Mammographic measures, stiffness and breast cancer risk.

N = 1018 (362 cases and 656 controls). Stiffness (N/cm) was log transformed. Square root transformation was applied on area measurements, cubic root transformation on volume measurements. Standardization was applied on transformed variables.aRisk Factors (RF): age at mammogram, age at birth of first child, weight (kg), height (cm), menopausal status (pre/post) and parity (parous/nonparous).bInter-quartile odds ratios and 95% confidence intervals were calculated as.IQOR = exp{beta*IQR}, where beta is the standardized regression coefficient, and IQR is the observed inter-quartile range, in controls, for standardized transformed percent dense area, percent dense volume, dense area, dense volume and stiffness: 1.51, 1.43, 1.15, 1.37 and 1.19, respectively.cP-value corresponds to the change in the likelihood ratio for the addition of the specific variable to a model with all others included.dAUC: area under the curve.