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The American Journal of Gastroenterology Jan 2017Celiac disease (CD) and irritable bowel syndrome (IBS) share similar symptoms, leading to confusion between the two and diagnostic delay. International guidelines... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
Celiac disease (CD) and irritable bowel syndrome (IBS) share similar symptoms, leading to confusion between the two and diagnostic delay. International guidelines recommend screening individuals with IBS for CD, via serological testing. However, studies published recently have cast doubt on the utility of this. We updated a previous meta-analysis examining this issue.
METHODS
MEDLINE, EMBASE, and EMBASE Classic were searched through to May 2016. Eligible studies recruited adults with IBS according to symptom-based criteria, physician's opinion, or questionnaire data. Tests for CD included IgA-class antigliadin antibodies (AGA), endomysial antibodies (EMA), tissue transglutaminase antibodies (tTG), or duodenal biopsies following positive serology. The proportion of individuals meeting criteria for IBS testing positive for CD was combined to give a pooled prevalence for all studies, and compared between cases with IBS and, healthy controls without (where reported), using an odds ratio (OR) with a 95% confidence interval (CI).
RESULTS
There were 36 eligible studies, recruiting 15,256 individuals, of whom 9,275 (60.8%) met criteria for IBS. Pooled ORs for positive IgA AGAs, EMA and/or tTG, and biopsy-proven CD in IBS subjects vs. controls were 3.21 (95% CI 1.55-6.65), 2.75 (95% CI 1.35-5.61), and 4.48 (95% CI 2.33-8.60), respectively. There was no increase in ORs for any test for CD among cases with IBS in North American studies, and results were inconsistent in population-based studies. The prevalence of biopsy-proven CD was significantly higher across all subtypes of IBS. Limitations included heterogeneity in some analyses, and few North American studies.
CONCLUSIONS
Overall, prevalence of positive celiac serology and biopsy-proven CD was significantly higher in subjects with symptoms suggestive of IBS vs. healthy controls. However, the utility of screening for CD in individuals with suspected IBS in North America or in the community is less clear.
Topics: Antibodies; Autoantibodies; Biopsy; Case-Control Studies; Celiac Disease; Delayed Diagnosis; Diagnosis, Differential; Duodenum; GTP-Binding Proteins; Gliadin; Humans; Immunoglobulin A; Irritable Bowel Syndrome; Mass Screening; Odds Ratio; Prevalence; Protein Glutamine gamma Glutamyltransferase 2; Serologic Tests; Transglutaminases
PubMed: 27753436
DOI: 10.1038/ajg.2016.466 -
Medicine Aug 2016Rs1495741 has been identified to infer N-acetyltransferase 2 (NAT2) acetylator phenotype, and to decrease the risk of bladder cancer. However, a number of studies... (Meta-Analysis)
Meta-Analysis Review
rs1495741 as a tag single nucleotide polymorphism of N-acetyltransferase 2 acetylator phenotype associates bladder cancer risk and interacts with smoking: A systematic review and meta-analysis.
Rs1495741 has been identified to infer N-acetyltransferase 2 (NAT2) acetylator phenotype, and to decrease the risk of bladder cancer. However, a number of studies conducted in various regions showed controversial results. To quantify the association between rs1495741 and the risk of bladder cancer and to estimate the interaction effect of this genetic variant with smoking, we performed a systematic literature review and meta-analysis involving 14,815 cases and 58,282 controls from 29 studies. Our results indicates rs1495741 significantly associated with bladder cancer risk (OR = 0.85, 95% CI = 0.82-0.89, test for heterogeneity P = 0.36, I = 7.0%). And we verified this association in populations from Europe, America, and Asia. Further, our stratified meta-analysis showed rs1495741's role is typically evident only in ever smokers, which suggests its interaction with smoking. This study may provide new insight into gene-environment study on bladder cancer.
Topics: Arylamine N-Acetyltransferase; Female; Genetic Predisposition to Disease; Genotype; Humans; Male; Phenotype; Polymorphism, Single Nucleotide; Prevalence; Prognosis; Risk Assessment; Smoking; Urinary Bladder Neoplasms
PubMed: 27495060
DOI: 10.1097/MD.0000000000004417 -
The Turkish Journal of Gastroenterology... Mar 2016The current systematic review and meta-analysis study assessed the prevalence of celiac disease (CD) in Iran. (Meta-Analysis)
Meta-Analysis Review
BACKGROUND/AIMS
The current systematic review and meta-analysis study assessed the prevalence of celiac disease (CD) in Iran.
MATERIALS AND METHODS
Electronic databases, including MEDLINE, SCOPUS, Web of Science, Cochrane library Collaboration, and Iranian scientific databases, were searched from 1993 to 2013 for English and Persian articles. The following terms were used, alone or combined, "celiac (MeSH)," "ceoliac," "prevalence (MeSH)," and "Iran*." Heterogeneity was assessed using the I2 statistic with a cut-off value of 50%, and the Chi-square test was used to define a statically significant degree of heterogeneity with a p value of <0.10. The publication bias of literatures was assessed by visual examination of the funnel plot and Begger's funnel plot.
RESULTS
Meta-analysis was conducted on seven publications with 9,720 subjects. Overall, the pooled prevalence of CD among the Iranian population was 0.72% [95% confidence interval (CI): 0.62%-0.98%]. There was no significant heterogeneity among the studies (I2=4%, p=0.396). The pooled prevalence of CD on the basis of IgA-anti tissue transglutaminase (tTGA) and tTGA and duodenal biopsy positivity was 0.83% (95% CI: 0.69%-1.14%) and 0.79% (95% CI: 0.66%-1.09%), respectively. No significant publication bias was observed using the funnel plot and Begger's funnel plot.
CONCLUSION
CD prevalence among the Iranian population was approximately similar to that of the American and European populations.
Topics: Biopsy; Celiac Disease; Duodenum; Female; Humans; Immunoglobulin A; Iran; Male; Observational Studies as Topic; Prevalence; Transglutaminases
PubMed: 27015617
DOI: 10.5152/tjg.2015.150191 -
Arquivos de Gastroenterologia 2015The standard treatment of chronic hepatitis C is the administration of pegylated interferon α2a or α2b in combination with ribavirin, but adverse effects can be... (Review)
Review
BACKGROUND
The standard treatment of chronic hepatitis C is the administration of pegylated interferon α2a or α2b in combination with ribavirin, but adverse effects can be observed, as well as the high cost of this therapy. Therefore, there is interest in understanding the predictors of sustained virologic response, as the gamma glutamyltransferase.
OBJECTIVE
To evaluate the serum levels of gamma glutamyltransferase as a predictor of response to treatment with pegylated interferon α and ribavirin in chronic hepatitis C.
METHODS
This is a systematic review of literature, conducted by consulting PUBMED, LILACS, MEDLINE, SCOPUS, Cochrane electronic databases, and active search of articles selected between January 2000 and April 2013.
RESULTS
A total of 4,785 titles were identified. Out of those material, following inclusion and exclusion criteria, 273 abstracts were selected, by two independent researchers. After reading those texts, the reviewers consensually included ten studies for systematization and classification, according to the criteria of the Oxford Scale. 1B studies are predominant (prospective cohort study - six studies). Rapid virologic response and early virological response were considered as estimates for the sustained virological response. The frequency of virologic response was identified in three studies and early virological response in two, with a total of 392 and 413 patients, respectively; sustained virologic response was reported in nine articles corresponding to 3,787 patients (76.5 %).
CONCLUSION
Gamma glutamyltransferase is a predictor of sustained virologic response in the treatment of chronic hepatitis C with pegylated interferon α2a or α2b associated with ribavirin.
Topics: Antiviral Agents; Drug Therapy, Combination; Hepatitis C, Chronic; Humans; Interferon-alpha; Ribavirin; gamma-Glutamyltransferase
PubMed: 26486294
DOI: 10.1590/S0004-28032015000300016 -
International Journal of Epidemiology Feb 2016Low penetrance genetic variants, primarily single nucleotide polymorphisms, have substantial influence on colorectal cancer (CRC) susceptibility. Most CRCs develop from... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Low penetrance genetic variants, primarily single nucleotide polymorphisms, have substantial influence on colorectal cancer (CRC) susceptibility. Most CRCs develop from colorectal adenomas (CRA). Here we report the first comprehensive field synopsis that catalogues all genetic association studies on CRA, with a parallel online database [http://www.chs.med.ed.ac.uk/CRAgene/].
METHODS
We performed a systematic review, reviewing 9750 titles, and then extracted data from 130 publications reporting on 181 polymorphisms in 74 genes. We conducted meta-analyses to derive summary effect estimates for 37 polymorphisms in 26 genes. We applied the Venice criteria and Bayesian False Discovery Probability (BFDP) to assess the levels of the credibility of associations.
RESULTS
We considered the association with the rs6983267 variant at 8q24 as 'highly credible', reaching genome-wide statistical significance in at least one meta-analysis model. We identified 'less credible' associations (higher heterogeneity, lower statistical power, BFDP > 0.02) with a further four variants of four independent genes: MTHFR c.677C>T p.A222V (rs1801133), TP53 c.215C>G p.R72P (rs1042522), NQO1 c.559C>T p.P187S (rs1800566), and NAT1 alleles imputed as fast acetylator genotypes. For the remaining 32 variants of 22 genes for which positive associations with CRA risk have been previously reported, the meta-analyses revealed no credible evidence to support these as true associations.
CONCLUSIONS
The limited number of credible associations between low penetrance genetic variants and CRA reflects the lower volume of evidence and associated lack of statistical power to detect associations of the magnitude typically observed for genetic variants and chronic diseases. The CRA gene database provides context for CRA genetic association data and will help inform future research directions.
Topics: Adenoma; Alleles; Arylamine N-Acetyltransferase; Bayes Theorem; Colorectal Neoplasms; Genetic Predisposition to Disease; Genome-Wide Association Study; Humans; Isoenzymes; Methylenetetrahydrofolate Reductase (NADPH2); NAD(P)H Dehydrogenase (Quinone); Polymorphism, Single Nucleotide; Risk Factors; Tumor Suppressor Protein p53
PubMed: 26451011
DOI: 10.1093/ije/dyv185