Background: The findings of individual epidemiological studies that suggest an association between some Persistent Organic Pollutants (POPs) and Gestational Diabetes Mellitus (GDM) are inconclusive. Objectives: To estimate the strength of the association between POPs exposure and GDM in a systematic review with meta-analysis. Search strategy: MEDLINE, Scopus, and Web of Science were searched until 2022. Selection criteria: Cohort and case-control studies analyzing the association between POPs and GDM in healthy pregnant women. Data collection and analysis: Quality was assessed using QUIPS scale and standardized mean differences (SMD) and 95% confidence intervals (CI) was pooled using random-effect model. Main results: Fourteen articles including 11,422 participants were selected. The risk of bias of included studies was high in 4 (28.6%), moderate in 9 (64.3%) and low in 1 (7.14%). Only six POPs showed a significative SMD between GDM cases and controls: Perfluorobutanesulfonic acid (PFBS) 0.33 (95% CI 0.23, 0.43; I2=0%); Perfluorodecanoic acid (PFDA) -0.11 (95% CI -0.20, -0.01, I2 = 0.0%); 2,2’,3,4,4’,5,5’-Heptachlorobiphenyl (PCB 180) 0.37 (95% CI 0.19, 0.56; I2=25.3%); 2,2’,4,4’,5-Decabromodiphenyl ether (BDE 99) 0.36 (95% CI 0.14, 0.59; I2=0%); 2,2’,4,4’,6-Decabromodiphenyl ether (BDE 100) 0.42 (95% CI 0.19, 0.38; I2=0%); and, Hexachlorobenzene (HCB) 0.22 (95% CI 0.01, 0.42, I2=39.6%). For other POPs, no statistically significant association was observed. Conclusion: The available evidence is variable on quality and results were heterogeneous making impossible to establish a clear association between POPs exposure and risk of GDM. Improve the methodology of epidemiological studies assessing the association of POPs and risk of adverse clinical outcomes are needed.

Background: The trustworthiness of randomised clinical trials (RCTs) is suffering a crisis of confidence. Objectives: We undertook an umbrella review of the research integrity literature concerning RCTs. Search strategy and selection criteria: Following prospective registration (https://osf.io/3ursn), two reviewers independently searched PubMed, Scopus, Cochrane Library and Google Scholar, without language or time restrictions until November 2021. We included systematic reviews covering any aspect of research integrity throughout the RCT lifecycle. Data collection and analysis: We assessed methodological quality using a modified AMSTAR-2 tool and collated the main findings. Main results: There were 55 relevant reviews summarising a total of 6001 studies (median per review 63; range 8-1106 studies). The overall quality of 53 (96.4%) reviews was critically low. Eight (14.6%) reviews focused on the general aspects of a RCT, 12 (21.8%) on the design and approval, 6 (10.9%) on the conduct and monitoring, 21 (38.2%) on the reporting of protocols and findings, one (1.8%) on post-publication concerns and 7 (12.7%) on future research and development. The integrity issues covered were varied, the most common being the importance of ethics (10/55, 18.2%) and transparency (10/55, 18.2%). Conclusions: Various research integrity issues covering RCT lifecycle, captured from mostly low-quality reviews, provided a broad overview emphasising the need for high level of ethical standards and professionalism. Many gaps in the RCT integrity landscape were also identified. There is a need to generate multistakeholder consensus to create specific RCT integrity standards.

Background: Endometriosis is a chronic, often debilitating condition with a current significant delay from symptom onset to diagnosis. Objectives: To investigate the accuracy of symptoms, clinical history and non-invasive tests to predict pelvic endometriosis. Data sources: Medline, Embase, Web of Science and Scopus from conception to September 2022. Selection criteria: Primary test accuracy studies assessing selected non-invasive tests against a reference standard diagnosis for endometriosis. Data extraction and synthesis: Two authors independently conducted data extraction and study quality assessment. Grading of evidence was performed using a novel visual pentagon model. Meta-analyses of test accuracy was estimated using bivariate random effects models. Results: The 125 included studies (250,574 participants) showed mixed quality. Studies applying non-surgical (database/self-reporting) reference standard had a greater risk of bias. In 98 studies applying surgical reference standard, summary diagnostic odds ratios were: dysmenorrhoea 2.56 (95% confidence interval 1.99-3.29); pelvic pain 2.56 (1.73-3.74); dyschezia 2.05 (1.36-3.10); dyspareunia 2.45 (1.71-3.52); family history of endometriosis 6.79 (4.08-11.3); nulligravidity of 2.01 (1.62-2.50); BMI ≥30kg/m2 0.37 (0.19-0.68); TVUSS endometrioma 91.2 (44.0-189); TVUSS invasive endometriosis 26.1 (9.28-73.5); and CA-125 >35U/mL 16.0 (8.09-31.7). Sensitivity analysis excluding all high-risk studies found concordant results. Conclusions: This meta-analysis collated the performance of non-invasive tests for endometriosis across a comprehensive and geographically varied population. Study quality was mixed, however results were consistent with high-risk studies excluded. These findings will inform future prediction models for triage in primary care. Funding: This research received no specific funding. Keywords: Endometriosis; diagnosis; laparoscopy; pelvic pain; sub-fertility