Table 4.

Accessing confidence in body of evidence in selected studies.

Author, Date	Initial Confidence by Features of Study Design				Initial Confidence Rating	Factors Decreasing Confidence	Factors Increasing Confidence	Final Confidence
	Controlled Exposure	Exposure Prior to Outcome	Individual Outcome Data	Use of Comparison Groups
Fekete, 2015	×	√	×	×	Very low	Risk of bias Unexplained consistency Indirectness Imprecision	Magnitude effect Dose Response Residual Confounding Consistency	Very low
Braicu, 2014	×	√	√	√	Moderate			Low
Nguyen, 2019	√	√	√	×	Moderate			Moderate
Cao, 2011	√	√	√	√	High			High
Miyake, 2019	×	√	√	×	Low			Low