. Author manuscript; available in PMC: 2011 Dec 1.

Published in final edited form as: Int J Eat Disord. 2010 Dec;43(8):679–688. doi: 10.1002/eat.20772

Table 3. Intraclass Twin Correlations for the Weight and Shape Concerns Subscale.

		Test of Equality

Age Group	Twin Correlation	z	One-tailed p
10-12 years
MZ (n = 31 pairs)	.54^***	.21	.42
DZ (n = 30 pairs)	.51^**	--	--
13-15 years
MZ (n = 181 pairs)	.52^***	3.44	.0003
DZ (n = 115 pairs)	.16^*	--	--
16-19 years
MZ (n = 56 pairs)	.59^***	1.52	.06
DZ (n = 28 pairs)	.30^†	--	--
20-25 years
MZ (n = 199 pairs)	.51^***	3.34	.0004
DZ (n = 110 pairs)	.16^*	--	--
26-30 years
MZ (n = 60 pairs)	.59^***	1.16	.054
DZ (n = 38 pairs)	.32^*	--	--
31-41 years
MZ (n = 117 pairs)	.59^***	1.41	.079
DZ (n = 45 pairs)	.40^**	--	--

Note. MZ = monozygotic; DZ = dizygotic. The “Test of Equality z” tests for differences between the MZ and DZ twin correlations. Only pairs with complete data for both twins were included in the analysis.

^†

p < .10,

p < .05,

^**

p < .01,

^***

p < .001.

The twin correlation is greater than zero.