Table 1.

Sample Characteristics in 1987 Overall and by Smoking and Smokeless Tobacco Trajectory Group

Characteristic in 1987	Overall, n = 2230, % or mean (SD)	Smoking trajectory groups, % or mean (SD)						Smokeless trajectory groups, % or mean (SD)
		(1) consistent abstainer from cigarettes, n = 649	(2) late onset, cessation, n = 214	(3) early onset, cessation, n = 235	(4) delayed onset regular, cessation, n = 270	(5) regular, n = 862	P (ANOVA or chi-square)	(1) early onset, cessation, n = 367	(2) consistent abstainer from smokeless tobacco, n = 1070	(3) late onset, n = 139	(4) regular n = 654	P (ANOVA or chi-square)
Age	20.1 (2.7)	20.2 (2.7)	20.5 (2.9)	19.7 (2.8)	20.1 (2.8)	20.1 (2.7)	.096	19.5 (2.8)	20.3 (2.7)	20.3 (2.8)	20.1 (2.7)	<.001
At least one parent with college education or higher	40.5	38.2	43.6	53.1	48.5	34.4	<.001	40.6	47.2	32.4	32.3	<.001

ANOVA = analysis of variance.