Table 4

- Fixed-effects analysis of variance (ANOVA) comparing age of first concern, age of first ASD diagnosis, and time from concern to diagnosis with patient characteristics.

Variables	AOC		AOD		TTD
Variables	F-ratio	P-value	F-ratio	P-value	F-ratio	P-value
Number of siblings (n=66)	3.2423	0.0278^*	1.1176	0.3487	0.7762	0.5116
Family history (n=66)
ASD	0.2121	0.6466	2.2053	0.1424	6.2956	0.0146^*
Speech delay	1.1655	0.3183	0.3020	0.7404	0.3799	0.6855
Intellectual disability	2.1118	0.1294	0.5172	0.5987	1.0536	0.3547
Attention-deficit/hyperactivity disorder	3.1187	0.0510	1.9204	0.1549	1.4248	0.2481
Psychiatric disability	2.2088	0.1181	2.6351	0.0795	0.7945	0.4562
Seizure disorder (n=63)	2.0959	0.1317	0.5198	0.5972	1.3800	0.2593
Down’s syndrome (n=60)	0.0069	0.9340	0.0069	0.9340	0.6511	0.4230
Parent’s initial concerns (n=66)
Language delay	1.1162	0.2947	0.0013	0.9717	0.0040	0.9501
Social skills delays	0.8809	0.3514	0.2616	0.6107	0.5221	0.4726
Stereotypic behavior or restricted repetitive interests	0.5973	0.4424	0.4805	0.4907	0.5560	0.4586
Disruptive behavior - hyperactive, agitated, impulsive, aggressive	0.3048	0.5828	4.8450	0.0313^*	4.0284	0.0489^*
Inattention and distractibility	0.0583	0.8100	0.5770	0.4502	1.2831	0.2615
Self-injurious behavior	11.5057	0.0012^*	2.7308	0.1033	0.3031	0.5838
Motor delay	0.6220	0.4332	0.1231	0.7268	0.0060	0.9386
ASD symptom severity
Vineland ABC composite score (n=52)	0.4480	0.9754	1.4736	0.1616	0.4480	0.9754
The autism diagnostic observation schedule calibrated severity scores (n=64)	1.4329	0.2178	1.9802	0.0832	0.9587	0.4611

↵* p<0.05, ASD: autism spectrum disorder, AOC: age of first concern, AOD: age of first ASD diagnosis, TTD: time from concern to diagnosis