The methodological quality assessment tools for preclinical and clinical studies, systematic review and meta-analysis, and clinical practice guideline: a systematic review

Impact of Obstructive Sleep Apnea Syndrome on Endothelial Function, Arterial Stiffening, and Serum Inflammatory Markers: An Updated Meta-analysis and Metaregression of 18 Studies

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) has been indicated to contribute to the development of cardiovascular disease; however, the underlying mechanism remains unclear. This study aimed to test the hypothesis that OSAS may be associated with cardiovascular disease by elevating serum levels of inflammatory markers and causing arterial stiffening and endothelial dysfunction.

METHODS AND RESULTS

Related scientific reports published from January 1, 2006, to June 30, 2015, were searched in the following electronic literature databases: PubMed, Excerpta Medica Database, ISI Web of Science, Directory of Open Access Journals, and the Cochrane Library. The association of OSAS with serum levels of inflammatory markers, endothelial dysfunction, and arterial stiffening were investigated. Overall, 18 eligible articles containing 736 patients with OSAS and 424 healthy persons were included in this meta-analysis. Flow-mediated dilation in patients with moderate-severe OSAS was significantly lower than that in controls (standardized mean difference -1.02, 95% CI -1.31 to -0.73, P<0.0001). Carotid-femoral pulse wave velocity (standardized mean difference 0.45, 95% CI 0.21-0.69, P<0.0001), augmentation index (standardized mean difference 0.57, 95% CI 0.25-0.90, P<0.0001), and serum levels of high-sensitivity C-reactive protein and C-reactive protein (standardized mean difference 0.58, 95% CI 0.42-0.73, P<0.0001) were significantly higher in patients with OSAS than in controls.

CONCLUSION

OSAS, particularly moderate-severe OSAS, appeared to reduce endothelial function, increase arterial stiffness, and cause chronic inflammation, leading to the development of cardiovascular disease.

The association between XRCC1 Arg399Gln polymorphism and risk of leukemia in different populations: a meta-analysis of case-control studies

BACKGROUND

Associations between Arg399Gln single-nucleotide polymorphism (SNP) in the XRCC1 gene and leukemia susceptibility have been studied extensively, however, the results are inconsistent. The aim of this study was to determine these associations using meta-analytical methods.

METHODS

A meta-analysis was performed to examine the associations between XRCC1 Arg399-Gln SNP and leukemia risk. A literature search of PubMed and Web of Science databases was conducted to identify relevant studies published up to March 10, 2015. The references of the retrieved articles were also screened. All the statistical analyses were conducted using Review Manager software.

RESULTS

The XRCC1 Arg399Gln SNP was found to be associated with increased childhood risk of acute lymphoblastic leukemia among Asians under the dominant (odds ratio [OR] 2.11, 95% confidence interval [CI] 1.50-2.97, P<0.0001), allele contrast (OR 1.72, 95% CI 1.33-2.23, P<0.0001), and homozygote contrast (OR 2.34, 95% CI 1.25-4.36, P=0.008) models. However, no association was found in Caucasians between the SNP and risk of either chronic myeloid leukemia or chronic lymphocytic leukemia under any contrast model.

CONCLUSION

The findings of the current meta-analysis indicate that the XRCC1 Arg399Gln SNP is a risk factor for childhood lymphoblastic leukemia in Asians.

The diagnostic accuracy of CT-guided percutaneous core needle biopsy and fine needle aspiration in pulmonary lesions: a meta-analysis

AIM

To determine and compare the diagnostic value of computed tomography (CT)-guided percutaneous core needle biopsy (PCNB) and percutaneous fine-needle aspiration biopsy (PNAB) in pulmonary lesions.

MATERIALS AND METHODS

PubMed, EMBASE, and the Web of Science were systematically searched for relevant studies that investigated the diagnostic accuracy of CT-guided PCNB and/or PNAB for pulmonary lesions up to December 2014. After study selection, data extraction, and quality assessment, the sensitivity (SEN), specificity (SPE), diagnostic odds rate (DOR), positive likelihood ratios (PLR), negative likelihood ratios (NLR), and summary receiver operating characteristic (SROC) curves were calculated using the Meta-Disc 1.4 software.

RESULTS

Nineteen publications, including 21 independent studies, met the inclusion criteria. Of them, 15 studies were included in the PCNB group and six studies in the PNAB group. The pooled SEN, SPE, DOR, PLR, NLR, and SROC were 0.95, 0.99, 54.72, 0.06, 821.90, and 0.98 in the PCNB group and 0.90, 0.99, 24.71, 0.14, 210.72, and 0.98 in the PNAB group, respectively.

CONCLUSION

Based on current evidence, both PCNB and PNAB can be used as diagnostic methods to distinguish benign and malignant pulmonary lesions; the difference between PCNB and PNAB regarding diagnostic accuracy of benign or malignant pulmonary lesions is not obvious.

Promoter Methylation of the Retinoic Acid Receptor Beta2 (RARβ2) Is Associated with Increased Risk of Breast Cancer: A PRISMA Compliant Meta-Analysis

BACKGROUND

Epigenetic studies demonstrate that an association may exist between methylation of the retinoic acid receptor beta2 (RARβ2) gene promoter and breast cancer onset risk, tumor stage, and histological grade, however the results of these studies are not consistent. Hence, we performed this meta-analysis to ascertain a more comprehensive and accurate association.

MATERIALS AND METHODS

Relevant studies were retrieved from the PubMed, Embase and Chinese National Knowledge Infrastructure databases up to February 28, 2015. After two independent reviewers screened the studies and extracted the necessary data, meta-analysis was performed using Review Manager 5.2 software.

RESULTS

Nineteen eligible articles, including 20 studies, were included in our analysis. Compared to non-cancerous controls, the frequency of RARβ2 methylation was 7.27 times higher in patients with breast cancer (odds ratio (OR) = 7.27, 95% confidence interval (CI) = 3.01-17.52). Compared to late-stage RARβ2 methylated patients, the pooled OR of early-stage ones was 0.81 (OR = 0.81, 95% CI = 0.55-1.17). The OR of low-grade RARβ2 methylated patients was 0.96 (OR = 0.96, 95% CI = 0.74-1.25) compared to high-grade RARβ2 methylated patients.

CONCLUSION

RARβ2 methylation is significantly increased in breast cancer samples when compared to non-cancerous controls. RARβ2 could serve as a potential epigenetic marker for breast cancer detection and management.

Association Between TP53 Gene Codon 72 Polymorphism and Acute Myeloid Leukemia Susceptibility: Evidence Based on a Meta-Analysis

Background

Many studies have reported that the p53 codon 72 polymorphism is associated with acute myeloid leukemia (AML) susceptibility; however, the conclusions are inconsistent. Therefore, we performed this meta-analysis to obtain a more precise result.

Material/Methods

We searched PubMed to identify relevant studies, and 6 published case-control studies were retrieved, including 924 AML patients and 3832 controls. Odds ratio (OR) with corresponding 95% confidence interval (95%CI) was applied to assess the association between p53 codon 72 polymorphism and AML susceptibility. The meta-analysis was performed with Comprehensive Meta-Analysis software, version 2.2.

Results

Overall, no significant association between p53 codon 72 polymorphism and AML susceptibility was found in this meta-analysis (Pro vs. Arg: OR=0.94, 95%CI=0.81–1.10; Pro/Pro vs. Arg/Arg: OR=0.93, 95%CI=0.71–1.22; Arg/Pro vs. Arg/Arg: OR=0.79, 95%CI=0.55–1.13; (Pro/Pro + Arg/Pro) vs. Arg/Arg: OR=0.84, 95%CI=0.62–1.13; Pro/Pro vs. (Arg/Arg + Arg/Pro): OR=1.06, 95%CI=0.83–1.35). Similar results were also found in stratified analysis according to ethnicity and source of controls.

Conclusions

Our meta-analysis demonstrates that p53 codon 72 polymorphism may not be a risk factor for AML, which should be verified in future studies.

Piezoelectric Versus Conventional Rotary Techniques for Impacted Third Molar Extraction: A Meta-analysis of Randomized Controlled Trials

Impacted third molars are frequently encountered in clinical work. Surgical removal of impacted third molars is often required to prevent clinical symptoms. Traditional rotary cutting instruments are potentially injurious, and piezosurgery, as a new osteotomy technique, has been introduced in oral and maxillofacial surgery. No consistent conclusion has been reached regarding whether this new technique is associated with fewer or less severe postoperative sequelae after third molar extraction.The aim of this study was to compare piezosurgery with rotary osteotomy techniques, with regard to surgery time and the severity of postoperative sequelae, including pain, swelling, and trismus.We conducted a systematic literature search in the Cochrane Library, PubMed, Embase, and Google Scholar.The eligibility criteria of this study included the following: the patients were clearly diagnosed as having impacted mandibular third molars; the patients underwent piezosurgery osteotomy, and in the control group rotary osteotomy techniques, for removing impacted third molars; the outcomes of interest include surgery time, trismus, swelling or pain; the studies are randomized controlled trials.We used random-effects models to calculate the difference in the outcomes, and the corresponding 95% confidence interval. We calculated the weighted mean difference if the trials used the same measurement, and a standardized mean difference if otherwise.A total of seven studies met the eligibility criteria and were included in our analysis. Compared with rotary osteotomy, patients undergoing piezosurgery experienced longer surgery time (mean difference 4.13 minutes, 95% confidence interval 2.75-5.52, P < 0.0001). Patients receiving the piezoelectric technique had less swelling at postoperative days 1, 3, 5, and 7 (all Ps ≤0.023). Additionally, there was a trend of less postoperative pain and trismus in the piezosurgery groups.The number of included randomized controlled trials and the sample size of each trial were relatively small, double blinding was not possible, and cost analysis was unavailable due to a lack of data.Our meta-analysis indicates that although patients undergoing piezosurgery experienced longer surgery time, they had less postoperative swelling, indicating that piezosurgery is a promising alternative technique for extraction of impacted third molars.

Effect of Probiotics on Blood Lipid Concentrations: A Meta-Analysis of Randomized Controlled Trials

Previous clinical studies have reported mixed results regarding the effect of probiotics on lipid metabolism. Therefore, we conducted a meta-analysis of randomized controlled trials to quantify the direction and magnitude of the potential effect of probiotics on blood lipid concentrations.Eligible studies were randomized, placebo-controlled trials whose interventions were probiotic products containing live bacteria. The studies reported net changes in lipid profiles (total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides) and their associated standard deviations (or the data to calculate them). The probiotic products did not contain prebiotics or other active ingredients, and the full article was accessible in English.The pooled mean net change in lipid profiles and 95% confidence intervals (95% CIs) were calculated. Q statistics and I were calculated to examine heterogeneity. Potential sources of heterogeneity were investigated via subgroup and sensitivity analyses, and publication biases were estimated.A total of 30 randomized controlled trials with 1624 participants (828 in intervention groups and 796 in placebo groups) were included in this analysis. Subjects treated with probiotics demonstrated reduced total cholesterol and LDL cholesterol compared to control subjects by 7.8 mg/dL (95% CI: -10.4, -5.2) and 7.3 mg/dL (95% CI: -10.1, -4.4), respectively. There was no significant effect of probiotics on HDL cholesterol or triglycerides. The effect of probiotics on total cholesterol and LDL cholesterol depended on a variety of factors. The significant effects were greater for higher baseline total cholesterol levels, longer treatment durations, and certain probiotic strains. In addition, these associations seem stronger in studies supported by probiotics companies.The studies included in this meta-analysis showed significant heterogeneity as indicated by the Q statistics and I. In addition, industry sponsorship may affect study findings.These results suggest that the use of probiotics may improve lipid metabolism by decreasing total and LDL cholesterol concentrations. However, both the efficacy of probiotics for cholesterol lowering and safety should be investigated further in well-designed clinical trials.

Tumor necrosis factor-alpha G-238A polymorphism and coronary artery disease risk: a meta-analysis of 4,222 patients and 4,832 controls

BACKGROUND

The aim of the present study was to investigate the association between tumor necrosis factor-alpha (TNF-α) gene G-238A polymorphism and risk of coronary artery disease (CAD) using a meta-analytical approach.

METHODS

The PubMed and Embase databases were searched for relevant publications up to January 13, 2015. Four authors (XPH, XDZ, XTZ, and ZJZ) independently selected the studies, extracted, and analyzed the data using the Comprehensive Meta-Analysis software. The sensitivity and subgroups analyses were also performed. Either a fixed effects or a random effects model was used to estimate pooled odds ratios (ORs) and their 95% confidence intervals (CIs).

RESULTS

Finally, ten articles including eleven case-control studies involving 4,222 patients and 4,832 controls were yielded. The results indicated no significant association between G-238A polymorphism and CAD risk (A vs G: OR =1.08, 95% CI =0.89-1.30; AA vs GG: OR =1.15, 95% CI =0.59-2.25; GA vs GG: OR =1.14, 95% CI =0.88-1.48; AA vs [GG + GA]: OR =1.09, 95% CI =0.56-2.14; (GA + AA) vs GG: OR =1.11, 95% CI =0.90-1.38). In the subgroup analyses, similar results were obtained with overall populations. The sensitivity analyses showed that the overall results were robust. No publication bias was detected.

CONCLUSION

Based on current evidence, we can conclude that TNF-α G-238A polymorphism might not be associated with CAD risk.

Causes of Death Following Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-Analysis

Background

Transcatheter aortic valve replacement (TAVR) is an effective alternative to surgical aortic valve replacement in patients at high surgical risk. However, there is little published literature on the exact causes of death.

Methods and Results

The PubMed database was systematically searched for studies reporting causes of death within and after 30 days following TAVR. Twenty-eight studies out of 3934 results retrieved were identified. In the overall analysis, 46.4% and 51.6% of deaths were related to noncardiovascular causes within and after the first 30 days, respectively. Within 30 days of TAVR, infection/sepsis (18.5%), heart failure (14.7%), and multiorgan failure (13.2%) were the top 3 causes of death. Beyond 30 days, infection/sepsis (14.3%), heart failure (14.1%), and sudden death (10.8%) were the most common causes. All possible subgroup analyses were made. No significant differences were seen for proportions of cardiovascular deaths except the comparison between moderate (mean STS score 4 to 8) and high (mean STS score >8) -risk patients after 30 days post-TAVR (56.0% versus 33.5%, P=0.005).

Conclusions

Cardiovascular and noncardiovascular causes of death are evenly balanced both in the perioperative period and at long-term follow-up after TAVR. Infection/sepsis and heart failure were the most frequent noncardiovascular and cardiovascular causes of death. This study highlights important areas of clinical focus that could further improve outcomes after TAVR.

Quantitative assessment of the effect of epidermal growth factor 61A/G polymorphism on the risk of hepatocellular carcinoma

The association between hepatocellular carcinoma (HCC) and the epidermal growth factor (EGF) 61A/G polymorphism has been analyzed in several studies, but results remain inconsistent. Therefore, the aim of the present study was to quantitatively summarize the association between the EGF 61A/G polymorphism and the risk of HCC. The PubMed and EMBASE databases were searched for studies published prior to May 1, 2014. The overall, subgroup and sensitivity analyses were conducted using Comprehensive Meta-Analysis software, version 2.2. In total, 12 published case-control studies, consisting of 2,095 patients with HCC and 3,766 control individuals, were included in the present study. Meta-analysis of the included studies revealed that EGF 61A/G polymorphism contributed to the risk of HCC under all four genetic models, consisting of the G vs. A (OR, 1.25; 95% CI, 1.11-1.40), GG vs. AA (OR, 1.53; 95% CI, 1.26-1.85), GG vs. AG + AA (OR, 1.34; 95% CI, 1.13-1.58) and GG + AG vs. AA (OR, 1.27; 95% CI, 1.08-1.49) comparisons. Subgroup analysis further suggested that EGF 61A/G polymorphism was associated with the risk of HCC in patients and control individuals with liver disease, based on ethnicity and source of control, respectively. No other significance in residual subgroup analysis was observed. The present meta-analysis suggests that the EGF 61A/G polymorphism is associated with an increased risk of HCC and may be a potential marker for liver disease, such as hepatitis B virus infection, hepatitis C virus infection and liver cirrhosis.

The Role of TP53 Gene Codon 72 Polymorphism in Leukemia: A PRISMA-Compliant Systematic Review and Meta-Analysis

The purpose of this meta-analysis was aimed to evaluate the association of tumor protein p53 (TP53) gene codon 72 polymorphism with leukemia susceptibility. We searched PubMed to identify relevant studies, and 16 case-control studies from 14 published articles were identified as eligible studies, including 2062 leukemia patients and 5826 controls. After extracting data, odds ratio (OR) with the corresponding 95% confidence interval (95%CI) was applied to assess the association between TP53 codon 72 polymorphism and leukemia susceptibility. The meta-analysis was performed with the Comprehensive Meta-Analysis software, version 2.2. Overall, no significant association between TP53 codon 72 polymorphism and leukemia susceptibility was found in this meta-analysis (Pro vs Arg: OR = 1.05, 95%CI = 0.90-1.21; Pro/Pro vs Arg/Arg: OR = 1.13, 95%CI = 0.84-1.52; Arg/Pro vs Arg/Arg: OR = 0.94, 95%CI = 0.76-1.15; [Pro/Pro + Arg/Pro] vs Arg/Arg: OR = 0.99, 95%CI = 0.80-1.21; Pro/Pro vs [Arg/Arg + Arg/Pro]: OR = 1.19, 95%CI = 0.93-1.51). Similar results were also found in subgroup analysis by ethnicity, source of controls, and types of leukemia (either acute myeloid leukemia or acute lymphocytic leukemia). Our meta-analysis demonstrates that TP53 codon 72 polymorphism may not be a risk factor for acute leukemia; however, due to the limitations of this study, it should be verified in future studies.

Long-Term Coffee Consumption and Risk of Gastric Cancer: A PRISMA-Compliant Dose-Response Meta-Analysis of Prospective Cohort Studies

Association between coffee consumption and gastric cancer risk remains controversial. Hence, we performed a meta-analysis to investigate and quantify the potential dose-response association between long-term coffee consumption and risk of gastric cancer.Pertinent studies were identified by searching PubMed and Embase from January 1996 through February 10, 2015 and by reviewing the reference lists of retrieved publications. Prospective cohort studies in which authors reported effect sizes and corresponding 95% confidence intervals (CIs) of gastric cancer for 3 or more categories of coffee consumption were eligible. Results from eligible studies were aggregated using a random effect model. All analyses were carried out using the STATA 12.0 software.Nine studies involving 15 independent prospective cohorts were finally included. A total of 2019 incident cases of gastric cancer were ascertained among 1,289,314 participants with mean follow-up periods ranging from 8 to 18 years. No nonlinear relationship of coffee consumption with gastric cancer risk was indentified (P for nonlinearity = 0.53; P for heterogeneity = 0.004). The linear regression model showed that the combined relative risk (RR) of every 3 cups/day increment of total coffee consumption was 1.07 (95% CI = 0.95-1.21). Compared with the lowest category of coffee consumption, the RR of gastric cancer was 1.18 (95% CI = 0.90-1.55) for the highest (median 6.5 cups/day) category, 1.06 (95% CI = 0.85-1.32) for the second highest category (median 3.5 cups/day), and 0.97 (95% CI = 0.79-1.20) for the third highest category (median 1.5 cups/day). Subgroup analysis showed an elevated risk in the US population (RR = 1.36, 95% CI = 1.06-1.75) and no adjustment for smoking (RR = 1.67, 95% CI = 1.08-2.59) for 6.5 cups/day.Current evidence indicated there was no nonlinear association between coffee consumption and gastric cancer risk. However, high coffee consumption (more than 6.5 cups/day) might increase the risk of gastric cancer in the US population. More high quality studies were warranted to further investigate the association.

Significant association between functional microRNA polymorphisms and head and neck cancer susceptibility: a comprehensive meta-analysis

Molecular epidemiological studies have showed a closer association between microRNA polymorphisms with and head and neck cancer (HNC) risk. But the results of these studies were inconsistent. We performed this meta-analysis to clarify the associations between microRNA polymorphisms and HNC risk. Four electronic databases (PubMed, Embase, CNKI, and Wanfang) were searched. Odds ratios (ORs) with 95% confidence interval (CIs) were calculated to assess the association between microRNA-146a rs2910164 G > C, microRNA-196a2 rs11614913 C > T, microRNA-149 rs2292832 C > T, microRNA-499 rs3746444 A > G polymorphisms and HNC risk. Heterogeneity, publication bias and sensitivity analysis were conducted to guarantee the statistical power. Overall, 11 selected articles involving 16100 subjects were included in this meta-analysis. Significantly increased risk between microRNA-146a rs2910164 G > C polymorphism and HNC risk were observed in Caucasian population (GC vs. GG: OR = 1.31, 95%CI = 1.01–1.68; GC + CC vs. GG: OR = 1.26, 95%CI = 1.02–1.57). For microRNA-196a2 rs11614913 C > T, similarly increased risk were also found in Asian population (T vs. C, OR = 1.14, 95%CI = 1.04–1.25; TT vs. CC, OR = 1.33, 95%CI = 1.09–1.61; CT + TT vs. CC OR = 1.32, 95%CI = 0.99–1.76; TT vs. CC + CT, OR = 1.14, 95%CI = 0.99–1.33). In addition, no significant association was detected between microRNA-149 rs2292832 C > T and microRNA-499 rs3746444 A > G polymorphism and HNC risk. This meta-analysis demonstrates that microRNA polymorphisms are associated with HNC development based on ethnicity diversity.

Subclinical Hypothyroidism and Type 2 Diabetes: A Systematic Review and Meta-Analysis

Background

Abundant evidence suggests an association between subclinical hypothyroidism (SCH) and type 2 diabetes mellitus (T2DM), but small sample sizes and inconclusive data in the literature complicate this assertion.

Objective

We measured the prevalence of SCH in T2DM population, and investigated whether T2DM increase the risk of SCH and whether SCH was associated with diabetic complications.

METHODS

We conducted a meta-analysis using PubMed, EMBASE, Web of Science, Wan Fang, CNKI and VIP databases for literature search. We obtained studies published between January 1, 1980 to December 1, 2014. The studies were selected to evaluate the prevalence of SCH in T2DM subjects, compare the prevalence of SCH in T2DM subjects with those non-diabetics, and investigate whether diabetic complications were more prevalent in SCH than those who were euthyroid. Fixed and random effects meta-analysis models were used, and the outcome was presented as a pooled prevalence with 95% confidence interval (95% CI) or a summary odds ratio (OR) with 95% CI.

RESULTS

Through literature search, 36 articles met the inclusion criteria and these articles contained a total of 61 studies. Funnel plots and Egger’s tests showed no publication bias in our studies, except for the pooled prevalence of SCH in T2DM (P = 0.08) and OR for SCH in T2DM (P = 0.04). Trim and fill method was used to correct the results and five potential missing data were replaced respectively. The adjusted pooled prevalence of SCH in T2DM patients was 10.2%, meanwhile, T2DM was associated with a 1.93-fold increase in risk of SCH (95% CI: 1.66, 2.24). Furthermore, SCH might affect the development of diabetic complications with an overall OR of 1.74 (95% CI: 1.34, 2.28) for diabetic nephropathy, 1.42 (95% CI: 1.21, 1.67) for diabetic retinopathy, 1.85 (95% CI: 1.35, 2.54) for peripheral arterial disease, and 1.87 (95% CI: 1.06, 3.28) for diabetic peripheral neuropathy.

Conclusions

T2DM patients are more likely to have SCH when compared with healthy population and SCH may be associated with increased diabetic complications. It is necessary to screen thyroid function in patients with T2DM, and appropriate individualized treatments in addition to thyroid function test should be given to T2DM patients with SCH as well.

Systematic Review by Multivariate Meta-analyses on the Possible Role of Tumor Necrosis Factor-α Gene Polymorphisms in Association with Ischemic Stroke

A number of studies have investigated the association between tumor necrosis factor (TNF)-α gene polymorphisms and ischemic stroke susceptibility. However, results of different individual studies are often inconsistent. To provide a more robust evaluation of the association between polymorphisms of the TNF-α gene and ischemic stroke risk, we performed a systematic review with multivariate meta-analyses. PubMed, Embase, CNKI, and WanFang databases were searched up to December 20, 2014. Two reviewers independently extracted information and assessed quality of included studies after all the eligible studies were identified. Afterward, multivariate meta-analyses were performed using Stata 13. The estimation of polymorphisms and disease risk was presented by odds ratios (ORs) and corresponding 95 % confidence intervals (CIs). Forty-nine eligible case-control studies from 25 articles that explored the association between 10 TNF-α polymorphisms and ischemic stroke were indentified from aforementioned databases. The results of multivariate meta-analysis showed a significant association between -238G/A polymorphism (4760 patients and 4389 controls) and ischemic stroke risk in heterozygotes compared with wild genotype (AG vs. GG: OR 1.44, 95 % CI 1.11-1.87; AA vs. GG: OR 1.98, 95 % CI 0.73-5.40). No significant association of -308G/A, -857C/T, and -1031T/C polymorphisms was observed. The results of stratification analyses of -238G/A polymorphism showed that the AG genotype only increased the risk of ischemic stroke in Asians compared to GG genotype. No additional significant association was observed in this study. In conclusion, the present systematic review and meta-analysis support a prominent role of the TNF-α -238G/A polymorphism in the risk of ischemic stroke in Asian adults only, but do not support the role of -308G/A, -857C/T, -1031T/C, -244G/A, -367G/A, -646G/A, -806C/T, -863C/A, and +448G/A in the risk of ischemic stroke. The current evidence warrants further studies with high quality and large sample size to confirm.

Oral sex and risk of oral cancer: a meta-analysis of observational studies

OBJECTIVE

Association between oral sex and oral cancer is a highlighted topic all the time; however, many published epidemiological studies remain failed to obtain a consistent conclusion. We performed this meta-analysis to ascertain whether oral sex is a risk factor or a risk marker for oral cancer.

METHOD

The PubMed database was searched up to 30 August 2013 (latest updated on 21 December 2014) for relevant observational studies that tested the association between oral sex and oral cancer risk. After data extraction from eligible studies, the meta-analysis was conducted using the Comprehensive Meta-Analysis software.

RESULTS

Finally we yielded six case-control studies and one cross-sectional study with 5553 individuals. The results based on random-effects model indicated that there was no significant association between oral sex and risk of oral cancer (OR 1.15, 95% CI 0.86 to 1.54; P = 0.33). Sensitivity analysis showed that the result was robust and subgroups analyses also revealed similar results. Publication bias was not detected.

CONCLUSION

Current evidence suggests that oral sex is a risk marker rather than an independent risk factor for oral cancer. However, the practitioners should assure they are without sexually transmitted diseases and with good oral health, and at least cleaned carefully and thoroughly before oral sex.

Fat Intake Is Not Linked to Prostate Cancer: A Systematic Review and Dose-Response Meta-Analysis

Background

Since the late 1960s, the average global supply of fat has increased by 20 g per capita per day. While fat intake has been considered a potential risk factor for prostate cancer (Pca), the hypothesis from previous epidemiologic studies remained equivocal.

Materials and Methods

Relevant cohort studies were identified through a literature search in PubMed, ScienceDirect and Wiley Online Library up to March 1, 2015. A systematic review and dose-response meta-analysis were used to assess the relationship between fat intake and the risk for Pca.

Results

We identified 14 cohort studies, which included 37,349 cases and a total of 751,030 participants. We found no evidence of a non-linear association between fat intake and the risk for Pca. Overall, the summarized relative risks for every 28.35 g increment a day was 0.99 (95%CI: 0.98, 1.01; P=0.94; n=13) for total fat intake, 1.00 (95%CI: 1.00, 1.00; P=0.72; n=9) for saturated fat, 0.99 (95%CI: 0.95, 1.03; P=0.55; n=7) for polyunsaturated fat, and 1.00 (95%CI: 0.95, 1.04; P=0.85; n=8) for monounsaturated fat. Additionally, there was no link to the risk for advanced stage Pca regarding total fat intake (RR=1.02, 95%CI: 0.96, 1.08; P=0.63; n=5), saturated fat (RR=0.96, 95%CI: 0.84, 1.11; P=0.61; n=6), polyunsaturated fat (RR=0.96, 95%CI: 0.79, 1.17; P=0.68; n=6), or monounsaturated fat (RR=0.96, 95%CI: 0.86, 1.07; P=0.42; n=6). Subgroup and sensitively analyses showed consistent results.

Conclusion

Little evidence from published cohort studies supports the statement that total fat, saturated fat or unsaturated fat intake increases the risk for Pca or advanced stage Pca.

Association of Dietary Vitamin D and Calcium With Genetic Polymorphisms in Colorectal Neoplasia

The incidence trends of colorectal cancer have varied over time, and there is wide geographical variation across the world. Regarding colorectal cancer, diverse modifiable environmental or intrinsic risk factors have been investigated. This review summarizes the effects of both dietary intake of vitamin D and calcium in particular and diet-associated genetic factors on colorectal cancer risk. We searched the electronic database PubMed for articles published between January 2000 and March 2015. We reviewed case-control studies that included dietary factors, genetic polymorphisms, and gene-diet interactions in association with colorectal cancer risk. Overall, 21 studies were selected as eligible studies. These studies demonstrated that dietary consumption of vitamin D and calcium may decrease the risk of colorectal cancer or adenoma. Colorectal carcinogenesis was discussed in conjunction with dietary factors and mediating genetic factors. The epidemiological findings suggested that the gene-diet interactions may possibly alter the associations between dietary intake, genetic polymorphisms, and the risk of colorectal cancer. However, the reported effects of the same potential factors on colorectal cancer risk were inconsistent, depending on the study population and geographical location. This finding may imply the necessity of considering the environmental differences and genetic variations existing between individuals or specified populations. Therefore, further studies are required to investigate modifiable risk factors in diverse locations to derive useful implications for colorectal neoplasia.

Intramedullary nailing versus plating for distal tibia fractures without articular involvement: a meta-analysis

Background

The choice between intramedullary (IM) nailing or plating of distal tibia fractures without articular involvement remains controversial. A meta-analysis of randomized controlled trials (RCTs) and observational studies was performed to compare IM nailing with plating for distal tibia fractures without articular involvement and to determine the dominant strategy.

Materials and methods

The PubMed, Embase, Cochrane Library databases, Chinese Wan-Fang Database, and China National Knowledge Infrastructure were searched.

Results

Twenty-eight studies, which included 1863 fractures, met the eligible criteria. The meta-analysis did not identify a statistically significant difference between the two treatments in terms of the rate of deep infection, delayed union, removal of instrumentation, or secondary procedures either in the RCT or retrospective subgroups. IM nailing was associated with significantly more malunion events and a higher incidence of knee pain in the retrospective subgroup and across all the studies, but not significantly in the RCT subgroup, and a lower rate of delayed wound healing and superficial infection both in the RCT and retrospective subgroups relative to plating. A meta-analysis of the functional scores or questionnaires was not possible because of the considerable variation among the included studies, and no significant differences were observed.

Conclusions

Evidence suggests that both IM nailing and plating are appropriate treatments as IM nailing shows lower rate of delayed wound healing and superficial infection and plating may avoid malunion and knee pain. These findings should be interpreted with caution, however, because of the heterogeneity of the study designs. Large, rigorous RCTs are required.

Sleep in patients with primary dystonia: A systematic review on the state of research and perspectives

Patients with primary dystonia, the third most prevalent movement disorder, suffer from a markedly reduced quality of life. This might, at least in part, be mediated by non-motor symptoms, including sleep disturbances. Characterising and treating sleep disturbances might provide new inroads to improve relevant patient-centred outcomes. This review evaluates the state of research on sleep in patients with dystonia and outlines an agenda for future research. A literature search was performed in July 2014 using PubMed, Medline via Ovid, PsycInfo, PsycArticles via Proquest and Embase via Ovid. Search results were screened for eligibility by two independent raters. Peer-reviewed publications reporting on sleep in patients with primary dystonia were included. Of 1445 studies identified through the search strategy, 18 met the inclusion criteria. In total, the included studies reported on 708 patients diagnosed with focal dystonia (cervical dystonia or blepharospasm), torsion dystonia, and dopa-responsive dystonia. The results indicate that at least half of the patients with focal cranial dystonia suffer from sleep disturbances, but excessive daytime sleepiness is uncommon. Sleep disturbance is associated with depressive symptoms. The frequency and duration of dystonic movements is markedly reduced during sleep. Reduced sleep quality appears to persist after treatment with botulinum toxin that successfully reduces motor symptoms. The findings are limited by a high clinical and methodological heterogeneity. Future research is needed to i) further characterize subjective and PSG sleep in patients with different types of dystonia, ii) determine the aetiology of sleep disturbances (e.g., abnormal brain function associated with dystonia, side effects of medication, psychological reasons), and iii) test whether targeted sleep interventions improve sleep and quality of life in patients with primary dystonia.