76 μg/g (95% PI: 0.79-2.73), with individual estimates ranging between 1.20 and 2.41. The pooled estimate for unadjusted urinary BPA was 1.91 μg/l (95% PI: 0-3.97), ranging between 0.81 and 3.50, while the pooled estimate for serum BPA was 1.75 μg/l (95% PI: 0-10.58), ranging between 0.34 and 3.76. No differences were found by sex, geographic area or analytical technique. Larger sample sizes were associated with lower BPA concentrations. There was large heterogeneity across studies, whereas data for urinary BPA levels suggested a publication bias affecting research in low exposed populations.

CONCLUSION

This first meta-analysis of human BPA concentrations highlights a widespread population exposure to BPA. Although there was high heterogeneity across studies, the expected range of estimated human BPA concentrations suggests that potential health risks are unlikely. Further studies are warranted to better characterize the epidemiology of human BPA exposure, accounting for ethnic, geographic, individual and environmental variability.

A Meta-analysis of Gut Microbiota in Children with Autism

Previous studies have reported dysbiosis in the gut microbiota (GM) of children with autism spectrum disorders (ASD), which may be a determining factor on child development through the microbiota-gut-brain axis. However, it is not clear if there is a specific group of dysbiotic bacteria in ASD. The aim of this study was to carry out a meta-analysis on the studies that analyze GM in children with ASD. 18 studies fulfilled our selection criteria. Our results showed a lower relative abundance of Streptococcus (SMD₊ = - 0.999; 95% CI - 1.549, - 0.449) and Bifidobacterium genera (SMD₊ = - 0.513; 95% CI - 0.953, - 0.073) in children with ASD. Overall, the Bifidobacterium genera is involved. However, differences found between studies are attributed to factors such as reporting bias.

Persistent Moderate-to-Weak Mediterranean Diet Adherence and Low Scoring for Plant-Based Foods across Several Southern European Countries: Are We Overlooking the Mediterranean Diet Recommendations?

The Mediterranean diet (MD) has been sponsored worldwide as a healthy and sustainable diet. Our aim was to update and compare MD adherence and food choices across several Southern European countries: Spain (SP), Portugal (PT), Italy (IT), Greece (GR), and Cyprus (CY) (MED, Mediterranean), and Bulgaria (BG) and the Republic of North Macedonia (NMK) (non-MED, non-Mediterranean). Participants (N = 3145, ≥18 y) completed a survey (MeDiWeB) with sociodemographic, anthropometric, and food questions (14-item Mediterranean Diet Adherence Screener, 14-MEDAS). The MED and non-MED populations showed moderate (7.08 ± 1.96) and weak (5.58 ± 1.82) MD adherence, respectively, with significant yet small differences across countries (SP > PT > GR > IT > CY > BG > NMK, p-value < 0.001). The MED participants scored higher than the non-MED ones for most of the Mediterranean-typical foods, with the greatest differences found for olive oil (OO) and white meat preference. In most countries, ≥70% of the participants reported quantities of red meat, butter, sweet drinks, and desserts below the recommended cutoff points, whereas <50% achieved the targets for plant-based foods, OO, fish, and wine. Being a woman and increasing age were associated with superior adherence (p-value < 0.001), but differences were rather small. Our results suggest that the campaigns carried out to support and reinforce the MD and to promote plant-based foods have limited success across Southern Europe, and that more hard-hitting strategies are needed.

Homicide as a Source of Posttraumatic Stress?: A Meta-Analysis of the Prevalence of Posttraumatic Stress Disorder After Committing Homicide

There is a growing body of literature on the diagnosis of posttraumatic stress disorder (PTSD) after committing homicide that has examined the prevalence of this phenomenon among individuals who have been convicted, but these studies considerably vary. The present study was the first meta-analysis to synthesize scientific evidence regarding the prevalence of offense-related PTSD among convicted killers. A total of 691 articles were identified through an initial screening process, and the final analysis included 11 studies that met the analysis criteria. We examined the prevalence of PTSD after committing homicide and explored how these rates varied by sample type, offender type, diagnosis timeframe, and diagnosis type. Among adult offenders, the pooled prevalence was 42.6%, 95% CI [38.0%, 47.4%], for current full-criteria homicide-related PTSD and 13.1%, 95% CI [9.9%, 17.2%], for current partial-criteria homicide-related PTSD. For mixed offenders (i.e., killers and violent offenders), the pooled prevalence of current full-criteria offense-related PTSD was 33.1% (95% CI [14.1, 59.8]). Thus, we found that PTSD prevalence was higher in killers than mixed offenders, although this difference was not statistically significant. Finally, among youth mixed offenders, the pooled prevalence for current full-criteria offense-related PTSD was 5.3%, 95% CI [2.9%, 9.5%]. These findings provide evidence of the high rate of this phenomenon, especially among convicted adults.

Improving the reporting quality of reliability generalization meta-analyses: The REGEMA checklist

Reliability generalization (RG) is a meta-analytic approach that aims to characterize how reliability estimates from the same test vary across different applications of the instrument. With this purpose RG meta-analyses typically focus on a particular test and intend to obtain an overall reliability of test scores and to investigate how the composition and variability of the samples affect reliability. Although several guidelines have been proposed in the meta-analytic literature to help authors improve the reporting quality of meta-analyses, none of them were devised for RG meta-analyses. The purpose of this investigation was to develop REGEMA (REliability GEneralization Meta-Analysis), a 30-item checklist (plus a flow chart) adapted to the specific issues that the reporting of an RG meta-analysis must take into account. Based on previous checklists and guidelines proposed in the meta-analytic arena, a first version was elaborated by applying the nominal group methodology. The resulting instrument was submitted to a list of independent meta-analysis experts and, after discussion, the final version of the REGEMA checklist was reached. In a pilot study, four pairs of coders applied REGEMA to a random sample of 40 RG meta-analyses in Psychology, and results showed satisfactory inter-coder reliability. REGEMA can be used by: (a) meta-analysts conducting or reporting an RG meta-analysis and aiming to improve its reporting quality; (b) consumers of RG meta-analyses who want to make informed critical appraisals of their reporting quality, and (c) reviewers and editors of journals who are considering submissions where an RG meta-analysis was reported for potential publication.

The heritability of insomnia: Systematic review and meta-analysis of twin studies

Twin studies have consistently found that genetic factors explain a substantial proportion of the variance for insomnia. However, studies vary widely in their heritability estimates. Therefore, this meta-analysis aimed to: 1) Estimate the mean heritability of insomnia; 2) Assess heterogeneity among twin studies of insomnia; and 3) Search and analyse characteristics of the studies (moderator variables) that may explain heterogeneity among estimates. For this purpose, separate meta-analyses were carried out for MZ and DZ correlations and for heritability estimates by assuming random-effects models. Thirteen independent samples were included in this meta-analysis. The heterogeneity index for heritability estimates was significant in both best fitting models (I² = 98.77, P < .0001) and full models (I² = 97.80, P < .0001). MZ correlations were higher (0.37; 95%CI: 0.31,.43) than DZ correlations (0.15; 95%CI: 0.12,.18). A mean heritability of 0.39 (95%CI: 0.32,.44) was found for insomnia. These results highlight the role of genetic factors in explaining differences among the population on insomnia and Emphasize heterogeneity among studies. Further research is needed to identify variables that could explain this heterogeneity.

Craniofacial morphology in down syndrome: a systematic review and meta-analysis

The aim of this study was to evaluate the craniofacial cephalometric characteristics of individuals with Down syndrome (DS), comparing them with healthy subjects. An electronic search was made in Pubmed, Embase, Lilacs, Scopus, Medline and Web of Science without imposing limitations on publication date or language. Studies were selecting following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. The PECO acronym was applied as follows: P (population), individuals with DS; E, (exposition) diagnosis of DS; C (comparison), individuals without DS; O (outcomes) craniofacial characteristics based on cephalometric measurements. Independent reviewers performed data extraction and assessed the methodological quality of the articles using the Newcastle–Ottawa Quality-Assessment-scale. Seven case–control studies were included in meta-analysis. Given the variability of the cephalometric measurements used, only those that had been reported in at least three or more works could be included. Anterior cranial base length (SN), posterior cranial base length (SBa), total cranial base length (BaN), effective length of the maxilla (CoA), sagittal relationship between subspinale and supramentale (ANB), anterior facial height (NMe), and posterior facial height (SGo) values were significantly lower in the DS population than among control subjects. No significant differences were found in sagittal position of subspinale relative to cranial base (SNA) and sagittal position of supramentale relative to cranial base (SNB). Summarizing, individuals with DS present a shorter and flatter cranial base than the general population, an upper jaw of reduced sagittal dimension, as well as a tendency toward prognatic profile, with the medium third of the face flattened and a reduced anterior and posterior facial heights.

Suicide and dementia: Systematic review and meta-analysis

INTRODUCTION

To analyse the possible relationship between dementia in the elderly and the subsequent development of suicide ideation, attempts and / or completed suicides.

METHODS

Systematic review and meta-analysis.

SELECTION CRITERIA

studies that analysed the relationship between dementia and suicide.

SEARCH STRATEGY

i) in PubMed, EMBASE, CINAHL, IME and Lilacs until December 2018; ii) manual search of the bibliography of selected articles; iii) contact with leading authors. Article selection and data extraction according to a predefined protocol, including bias risk assessment, were performed by independent peer reviewers. The effect size index was calculated using Odds Ratio (OR) and its 95% confidence interval (random-effects model). Heterogeneity was evaluated with forest plots, Cochran's Q and I² index. Assessment of publication bias using funnel plots ("trim-and-fill" method) and the Egger test. The analysis of moderating variables was performed using a multiple meta-regression under a mixed-effects model.

RESULTS

37 studies and 47 basic units of study were identified. Effect size of the association of dementia with: Suicidal Ideation OR = 1.37 (95% CI: .78-2.39); Suicide Attempt: OR = 2.24 (95% CI: 1.01-4.97); and Completed Suicide: OR = 1.28 (95% CI: .77-2.14). Possible publication bias was ruled out.

CONCLUSIONS

A trend towards suicidal events is identified, especially suicide attempts in people with dementia. Greater attention and care are recommended after a recent diagnosis of dementia, especially with adequate assessment of comorbidities, which could influence the occurrence and outcome of suicidal events.

A Meta-Analysis of the Reliability of Four Field-Based Trunk Extension Endurance Tests

This meta-analysis aimed to estimate the inter- and intra-tester reliability of endurance measures obtained through trunk extension field-based tests and to explore the influence of the moderators on the reliability estimates. The reliability induction rate of trunk extension endurance measures was also calculated. A systematic search was conducted using various databases, and subsequently 28 studies were selected that reported intraclass correlation coefficients for trunk extension endurance measures. Separate meta-analyses were conducted using a random-effects model. When possible, analyses of potential moderator variables were carried out. The inter-tester average reliability of the endurance measure obtained from the Biering-Sorensen test was intraclass correlation coefficient (ICC) = 0.94. The intra-session reliability estimates of the endurance measures recorded using the Biering-Sorensen test, the prone isometric chest raise test, and the prone double straight-leg test were ICC = 0.88, 0.90, and 0.86, respectively. The inter-session average reliability of the endurance measures from the Biering-Sorensen test, the prone isometric chest raise test, and the dynamic extensor endurance test were ICC = 0.88, 0.95, and 0.99, respectively. However, due to the limited evidence available, the reliability estimates of the measures obtained through the prone isometric chest raise, prone double straight-leg, and dynamic extensor endurance tests should be considered with a degree of caution. Position control instruments, tools, and familiarization session demonstrated a statistical association with the inter-session reliability of the Biering-Sorensen test. The reliability induction rate was 72.8%. Only the trunk extension endurance measure obtained through the Biering-Sorensen test presented sufficient scientific evidence in terms of reliability to justify its use for research and practical purposes.

Success rate of proximal tooth-coloured direct restorations in primary teeth at 24 months: a meta-analysis

The aim was to determine the survival of tooth-coloured restorative materials in proximal restorations of primary teeth at 24 months of follow-up and the influence of the following variables: use of coating, use of cavity conditioner, use of rubber dam isolation, the cavity form, the dentist's experience and the methodological characteristics of the studies. We conducted a search until May 2019, obtaining 16 articles from which 30 independent studies were extracted, which were considered as units of analysis. Four outcome measures were extracted from each study: retention, marginal integrity, anatomic form, and absence of recurrent caries. Separate meta-analyses were carried for each outcome and multiple meta-regression model was applied. The outcomes with the highest mean success rates were absence of recurrent caries and anatomic form. The type of material significantly influenced success rates. The best materials were resin-based material plus total-etching adhesion and resin-modified glass ionomer cement (RMGIC), and the worst high viscosity glass ionomer cement (HVGIC). Atraumatic restorative treatment (ART) had a lower success rate than the conventional cavity form. RMGIC had the best clinical performance and HVGIC the worst. The form of the cavity, blinding and the experience of the operator were the variables that influenced success rates. Proximal primary molar restorations should be performed with RMGIC as it combines good mechanical performance of the resins together with the prevention of secondary caries of glass ionomers.

Efficacy of Nonpharmacological Treatments on Comorbid Internalizing Symptoms of Adults With Attention-Deficit/Hyperactivity Disorder: A Meta-Analytic Review

Background: Attention-deficit/hyperactivity disorder (ADHD) is highly comorbid in adulthood. This meta-analysis was aimed at ascertaining the efficacy of different psychotherapies in improving comorbid internalizing symptoms in adults with ADHD. Method: Twenty randomized controlled trials and 12 uncontrolled pretest-posttest studies were included and combined using the inverse variance method. Risk of bias and heterogeneity assessment and moderator analyses were performed. Results: Cognitive-behavioral therapy (CBT) improved quality of life (QoL), emotional dysregulation (ED), depression, and anxiety symptoms, particularly at follow-up, which was predicted by core symptoms reduction. A significant between-group effect was obtained only on QoL, ED, and self-esteem for dialectical behavior therapy (DBT), mindfulness-based therapies (MBTs), and neurofeedback, respectively. Conclusion: Results support CBT efficacy for treating comorbid internalizing symptoms. More research is needed to determine the effectiveness of DBT, MBT, and neurofeedback. The small number of studies evaluating some therapies and the high risk of bias observed might limit these results.

The association of telomere length with substance use disorders: systematic review and meta-analysis protocol

BACKGROUND

The present protocol was designed for a systematic review and meta-analysis aimed at determining the association of telomere length with substance use disorders with the exclusion of nicotine addiction, and to identify potential moderators of the effect of telomere length. Such methodological information may provide guidance to improve the quality of future research on this important topic.

METHODS

Potential studies will be identified through electronic databases (PubMed/MEDLINE, EMBASE, PsycINFO, and Web of Science) up from inception onwards. The inclusion criteria will include published or unpublished observational studies (cohort, case-control, and cross-sectional studies) reporting telomere length in adult patients with substance use disorder compared with a control group. Non-human studies or other study designs such as reviews, case-only, family-based, and/or population studies with only healthy participants will be excluded, as well as those focused solely on nicotine addiction. The main outcome will be telomere length in adults with substance use disorder (primary) and, specifically, in those with alcohol use disorder (secondary). Two investigators will independently evaluate the preselected studies for possible inclusion and will extract data following a standardized protocol. Disagreements will be resolved by consensus. The risk of bias of all included studies will be assessed using the Newcastle-Ottawa Quality Assessment Scale for non-randomized studies. Data will be converted into standardized mean differences as effect size index, and random-effects models will be used for the meta-analysis. Cochran's Q statistic, I² index, and visual inspection of the forest plot will be used to verify study heterogeneity. Subgroup analyses and meta-regressions will be conducted to ascertain heterogeneity. Several sensitivity analyses will be conducted to address the influence of potential confounding factors. Publication bias will be examined using the "funnel plot" method with Duval and Tweedie's trim-and-fill method and Egger test.

DISCUSSION

This systematic review will assess the association of telomere length with substance use disorders aside from nicotine addiction.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42019119785.

Effects of the Best Possible Self intervention: A systematic review and meta-analysis

The Best Possible Self (BPS) exercise promotes a positive view of oneself in the best possible future, after working hard towards it. Since the first work that attempted to examine the benefits of this intervention in 2001, studies on the BPS have grown exponentially and, currently, this is one of the most widely used Positive Psychology Interventions. However, little is yet known about its overall effectiveness in increasing wellbeing outcomes. Thus, the aim of this meta-analysis is to shed light on this question. A systematic literature search was conducted, and 29 studies (in 26 articles) met the inclusion criteria of empirically testing the intervention and comparing it to a control condition. In addition, BPS was compared to gratitude interventions in some of the included studies. A total of 2,909 participants were involved in the analyses. The outcome measures were wellbeing, optimism, depressive symptoms, and positive and negative affect. Results showed that the BPS is an effective intervention to improve wellbeing (d+ = .325), optimism (d+ = .334) and positive affect (d+ = .511) comparing to controls. Small effect sizes were obtained for negative affect and depressive symptoms. Moderator analyses did not show statistically significant results for wellbeing, except for a trend towards significance in the age of the participants (years) and the magnitude of the intervention (total minutes of practice). In addition, the BPS was found to be more beneficial for positive and negative affect than gratitude interventions (d+ = .326 and d+ = .485, respectively). These results indicate that the BPS can be considered a valuable Positive Psychology Intervention to improve clients' wellbeing, and it seems that it might be more effective for older participants and with shorter practices (measured as total minutes of practice).

The association between muscle dysmorphia and eating disorder symptomatology: A systematic review and meta-analysis

BACKGROUND AND AIMS

Research shows inconsistent findings about the link between muscle dysmorphia (MD) and eating disorder (ED) symptomatology. The aim of this study is to synthesize the scientific evidence available on this topic, the researchers conducted a systematic review and meta-analysis.

METHODS

The literature search enabled us to identify 39 published articles, which provided 36 independent estimations of the correlation between the two variables.

RESULTS

Our analysis found a positive association between MD and ED symptoms (r₊ = .36; 95% CI = 0.30, 0.41). Moderator analyses showed that the type of sample and the tools for assessing MD and ED were statistically associated with the MD-ED effect sizes. The methodological quality of the studies exhibited a positive, statistically significant association with the MD-ED effect sizes.

CONCLUSIONS

Higher levels of MD were related to greater ED symptomatology, but several study characteristics may moderate the association between the two variables. In this study, we discuss limitations and implications for clinical practice and future research.

Small-sized and well-enforced Marine Protected Areas provide ecological benefits for piscivorous fish populations worldwide

Many piscivorous fish species are depleted and/or threatened around the world. Marine Protected Areas (MPAs) are tools for conservation and fisheries management, though there is still controversy regarding the best design for increasing their ecological effectiveness. Here, on the basis of a weighted meta-analytical approach, we have assessed the effect of 32 MPAs, distributed worldwide, on the biomass and density of piscivorous fishes. We analysed the MPA features and the biological, commercial and ecological characteristics of fishes that may affect the response of species to protection. We found a positive effect on the biomass and density of piscivores inside MPAs. This effect was stronger for the biomass of medium-sized fishes (in relation to the maximum size reported for the species) and the density of large and gregarious species. The size of the no-take zone had a significant negative impact on both response variables and differed according to the level of enforcement, with smaller no-take zones having higher levels of enforcement. Thus, MPAs help to protect piscivorous fish species, with smaller, but well enforced reserves being more effective for the protection of the local populations of piscivorous fishes throughout the world.

The Relationship Between Internalized Homophobia and Intimate Partner Violence in Same-Sex Relationships: A Meta-Analysis

A meta-analysis was conducted to investigate the association between internalized homophobia and intimate partner violence (IPV) perpetration and victimization in same-sex relationships. The literature search and the application of the inclusion criteria made it possible to identify 10 studies, 2 of which were excluded due to missing data. Therefore, eight studies were finally included in the meta-analysis. The results showed positive and statistically significant associations between internalized homophobia and IPV perpetration and victimization, indicating that higher levels of internalized homophobia were related to higher levels of IPV. Specifically, the pooled effect size for the relationship between internalized homophobia and IPV perpetration (all forms), it was r₊ = .147, 95% confidence interval (CI) = [.079, .214]; for the association between internalized homophobia and physical/sexual IPV perpetration, it was r₊ = .166, 95% CI [.109, .221]; p < .0001; for the relationship between internalized homophobia and psychological IPV perpetration, it was r₊ = .145, 95% CI [.073, .216]; and for the association between internalized homophobia and any type of IPV victimization, it was r₊ = .102, 95% CI [.030, .173]. Implications of these results for clinical practice and future research are discussed.

A reliability generalization meta-analysis of the child and adolescent perfectionism scale

BACKGROUND

Perfectionism is a prevalent disposition of personality involved in the development and maintenance of a wide range of psychological disorders. The Child and Adolescent Perfectionism Scale (CAPS) is the most usually applied test to assess perfectionism in children and adolescents. This study aimed: (a) to conduct a reliability generalization meta-analysis to estimate the average reliability of the CAPS scores and to search for characteristics of the studies that may explain the variability among reliability estimates, and (b) to estimate the reliability induction rate of the CAPS.

METHOD

An exhaustive search allowed to select 56 studies that reported alpha coefficients with the data at hand for the CAPS.

RESULTS

The average alpha coefficients were 0.87, 0.84 and 0.83, respectively for the CAPS total score and its two subscales, Socially Prescribed Perfectionism (SPP) and Self-Oriented Perfectionism (SOP). Regarding O'Connor's version, the average reliability coefficients were 0.82, 0.74 and 0.73, respectively, for SPP, SOP-Critical and SOP-Strivings. Some study characteristics (ethnicity, language, mean age and standard deviation of the scores, psychometric vs applied) showed a statistical association with the reliability coefficients of SPP and SOP. The reliability induction rate was 29.8%.

LIMITATIONS

Due to the scarcity of studies, we could not examine the reliability scores of other versions of the CAPS and test-retest reliability.

CONCLUSIONS

In terms of reliability, the original version of the CAPS present better results than O'Connor's version. The original version of the CAPS is a reliable instrument to be employed with general research purposes, but not for clinical practice.

[Neuroticism and suicidal thoughts: a meta-analytic study]

BACKGROUND

There are conflicting results on the relationship between neuroticism and suicidal ideation in community population. The objectives of this study were to estimate the magnitude and direction of the association between neuroticism and suicide ideation, and to analyze the influence of moderator variables on the effect size.

METHODS

A systematic review and a meta-analysis were carried out. The search for studies was conducted in PubMed/MEDLINE, IME, Lilacs, CINAHL, and EMBASE, until January 2015. A manual search was also carried out and main researchers were contacted. The inclusion criteria were: (a) studies of the association between neuroticism and suicidal ideation; (b) observational and descriptive studies; (c) studies carried out with community population over 18 years; (d) in any geographic region; and (e) written in English, Spanish, French, Portuguese or Italian. The random-effects model was applied to obtain the mean effect size and to explore moderators.

RESULTS

Thirteen articles focused on the association between neuroticism and suicide ideation were included in the meta-analysis. The mean effect size was r+ = 0.446 (IC 95%: 0.266-0.595). Publication bias was discarded as a threat against the validity of the results. A predictive model was stablished with two moderator variables: gender and type of self-report to measure neuroticism.

CONCLUSIONS

Neuroticism can be considered as a risk factor for suicide ideation. This result is important to prevent both suicidal ideation and suicide behavior.

The Padua Inventory-Washington State University Revision of Obsessions and Compulsions: A Reliability Generalization Meta-Analysis

The Padua Inventory-Washington State University Revision (PI-WSUR) is a frequently used test to assess obsessive-compulsive symptoms in screening and clinical contexts. A reliability generalization meta-analysis was carried out to estimate the average reliability of the PI-WSUR scores and its subscales and to search for characteristics of the studies that can explain the heterogeneity among reliability coefficients. A total of 124 independent samples reported some coefficient alpha or test-retest correlation with the data at hand for the PI-WSUR scores. The average internal consistency reliability of the PI-WSUR total scores was .929 (95% CI [.922, .936]), and for the subscales, the means ranged from .792 to .900. The test-retest reliability for PI-WSUR total scores was .767 (95% CI [.700, .820]), with the subscales ranging from .540 to .790. Moderator analyses revealed a positive relationship between the standard deviation of PI-WSUR total scores and alpha coefficients, as well as higher reliability estimates for the original version of the test and for studies from North America. The reliability induction rate for the PI-WSUR was 53.7%. Regarding reliability, the PI-WSUR ranks among the best scales for assessing obsessive-compulsive symptoms. Internal consistency reliability was excellent for the PI-WSUR total score and good for the subscales.

Inter- and intra-rater reliability of the Modified Ashworth Scale: a systematic review and meta-analysis

INTRODUCTION

The Modified Ashworth Scale is the most widely clinical scale used to measure the increase of muscle tone. Reliability is not an immutable property of a scale and can vary as a function of the variability and composition of the sample to which it is administered. The best method to examine how the reliability of a test scores varies is by conducting a systematic review and meta-analysis of the reliability coefficients obtained in different applications of the test with the data at hand. The objectives of this systematic revision are: what is the mean inter- and intra-rater reliability of the Modified Ashworth Scale's scores in upper and lower extremities? Which study characteristics affect the reliability of the scores in this scale?

EVIDENCE ACQUISITION

The PubMed, Embase and CINAHL databases were searched from 1987 to February 2015. Two reviewers independently selected empirical studies published in English or in Spanish that applied the Modified Ashworth Scale and reported any reliability coefficient with the data at hand in children, adolescents or adults with spasticity.

EVIDENCE SYNTHESIS

Thirty-three studies reported any reliability estimate of Modified Ashworth Scale scores (N.=1065 participants). For lower extremities and inter-rater agreement, the mean intraclass correlation was ICC+=0.686 (95% CI: 0.563 and 0.780) and for kappa coefficients, κ+=0.360 (95% CI: 0.241 and 0.468); for intra-rater agreement: ICC+=0.644 (95% CI: 0.543 and 0.726) and κ+=0.488 (95% CI: 0.370 and 0.591). For upper extremities and inter-rater agreement: ICC+=0.781 (95% CI: 0.679 and 0.853) and κ+=0.625 (95% CI: 0.350 and 0.801); for intra-rater agreement: ICC+=0.748 (95% CI: 0.671 and 0.809) and κ+=0.593 (95% CI: 0.467 and 0.696). The type of design, the study focus, and the number of raters presented statistically significant relationships with ICC both for lower and upper extremities.

CONCLUSIONS

Inter- and intra-rater agreement for Modified Ashworth Scale scores was satisfactory. Modified Ashworth Scale' scores exhibited better reliability when measuring upper extremities than lower. Several characteristics of the studies were statistically associated to inter-rater reliability of the scores for lower and upper extremities.

Long-Term Efficacy of Psychosocial Treatments for Adults With Attention-Deficit/Hyperactivity Disorder: A Meta-Analytic Review

Background: Recent evidence suggests that psychosocial treatments, particularly cognitive-behavioral therapy (CBT), are effective interventions for adult attention deficit hyperactivity disorder (ADHD). The objective of this review was to determine the long-term efficacy of psychosocial interventions in improving clinically relevant variables, including ADHD core symptoms, clinical global impression (CGI), and global functioning. Methods: In total, nine randomized controlled trials and three uncontrolled single-group pretest-posttest studies were included. The data from these studies were combined using the inverse variance method. Heterogeneity and risk of bias were assessed. Subgroup analyses and meta-regressions were performed, to determine the influence of different potential moderator variables (risk of bias, medication status, follow-up length, therapy type and setting, and control group type) on effect size (ES) estimates. Results: Up to 680 of a total of 1,073 participants assessed pre-treatment were retained at follow-up. Treatment groups showed greater improvement than control groups in self-reported total ADHD symptoms, inattention, and hyperactivity/impulsivity, in addition to CGI and global functioning. Blind assessors also reported a large ES in within-subject outcomes. Studies using dialectical behavioral therapy (DBT) in a group setting, with active control matching, and that were rated as having an unclear risk of bias, achieved significantly lower ES estimates for most outcomes. Treatment effectiveness, according to the CGI measure, and global functioning were significantly increased when the percentage of medicated participants was greater. Conclusions: Our results indicate that the post-treatment gains reported in previous reviews are sustained for at least 12 months. Nevertheless, these results must be interpreted with caution, because of a high level of heterogeneity among studies and the risk of bias observed in the majority of outcomes. Thus, these findings indicate that psychological interventions are a highly valuable and stable clinical tool for the treatment of core symptoms and global functioning in adults with ADHD.

Analysis of categorical moderators in mixed-effects meta-analysis: Consequences of using pooled versus separate estimates of the residual between-studies variances

Subgroup analyses allow us to examine the influence of a categorical moderator on the effect size in meta-analysis. We conducted a simulation study using a dichotomous moderator, and compared the impact of pooled versus separate estimates of the residual between-studies variance on the statistical performance of the Q _B(P) and Q _B(S) tests for subgroup analyses assuming a mixed-effects model. Our results suggested that similar performance can be expected as long as there are at least 20 studies and these are approximately balanced across categories. Conversely, when subgroups were unbalanced, the practical consequences of having heterogeneous residual between-studies variances were more evident, with both tests leading to the wrong statistical conclusion more often than in the conditions with balanced subgroups. A pooled estimate should be preferred for most scenarios, unless the residual between-studies variances are clearly different and there are enough studies in each category to obtain precise separate estimates.

A Systematic Review and Meta-Analysis of the Effects of Flavanol-Containing Tea, Cocoa and Apple Products on Body Composition and Blood Lipids: Exploring the Factors Responsible for Variability in Their Efficacy

Several randomized controlled trials (RCTs) and meta-analyses support the benefits of flavanols on cardiometabolic health, but the factors affecting variability in the responses to these compounds have not been properly assessed. The objectives of this meta-analysis were to systematically collect the RCTs-based-evidence of the effects of flavanol-containing tea, cocoa and apple products on selected biomarkers of cardiometabolic risk and to explore the influence of various factors on the variability in the responses to the consumption of these products. A total of 120 RCTs were selected. Despite a high heterogeneity, the intake of the flavanol-containing products was associated using a random model with changes (reported as standardized difference in means (SDM)) in body mass index (−0.15, p < 0.001), waist circumference (−0.29, p < 0.001), total-cholesterol (−0.21, p < 0.001), LDL-cholesterol (−0.23, p < 0.001), and triacylglycerides (−0.11, p = 0.027), and with an increase of HDL-cholesterol (0.15, p = 0.005). Through subgroup analyses, we showed the influence of baseline-BMI, sex, source/form of administration, medication and country of investigation on some of the outcome measures and suggest that flavanols may be more effective in specific subgroups such as those with a BMI ≥ 25.0 kg/m², non-medicated individuals or by specifically using tea products. This meta-analysis provides the first robust evidence of the effects induced by the consumption of flavanol-containing tea, cocoa and apple products on weight and lipid biomarkers and shows the influence of various factors that can affect their bioefficacy in humans. Of note, some of these effects are quantitatively comparable to those produced by drugs, life-style changes or other natural products. Further, RCTs in well-characterized populations are required to fully comprehend the factors affecting inter-individual responses to flavanol and thereby improve flavanols efficacy in the prevention of cardiometabolic disorders.

Cognitive-behavioral high parental involvement treatments for pediatric obsessive-compulsive disorder: A meta-analysis

A meta-analysis on the efficacy of cognitive-behavior-family treatment (CBFT) on children and adolescents with obsessive-compulsive disorder (OCD) was accomplished. The purposes of the study were: (a) to estimate the effect magnitude of CBFT in ameliorating obsessive-compulsive symptoms and reducing family accommodation on pediatric OCD and (b) to identify potential moderator variables of the effect sizes. A literature search enabled us to identify 27 studies that fulfilled our selection criteria. The effect size index was the standardized pretest-postest mean change index. For obsessive-compulsive symptoms, the adjusted mean effect size for CBFT was clinically relevant and statistically significant in the posttest (d_adj=1.464). For family accommodation the adjusted mean effect size was also positive and statistically significant, but in a lesser extent than for obsessive-compulsive symptoms (d_adj=0.511). Publication bias was discarded as a threat against the validity of the meta-analytic results. Large heterogeneity among effect sizes was found. Better results were found when CBFT was individually applied than in group (d₊=2.429 and 1.409, respectively). CBFT is effective to reduce obsessive-compulsive symptoms, but offers a limited effect for family accommodation. Additional modules must be included in CBFT to improve its effectiveness on family accommodation.

A Reliability Generalization Meta-analysis of the Leyton Obsessional Inventory Child Version Survey Form

BACKGROUND

The Leyton Obsessional Inventory Child Version Survey Form (LOI-CV-SF) is a scale created in order to detect obsessive-compulsive symptoms and their effects on the daily lives of children and adolescents from ages 10 to 18 and for the screening of non-clinic infant population. With the purpose of estimating the reliability of the test scores, and how it varies in relation to the characteristics of the studies, a meta-analysis of reliability generalization was carried out.

METHODS

A meta-analysis was accomplished. An exhaustive research allowed to select 13 studies that reported some reliability estimate of the test scores and, through the KR-21 formula, this number was increased to 43 estimations of internal consistency reliability. Taking these coefficients, an estimation of the average reliability and analyses of the variables that could be affecting the heterogeneity of reliability coefficients was accomplished.

RESULTS

On average, the reliability by internal consistency of the symptom scale scores was 0.79 (95%CI:0.76 and 0.82), with minimum and maximum values of 0.52 and 0.97, respectively. A large heterogeneity was found (I2 = 96%).The predictive model identified the standard deviation of tests scores as the most relevant variable. The analysis of moderator variables revealed that, mainly, the standard deviation of the test scores is the most statistically related to the reliability, presenting a positive relationship with it.

CONCLUSIONS

The results of the LOI-CV-SF showed a satisfactory average reliability for research purposes, but not for clinical practice purposes.

The Yale–Brown Obsessive Compulsive Scale

The Yale–Brown Obsessive Compulsive Scale (Y-BOCS) is the most frequently applied test to assess obsessive compulsive symptoms. We conducted a reliability generalization meta-analysis on the Y-BOCS to estimate the average reliability, examine the variability among the reliability estimates, search for moderators, and propose a predictive model that researchers and clinicians can use to estimate the expected reliability of the Y-BOCS. We included studies where the Y-BOCS was applied to a sample of adults and reliability estimate was reported. Out of the 11,490 references located, 144 studies met the selection criteria. For the total scale, the mean reliability was 0.866 for coefficients alpha, 0.848 for test–retest correlations, and 0.922 for intraclass correlations. The moderator analyses led to a predictive model where the standard deviation of the total test and the target population (clinical vs. nonclinical) explained 38.6% of the total variability among coefficients alpha. Finally, clinical implications of the results are discussed.

A comparison of procedures to test for moderators in mixed-effects meta-regression models

Several alternative methods are available when testing for moderators in mixed-effects meta-regression models. A simulation study was carried out to compare different methods in terms of their Type I error and statistical power rates. We included the standard (Wald-type) test, the method proposed by Knapp and Hartung (2003) in 2 different versions, the Huber-White method, the likelihood ratio test, and the permutation test in the simulation study. These methods were combined with 7 estimators for the amount of residual heterogeneity in the effect sizes. Our results show that the standard method, applied in most meta-analyses up to date, does not control the Type I error rate adequately, sometimes leading to overly conservative, but usually to inflated, Type I error rates. Of the different methods evaluated, only the Knapp and Hartung method and the permutation test provide adequate control of the Type I error rate across all conditions. Due to its computational simplicity, the Knapp and Hartung method is recommended as a suitable option for most meta-analyses.

[Neuroticism and post-traumatic stress disorder: a meta-analytic study]

BACKGROUND

There are conflicting results on the role of neuroticism as a risk factor for post-traumatic stress disorder (PTSD). The objectives of this study were to estimate the magnitude and direction of the association between neuroticism and PTSD, and to analyze the influence of different moderator variables on effect size.

METHODS

A systematic review and a meta-analysis were carried out. The search for studies was conducted in Medline, IME, PsycINFO, Trip Database, and Google Scholar, until October 2012. A hand search was also carried out and main researchers were contacted.

INCLUSION CRITERIA

(a) empirical studies of the association between neuroticism and PTSD using validated scales or diagnostic criteria (DSM, ICD), (b) in participants exposed to a traumatic event and (c) written in English or Spanish. Two independent evaluators performed the selection and extracted the data following a previously developed protocol. The random-effects model was applied to obtain the mean effect size and to explore moderators.

RESULTS

Out of 96 potential articles, 34 fulfilled the inclusion criteria (9,941 participants). The mean effect size was r+ = 0.371 (95%CI: 0.327 and 0.414). Publication bias was discarded as a threat. A predictive model was elaborated with three variables (reporting of ethnicity, age, and type of sample).

CONCLUSION

Neuroticism can be considered as a risk factor for PTSD in people who have been exposed to a traumatic event. These findings are relevant for developing preventive interventions and treatments.

Estimation of the predictive power of the model in mixed-effects meta-regression: A simulation study

Several methods are available to estimate the total and residual amount of heterogeneity in meta-analysis, leading to different alternatives when estimating the predictive power in mixed-effects meta-regression models using the formula proposed by Raudenbush (1994, 2009). In this paper, a simulation study was conducted to compare the performance of seven estimators of these parameters under various realistic scenarios in psychology and related fields. Our results suggest that the number of studies (k) exerts the most important influence on the accuracy of the results, and that precise estimates of the heterogeneity variances and the model predictive power can only be expected with at least 20 and 40 studies, respectively. Increases in the average within-study sample size (N¯) also improved the results for all estimators. Some differences among the accuracy of the estimators were observed, especially under adverse (small k and N¯) conditions, while the results for the different methods tended to convergence for more optimal scenarios.

Differential efficacy of cognitive-behavioral therapy and pharmacological treatments for pediatric obsessive-compulsive disorder: a meta-analysis

The aim of this paper is to present a meta-analysis about the differential efficacy of cognitive-behavioral therapy (CBT), pharmacological and combined treatment for pediatric obsessive-compulsive disorder (OCD). The literature research and the application of the inclusion criteria enabled us to locate 18 studies, yielding a total of 24 independent comparisons between a treated (10 pharmacological, 11 CBT, and 3 combined interventions) and a control group. All types of interventions were efficacious in reducing obsessive-compulsive symptoms, with effect sizes adjusted by the type of control group of d=1.203 for CBT, d=0.745 for pharmacological treatments, and d=1.704 for mixed treatments. Depression, anxiety and other secondary responses were also improved, especially with CBT interventions. The analysis of moderator variables showed that the CBT protocol and the total of intervention hours exhibited a significant influence on the effect size. Within pharmacological treatment, clomipramine (d=1.305) was more efficacious than selective serotonin reuptake inhibitors (d=0.644), but its adverse effects were more severe. Finally, the clinical implications of the results are discussed.

Some recommended statistical analytic practices when reliability generalization studies are conducted

Precursors of the reliability generalization (RG) meta-analytic approach have not established a single preferred analytic method. By means of five real RG examples, we examine how using different statistical methods to integrate coefficients alpha can influence results in RG studies. Specifically, we compare thirteen different statistical models for averaging reliability coefficients and searching for moderator variables that differ in terms of: (a) whether to transform or not the coefficients alpha, and (b) the statistical model assumed, distinguishing between ordinary least squares methods, the fixed-effect (FE) model, the varying coefficient (VC) model, and several versions of the random-effects (RE) model. The results obtained with the different methods exhibited important discrepancies, especially regarding moderator analyses. The main criterion for the model choice should be the extent to which the meta-analyst intends to generalize the results. RE models are the most appropriate when the meta-analyst aims to generalize to a hypothetical population of past or future studies, while FE and VC models are the most appropriate when the interest focuses on generalizing the results to a population of studies identical to those included in the meta-analysis. Finally, some guidelines are proposed for selecting the statistical model when conducting an RG study.

[Prevalence of low back pain during childhood and adolescence: a systematic review]

BACKGROUND

Low back pain in children and adolescents is a significant public health problem and its presence at this stage increases the risk of LBP in adulthood. The objective of this study was to describe the prevalence of back pain in children and adolescents and assess the methodological quality of the studies.

METHODS

A systematic review of observational epidemiology was conducted. The databases ISI Web of Knowledge, MEDLINE, PEDro, IME, LILACS and CINAHL, hand searching and consultation with experts were used. Selection of included studies: results of prevalence rates in the sample; published or performed between 1980 and 2011; sample size of at least 50 subjects; 18 years or less and of any ethnicity. Moderating variables of the studies were coded by two authors. Analysis descriptive of frequency distributions, percentages, numbers of cases, and medium estimates for prevalence rates were performed.

RESULTS

59 articles were included. The mean age was 13.56, 51.15% males. The medians for point, period and lifetime LBP prevalence were respectively 13.60%, 24.75%, and 38.50%.

CONCLUSIONS

The prevalence of LBP increases with age. Sex influences the prevalence rates. The lack of an adequate definition and delimitation of low back pain and the absence of specifications such as frequency, duration, and intensity of pain were the most common methodological flaws in the studies.

Meta-analyses of the 5-HTTLPR polymorphisms and post-traumatic stress disorder

Objective

To conduct a meta-analysis of all published genetic association studies of 5-HTTLPR polymorphisms performed in PTSD cases

Methods Data Sources

Potential studies were identified through PubMed/MEDLINE, EMBASE, Web of Science databases (Web of Knowledge, WoK), PsychINFO, PsychArticles and HuGeNet (Human Genome Epidemiology Network) up until December 2011. Study Selection: Published observational studies reporting genotype or allele frequencies of this genetic factor in PTSD cases and in non-PTSD controls were all considered eligible for inclusion in this systematic review. Data Extraction: Two reviewers selected studies for possible inclusion and extracted data independently following a standardized protocol. Statistical analysis: A biallelic and a triallelic meta-analysis, including the total S and S' frequencies, the dominant (S+/LL and S'+/L'L') and the recessive model (SS/L+ and S'S'/L'+), was performed with a random-effect model to calculate the pooled OR and its corresponding 95% CI. Forest plots and Cochran's Q-Statistic and I² index were calculated to check for heterogeneity. Subgroup analyses and meta-regression were carried out to analyze potential moderators. Publication bias and quality of reporting were also analyzed.

Results

13 studies met our inclusion criteria, providing a total sample of 1874 patients with PTSD and 7785 controls in the biallelic meta-analyses and 627 and 3524, respectively, in the triallelic. None of the meta-analyses showed evidence of an association between 5-HTTLPR and PTSD but several characteristics (exposure to the same principal stressor for PTSD cases and controls, adjustment for potential confounding variables, blind assessment, study design, type of PTSD, ethnic distribution and Total Quality Score) influenced the results in subgroup analyses and meta-regression. There was no evidence of potential publication bias.

Conclusions

Current evidence does not support a direct effect of 5-HTTLPR polymorphisms on PTSD. Further analyses of gene-environment interactions, epigenetic modulation and new studies with large samples and/or meta-analyses are required.

Physical therapy treatments for low back pain in children and adolescents: a meta-analysis

Background

Low back pain (LBP) in adolescents is associated with LBP in later years. In recent years treatments have been administered to adolescents for LBP, but it is not known which physical therapy treatment is the most efficacious. By means of a meta-analysis, the current study investigated the effectiveness of the physical therapy treatments for LBP in children and adolescents.

Methods

Studies in English, Spanish, French, Italian and Portuguese, and carried out by March 2011, were selected by electronic and manual search. Two independent researchers coded the moderator variables of the studies, and performed the effect size calculations. The mean effect size index used was the standardized mean change between the pretest and posttest, and it was applied separately for each combination of outcome measures, (pain, disability, flexibility, endurance and mental health) and measurement type (self-reports, and clinician assessments).

Results

Eight articles that met the selection criteria enabled us to define 11 treatment groups and 5 control groups using the group as the unit of analysis. The 16 groups involved a total sample of 334 subjects at the posttest (221 in the treatment groups and 113 in the control groups). For all outcome measures, the average effect size of the treatment groups was statistically and clinically significant, whereas the control groups had negative average effect sizes that were not statistically significant.

Conclusions

Of all the physical therapy treatments for LBP in children and adolescents, the combination of therapeutic physical conditioning and manual therapy is the most effective. The low number of studies and control groups, and the methodological limitations in this meta-analysis prevent us from drawing definitive conclusions in relation to the efficacy of physical therapy treatments in LBP.

Prevalence of low back pain in children and adolescents: a meta-analysis

BACKGROUND

Low back pain (LBP) is common in children and adolescents, and it is becoming a public health concern. In recent years there has been a considerable increase in research studies that examine the prevalence of LBP in this population, but studies exhibit great variability in the prevalence rates reported. The purpose of this research was to examine, by means of a meta-analytic investigation, the prevalence rates of LBP in children and adolescents.

METHODS

Studies were located from computerized databases (ISI Web of Knowledge, MedLine, PEDro, IME, LILACS, and CINAHL) and other sources. The search period extended to April 2011. To be included in the meta-analysis, studies had to report a prevalence rate (whether point, period or lifetime prevalence) of LBP in children and/or adolescents (≤ 18 years old). Two independent researchers coded the moderator variables of the studies, and extracted the prevalence rates. Separate meta-analyses were carried out for the different types of prevalence in order to avoid dependence problems. In each meta-analysis, a random-effects model was assumed to carry out the statistical analyses.

RESULTS

A total of 59 articles fulfilled the selection criteria. The mean point prevalence obtained from 10 studies was 0.120 (95% CI: 0.09 and 0.159). The mean period prevalence at 12 months obtained from 13 studies was 0.336 (95% CI: 0.269 and 0.410), whereas the mean period prevalence at one week obtained from six studies was 0.177 (95% CI: 0.124 and 0.247). The mean lifetime prevalence obtained from 30 studies was 0.399 (95% CI: 0.342 and 0.459). Lifetime prevalence exhibited a positive, statistically significant relationship with the mean age of the participants in the samples and with the publication year of the studies.

CONCLUSIONS

The most recent studies showed higher prevalence rates than the oldest ones, and studies with a better methodology exhibited higher lifetime prevalence rates than studies that were methodologically poor. Future studies should report more information regarding the definition of LBP and there is a need to improve the methodological quality of studies.