Mammographic breast density refines Tyrer-Cuzick estimates of breast cancer risk in high-risk women: findings from the placebo arm of the International Breast Cancer Intervention Study I

Table 2 Odds ratios (OR) and area under the curve (AUC) from the logistic regression models including absolute Tyrer-Cuzick (TC) risk score, unadjusted percent dense area and density residual as independent variables

Model	Odds ratio^†(95% CI)	AUC	LR-CHI2	Δ χ²(Pvalue)^a
Univariate
Absolute TC risk score	1.18 (10.99-1.39)	0.51	3.5	0.06
Unadjusted percent dense area	1.83 (1.14-2.94)	0.59	6.5	0.01
Density residual	1.90 (1.31-2.77)	0.62	11.7	0.001
Multivariate
Absolute TC risk	1.12 (0.94-1.33)		3.5	0.06
Density residual	1.82 (1.25-2.67)	0.62	9.9	0.002

^†Odds ratio is for the difference between the 75^th and 25^th percentiles of the Tyrer-Cuzick (TC) 10-year absolute risk, unadjusted percent dense area and the density residual; ^athis is the change in χ² when the variable is added to the model.

ISSN: 1465-542X