Systems for rating bodies of evidence used in systematic reviews of air pollution exposure and reproductive and children’s health: a methodological survey

Table 2 Considered characteristics regarding reproductive/children’s environmental health

Considerations applied to risk of bias or quality^a assessment tools for individual studies with regard to reproductive/ children’s environmental health	Considerations applied to systems for rating bodies of evidence with regard to reproductive/ children’s environmental health
• Is the exposure assessment method evaluated? [14, 17, 24, 25, 27,28,29] • Are co-exposures assessed? [17, 27, 30, 31] • Is confounding considered? [13,14,15,16,17]	• Are ratings assigned based on a hierarchy of study designs (i.e., experimental vs. observational studies)? [18,19,20,21,22,23] • Are developmental stages, child physiology or behaviors, or child-specific health outcomes explicitly considered in evaluating the applicability of the evidence, heterogeneity of results, or potential confounding/ biases? [17, 24,25,26] • As part of the directness or other domain, was the adequacy of the timing of exposure assessment and the length of follow-up considered? [24, 28, 29, 67] • How is evidence for absence of an association assessed? [28, 33,34,35,36]

^aRisk of bias and quality assessments of individual studies were considered jointly herein

ISSN: 1476-069X