Helicobacter pylori infection and risk of preeclampsia: a systematic review and meta-analysis.

OBJECTIVE: Helicobacter pylori is associated with many pregnancy adverse effects such as preeclampsia (PE). We performed this systematic review and meta-analysis study to assess the possible association between H. pylori infection and PE and this is the first meta-analysis to clarify this issue. METHODS: PubMed, ISI (Web of Science), SCOPUS, and Google Scholar databases were searched (up to April 2017) to identify the relevant studies. The Meta-analysis of Observational Studies in Epidemiology and Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines were used to do this study. Pooled odds ratio (OR) and 95% confidence intervals (CI) were estimated using a random-effects meta-analysis model. Heterogeneity was assessed with the χ2-based Q-test and I2 statistic. RESULTS: A total of eight studies including 889 participants (460 preeclamptic women and 429 controls) met the eligibility criteria. A positive association was found between H. pylori infection and PE (OR: 3.35; 95% CI: 2.21-5.10). Heterogeneity was acceptable (χ2 = 13.39; I2 = 47.7, 95% CI: 0-77). In subgroup analysis, cytotoxin-associated antigen A seropositivity was a substantial risk factor for PE when immunoblotting methods (OR: 11.12; 95% CI: 5.34-23.16; χ2 = 6.42; I2 = 53.3, 95% CI: 0-85) were used, whereas it was not potential risk factor for PE when ELISA was used as a detecting method (OR: 1.11; 95% CI: 0.6-2.06; χ2 = 1.83; I2 = 0, 95% CI: 0-90). CONCLUSIONS: This study indicated that women with H. pylori infection, especially those infected with Cag A positive strains are more likely to have PE compared with the uninfected women.

The role of Blastocystis sp. and Dientamoeba fragilis in irritable bowel syndrome: a systematic review and meta-analysis.

Irritable bowel syndrome (IBS) is globally one of the most prevalent gastrointestinal disorders with a negative impact on quality of life and socio-economic status of patients. Recently, controversial evidences suggest that Blastocystis sp. and Dientamoeba fragilis infections may be implicated in the development of IBS. We performed a systematic review and meta-analysis to examine the possible association regarding this issue. PubMed, ScienceDirect, Scopus, Web of Science, and Cochrane electronic databases were searched (up to February 2017) to identify the relevant studies. Pooled odds ratio (OR) and 95% confidence intervals were estimated using a random effects meta-analysis model on data from included studies. A total of 17 studies including 5882 participants (2527 patients and 3310 controls) met the eligibility criteria. Individuals with Blastocystis infection were found to have a positive association with IBS (OR, 2.19; 95% CI, 1.54-3.13), while this association was not observed for D. fragilis infection (OR, 1.13; 95% CI, 0.22-5.72). In subgroup analysis for Blastocystis infection, the pooled ORs were OR 2.29, 95% CI 1.55-3.41; OR 1.70, 95% CI 0.83-3.44; and OR 3.83, 95% CI 2.34-6.27 for hospital-based, healthy volunteers, and combined controls, respectively. Considering the subtypes, meta-analysis result demonstrated significant positive ORs for ST1 (OR, 4.40; 95% CI, 2.81-6.90) and ST3 (OR, 1.94; 95% CI, 1.36-2.77) to be potential risk factors for IBS. Our results support the existence of a positive association between Blastocystis sp. and IBS. Further studies with more sample size should be performed to better investigate the real impact of these parasites on the occurrence of IBS.