Table 1 Summary statistics for the overall sample (N = 533) with inhibitory control measures on the 4 tasks. Median and interquartile range presented. We used Mann-Whitney U test to compare continuous variables and chi-square test to compare categorical variables

Child age in years (median [IQR])

9.00 [9.00, 10.00]

9.00 [9.00, 10.00]

9.00 [9.00, 10.00]

0.2

Umbilical cord blood lead (median [IQR])

2.76 [1.63, 4.50]

3.04 [1.65, 4.81]

2.47 [1.61, 4.15]

45.6

4-year lead (median [IQR])

1.71 [1.27, 2.51]

1.69 [1.25, 2.41]

1.72 [1.31, 2.56]

22.1

SES at birth (%)

0

 1

9.9

10.2

9.7

 2

42.6

42.0

43.2

 3

23.3

22.3

24.3

 4

13.9

15.0

12.7

 5

8.8

9.9

7.7

 6

1.5

0.7

2.3

SES at 4 years (%)

22.7

 1

1.2

1.5

1.0

 2

27.2

26.1

28.2

 3

30.6

34.0

27.3

 4

21.4

20.2

22.5

 5

10.9

10.8

11.0

 6

7.5

6.4

8.6

 7

1.2

1.0

1.4

Mother’s IQ (median [IQR])

86.00 [76.00, 94.00]

85.00 [75.00, 95.00]

86.00 [77.00, 94.00]

3.2

Happy Go/NoGo commission errors (median [IQR])

0.21 [0.12, 0.29]

0.21 [0.12, 0.33]

0.17 [0.10, 0.27]

0

Happy Go/NoGo reaction time (median [IQR])

572.01 [527.89, 617.80]

575.31 [529.36, 623.38]

567.85 [526.80, 611.08]

0

Letter Go/NoGo commission errors (median [IQR])

0.21 [0.12, 0.33]

0.21 [0.12, 0.33]

0.21 [0.12, 0.29]

0

Letter Go/NoGo reaction time (median [IQR])

498.93 [455.46, 536.86]

495.54 [454.17, 532.94]

500.62 [456.06, 542.81]

0

Neutral Go/NoGo commission errors (median [IQR])

0.21 [0.12, 0.29]

0.21 [0.12, 0.33]

0.21 [0.12, 0.29]

0

Neutral Go/NoGo reaction time (median [IQR])

572.51 [533.14, 621.40]

567.33 [529.55, 620.51]

581.01 [542.22, 622.34]

0

DKEFS condition 3 reaction time (median [IQR])

88.00 [75.00, 107.00]

87.50 [74.25, 105.00]

89.00 [76.50, 111.00]

0

DKEFS condition 3 total mistakes (median [IQR])

5.00 [3.00, 7.00]

5.00 [3.00, 8.00]

5.00 [3.00, 7.00]

0