. Author manuscript; available in PMC: 2016 Apr 25.

Published in final edited form as: Biodemography Soc Biol. 2014;60(2):117–136. doi: 10.1080/19485565.2014.946590

Table 6. Gene-Environment Interaction Models of Tobacco and Alcohol Co-use.

Any Co-Use	Baseline		+ School & Demographic Controls		+ Psychological Controls
Any Co-Use	All	Sibling FE	All	Sibling FE	All	Sibling FE
EP	1.096^*	--	0.998	--	1.011	--
5HTTLPR*S′	0.936	2.039	0.915	2.039	1.017	1.994
EP × 5HTTLPR*S′	1.007	0.931	1.010	0.931	0.999	0.931
Prop Co-Use (PC)	1.038^*	--	0.988	--	0.994	--
5HTTLPR*S′	0.774^*	0.663	0.748^*	0.664	0.807^*	0.612
PC × 5HTTLPR*S′	1.009^*	1.013	1.010^*	1.013	1.008^*	1.015

Heavy Co-Use	Baseline		+ School & Demographic Controls		+ Psychological Controls
	All	Sibling FE	All	Sibling FE	All	Sibling FE

EP	1.306^*	--	1.033	--	1.056	--
5HTTLPR*S′	0.813^*	1.907	0.829+	1.875	0.878	1.997
EP × 5HTTLPR*S′	1.050+	0.802	1.051+	0.795	1.034	0.786
Prop Co-Use (PC)	1.182^*	--	1.019	--	1.057	--
5HTTLPR*S′	0.773^*	1.588	0.784^*	1.529	0.878	1.493
PC × 5HTTLPR*S′	1.047^*	0.901	1.048^*	0.900	1.034	0.910

Note:

: p<.05;

+: p<0.10.

Two-tailed tests are used for all coefficients except interactions, which are one-tailed tests.