Table 3.

Regression estimates and SEs of association between mammographic measures at time 2 and mammographic measures at time 1 adjusting for co-twin and/or zygosity; N = 654

	Dense area^a		Percent dense area^a
	Estimate (SE)	P	Estimate (SE)	P
Model I
Self	0.86 (0.021)	<0.001	0.77 (0.022)	<0.001
Co-twin
Model IIa
Self
Co-twin	0.78 (0.024)	<0.001	0.66 (0.027)	<0.001
Model IIb
Self
Co-twin
MZ	0.84 (0.031)	<0.001	0.73 (0.035)	<0.001
DZ	0.63 (0.042)	<0.001	0.42 (0.046)	<0.001
Model IIIa
Self	0.83 (0.020)	<0.001	0.75 (0.023)	<0.001
Co-twin	0.063 (0.022)	0.004	0.066 (0.023)	0.004
Model IIIb
Self	0.82 (0.020)	<0.001	0.74 (0.025)	<0.001
Co-twin
MZ	0.090 (0.031)	0.004	0.100 (0.032)	0.002
DZ	0.035 (0.031)	0.3	0.029 (0.033)	0.4

↵^aResiduals after square root transformation and adjustment for age and BMI.