Table 3.

Examination of covariates included in statistical models across studies.

	Author, Year	Braun et al., 2014	Sagiv et al., 2015	Zhang et al., 2016	Vuong et al., 2016	Chen et al., 2014	Vuong et al., 2017a	Vuong et al., 2017b	Braun et al., 2017	Gascon et al., 2011	Herbstman et al., 2010	Chevrier et al., 2016	Cowell et al., 2015	Kim et al., 2018	Ding et al., 2015	Eskenazi et al., 2013	Roze et al., 2009	Shy et al., 2011
Adjusted Covariates (Confounders)	Mat. Age	√	√	√	√	√	√	√	√	√	√	√	√	√	√			√
	Gest. Age 1	√									√			√
	Edu. 1	√	√	√	√	√		√	√	√	√	√		√	√	√
	Race	√		√	√	√	√	√	√		√		√
	Infant sex	√	√	√	√	√	√	√		√	√		√	√	√	√	√
	Infant age at testing		√							√	√		√			√
	BFD 1		√							√	√	√
	SES 1	√	√	√	√	√	√	√	√	√				√	√		√
	Smoking Status 1	√	√	√	√	√	√	√	√	√		√			√
	Maternal IQ	√	√	√	√	√	√	√	√		√	√	√
	Marital Status	√	√	√	√	√	√	√	√				√			√
	Parity	√	√	√			√			√				√				√
	HOME score 1	√		√	√	√	√	√	√			√				√	√
	Other chemicals 1	√	√	√								√
	Total	12	11	10	9	9	9	9	8	8	8	7	6	6	5	5	3	2

¹ Mat. Age = maternal age; Gest. Age = gestational age; Edu. = maternal education, Gest. Age = gestational age, BFD = breastfeeding duration, SES = socioeconomic status (including proxies), Smoking Status = either self-reported or by serum cotinine concentrations, HOME score = Home Observation for Measurement of the Environment, Other Chemicals include heavy metals and PCBs.