Phthalate concentrations in house dust in relation to autism spectrum disorder and developmental delay in the CHildhood Autism Risks from Genetics and the Environment (CHARGE) study

Table 1 Characteristics of the study sample according to diagnostic group (CHARGE study, n = 145)

Characteristics	ASD (n = 50)		DD (n = 27)		TD (n = 68)		p-values (ASD versus TD)^a	p-values (DD versus TD)^a
	N	%	N	%	N	%	p-values (ASD versus TD)^a	p-values (DD versus TD)^a
Child gender							0.45	0.02
Male	40	80	17	63	58	85
Female	10	20	10	37	10	15
Child race							0.12	0.05
White, non-Hispanic	26	52	14	52	45	66
Hispanic (any)	17	34	11	41	12	18
Other	7	14	2	7	11	16
Child age at dust collection (years)							0.03	0.12
<3	5	10	2	7	11	16
3 to 4	10	20	6	22	26	38
>4	35	70	18	67	31	46
Missing	0	0	1	4	0	0
Maternal education							0.42	0.04
High school diploma or lower, < 1 year college, technical vocational school	8	16	7	26	6	9
>1 year college, associate degree	12	24	10	37	21	31
Bachelor degree	20	40	7	26	29	43
Graduate school	10	20	3	11	12	18
Delivery payer							0.76	0.20
Government program/no insurance	5	10	6	22	8	12
Private insurance	45	90	21	78	60	88
Regional center catchment area at enrollment							0.88	0.50
Alta, Far Northern and Redwood Coast	26	52	20	74	39	57
North Bay	9	18	3	11	13	19
East Bay, San Andreas, and Golden Gate	6	12	2	7	7	10
Valley Mt, Central Valley, and Kern	9	18	2	7	9	13
Number of rooms with vinyl flooring							0.16	0.09
0	37	74	11	41	42	62
≥1	13	26	15	56	26	38
Missing	0	0	1	4	0	0
Years of dust collection							0.02	0.38
2010	47	94	18	67	53	78
2011	3	6	8	30	15	22
Missing	0	0	1	4	0	0
Continuous variables	Mean	SD	Mean	SD	Mean	SD
Paternal age (years)	37	5.1	35	7	34	6	0.01	0.49
Maternal age (years)	34	4.7	33	6	32	6	0.06	0.78
Birth weight (g)	3456	715	2991	771	3402	557	0.48	0.01
Gestational duration (wks)	39	2.1	38	3	39	2	0.54	0.91

ASD autism spectrum disorders, DD developmental delay, TD typically developing
^aChi-square test for categorical variables and Mann–Whitney test for continuous variables

ISSN: 1476-069X