Table 1.

Traffic exposure and ADHD and CD diagnoses by sociodemographics, behavior, and biomarkers of environmental contaminants

	n	Distance to a major road (%)				Diagnosis (%)
		≥500 m	300–499 m	100–299 m	<100 m	ADHD	CD
Age groupc
8–11 years	463	49.57	17.09	22.57	10.78	7.28	1.73
12–15 years	704	52.66	14.64	23.66	9.04	5.74	4.14
PIR groupa
<1	367	35.29	15.53	32.03	17.15	14.22	2.92
1-	280	49.26	14.57	23.20	12.98	1.89	2.34
≥2	467	56.96	16.66	20.10	6.29	5.36	3.25
Racea
White	303	55.53	14.75	21.68	8.04	7.04	2.58
Black	428	48.11	17.09	23.68	11.11	7.46	4.39
Others	436	41.90	17.86	26.36	13.88	4.34	2.97
Sexb
Boy	568	51.11	15.10	24.40	9.38	9.30	2.10
Girl	599	51.11	16.64	21.79	10.45	3.64	3.80
ETS
Yes	235	50.98	12.72	25.97	10.33	9.83	5.22
No	923	51.19	16.68	22.33	9.80	5.73	2.40
Maternal smoking during pregnancyb,c
Yes	181	53.54	11.90	25.34	9.22	15.01	6.78
No	973	50.06	17.02	22.72	10.20	4.36	1.64
Maternal age at birth (years)
<25	544	49.75	13.20	25.91	11.14	10.14	4.66
25–29	309	48.63	19.24	21.04	11.09	4.26	1.74
≥30	314	54.95	16.07	21.59	7.39	4.62	2.15
Household reference person educationb
< High school	391	47.63	15.29	25.04	12.05	3.30	1.93
High school	303	43.46	15.17	29.25	12.11	11.28	2.51
Some college or above	436	57.19	15.65	18.91	8.24	5.12	3.50
Blood lead levelsb
<1 ug/dL	400	54.30	16.62	20.13	8.95	3.52	2.41
1- ug/dL	462	50.99	12.93	23.69	12.39	9.34	3.70
≥2 ug/dL	202	39.27	22.31	30.10	8.32	10.69	3.66
Survey yearsc
2001–2002	615	49.33	15.44	25.20	10.03	7.99	1.52
2003–2004	552	53.01	16.32	20.88	9.79	4.95	4.43
US bornb
Yes	1050	51.64	15.34	22.90	10.11	6.79	3.05
No	117	43.46	23.39	26.16	6.99	1.07	0.75
Serum cotinine levelsc
<0.1 ng/mL	565	49.74	16.98	23.61	9.68	4.68	1.31
0.1- ng/mL	315	56.47	15.59	19.52	8.42	7.44	4.80
≥1 ng/mL	157	45.80	12.17	27.43	14.60	13.21	7.00

^a:p<0.05 for distance from a major road

^b:p<0.05 for ADHD diagnosis

^c:p<0.05 for CD diagnosis