Greater Effect Size Research Articles

Thiazolidinedione therapy and breast cancer risk in diabetic women: A systematic review and meta-analysis.

Rising experimental evidence suggests that thiazolidinediones (TZDs) exert a protective effect on breast cancer. However, studies concerning this issue were inconsistent and limited. Hence, we performed a meta-analysis with data from currently available studies to evaluate the effect of TZDs on breast cancer risk among diabetic women. We comprehensively searched for all pertinent studies addressing TZDs use and breast cancer risk published before January 1, 2016, in PubMed, Clinical Trials, and Cochrane Library. Data synthesis was performed in a random-effects model using Stata version 12.0 (Stata Corp, College Station, Texas). Fourteen independent studies were eventually selected in this meta-analysis, including 5 randomized controlled clinical trials (RCTs), 7 cohort studies, and 2 case-control studies. No significant associations of TZD use and risk of breast cancer were observed in the RCTs (pooled risk ratio [RR]: 0.77, 95% confidence interval (CI), 0.39-1.53, I2 =26%) or case-control studies (pooled odds ratio, 0.99, 95% CI, 0.76-1.28, I2 =31%). A 19% reduction in breast cancer risk (pooled RR: 0.81, 95% CI, 0.66-0.99, I2 =72%) was found in the cohort studies. However, after removing the study with the smallest event number and the greatest effect size, the association became nonsignificant with greatly decreased heterogeneity (pooled RR: 0.94, 95% CI, 0.86-1.03, I2 =16%). This meta-analysis did not find any significant association between TZDs use and risk of breast cancer among diabetic women.

Accuracy of various impression materials and methods for two implant systems: An effect size study

PurposeAn accurate impression is required for implant treatment. The aim of this in-vitro study was to determine the effect size of the impression material/method, implant system and implant angulation on impression transfer precision. MethodsAn upper jaw model with three BEGO and three Straumann implants (angulations 0°, 15°, 20°) in the left and right maxilla was used as a reference model. One polyether (Impregum Penta) and two polyvinyl siloxanes (Flexitime Monophase/Aquasil Ultra Monophase) were examined with two impression techniques (open and closed tray). A total of 60 impressions were made. A coordinate measurement machine was used to measure the target variables for 3D-shift, implant axis inclination and implant axis rotation. All the data were subjected to a four-way ANOVA. The effect size (partial eta-squared [η2P]) was reported. ResultsThe impression material had a significant influence on the 3D shift and the implant axis inclination deviation (p-values=.000), and both factors had very large effect sizes (3D-shift [η2P]=.599; implant axis inclination [η2P]=.298). Impressions made with polyvinyl siloxane exhibited the highest transfer precision. When the angulation of the implants was larger, more deviations occurred for the implant axis rotational deviation. The implant systems and impression methods showed partially significant variations (p-values=.001–.639) but only very small effect sizes (η2P=.001–.031). ConclusionsThe impression material had the greatest effect size on accuracy in terms of the 3D shift and the implant axis inclination. For multiunit restorations with disparallel implants, polyvinyl siloxane materials should be considered. In addition, the effect size of a multivariate investigation should be reported.

Footwear effects on free moment application in running

The free moment is considered an important variable during running in lower extremity transverse plane loading of the support leg. The effect of current footwear technology on free moment application has not been widely studied despite evidence that greater free moment amplitudes may be related to common lower extremity overuse injuries. Therefore, the purpose of this study was to determine the effect of current running shoe types on the free moment application in running and to identify which design features specifically influence free moment waveforms. The free moments and lower extremity kinematics of 103 recreational runners were collected when running at 3.5 m/s using force plates embedded in the ground. Six conditions were analysed, ranging from minimalistic to motion-control footwear. Runners were classified into three groups of different free moment pattern using functional principal component and cluster analysis techniques. The results revealed that the free moment application can be affected by footwear technologies used in modern running shoes. Nonetheless, the free moment application was influenced to a greater extent by the overall running technique highlighted by the greater effect sizes for pattern membership compared to footwear effects. Footwear may affect the free moment application as a function of its torsional flexibility and to a lesser extent by means of motion-control features. Future studies should address the effect of footwear design features (such as shoe-mass and traction) on free moment application in greater detail to improve the running style with respect to injury prevention and performance enhancement.

Imaging of Cerebrovascular Function in Chronic Traumatic Brain Injury.

Traumatic cerebrovascular injury (TCVI) is a common pathologic mechanism of traumatic brain injury (TBI) and presents an attractive target for intervention. The aims of this study were to assess cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) using magnetic resonance imaging (MRI) to assess their value as biomarkers of TCVI in chronic TBI, characterize the spatial distribution of TCVI, and assess the relationships between each biomarker and neuropsychological and clinical assessments. Forty-two subjects (27 chronic TBI, 15 age- and gender-matched healthy volunteers) were studied cross-sectionally. CBF was measured by arterial spin labeling and CVR by assessing the MRI-blood oxygen level-dependent signal with hypercapnia challenge. A focused neuropsychological battery adapted from the TBI Common Data Elements and neurobehavioral symptom questionnaires were administered at the time of the imaging session. Chronic TBI subjects showed a significant reduction in mean global, gray matter (GM), and white matter (WM) CVR, compared with healthy volunteers (p < 0.001). Mean GM CVR had the greatest effect size (Cohen's d = 0.9). CVR maps in chronic TBI subjects showed patchy, multifocal CVR deficits. CBF discriminated poorly between TBI subjects and healthy volunteers and did not correlate with CVR. Mean global CVR correlated best with chronic neurobehavioral symptoms among TBI subjects. Global, GM, and WM CVR are reliable and potentially useful biomarkers of TCVI in the chronic stage after moderate-to-severe TBI. CBF is less useful as biomarker of TCVI. CVR correlates best with chronic TBI symptoms. CVR has potential as a predictive and pharmacodynamic biomarker for interventions targeting TCVI.

Hypertrophic Effects of Concentric vs. Eccentric Muscle Actions: A Systematic Review and Meta-analysis.

Schoenfeld, BJ, Ogborn, DI, Vigotsky, AD, Franchi, MV, and Krieger, JW. Hypertrophic effects of concentric vs. eccentric muscle actions: A systematic review and meta-analysis. J Strength Cond Res 31(9): 2599-2608, 2017-Controversy exists as to whether different dynamic muscle actions produce divergent hypertrophic responses. The purpose of this paper was to conduct a systematic review and meta-analysis of randomized controlled trials comparing the hypertrophic effects of concentric vs. eccentric training in healthy adults after regimented resistance training (RT). Studies were deemed eligible for inclusion if they met the following criteria: (a) were an experimental trial published in an English-language refereed journal; (b) directly compared concentric and eccentric actions without the use of external implements (i.e., blood pressure cuffs) and all other RT variables equivalent; (c) measured morphologic changes using biopsy, imaging (magnetic resonance imaging, computerized tomography, or ultrasound), bioelectrical impedance, and/or densitometry; (d) had a minimum duration of 6 weeks; and (e) used human participants without musculoskeletal injury or any health condition that could directly, or through the medications associated with the management of said condition, be expected to impact the hypertrophic response to resistance exercise. A systematic literature search determined that 15 studies met inclusion criteria. Results showed that eccentric muscle actions resulted in a greater effect size (ES) compared with concentric actions, but results did not reach statistical significance (ES difference = 0.25 ± 0.13; 95% confidence interval: -0.03 to 0.52; p = 0.076). The mean percent change in muscle growth across studies favored eccentric compared with concentric actions (10.0% vs. 6.8, respectively). The findings indicate the importance of including eccentric and concentric actions in a hypertrophy-oriented RT program, as both have shown to be effective in increasing muscle hypertrophy.

Association of Dynamic Changes in the CD4 T-Cell Transcriptome With Disease Severity During Primary Respiratory Syncytial Virus Infection in Young Infants.

Nearly all children are infected with respiratory syncytial virus (RSV) within the first 2 years of life, with a minority developing severe disease (1%-3% hospitalized). We hypothesized that an assessment of the adaptive immune system, using CD4+ T-lymphocyte transcriptomics, would identify gene expression correlates of disease severity. Infants infected with RSV representing extremes of clinical severity were studied. Mild illness (n = 23) was defined as a respiratory rate (RR) < 55 and room air oxygen saturation (SaO2) ≥ 97%, and severe illness (n = 23) was defined as RR ≥ 65 and SaO2 ≤ 92%. RNA from fresh, sort-purified CD4+ T cells was assessed by RNA sequencing. Gestational age, age at illness onset, exposure to environmental tobacco smoke, bacterial colonization, and breastfeeding were associated (adjusted P < .05) with disease severity. RNA sequencing analysis reliably measured approximately 60% of the genome. Severity of RSV illness had the greatest effect size upon CD4 T-cell gene expression. Pathway analysis identified correlates of severity, including JAK/STAT, prolactin, and interleukin 9 signaling. We also identified genes and pathways associated with timing of symptoms and RSV group (A/B). These data suggest fundamental changes in adaptive immune cell phenotypes may be associated with RSV clinical severity.

Interventions affecting mortality in critically ill and perioperative patients: A systematic review of contemporary trials

PurposeConfounders in randomized controlled trials (RCTs) reporting significant effects on mortality in critically ill patients using non-surgical techniques have not been systematically explored. We aimed to identify factors unrelated to the reported intervention that might have affected the findings and robustness of such trials. MethodsWe searched Pubmed/MEDLINE for all RCTs on any non-surgical interventions reporting an effect on unadjusted mortality in critically ill patients between 1/1/2000 and 1/12/2015. We assessed: the number needed to treat/harm (NNT or NNH), sample size, trial design (blinded/unblinded, single or multinational, single or multicenter (sRCT or mRCT)), intention to treat (ITT) analysis, and countries of origin. ResultsAlmost half of RCTs were sRCTs. Median sample size was small, and 1/3 were not analyzed according to ITT principle. Lack of ITT analysis was associated with greater effect size (p=0.0028). Harm was more likely in mRCTs (p=0.002) and/or in blinded RCTs (p=0.003). Blinded RCTs had double sample size (p=0.007) and an increased NNT/NNH (p=0.002). Finally, mRCTs had higher NNT (p=0.005) and NNH (p=0.02), and harm was only detected in studies from Western countries (p=0.007). ConclusionsThese observations imply that major systematic biases exist and affect trial findings irrespective of the intervention being studied.

A Multicollinearity and Measurement Error Statistical Blind Spot: Correcting for Excessive False Positives in Regression and PLS

Multiple regression has a previously unrecognized statistical blind spot because when multicollnearity and measurement error are present, both path estimates and variance inflation factors are biased. This can result in overestimated t-statistics, and excessive false positives. PLS has the same weakness, but CB-SEM's estimation process accounts for measurement error, avoiding the problem. Bringing together partial insights from a range of disciplines to provide a more comprehensive treatment of the problem, we derive equations showing false positives will increase with greater multicollinearity, lower reliability, greater effect size in the dominant correlated construct, and, surprisingly, with higher sample size. Using Monte Carlo simulations, we show that false positives increase as predicted. We also provide a correction for the problem. A literature search found that of IS research papers using regression or PLS for path analysis, 33% were operating in this danger zone. Our findings are important not only for IS, but for all fields using regression or PLS in path analysis.

Consumer perceptions of electric utilities: Insights from the Center for Analytics Research & Education Project in the United States

The Environmental Protection Agency’s Clean Power Plan calls for government entities, business organizations and citizen groups to reduce use of “dirty energy” and related carbon pollution. Peak power consumption is associated with dirty energy sources. The Center for Analytics Research & Education (CARE) at Appalachian State University in Boone, North Carolina, is developing predictive models for peak energy spikes, so that corrective action can reduce power use. This study supports the CARE initiative and explores consumer perception of power providers. Results allow practitioners to influence peak power use reduction through targeted messaging in marketing and promotions campaigns. Factor analysis revealed the psychological dimensions “Good Citizen,” “Detrimental Citizen,” “Corporate Machine” and “Environmental Partner.” A 9-item Perception of Power Provider Scale was introduced. Correlated items with the greatest effect size were “My power company provides a bill for services that is easy to understand” with “I am pleased with the customer service provided by my power company.” It is suggested that power providers partner with university researchers to develop proprietary social science research. Results can be framed to craft a communication agenda that resonates with target customer groups. Developing a narrative that originates in a psychological understanding of consumer perception can affect change.

Selection of an optimal set of biomarkers and comparative analyses of biological age estimation models in Korean females

To date, an optimal working model which predicts biological age (BA) with a set of working biomarkers has not been devised to represent the Korean female population. Accuracy of prediction and applicability are required of an optimal set of commonly assessed biomarkers to provide information on the health status. The goal of this study was to identify a set of biomarkers that represent the aging process and to develop and compare different BA prediction models to elucidate the most fitting and applicable model for providing information on health status in the Korean female population. Using a series of selection processes, eight clinically assessable variables were selected by analyzing relations between 31 clinical variables and chronologic age in 912 normal, healthy individuals among 3642 female participants with ages ranging from 30 to 80 years. The multiple linear regression (MLR), principal component analysis (PCA), and the Klemera-Doubal (KDM) statistical methods were applied to obtain three different sets of BA prediction models. These three models were assessed by calculating and performing the coefficient determinations (r2), regression slopes, effect sizes, pairwise t-tests, and Bland-Altman plots. The BA models were further compared for the applicability by calculating the BAs of clinical risk groups. MLR showed the narrowing effects at the either ends of the age spectrum with greatest effect sizes. PCA showed the greatest degree of dispersion and deviation from the regression center. These MLR and PCA trends were also exhibited by clinically risk groups. In conclusion, the KDM BA prediction model based on the selected biomarkers was found to provide the most reliable and stable results for the practical assessment of BA.

Results of Database Studies in Spine Surgery Can Be Influenced by Missing Data.

National databases are increasingly being used for research in spine surgery; however, one limitation of such databases that has received sparse mention is the frequency of missing data. Studies using these databases often do not emphasize the percentage of missing data for each variable used and do not specify how patients with missing data are incorporated into analyses. This study uses the American College of Surgeons National SurgicalQuality Improvement Program (ACS-NSQIP) database to examine whether different treatments of missing data can influence the results of spine studies. (1) What is the frequency of missing data fields for demographics, medical comorbidities, preoperative laboratory values, operating room times, and length of stay recorded in ACS-NSQIP? (2) Using three common approaches to handling missing data, how frequently do those approaches agree in terms of finding particular variables to be associated with adverse events? (3) Do different approaches to handling missing data influence the outcomes and effect sizes of an analysis testing for an association with these variables with occurrence of adverse events? Patients who underwent spine surgery between 2005 and 2013 were identified from the ACS-NSQIP database. A total of 88,471 patients undergoing spine surgery were identified. The most common procedures were anterior cervical discectomy and fusion, lumbar decompression, and lumbar fusion. Demographics, comorbidities, and perioperative laboratory values were tabulated for each patient, and the percent of missing data was noted for each variable. These variables were tested for an association with "any adverse event" using three separate multivariate regressions that used the most common treatments for missing data. In the first regression, patients with any missing data were excluded. In the second regression, missing data were treated as a negative or "reference" value; for continuous variables, the mean of each variable's reference range was computed and imputed. In the third regression, any variables with >10% rate of missing data were removed from the regression; among variables with ≤10% missing data, individual cases with missing values were excluded. The results of these regressions were compared to determine how the different treatments of missing data could affect the results of spine studies using the ACS-NSQIP database. Of the 88,471 patients, as many as 4441 (5%) had missing elements among demographic data, 69,184 (72%) among comorbidities, 70,892 (80%) among preoperative laboratory values, and 56,551 (64%) among operating room times. Considering the three different treatments of missing data, we found different risk factors for adverse events. Of 44 risk factors found to be associated with adverse events in any analysis, only 15 (34%) of these risk factors were common among the three regressions. The second treatment of missing data (assuming "normal" value) found the most risk factors (40) to be associated with any adverse event, whereas the first treatment (deleting patients with missing data) found the fewest associations at 20. Among the risk factors associated with any adverse event, the 10 with the greatest effect size (odds ratio) by each regression were ranked. Of the 15 variables in the top 10 for any regression, six of these were common among all three lists. Differing treatments of missing data can influence the results of spine studies using the ACS-NSQIP. The current study highlights the importance of considering how such missing data are handled. Until there are better guidelines on the best approaches to handle missing data, investigators should report how missing data were handled to increase the quality and transparency of orthopaedic database research. Readers of large database studies should note whether handling of missing data was addressed and consider potential bias with high rates or unspecified or weak methods for handling missing data.

How Do Recommender Systems Affect Sales Diversity? A Cross-Category Investigation via Randomized Field Experiment

We investigate the impact of collaborative filtering recommender algorithms (e.g., Amazon’s “Customers who bought this item also bought”) commonly used in e-commerce on sales diversity. We use data from a randomized field experiment run on the website of a top retailer in North America across 82,290 products and 1,138,238 users. We report four main findings. First, we demonstrate and quantify across a wide range of product categories that the use of traditional collaborative filters (or CFs) is associated with a decrease in sales diversity relative to a world without product recommendations. Furthermore, the design of the CF matters. CFs based on purchase data are associated with a greater effect size than those based on product views. Second, the decrease in aggregate sales diversity may not always be accompanied by a corresponding decrease in individual-level consumption diversity. In fact, it is even possible for individual consumption diversity to increase while aggregate sales diversity decreases. Third, co-purchase network analysis shows that while recommenders can help individuals explore new products, similar users still end up exploring the same kinds of products, resulting in concentration bias at the aggregate level. Fourth and finally, there is a difference between absolute and relative impact on niche items. Specifically, absolute sales and views for niche items in fact increase, but their gains are smaller compared to the gains in views and sales for popular items. Thus, while niche items gain in absolute terms, they lose out in terms of market share. We discuss economic impact and managerial implications.

Cultural Adaptation of Minimally Guided Interventions for Common Mental Disorders: A Systematic Review and Meta-Analysis.

BackgroundCultural adaptation of mental health care interventions is key, particularly when there is little or no therapist interaction. There is little published information on the methods of adaptation of bibliotherapy and e-mental health interventions.ObjectiveTo systematically search for evidence of the effectiveness of minimally guided interventions for the treatment of common mental disorders among culturally diverse people with common mental disorders; to analyze the extent and effects of cultural adaptation of minimally guided interventions for the treatment of common mental disorders.MethodsWe searched Embase, PubMed, the Cochrane Library, and PsycINFO for randomized controlled trials that tested the efficacy of minimally guided or self-help interventions for depression or anxiety among culturally diverse populations. We calculated pooled standardized mean differences using a random-effects model. In addition, we administered a questionnaire to the authors of primary studies to assess the cultural adaptation methods used in the included primary studies. We entered this information into a meta-regression to investigate effects of the extent of adaptation on intervention efficacy.ResultsWe included eight randomized controlled trials (RCTs) out of the 4911 potentially eligible records identified by the search: four on e-mental health and four on bibliotherapy. The extent of cultural adaptation varied across the studies, with language translation and use of metaphors being the most frequently applied elements of adaptation. The pooled standardized mean difference for primary outcome measures of depression and anxiety was -0.81 (95% CI -0.10 to -0.62). Higher cultural adaptation scores were significantly associated with greater effect sizes (P=.04).ConclusionsOur results support the results of previous systematic reviews on the cultural adaptation of face-to-face interventions: the extent of cultural adaptation has an effect on intervention efficacy. More research is warranted to explore how cultural adaptation may contribute to improve the acceptability and effectiveness of minimally guided psychological interventions for common mental disorders.

Seven-year survey of sleep timing in Russian children and adolescents: chronic 1-h forward transition of social clock is associated with increased social jetlag and winter pattern of mood seasonality

Previous studies indicate that solar clock (daily changes in the Earth’s surface illumination) is a main zeitgeber for human circadian system. It has been shown that human biological clock is weakly adjusted to such changes in social clock as daylight saving time (DST). There are two changes of social clock in Russian Federation: on 25 March 2011, DST has been replaced by permanent DST (DSTp), which was subsequently revoked on 26 October 2014 (non-DSTp). These manipulations with social clock may lead to prolonged disturbances of human circadian system. Our hypothesis is that during period of DSTp, the dissociation between social and biological clocks was greatest as compared with DST and non-DSTp periods. Here, we examine the effects of DSTp on the sleep timing, social jetlag (SJL), academic performance, and winter and summer seasonality of mood and behavior of 10–24-year-old inhabitants of European North of Russia. A cross-sectional retrospective analysis of questionnaire data (n = 7968) was performed using chi squared-test and analysis of covariance. Our findings indicate that SJL (F2,7967 = 31.9; p < 0.0001; η2 = 0.009), and winter pattern of mood seasonality (χ22,7967 = 10.5; p < 0.01) were increased in adolescents during the period of DSTp as compared with DST and non-DSTp periods. The largest increase in SJL was occurred in ages between 10 and 17-year-olds. The finding suggests that increase in SJL can be attributed to a later rise time on free days (F2,7967 = 44.9; p < 0.0001; η2 = 0.012). Similar changes were observed in three subsamples obtained in Syktyvkar, Petrozavodsk, and Vorkuta. Effect sizes of studied relationships were small or very small. The greatest effect sizes (η2 ∼ 0.05) were observed in Arctic city of Vorkuta indicating that in polar region, solar clock is still stronger zeitgeber for human circadian system, than the social clock. In conclusion, we have shown for the first time that there is a greatest dissociation between social and biological clocks during the period of DSTp which potentially exerts a negative influence on adolescents’ sleep habits, mood, and behavior. Our data indicate that “non-DSTp” social clock system most suitable for prevention dissociation between social and biological clocks.

Sildenafil Improves Functional and Structural Outcome of Retinal Injury Following Term Neonatal Hypoxia-Ischemia

The purpose of this study was to investigate the effects of sildenafil on retinal injury following neonatal hypoxia-ischemia (HI) at term-equivalent age in rat pups. Hypoxia-ischemia was induced in male Long-Evans rat pups at postnatal day 10 (P10) by a left common carotid ligation followed by a 2-hour exposure to 8% oxygen. Sham-operated rats served as the control group. Both groups were administered vehicle or 2, 10, or 50 mg/kg sildenafil, twice daily for 7 consecutive days. Retinal function was assessed by flash electroretinograms (ERGs) at P29, and retinal structure was assessed by retinal histology at P30. Hypoxia-ischemia caused significant functional (i.e., attenuation of the ERG a-wave and b-wave amplitudes and photopic negative response) and structural (i.e., thinning of the total retina, especially the inner retinal layers) retinal damage in the left eyes (i.e., ipsilateral to the carotid ligation). Treatment with the different doses of sildenafil led to a dose-dependent increase in the amplitudes of the ERG a- and b-waves and of the photopic negative response in HI animals, with higher doses associated with greater effect sizes. Similarly, a dose response was observed in terms of improvements in the retinal layer thicknesses. Hypoxia-ischemia at term-equivalent age induced functional and structural damage mainly to the inner retina. Treatment with sildenafil provided a dose-dependent recovery of retinal function and structure.

Prevalence of cancer chemotherapy-related problems, their relation to health-related quality of life and associated supportive care: a cross-sectional survey

The purpose of this study was to identify the treatment-associated problems that most impact on patients undergoing cancer chemotherapy, how problems relate to experiences of supportive care and variations in experience between cancer treatment centres. A survey administered to patients at six cancer centres in England explored variations of prevalence of 17 cancer chemotherapy-associated problems and associated supportive care. Problem items were identified as the most frequently experienced and severe when experienced in a scoping and consensus exercise. A health-related quality of life (HRQoL) measure, the EQ5D, was included to measure impact of problems. A total of 363 completed questionnaires were returned (response rate 43%, median 61%). The most prevalent problem was 'tiredness/fatigued' (90%), followed by 'changes in taste & smell' (69%) and 'difficulty managing everyday tasks' (61%). Significant variations in problem prevalence existed between centres, and some common problems were rarely reported in the literature. Regression analysis found that almost all problems were significantly associated with HRQoL, with social/emotional problems having as much impact on HRQoL as physical/psychological side effects of treatment. Greatest effect size was for difficulty managing everyday tasks. Respondents reported significant variations in supportive care between centres, with more supportive care received for physical/psychological problems than for social/emotional problems. Findings indicated that patients who received increased supportive care experienced less severe problems. The most common and distressing chemotherapy-associated problems were identified. These problems are mitigated by quality supportive care. Routine measurement and monitoring of problem items and supportive care are warranted to facilitate benchmarking and service improvements both within and between cancer centres.

Muscle Activity Onset Prior to Landing in Patients after Anterior Cruciate Ligament Injury: A Systematic Review and Meta-Analysis.

Muscle activation during landing is paramount to stabilise lower limb joints and avoid abnormal movement patterns. Delayed muscle activity onset measured by electromyography (EMG) has been suggested to be associated with anterior cruciate ligament (ACL) injury. Therefore, the aim of this systematic review and meta-analysis was to test the hypothesis if ACL-injured patients display different results for muscle onset timing during standard deceleration tasks compared to healthy control participants. PubMed, Embase, Scopus and ScienceDirect databases were systematically searched over the period from January 1980 to February 2015, yielding a total of 1461 citations. Six studies meeting inclusion criteria underwent quality assessment, data extraction and re-computing procedures for the meta-analysis. The quality was rated “moderate” for 2 studies and “poor” for 4. Patients included and procedures used were highly heterogeneous. The tasks investigated were single leg hopping, decelerating from running or walking, tested on a total of 102 ACL-injured participants and 86 controls. EMG analyses of the muscles vastus lateralis, vastus medialis, lateral and medial hamstrings revealed trivial and non-significant standardised mean differences (SMD<0.20; p>0.05) between patients and control participants. Furthermore, no differences were found between the contralateral leg of patients and controls for muscle activity onset of the medial and lateral gastrocnemius (SMD<0.20; p>0.05). Based on 3 studies, the involved legs of ACL-injured patients showed overall earlier muscle activity onset compared to control participants for the medial gastrocnemius (SMD = 0.5; p = 0.05). Similar results were found for the lateral gastrocnemius (SMD = 2.1; p<0.001), with a greater effect size but based only on a single study. We conclude that there are no differences between leg muscles of ACL-injured patients and healthy controls regarding the muscle activity onset during landing. However, current evidence is scarce and weak, which highlights the need for further research in this area.

Maternal marijuana use has independent effects on risk for spontaneous preterm birth but not other common late pregnancy complications.

Widespread legalisation of marijuana raises safety concerns for its use in pregnancy. This study investigated the association of marijuana use prior to and during pregnancy with pregnancy outcomes in a prospective cohort of 5588 nulliparous women from the international SCOPE study. Women were assessed at 15±1 and 20±1 weeks' gestation. Cases [278 Preeclampsia, 470 gestational hypertension, 633 small-for-gestational-age, 236 spontaneous preterm births (SPTB), 143 gestational diabetes] were compared separately with 4114 non-cases. Although the numbers are small, continued maternal marijuana use at 20 weeks' gestation was associated with SPTB independent of cigarette smoking status [adj OR 2.28 (95% CI:1.45-3.59)] and socioeconomic index (SEI) [adj OR 2.17 (95% CI:1.41-3.34)]. When adjusted for maternal age, cigarette smoking, alcohol and SEI, continued maternal marijuana use at 20 weeks' gestation had a greater effect size [adj OR 5.44 (95% CI 2.44-12.11)]. Our data indicate that increasing use of marijuana among young women of reproductive age is a major public health concern.

Effects of Resistance Training Frequency on Measures of Muscle Hypertrophy: A Systematic Review and Meta-Analysis.

A number of resistance training (RT) program variables can be manipulated to maximize muscular hypertrophy. One variable of primary interest in this regard is RT frequency. Frequency can refer to the number of resistance training sessions performed in a given period of time, as well as to the number of times a specific muscle group is trained over a given period of time. We conducted a systematic review and meta-analysis to determine the effects of resistance training frequency on hypertrophic outcomes. Studies were deemed eligible for inclusion if they met the following criteria: (1) were an experimental trial published in an English-language refereed journal; (2) directly compared different weekly resistance training frequencies in traditional dynamic exercise using coupled concentric and eccentric actions; (3) measured morphologic changes via biopsy, imaging, circumference, and/or densitometry; (4) had a minimum duration of 4weeks; and (5) used human participants without chronic disease or injury. A total of ten studies were identified that investigated RT frequency in accordance with the criteria outlined. Analysis using binary frequency as a predictor variable revealed a significant impact of training frequency on hypertrophy effect size (P=0.002), with higher frequency being associated with a greater effect size than lower frequency (0.49±0.08 vs. 0.30±0.07, respectively). Statistical analyses of studies investigating training session frequency when groups are matched for frequency of training per muscle group could not be carried out and reliable estimates could not be generated due to inadequate sample size. When comparing studies that investigated training muscle groups between 1 to 3days per week on a volume-equated basis, the current body of evidence indicates that frequencies of training twice a week promote superior hypertrophic outcomes to once a week. It can therefore be inferred that the major muscle groups should be trained at least twice a week to maximize muscle growth; whether training a muscle group three times per week is superior to a twice-per-week protocol remains to be determined.

Genome-Wide Association Studies for life-style related diseases

After the completion of human genome project, development of single nucleotide polymorphism (SNP) typing technology and collation of information regarding linkage disequilibrium in the human genome have facilitated genome-wide association studies (GWAS) for investigating genes associated with disease susceptibility across the entire human genome. In case of type 2 diabetes, approximately 100 genetic loci have been identified and confirmed as susceptibility to the disease through GWAS in different ethnic groups, including Japanese, European, East Asian and South Asian populations. However, integration of these information accounts for less than 20% of the disease heritability, and thus most of the heritability of type 2 diabetes remain to be identified. Since the rationale of GWAS is based on the hypothesis that common variants contribute to the susceptibility to common diseases, common disease-common variant hypothesis, GWAS have selectively identified common susceptibility variants (allele frequency>=0.05) with lower effect size (odds ratio<1.5), that is a limitation of the GWAS approach. Although GWAS have brought a significant breakthrough in the field of genetic study for life-style related diseases, new approaches other than GWAS, such as whole genome sequencing to identify rare variants with greater effect size or integration of genetic and environmental information, will be required to elucidate a heritability of life-style related diseases completely.