. Author manuscript; available in PMC: 2015 Jan 1.

Published in final edited form as: J Adolesc Health. 2013 Aug 29;54(1):10.1016/j.jadohealth.2013.07.013. doi: 10.1016/j.jadohealth.2013.07.013

Table 2.

Frailty models predicting sexual intercourse onset

	Model 1		Model 2^a		Model 3

Variable	Hazard Ratio	95% CI	Hazard Ratio	95% CI	Hazard Ratio	95% CI
Zygosity	1.09	.99 – 1.18	1.08	.99–1.18	1.08	.99–1.16
Age	.98^**	.96 – .99	.98^**	.96 – .99	.98^**	.96–.99
Gender	1.03	.94–1.12	.94	.85–1.03	.93	.85–1.03
Level 1 Smoking Onset	1.00	.97 – 1.02	1.00	.97–1.02	1.00	.97–1.02
Level 2 Smoking Onset	.98^**	.96–.99	.99	.97–1.00	.99	.97 – 1.00
Level 1 Drinking Onset	.98	.95–1.02	.99	.95–1.02	.98	.95–1.02
Level 2 Drinking Onset	1.01	.98 – 1.04	1.02	.99–1.05	1.02	.99–1.05
Level 1 Drunkenness Onset	.96^*	.92–1.00	.96^*	92.–1.00	1.00	.95–1.05
Level 2 Drunkenness Onset	.87^**	.84–.89	.88^**	.85–.90	.88^**	.85–.90
Level 1 Conduct Disorder	-	-	1.07	.92 – 1.24	1.06	.92–1.23
Level 2 Conduct Disorder	-	-	1.38^**	1.23 – 1.54	1.39^**	1.25–1.54
Level 1 Drunkenness Onset x Zygosity	-	-	-	-	.92^**	.86–.98

p<.05;

^**

p<.01

Note: When Model 2 is re-run using grand-mean centered level-2 predictors, results indicated that when controlling for level-1 effects and conduct disorder symptoms, average age of smoking (HR = 1.00, p=.67), drinking (HR =.99, p=.49), and conduct disorder (HR = 1.19, p=.06) were not significant contextual effects. Average age of drunkenness (HR= .91, p<.001) was a significant contextual effect, indicating that this effect was significantly stronger than the respective level-1 variable.