Table 1.

Characteristics of the ASD and control cases.

Variable	ASD	Control cases	p-value †
N	164	164	_
Age, years	5(4-6)	5(4-6)	1.00
Sex-male	129(78.7)	129(78.7)	1.00
Ethnic-Han	158(96.3)	155(94.5)	0.43
BMI, kg/m2	16.6(16.2-	17.0(16.1-	0.18
	17.4)	17.6)
The time from symptom onset to	105(78-141)	—	—
admission, days
Family history of ASD	15(9.1)	2(1.2)	0.001
CARS	40(36-47)	22(18-25)	< 0.001
Mild to moderate autism‡	66(40.2)	—	—
Laboratory findings
TMAO (umol/1)	4.2(3.0-5.6)	3.0(2.0-4.4)	< 0.001
Choline (^imol/1)	9.0(6.4-13.6)	7.8(5.2-12.3)	0.012
Betaine (^imol/1)	21.4(16.5-	19.8(14.8-	0.019
	26.4)	25.3)

The discrete variable was expressed in the percentage or frequency, continuous variable was expressed in the medians (interquartile range, IQR).

ASD: Autism spectrum disorders; BMI, body mass index; CARS, Childhood Autism Rating Scale; TMAO, Trimethylamine N-oxide.

^†P value was tested by chi-squared test or Mann-Whitney U test.

^‡A total score of between 30 and 36 indicates mild-to-moderate autism, whereas the interval between 37 and 60 denotes severe autism.