Table 4 Characteristics of the 18 studies that conducted sex-stratified analyses

Claus Henn 2018 [37]

6–16

Cognition

↓

NS

NA

Teeth: 12^ab (n = 138)

Dion 2018 [20]

10.5–18

Cognition

↑ (W-Mn)

↓ (W-Mn)

<  0.01 (W-Mn)

Drinking water: 14.5 μg/L^c (n = 287), hair: 1.4 μg/g^c (n = 274)

Gunier 2015 [31]

0.5, 1, 2

Cognition and motor

NS

↓

0.02 (Cognition), 0.03 (Motor)

Teeth: prenatal: 0.51 ± 0.19^bd (n = 197), postnatal: 0.20 ± 0.23^bd (n = 193)

Mora 2015 [38]

7, 9, 10.5

Cognition and motor

↑

NS

<  0.1

Teeth: prenatal: 0.50 ± 0.18^bd (n = 248), postnatal: 0.19 ± 0.21^bd (n = 244)

Mora 2018 [33]

1

Cognition

NS

↓

0.01

Maternal hair: 3.7 ± 5.4 μg/g^d (n = 661), maternal blood: 24.4 ± 6.2 μg/L^d (n = 571)

Rahman 2017 [69]

10

Cognition

NS

↑

<  0.081

Drinking water: 339 μg/L^a (n = 1265)

Takser 2003 [34]

Newborns

Motor

↓

NS

0.03

Cord blood: 38.5 μg/L^c (n = 222), maternal blood: 20.4 μg/L^c (n = 222), maternal hair: 0.36 μg/g^c (n = 173), newborns hair: 0.75 μg/g^c (n = 173), placenta: 0.1 μg/g^c (n = 200)

Zhou 2019 [39]

6–8

Cognition

↑

NS

NA

Cord blood: 29.29 ± 1.48 μg/L (n = 296), urine: 0.66 ± 3.81 μg/L (n = 207)

Bauer 2017 [42]

10–14

Cognition

NS

↓

0.05

Teeth: prenatal: 0.42^cb (n = 142), postnatal: 0.12^cb (n = 142)

Bouchard 2011 [16]

6–13

Cognition

NS

↓

0.55 (H-Mn), 0.14 (W-Mn)

Hair: 0.7 μg/g^a (n = 302), drinking water: 0.8 μg/L^a (n = 362)

Bouchard 2018 [8]

6–14

Cognition

NS (Toe nail), ↑ (W-Mn)

↓ (Toe nail), NS (W-Mn)

0.028 (Toe nail), 0.015 (W-Mn)

Toe nail: 2.0 μg/g^c (n = 258), hair: 0.3 μg/g^c (n = 258), saliva: 1.1 μg/L^c (n = 226), drinking water: 5.2/7.3 μg/L^c (boy: 127, girl: 132)

Carvalho 2018 [46]

7–12

Cognition

↓

NS

0.047

Hair: 11.5 μg/g^a (n = 70)

Chiu 2017 [48]

11–14

Motor

NS (Prenatal and postnatal), ↓ (Childhood)

↓ (Prenatal and postnatal), NS (Childhood)

<  0.05 (Prenatal), <  0.01 (Postnatal), 0.01 (Childhood)

Teeth: prenatal: 0.43^ab (n = 189), postnatal: 0.13^ab (n = 185)

Hernandez-Bonilla 2016 [54]

7–11

Cognition

NS

↓

<  0.15

Hair: control: 0.55 μg/g^c (n = 119), exposed: 5.25 μg/g^c (n = 148)

Menezes-Filhoet 2014 [62]

7–12

Behavior

NS

↓

NA

Hair: boys: 12.1 μg/g^a (n = 34), girls: 12.4 μg/g ^a (n = 36)

Rink 2014 [41]

1.1–3.7

Cognition

↑

NS

<  0.05

Hair: 0.98 ± 0.74 μg/g^d (n = 60)

Riojas-Rodríguez 2010 [6]

7–11

Cognition

NS

↓

NA

Control: hair: 0.57 μg/g, blood: 8.22 μg/L^c (n = 93), exposed: hair: 12.13 μg/g, blood: 9.71 μg/L^c (n = 79)

Torres-Agustinet 2013 [67]

7–11

Cognition

NS

↓

NA

Control: hair: 0.6 μg/g, blood: 8.0 μg/L^a (n = 95), exposed: hair: 12.6 μg/g, blood:9.5 μg/L^a (n = 79)