Discover the most talked about and latest scientific content & concepts.

Concept: Meta-analysis


To review the evidence for the short term association between air pollution and stroke.

Concepts: Evidence-based medicine, Systematic review, Meta-analysis, Term, Finance


Objective To estimate the benefits and harms of using corticosteroids as an adjunct treatment for sore throat.Design Systematic review and meta-analysis of randomised control trials.Data sources Medline, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), trial registries up to May 2017, reference lists of eligible trials, related reviews.Study selection Randomised controlled trials of the addition of corticosteroids to standard clinical care for patients aged 5 or older in emergency department and primary care settings with clinical signs of acute tonsillitis, pharyngitis, or the clinical syndrome of sore throat. Trials were included irrespective of language or publication status.Review methods Reviewers identified studies, extracted data, and assessed the quality of the evidence, independently and in duplicate. A parallel guideline committee (BMJ Rapid Recommendation) provided input on the design and interpretation of the systematic review, including the selection of outcomes important to patients. Random effects model was used for meta-analyses. Quality of evidence was assessed with the GRADE approach.Results 10 eligible trials enrolled 1426 individuals. Patients who received single low dose corticosteroids (the most common intervention was oral dexamethasone with a maximum dose of 10 mg) were twice as likely to experience pain relief after 24 hours (relative risk 2.2, 95% confidence interval 1.2 to 4.3; risk difference 12.4%; moderate quality evidence) and 1.5 times more likely to have no pain at 48 hours (1.5, 1.3 to 1.8; risk difference 18.3%; high quality). The mean time to onset of pain relief in patients treated with corticosteroids was 4.8 hours earlier (95% confidence interval -1.9 to -7.8; moderate quality) and the mean time to complete resolution of pain was 11.1 hours earlier (-0.4 to -21.8; low quality) than in those treated with placebo. The absolute pain reduction at 24 hours (visual analogue scale 0-10) was greater in patients treated with corticosteroids (mean difference 1.3, 95% confidence interval 0.7 to 1.9; moderate quality). Nine of the 10 trials sought information regarding adverse events. Six studies reported no adverse effects, and three studies reported few adverse events, which were mostly complications related to disease, with a similar incidence in both groups.Conclusion Single low dose corticosteroids can provide pain relief in patients with sore throat, with no increase in serious adverse effects. Included trials did not assess the potential risks of larger cumulative doses in patients with recurrent episodes of acute sore throat.Systematic review registration PROSPERO CRD42017067808.

Concepts: Epidemiology, Clinical trial, Medical statistics, Systematic review, Randomized controlled trial, Relative risk, Meta-analysis, Random effects model


This review summarises the literature on shift work and its relation to insufficient sleep, chronic diseases, and accidents. It is based on 38 meta-analyses and 24 systematic reviews, with additional narrative reviews and articles used for outlining possible mechanisms by which shift work may cause accidents and adverse health. Evidence shows that the effect of shift work on sleep mainly concerns acute sleep loss in connection with night shifts and early morning shifts. A link also exists between shift work and accidents, type 2 diabetes (relative risk range 1.09-1.40), weight gain, coronary heart disease (relative risk 1.23), stroke (relative risk 1.05), and cancer (relative risk range 1.01-1.32), although the original studies showed mixed results. The relations of shift work to cardiometabolic diseases and accidents mimic those with insufficient sleep. Laboratory studies indicate that cardiometabolic stress and cognitive impairments are increased by shift work, as well as by sleep loss. Given that the health and safety consequences of shift work and insufficient sleep are very similar, they are likely to share common mechanisms. However, additional research is needed to determine whether insufficient sleep is a causal pathway for the adverse health effects associated with shift work.

Concepts: Medicine, Epidemiology, Hypertension, Heart, Chronic, Meta-analysis, Acute, Shift work


 To determine whether feeding infants with hydrolysed formula reduces their risk of allergic or autoimmune disease.

Concepts: Systematic review, Autoimmune disease, Meta-analysis


Reproducibility is a defining feature of science, but the extent to which it characterizes current research is unknown. We conducted replications of 100 experimental and correlational studies published in three psychology journals using high-powered designs and original materials when available. Replication effects were half the magnitude of original effects, representing a substantial decline. Ninety-seven percent of original studies had statistically significant results. Thirty-six percent of replications had statistically significant results; 47% of original effect sizes were in the 95% confidence interval of the replication effect size; 39% of effects were subjectively rated to have replicated the original result; and if no bias in original results is assumed, combining original and replication results left 68% with statistically significant effects. Correlational tests suggest that replication success was better predicted by the strength of original evidence than by characteristics of the original and replication teams.

Concepts: Scientific method, Psychology, Statistics, Statistical significance, Statistical hypothesis testing, Effect size, Meta-analysis, Statistical power


A systematic review to examine the efficacy of computer-based cognitive interventions for cognitively healthy older adults was conducted. Studies were included if they met the following criteria: average sample age of at least 55 years at time of training; participants did not have Alzheimer’s disease or mild cognitive impairment; and the study measured cognitive outcomes as a result of training. Theoretical articles, review articles, and book chapters that did not include original data were excluded. We identified 151 studies published between 1984 and 2011, of which 38 met inclusion criteria and were further classified into three groups by the type of computerized program used: classic cognitive training tasks, neuropsychological software, and video games. Reported pre-post training effect sizes for intervention groups ranged from 0.06 to 6.32 for classic cognitive training interventions, 0.19 to 7.14 for neuropsychological software interventions, and 0.09 to 1.70 for video game interventions. Most studies reported older adults did not need to be technologically savvy in order to successfully complete or benefit from training. Overall, findings are comparable or better than those from reviews of more traditional, paper-and-pencil cognitive training approaches suggesting that computerized training is an effective, less labor intensive alternative.

Concepts: Alzheimer's disease, Effectiveness, Cognitive psychology, Cognitive neuroscience, Efficacy, Meta-analysis, Video game, Mild cognitive impairment


Hippocampal volume increase in response to aerobic exercise has been consistently observed in animal models. However, the evidence from human studies is equivocal. We undertook a systematic review to identify all controlled trials examining the effect of aerobic exercise on the hippocampal volumes in humans, and applied meta-analytic techniques to determine if aerobic exercise resulted in volumetric increases. We also sought to establish how volume changes differed in relation to unilateral measures of left/right hippocampal volume, and across the lifespan. A systematic search identified 4398 articles, of which 14 were eligible for inclusion in the primary analysis. A random-effects meta-analysis showed no significant effect of aerobic exercise on total hippocampal volume across the 737 participants. However, aerobic exercise had significant positive effects on left hippocampal volume in comparison to control conditions. Post-hoc analyses indicated effects were driven through exercise preventing the volumetric decreases which occur over time. These results provide meta-analytic evidence for exercise-induced volumetric retention in the left hippocampus. Aerobic exercise interventions may be useful for preventing age-related hippocampal deterioration and maintaining neuronal health.

Concepts: Medical statistics, Volume, Systematic review, Thermodynamics, Hippocampus, Integral, Strength training, Meta-analysis


BACKGROUND: To evaluate the effect of lifestyle modifications on metabolic syndrome (MetS) as assessed by its resolution and improved values for its components. METHODS: This was a systematic review and meta-analysis. Searches were performed of MEDLINE and the Cochrane Database from January 1966 to October 2011 to identify randomized controlled trials (RCTs) related to the study objective. The included studies were RCTs restricted to the English language, with a follow-up period of 6 months or more, which reported overall resolution of MetS or values of MetS components (fasting blood glucose, waist circumference, high-density lipoprotein (HDL), triglycerides, and systolic and diastolic blood pressure (SBP, DBP)) . Two investigators independently assessed study eligibility. The effect sizes were the relative proportion of patients with resolved MetS and mean differences in MetS component values from baseline to 1-year follow-up in a lifestyle-modification intervention (LMI) group versus a control (conventional lifestyle education or no treatment) group. Meta-analyses were conducted using a random-effects model. RESULTS: Eleven interventions in eight RCTs were used for the meta-analyses. The relative proportion of patients with resolved MetS in the intervention group was approximately 2.0 (95% CI 1.5 to 2.7) times greater in the intervention group compared with the control group (7 interventions, n = 2.839). LMI (5 interventions, n = 748) significantly reduced mean values for SBP by 6.4 mmHg (95% CI 9.7 to 3.2), DBP by 3.3 mmHg (95% CI 5.2 to 1.4), triglycerides by 12.0 mg/dl ( 95% CI 22.2 to 1.7), waist circumference by 2.7 cm (95% CI 4.6 to 0.9), and fasting blood glucose by 11.5 mg/dl (95% CI 22.4 to 0.6) (5 interventions), but reductions were not significant for HDL (1.3 mg/dl; 95% CI 0.6 to 3.1). CONCLUSIONS: The LMI was effective in resolving MetS and reducing the severity of related abnormalities (fasting blood glucose, waist circumference, SBP and DBP, and triglycerides) in subjects with MetS.

Concepts: Atherosclerosis, Evidence-based medicine, Systematic review, Randomized controlled trial, Blood pressure, Blood sugar, Effect size, Meta-analysis


To summarise the evidence about the efficacy of a Mediterranean diet on the management of type 2 diabetes and prediabetic states.

Concepts: Nutrition, Insulin, Diabetes mellitus type 2, Obesity, Systematic review, Randomized controlled trial, Diabetes, Meta-analysis


BACKGROUND: The aim of this review was to systematically review and meta-analyze the effects of yoga on symptoms of schizophrenia, quality of life, function, and hospitalization in patients with schizophrenia. METHODS: MEDLINE/Pubmed, Scopus, the Cochrane Library, PsycInfo, and IndMED were screened through August 2012. Randomized controlled trials (RCTs) comparing yoga to usual care or non-pharmacological interventions were analyzed when they assessed symptoms or quality of life in patients with schizophrenia. Cognitive function, social function, hospitalization, and safety were defined as secondary outcomes. Risk of bias was assessed using the risk of bias tool recommended by the Cochrane Back Review Group. Standardized mean differences (SMD) and 95% confidence intervals (CI) were calculated. RESULTS: Five RCTs with a total of 337 patients were included; 2 RCTs had low risk of bias. Two RCTs compared yoga to usual care; 1 RCT compared yoga to exercise; and 2 3-arm RCTs compared yoga to usual care and exercise. No evidence was found for short-term effects of yoga compared to usual care on positive symptoms (SMD = -0.58; 95% CI -1.52 to 0.37; P = 0.23), or negative symptoms (SMD = -0.59; 95% CI -1.87 to 0.69; P = 0.36). Moderate evidence was found for short-term effects on quality of life compared to usual care (SMD = 2.28; 95% CI 0.42 to 4.14; P = 0.02). These effects were only present in studies with high risk of bias. No evidence was found for short-term effects on social function (SMD = 1.20; 95% CI -0.78 to 3.18; P = 0.23). Comparing yoga to exercise, no evidence was found for short-term effects on positive symptoms (SMD = -0.35; 95% CI -0.75 to 0.05; P = 0.09), negative symptoms (SMD = -0.28; 95% CI -1.42 to 0.86; P = 0.63), quality of life (SMD = 0.17; 95% CI -0.27 to 0.61; P = 0.45), or social function (SMD = 0.20; 95% CI -0.27 to 0.67; P = 0.41). Only 1 RCT reported adverse events. CONCLUSIONS: This systematic review found only moderate evidence for short-term effects of yoga on quality of life. As these effects were not clearly distinguishable from bias and safety of the intervention was unclear, no recommendation can be made regarding yoga as a routine intervention for schizophrenia patients.

Concepts: Evidence-based medicine, Cochrane Collaboration, Systematic review, Cochrane Library, Randomized controlled trial, MEDLINE, Meta-analysis, Centre for Reviews and Dissemination