Mark McEvoy

A systematic review and meta-analysis of dietary patterns and depression in community-dwelling adults

BACKGROUND Studies of single nutrients on depression have produced inconsistent results, and they have failed to consider the complex interactions between nutrients. An increasing number of studies in recent years are investigating the association of overall dietary patterns and depression. OBJECTIVE This study aimed to systematically review current literature and conduct meta-analyses of studies addressing the association between dietary patterns and depression. DESIGN Six electronic databases were searched for articles published up to August 2013 that examined the association of total diet and depression among adults. Only studies considered methodologically rigorous were included. Two independent reviewers completed study selection, quality rating, and data extraction. Effect sizes of eligible studies were pooled by using random-effects models. A summary of the findings was presented for studies that could not be meta-analyzed. RESULTS A total of 21 studies were identified. Results from 13 observational studies were pooled. Two dietary patterns were identified. The healthy diet pattern was significantly associated with a reduced odds of depression (OR: 0.84; 95% CI: 0.76, 0.92; P < 0.001). No statistically significant association was observed between the Western diet and depression (OR: 1.17; 95% CI: 0.97, 1.68; P = 0.094); however, the studies were too few for a precise estimate of this effect. CONCLUSIONS The results suggest that high intakes of fruit, vegetables, fish, and whole grains may be associated with a reduced depression risk. However, more high-quality randomized controlled trials and cohort studies are needed to confirm this finding, specifically the temporal sequence of this association.

Management of Chronic Prostatitis/ Chronic Pelvic Pain Syndrome: A Systematic Review and Network Meta-analysis

CONTEXT Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is common, but trial evidence is conflicting and therapeutic options are controversial. OBJECTIVE To conduct a systematic review and network meta-analysis comparing mean symptom scores and treatment response among α-blockers, antibiotics, anti-inflammatory drugs, other active drugs (phytotherapy, glycosaminoglycans, finasteride, and neuromodulators), and placebo. DATA SOURCES We searched MEDLINE from 1949 and EMBASE from 1974 to November 16, 2010, using the PubMed and Ovid search engines. STUDY SELECTION Randomized controlled trials comparing drug treatments in CP/CPPS patients. DATA EXTRACTION Two reviewers independently extracted mean symptom scores, quality-of-life measures, and response to treatment between treatment groups. Standardized mean difference and random-effects methods were applied for pooling continuous and dichotomous outcomes, respectively. A longitudinal mixed regression model was used for network meta-analysis to indirectly compare treatment effects. DATA SYNTHESIS Twenty-three of 262 studies identified were eligible. Compared with placebo, α-blockers were associated with significant improvement in symptoms with standardized mean differences in total symptom, pain, voiding, and quality-of-life scores of -1.7 (95% confidence interval [CI], -2.8 to -0.6), -1.1 (95% CI, -1.8 to -0.3), -1.4 (95% CI, -2.3 to -0.5), and -1.0 (95% CI, -1.8 to -0.2), respectively. Patients receiving α-blockers or anti-inflammatory medications had a higher chance of favorable response compared with placebo, with pooled RRs of 1.6 (95% CI, 1.1-2.3) and 1.8 (95% CI, 1.2-2.6), respectively. Contour-enhanced funnel plots suggested the presence of publication bias for smaller studies of α-blocker therapies. The network meta-analysis suggested benefits of antibiotics in decreasing total symptom scores (-9.8; 95% CI, -15.1 to -4.6), pain scores (-4.4; 95% CI, -7.0 to -1.9), voiding scores (-2.8; 95% CI, -4.1 to -1.6), and quality-of-life scores (-1.9; 95% CI, -3.6 to -0.2) compared with placebo. Combining α-blockers and antibiotics yielded the greatest benefits compared with placebo, with corresponding decreases of -13.8 (95% CI, -17.5 to -10.2) for total symptom scores, -5.7 (95% CI, -7.8 to -3.6) for pain scores, -3.7 (95% CI, -5.2 to -2.1) for voiding, and -2.8 (95% CI, -4.7 to -0.9) for quality-of-life scores. CONCLUSIONS α-Blockers, antibiotics, and combinations of these therapies appear to achieve the greatest improvement in clinical symptom scores compared with placebo. Anti-inflammatory therapies have a lesser but measurable benefit on selected outcomes. However, beneficial effects of α-blockers may be overestimated because of publication bias.

How to use an article about genetic association: B: Are the results of the study valid?

In the first article of this series, we reviewed the basic genetics concepts necessary to understand genetic association studies. In this second article, we enumerate the major issues in judging the validity of these studies, framed as critical appraisal questions. Was the disease phenotype properly defined and accurately recorded by someone blind to the genetic information? Have any potential differences between disease and nondisease groups, particularly ethnicity, been properly addressed? In genetic studies, one potential cause of spurious associations is differences between cases and controls in ethnicity, a situation termed population stratification. Was measurement of the genetic variants unbiased and accurate? Methods for determining DNA sequence variation are not perfect and may have some measurement error. Do the genotype proportions observe Hardy-Weinberg equilibrium? This simple mathematic rule about the distribution of genetic groups may be one way to check for errors in reading DNA information. Have the investigators adjusted their inferences for multiple comparisons? Given the thousands of genetic markers tested in genome-wide association studies, the potential for false-positive and false-negative results is much higher than in traditional medical studies, and it is particularly important to look for replication of results.

Common variants at 6p21.1 are associated with large artery atherosclerotic stroke

Genome-wide association studies (GWAS) have not consistently detected replicable genetic risk factors for ischemic stroke, potentially due to etiological heterogeneity of this trait. We performed GWAS of ischemic stroke and a major ischemic stroke subtype (large artery atherosclerosis, LAA) using 1,162 ischemic stroke cases (including 421 LAA cases) and 1,244 population controls from Australia. Evidence for a genetic influence on ischemic stroke risk was detected, but this influence was higher and more significant for the LAA subtype. We identified a new LAA susceptibility locus on chromosome 6p21.1 (rs556621: odds ratio (OR) = 1.62, P = 3.9 × 10−8) and replicated this association in 1,715 LAA cases and 52,695 population controls from 10 independent population cohorts (meta-analysis replication OR = 1.15, P = 3.9 × 10−4; discovery and replication combined OR = 1.21, P = 4.7 × 10−8). This study identifies a genetic risk locus for LAA and shows how analyzing etiological subtypes may better identify genetic risk alleles for ischemic stroke.

How to Use an Article About Genetic Association: A: Background Concepts

This is the first in a series of 3 articles serving as an introduction to clinicians wishing to read and critically appraise genetic association studies. We summarize the key concepts in genetics that clinicians must understand to review these studies, including the structure of DNA, transcription and translation, patterns of inheritance, Hardy-Weinberg equilibrium, and linkage disequilibrium. We review the types of DNA variation, including single-nucleotide polymorphisms (SNPs), insertions, and deletions, and how these can affect protein function. We introduce the idea of genetic association for both single-candidate gene and genome-wide association studies, in which thousands of genetic variants are tested for association with disease. We use the APOE polymorphism and its association with dementia as a case study to demonstrate the concepts and introduce the terminology used in this field. The second and third articles will focus on issues of validity and applicability.

Cohort Profile: The Hunter Community Study

In almost every country, the proportion of people aged 460 years is growing faster than any other age group and is expected to reach 2 billion worldwide by 2050. Internationally and nationally, considerable efforts are being made to promote active ageing. However, Australia lacks the kind of comprehensive longitudinal research underway in Europe and North America. Although Australia does have a number of longitudinal studies designed to address various issues of health and ageing among older adults, only a few of these studies include a broad and comprehensive range of physical and biological measures. The Hunter Community Study (HCS) is a collaborative study between the University of Newcastle’s School of Medicine and Public Health and the Hunter New England Area Health Service. It is a multi disciplinary initiative that was established to fill some existing gaps in ageing research in Australia and is unique in that it has collected detailed information across all six key policy themes as identified in the Framework for an Australian Ageing Research Agenda. What does the study cover?

Systematic Review and Meta-Analysis of the Association Between Complement Component 3 and Age-related Macular Degeneration: A HuGE Review and Meta-Analysis

The authors performed a meta-analysis to estimate the magnitude of polymorphism effects for the complement component C3 gene (C3) and their possible mode of action on age-related macular degeneration (AMD). The meta-analysis included 16 and 7 studies for rs2230199 and rs1047286, respectively. Data extraction and risk of bias assessments were performed in duplicate, and heterogeneity and publication bias were explored. There was moderate evidence for association between both polymorphisms and AMD in Caucasians. For rs2230199, patients with CG and GG genotypes were 1.44 (95% confidence interval (CI): 1.33, 1.56) and 1.88 (95% CI: 1.59, 2.23) times more likely to have AMD than patients with the CC genotype. For rs1047286, GA and AA genotypes had 1.27 (95% CI: 1.15, 1.41) and 1.70 (95% CI: 1.27, 2.11) times higher risk of AMD than did GG genotypes. These gene effects suggested an additive model. The population attributable risks for the GG/GC and AA/GA genotypes are approximately 5%-10%. Subgroup analysis by ethnicity indicates that these variants are very infrequent in Asians and that the observed gene effects are based largely on the high frequency within Caucasian populations. This meta-analysis supports the association between C3 and AMD and provides a robust estimate of the genetic risk.

Systematic review and meta-analysis of safety of laparoscopic versus open appendicectomy for suspected appendicitis in pregnancy.

Laparoscopic appendicectomy has gained wide acceptance as an alternative to open appendicectomy during pregnancy. However, data regarding the safety and optimal surgical approach to appendicitis in pregnancy are still controversial.

Mean platelet volume and coronary artery disease: a systematic review and meta-analysis

BACKGROUND Platelets with high hemostatic activity play an important role in the pathophysiology of coronary artery disease(CAD) and mean platelet volume(MPV) has been proposed as an indicator of platelet reactivity. Thus, MPV may emerge as a potential marker of CAD risk. The aim of this study was to conduct a systematic review and meta-analysis comparing mean difference in MPV between patients with CAD and controls and pooling the odds ratio of CAD in those with high versus low MPV. METHODS Medline and Scopus databases were searched up to 12 March 2013. All observational studies that considered MPV as a studys factor and measured CAD as an outcome were included. Two reviewers independently selected the studies and extracted the data. RESULTS Forty studies were included in this meta-analysis. The MPV was significantly larger in patients with CAD than controls with the unstandardized mean difference of 0.70 fL (95% CI: 0.55, 0.85). The unstandardized mean difference of MPV in patients with acute coronary event and in patients with chronic stable angina was 0.84 fL (95% CI: 0.63, 1.04) and 0.46 fL (95% CI: 0.11, 0.81) respectively. Patients with larger MPV (≥7.3 fL) also had a greater odds of having CAD than patients with smaller MPV with a pooled odds ratio of 2.28 (95% CI: 1.46, 3.58). CONCLUSION Larger MPV was associated with CAD. Thus, it might be helpful in risk stratification, or improvement of risk prediction if combining it with other risk factors in risk prediction models.

Efficacy and Adverse Events of Mycophenolate Mofetil Versus Cyclophosphamide for Induction Therapy of Lupus Nephritis Systematic Review and Meta-Analysis

We performed a systematic review and meta-analysis of randomized controlled trials to compare complete remission and adverse events (that is, infection, leukopenia, and gastrointestinal [GI] symptoms) between mycophenolate mofetil (MMF) and cyclophosphamide (CYC) for the treatment of lupus nephritis (LN). We identified trials from MEDLINE using the PubMed and Ovid search engines, and from The Cochrane Central Register of Randomized Controlled Trials. Eligible studies were randomized controlled trials comparing MMF with CYC with 1 of following outcomes: complete remission, complete/partial remission, infection, leukopenia, GI symptoms, serum creatinine, 24-hour urine protein, and urine albumin. Data were independently extracted by 2 reviewers. Five trials with a total of 638 patients were eligible for review. While the MMF group tended to achieve complete remission more frequently than the CYC group, this was not significant (pooled risk ratio [RR], 1.60; 95% confidence interval [CI], 0.87-2.93). Pooling based on the 4 homogeneous trials yielded similar results-that is, no benefit of MMF compared with CYC groups (RR, 1.15; 95% CI, 0.74-1.77). The complete or partial remission rates were also not different (pooled RR, 1.21; 95% CI, 0.97-1.48) among the groups. The adverse events (infection, renal function, and GI symptoms) were not significantly different, except for leukopenia, which was lower in the MMF group. In summary, patients treated with MMF and CYC had similar remission rates, but the MMF group had less frequent leukopenia than the CYC group. Further large-scale trials are needed to confirm these results. Abbreviations: CI = confidence interval, CYC = cyclophosphamide, df = degree of freedom, GI = gastrointestinal, LN = lupus nephritis, MMF = mycophenolate mofetil, NNH = number needed to harm, NNT = number needed to treat, PRISMA = preferred reporting items for systematic reviews and meta-analyses, RR = risk ratio, SE = standard error, SLE = systemic lupus erythematosus, SMD = standardized mean difference, WHO = World Health Organization.