Age 4 (N=50)	Age 6 (N=49)	
Characteristic	%	N	%	N	
At or below poverty (≤$20,000/year)	18.4	9	23.4	11	
Male gender	60.0	30	53.1	26	
Reported no child SHS exposure	83.3	40	77.1	37	
Child ADHD	8.0	4	22.4	11	
Child CD and/or ODD	24.0	12	26.5	13	
Mother reported prenatal smoking	16.7	8	16.7	8	
					
	Mean	SD	Mean	SD	
Child ADHD severity	3.12	3.54	4.00	4.14	
Child ADHD inattentive severity	1.48	1.94	2.94	2.70	
Child ADHD hyperactive/impulsive severity	1.64	1.89	1.31	2.32	
Child CD severity	0.84	1.15	0.92	1.17	
Child ODD severity	2.22	2.00	2.14	1.91	
Child CD/ODD severity	3.06	2.87	3.00	2.75	

Title:
Table 1. Characteristics of study participants (N = 60) at 4 and 6 years of age*
Footnote:
*There were 60 children with cotinine levels at age 4, age 6, or both age 4 and age 6. There were 50 children with cotinine levels at age 4 and 49 children with cotinine levels at age 6.
ADHD, Attention-deficit/hyperactivity disorder; CD, conduct disorder; ODD, oppositional defiant disorder; SD, standard deviation; SHS, secondhand smoke.