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.