Figure 1.

Adjusted mean percent dense area by genotype. ^aFrequency of the breast cancer risk allele. ^bIn order of increasing breast cancer risk observed in previous studies [8,9,16]. ^cAdjusted for age, age squared and body mass index at mammogram and ethnicity. Numeric data are shown in Additional data file 1. ^dP_c, co-dominant P value for the per-allele increase in percent dense area; P_d, dominant P value for an increase in percent dense area with any risk allele; P_r, recessive P value for an increase in percent dense area with both risk alleles. CI, confidence interval.