. Author manuscript; available in PMC: 2010 Jun 1.

Published in final edited form as: Neuropsychopharmacology. 2009 Aug 19;34(13):2721–2732. doi: 10.1038/npp.2009.112

Table 3.

Cox regression model predicting initiation of smoking in adolescents who had no prior smoking history at intake

	β (SE)	Wald	OR (CI)	p
HPA activity¹	0.70 (0.29)	5.92	2.01 (1.15-3.54)	.02
Stress at follow-up	1.26 (0.26)	23.78	3.54 (2.15-5.84)	.0001
HPA activity × stress at follow-up	0.09 (0.25)	0.02	1.09 (0.67-1.78)	NS

SE = standard error; OR = odds-ratio; CI = confidence interval; HPA (hypothalamic-pituitary-adrenal)

HPA activity (a composite measure of evening/night-time cortisol levels)

χ² = 37.79, df = 3, p = .0001