Skip to main content

View full-text article in PMC

. Author manuscript; available in PMC: 2015 Nov 4.

Published in final edited form as: Twin Res Hum Genet. 2015 Jul 31;18(5):497–506. doi: 10.1017/thg.2015.48

Table II.

Tetrachoric Correlations for Cigarette Use Initiation (95% CI) by Sex, Zygosity and Age Group

	Females		Males		DZO
	MZ	DZ	MZ	DZ	DZO
14-15 year-olds	0.91	0.88	0.85	0.72	0.38
(n=287 twin pairs)	(0.85, 0.97)	(0.81, 0.95)	(0.75, 0.94)	(0.59, 0.85)	(0.21, 0.55)
16-17 year-olds	0.64	0.63	0.82	0.57	0.55
(n=389 twin pairs)	(0.50, 0.79)	(0.50, 0.76)	(0.73, 0.91)	(0.40, 0.74)	(0.42, 0.69)
18-25 year-olds	0.83	0.41	0.88	0.34	0.16
(n=709 twin pairs)	(0.76, 0.90)	(0.27, 0.55)	(0.82, 0.94)	(0.17, 0.51)	(0.01, 0.31)
26-33 year-olds	0.87	0.41	0.87	0.51	0.03
(n=723 twin pairs)	(0.81, 0.93)	(0.28, 0.55)	(0.81, 0.94)	(0.36, 0.67)	(-0.15, 0.22)