The Navigation Guide—Evidence-Based Medicine Meets Environmental Health: Systematic Review of Nonhuman Evidence for PFOA Effects on Fetal Growth

Abstract

Background: In contrast to current methods of expert-based narrative review, the Navigation Guide is a systematic and transparent method for synthesizing environmental health research from multiple evidence streams. The Navigation Guide was developed to effectively and efficiently translate the available scientific evidence into timely prevention-oriented action.Objectives: We applied the Navigation Guide systematic review method to answer the question “Does fetal developmental exposure to perfluorooctanoic acid (PFOA) or its salts affect fetal growth in animals ?” and to rate the strength of the experimental animal evidence.Methods: We conducted a comprehensive search of the literature, applied prespecified criteria to the search results to identify relevant studies, extracted data from studies, obtained additional information from study authors, conducted meta-analyses, and rated the overall quality and strength of the evidence.Results: Twenty-one studies met the inclusion criteria. From the meta-analysis of eight mouse gavage data sets, we estimated that exposure of pregnant mice to increasing concentrations of PFOA was associated with a change in mean pup birth weight of –0.023 g (95% CI: –0.029, –0.016) per 1-unit increase in dose (milligrams per kilogram body weight per day). The evidence, consisting of 15 mammalian and 6 nonmammalian studies, was rated as “moderate” and “low” quality, respectively.Conclusion: Based on this first application of the Navigation Guide methodology, we found sufficient evidence that fetal developmental exposure to PFOA reduces fetal growth in animals.Citation: Koustas E, Lam J, Sutton P, Johnson PI, Atchley DS, Sen S, Robinson KA, Axelrad DA, Woodruff TJ. 2014. The Navigation Guide—evidence-based medicine meets environmental health: systematic review of nonhuman evidence for PFOA effects on fetal growth. Environ Health Perspect 122:1015–1027; http://dx.doi.org/10.1289/ehp.1307177

Ableitung von HBM-I-Werten für Perfluoroktansäure (PFOA) und Perfluoroktansulfonsäure (PFOS) – Stellungnahme der Kommission „Humanbiomonitoring“ des Umweltbundesamts

“…So werden Assoziationen zwischen PFOA-Exposition und verringertem Geburtsgewicht in den zitierten Metaanalysen sowohl für die tierexperimentellen als auch die humanepidemiologischen Studien berichtet [103][104][105]. Eine Verminderung von Markern der humoralen Immunität bei erhöhter PFAS-Belastung wurde in tierexperimentellen [106,107] und humanepidemiologischen Studien [81,83] beschrieben.…”

A five-step approach for stakeholder engagement in prioritisation and planning of environmental evidence syntheses

“…At that time, systematic review methodology in toxicology and chemical risk assessment was less developed than it has become more recently (see e.g. [34][35][36]), and the EviEM Executive Committee concluded that validation of the review methods would require significant efforts. One of the difficulties with the suggested review question was to define the outcome.…”

Systematic Reviews for Occupational Safety and Health Questions: Resources for Evidence Synthesis

“…Systems for prognostic studies may start with longitudinal cohort studies as high quality of evidence (Iorio et al, 2015) or use the phase of investigation (exploratory or confirmatory study) to determine the initial level (Huguet et al, 2013). One key difference between the standard GRADE approach and the Navigation Guide systematic review methodology is that observational human studies are initially rated as moderate quality rather than as low quality (Woodruff and Sutton, 2011;Johnson et al, 2014;Koustas et al, 2014;Lam et al, 2014;.…”

“…The Navigation Guide methodology (Woodruff and Sutton, 2011;Johnson et al, 2014;Koustas et al, 2014;Lam et al, 2014;) applies quality-of-evidence criteria separately for human and nonhuman studies. Detailed instructions can be found here.…”

“…The methodology describes four steps: (1) specify the study questions; (2) select evidence through a systematic search; (3) rate the risk of bias for individual studies and the quality and strength of evidence across studies (separately for human and nonhuman studies) and integrate the strength ratings; and (4) grade the strength of the recommendations. Published examples Koustas et al, 2014; report evidence ratings that reflect the level of certainty of toxicity: sufficient evidence, limited evidence, inadequate evidence, and evidence of lack of toxicity across all research studies. Considerations for determining strength of evidence include quality of the body of evidence, direction of effect estimates, confidence in effect estimates, and other aspects of the data that may affect certainty.…”