TABLE 4.

Significant results of linear regression analysis using backward elimination^a for hormone exposure factors, controlling for age and estimated verbal intelligence, for the overall, breast cancer, and control groups

	Visual learning and memory		Executive function		Verbal learning and memory		Attention		Psychomotor efficiency		Sustained attention
	β	P	β	P	β	P	β	P	β	P	β	P
Number of pregnancies
Overall									−0.123	0.020
Breast cancer
Control
Years since menopause
Overall			−0.102	0.053
Breast cancer	0.227	0.001	−0.111	0.053
Control
Years since oophorectomy
Overall									−0.111	0.032
Breast cancer
Control
Oral contraceptive use (yes/no)
Overall					0.154	0.003	0.110	0.052			0.138	0.011
Breast cancer					0.147	0.024					0.139	0.033
Control
Years since oral contraceptive use
Overall
Breast cancer							−0.144	0.032
Control					−0.206	0.045					−0.201	0.045
Duration of hormone therapy use
Overall							−0.123	0.028			−0.140	0.009
Breast cancer											−0.153	0.017
Control							−0.339	0.001

β refers to standardized β.

^aAll hormone exposure factors that were statistically significant at P < 0.20 were included in the first step. Then, one by one, predictors were eliminated up to P < 1.0.