Table 3.

Adjusted 5-class latent growth curve model: Smoking trajectory classes by covariates

Covariates	Smoking Trajectory
	Non- smokers (59.0%)	Occasional smokers (11.7%)	Quitters (5.4%)	Late onset regular (10.4%)	Early onset regular (13.4%)
		Odds ratio (95% CI)	Odds ratio (95% CI)	Odds ratio (95% CI)	Odds ratio (95% CI)
White (vs. other races)	Ref	1.61 (1.10, 2.37)	1.43 (0.83, 2.47)	1.33 (0.88, 2.00)	2.06 (1.27, 3.33)
Male	Ref	1.12 (0.88, 1.42)	0.94 (0.66, 1.36)	1.22 (0.92, 1.62)	1.10 (0.80, 1.49)
Parent education: college degree or higher	Ref	1.16 (0.89, 1.53)	1.36 (0.89, 2.06)	1.18 (0.88, 1.60)	1.30 (0.92, 1.84)
Participant education: 4-year college student/grad or higher	Ref	1.00 (0.75, 1.35)	0.97 (0.60, 1.56)	0.52 (0.36, 0.73)	0.51 (0.31, 0.86)
Number of friends who smoked (measured at ages 12– 18)	Ref	1.70 (1.46, 1.97)	2.87 (2.29, 3.59)	1.68 (1.41, 2.01)	3.76 (3.05, 4.63)
Number of friends who smoked (measured at ages 20– 24)	Ref	1.67 (1.47, 1.91)	2.17 (1.78, 2.64)	2.99 (2.57, 3.49)	3.47 (2.89, 4.16)
Parent smokes: one or both (measured at ages 12–18)	Ref	1.14 (0.80, 1.63)	1.04 (0.59, 1.84)	1.17 (0.79, 1.71)	1.64 (1.11, 2.44)
Parent smokes: one or both (measured at ages 20–24)	Ref	0.94 (0.52, 1.69)	1.08 (0.43, 2.72)	0.82 (0.42, 1.58)	0.65 (0.35, 1.21)

Boldface indicates statistical significance (p<.05)

CI= Confidence Interval