Table 1 Distribution of covariates of interest stratified by SRS group

Sex, N (%)

Female

1471

(44.49)

1145

(34.63)

690

(20.87)

Male

1320

(35.69)

1272

(34.39)

1107

(29.92)

 < 0.0001

7005

(100.00)

Age, mean (SD)

Years

9.88

(± 0.01)

9.90

(± 0.01)

9.90

(± 0.01)

0.2090

7005

(100.00)

Ethnicity, N (%)

White

1494

(42.07)

1196

(33.68)

861

(24.25)

Black/African American

364

(36.25)

365

(36.35)

275

(27.39)

Hispanic

585

(37.40)

547

(34.97)

432

(27.62)

Other

348

(39.28)

309

(34.88)

229

(25.85)

0.0060

7005

(100.00)

Cognition, mean (SD)

Standardised score

103.77

(± 0.33)

102

(0.38)

97.76

(± 0.45)

 < 0.0001

 < 0.0001

6769

(96.63)

Externalising symptoms, mean (SD)

Standardised score

42.21

(± 0.16)

45.69

(0.19)

52.22

(± 0.26)

 < 0.0001

 < 0.0001

7003

(99.97)

Internalising symptoms, mean (SD)

Standardised score

44.72

(± 0.17)

49.04

(0.20)

56.01

(± 0.25)

 < 0.0001

 < 0.0001

7003

(99.97)

ICV, mean (SD)

mm³

1,510,210

(± 2795.58)

1,512,337

(± 2986.24)

1,506,107

(± 3554.96)

0.605

0.3600

7005

(100.00)

SC volume, mean (SD)

mm³

60,301

(± 94.51)

60,296

(± 99.73)

60,101

(± 121.24)

0.972

0.1860

7005

(100.00)

Family income, N (%)

$34,999 or less

400

(29.50)

491

(36.21)

465

(34.29)

$99,999 or less

882

(39.10)

789

(34.97)

585

(25.93)

$199,999 or less

917

(45.13)

686

(33.76)

429

(21.11)

$200,000 + 

407

(49.69)

256

(31.26)

156

(19.05)

 < 0.0001

6463

(92.26)