TABLE 1.

Baseline Characteristics of Participants and Outcomes at Age 21 Years: Carolina Abecedarian Project, Chapel Hill, NC, 1972–1998

	Intervention Group (n = 55),Mean (SE) or %	Control Group (n = 54),Mean (SE) or %	Total (n = 109),Mean (SE) or %
Sociodemographic profile at randomization
Maternal age, y	19.6 (3.9)	20.3 (5.8)	19.9 (4.9)
Maternal education, y	10.4 (1.8)	10.0 (1.9)	10.2 (1.8)
Maternal IQa	85.5 (12.4)	84.2 (10.8)	84.8 (11.6)
Two-parent family	23	26	24
African American	96	100	98
Maleb	51*	43*	47*
Outcomes at age 21 y
Has a regular doctor	51.6	48.4	59.6
Always wears seat belt	53.6	46.4	53.9
Never drinks and drives	49.3	50.7	66.4
Never rides with a drinker	51.0	49.0	49.0
No health problems since age 15 y	51.3	48.7	73.1
Age began regular smoking, y
11–12	0.0	3.9	1.9
13–14	3.8	7.8	5.77
15–16	11.3	17.7	14.4
Never or ≥ 17	81.1	70.6	76.0
Cigarettes per d
≥ 20	5.7	7.8	6.7
6–19	9.4	23.5	16.4
2–5	17.0	11.8	14.4
> 0–1	7.6	5.9	6.7
0	56.6	51.0	53.9
Age began drinking, y
11–12	15.1	5.9	10.6
13–14	7.6	13.7	10.6
15–16	17.0	39.2	27.9
Never or ≥ 17	56.6	41.2	49.0
Binge drinking,c d/mo
≥ 20	7.6	7.8	7.7
10–19	5.7	5.9	5.7
6–9	11.3	9.8	10.6
3–5	11.3	3.9	7.7
0–2	60.4	72.6	66.4
Age first tried marijuana, y
9–10	3.8	9.8	6.7
11–14	5.7	7.8	6.7
15–16	13.2	23.5	18.3
Never or ≥ 17	73.6	58.8	66.4
No. of marijuana uses in past mo
≥ 40	3.8	7.8	5.7
20–39	0.0	7.8	3.9
10–19	3.8	9.8	6.7
3–9	5.7	5.9	4.8
1–2	5.7	7.8	6.7
0	79.3	60.8	70.2
Never used cocaine	90.6	96.1	93.3
Average depression score at age 21 yd	54.1**	58.6**	56.3**

Note. Percentages may not total 100% due to rounding.

^aAccording to the Wechsler Adult Intelligence Scale. The national mean is 100, and the standard deviation is 15.

^bOne mother randomized to the treatment group gave birth to twins.

^cDefined as 5 or more drinks in one sitting.

^dThe depression index score was measured with the Brief Symptom Inventory, a 53-item questionnaire that measures various dimensions of affect and psychopathology.²¹ Comparison was made to a control group.

*P < .1; **P < .05.