Table 1.

Characteristics of participants in the Autism Internet Research Survey 2005.

	Cases	Controls
For children aged 2–18 years:	N = 861	N = 123
	Mean (SD)	Mean (SD)
Age (years)	7.8 (3.9)	7.4 (4.5)
	%	%
No breastfeeding	28	16
Breastfeeding <2 months	23	20
Breastfeeding 2–6 months	19	22
Breastfeeding >6 months	25	36
Unknown	5	6
Parental report of regression in their child's development	25	---
For children aged 2–4 years:	N = 150	N = 38
	Mean (SD)	Mean (SD)
Age (years)	3.2 (0.5)	3.0 (0.6)
	%	%
Exclusive breastfeeding (no infant formula use)	8	16
Infant formula with DHA/ARA	26	58
Infant formula without DHA/ARA	43	18
Other infant formula (DHA/ARA content unknown)	17	3
Unknown	6	5
Parental report of regression in their child's development	23	---