The longitudinal bidirectional relationship between autistic traits and brain morphology from childhood to adolescence: a population-based cohort study

Table 1 Child and maternal demographic characteristics*

Characteristics	Cross-sectional (N = 1950)			Longitudinal (N = 304)
Child	N	%/mean	IQR/SD	N	%/mean	IQR/SD
Sex, female (%)	1049	53.8		161	53.0
Child ethnicity
Dutch (%)	1229	63.0		233	76.6
Non western (%)	527	27.0		54	17.8
Other western (%)	174	8.9		17	5.6
Missing (%)	20	1.0		0	0
Handedness
Right (%)	1747	89.6		271	89.1
Left (%)	198	10.2		32	10.5
Missing (%)	5	0.3		1	0.3
IQ (mean, SD)	1928	97.5	± 12.3	290	97.4	± 11.7
CBCL attention problems (median, IQR)	1937	2.2	1.0–5.0	192	3.0	1.0–5.5

	Mean/median	IQR/SD	Range	W1	IQR/SD	Range	W2	IQR/SD	Range
SRS weighted total score (median, IQR)	0.2	0.1–0.3	0.0–2.6	0.2	0.1–0.3	0.0–2.7	0.2	0.1–0.3	0.0–1.9
Age (years) at SRS assessment (mean, SD)	13.5	± 0.4	12.5–16.2	6.2	± 0.5	4.9–8.9	13.5	± 0.4	12.6–16.6
Age (years) at MRI scan (mean, SD)	13.8	± 0.6	12.6–16.4	8.0	± 1.0	6.2–10.7	14.1	± 0.6	13.0–16.6

Maternal	N	%	N	%
Education level
High	1099	56.4	191	62.8
Medium	623	31.9	104	34.2
Low	41	2.1	4	1.3
Missing	187	9.6	5	1.6
Monthly household income
High	1495	76.7	244	80.3
Medium	198	10.2	37	12.2
Low	104	5.3	10	3.3
Missing	153	7.8	13	4.3
Smoking during pregnancy
Never	1327	67.7	222	73.0
Until pregnancy was known	147	7.5	17	5.6
Continued during pregnancy	262	13.3	51	16.8
Missing	153	11.5	14	4.6
Alcohol use during pregnancy
Never	599	30.7	86	28.3
Until pregnancy was known	243	12.5	38	12.5
Continued occasionally	640	32.8	115	37.8
Continued frequently (at least 1 glass	188	9.6	46	15.1
a week for at least 2 trimesters)
Missing	280	14.4	19	6.2

ISSN: 2040-2392