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Table 1 Demographic Characteristics of Participants

From: Interaction between lead and noradrenergic genotypes affects neurocognitive functions in attention-deficit/hyperactivity disorder: a case control study

 

Patients

(n = 259)

Controls

(n = 96)

T or χ2

F

p (Effect size)

Age, mean (SD) years

8.8 (2.4)

10.5 (3.0)

4.957

11.306

< .001a (0.63*)

Male, n (%)

202 (78.0)

52 (54.2)

19.531

 

< .001a (0.51**)

IQ, mean (SD)

105.9 (14.5)

113.3 (16.4)

4.100

1.668

< .001a (0.48*)

ADHD subtypes, n (%)

Combined

73 (28.4)

    

Inattentive

98 (38.1)

    

Hyperactive-impulsive

57 (22.2)

    

Not otherwise specified

29 (11.3)

    

ADHD Rating Scale, mean (SD)

Inattention

15.0 (5.6)

3.6 (4.0)

−20.343

15.542

< .001a (2.76*)

Hyperactivity-impulsivity

10.2 (6.5)

1.7 (2.0)

−17.769

88.912

< .001a (2.02*)

Total

25.2 (10.7)

5.5 (5.7)

−21.239

34.852

< .001a (2.30*)

Continuous Performance Test, mean (SD)

Omission errors

65.5 (20.4)

53.5 (15.1)

−5.879

33.913

< .001a (0.70*)

Commission errors

65.5 (19.2)

55.5 (15.2)

−5.028

16.181

< .001a (0.58*)

Response time

55.4 (12.1)

54.4 (13.2)

−0.669

0.402

.504 (0.08*)

Response time variability

63.3 (17.9)

50.8 (15.4)

−6.402

10.405

< .001a (0.75*)

Stroop Color-Word Test, mean (SD)

Word reading score

44.0 (11.6)

49.0 (9.5)

0.692

3.755

< .001a (0.47*)

Color naming score

45.4 (10.9)

50.9 (9.7)

0.846

4.244

< .001a (0.53*)

Color-Word score

45.3 (12.5)

50.3 (11.9)

0.546

3.344

.001a (0.41*)

Interference score

52.5 (11.3)

49.1 (13.8)

3.067

−2.311

.021a (0.27*)

Environmental measure, mean (SD)

Lead (μg/dL)

Total

1.4 (.5)

1.3 (.5)

−2.818

0.526

.005a (0.20*)

Male

1.5 (0.5)

1.4 (0.6)

0.775

0.808

.439 (0.18*)

Female

1.3 (0.5)

1.1 (0.3)

2.432

7.295

.017a (0.49*)

Genotype

DAT1, n (%)*

  

1.288

 

.525 (0.15**)

10/10

217 (83.8)

85 (88.5)

   

With a 10

39 (15.1)

10 (10.4)

   

Without 10

3 (1.2)

1 (1.0)

   

DRD4, n (%)*

  

0.742

 

.690 (0.08**)

With 4/4

146 (56.4)

58 (60.4)

   

With a 4

99 (38.2)

32 (33.3)

   

Without 4

14 (5.4)

6 (6.3)

   

ADRA2A MspI, n (%)*

  

0.470

 

.791 (0.03**)

C/C

30 (11.6)

12 (12.5)

   

G/C

113 (43.6)

38 (39.6)

   

G/G

116 (44.8)

46 (47.9)

   

ADRA2A DraI, n (%)*

  

1.833

 

.400 (0.16**)

C/C

80 (30.9)

23 (24.0)

   

C/T

125 (48.3)

53 (55.2)

   

T/T

54 (20.8)

20 (20.8)

   
  1. Note: a: Items that are still significant after the multiple comparison adjustment with the 0.05 false discovery rate threshold which have a p-value <.05
  2. ADHD attention-deficit/hyperactivity disorder, IQ intelligence quotient, SD standard deviation
  3. *Cohen’s d values (0.80 = large, 0.50 = medium, 0.20 = small effect sizes)
  4. **Cohen’s h values (0.80 = large, 0.50 = medium, 0.20 = small effect sizes)