Our study covered a total of 3348 Caucasian women aged 45-68 years, recruited from seven Spanish breast cancer screening centres having DNA available. Mammographic density was blindly assessed by a single reader using a semiquantitative scale. Ordinal logistic models, adjusted for age, body mass index and menopausal status, were used to estimate the association between each genotype and MD.
Evidence of association with MD was found for variant rs3803662 (TOX3) (Odds Ratio (OR) = 1.13, 95 % Confidence Interval (CI) = 1.03-1.25), and marginal evidence of association for susceptibility loci rs3817198 (LSP1) (OR = 1.09, 95 % CI = 1.00-1.20) and rs2981582 (FGFR2) (OR = 0.92, 95 % CI = 0.84-1.01). Two other loci were associated with MD solely among pre-menopausal women, namely, rs4973768 (SLC4A7) (OR = 0.83, 95 % CI = 0.70-1.00) and rs4415084 (MEPS30) (OR = 1.22, 95 % CI = 1.00-1.49).
Our findings lend some support to the hypothesis which links these susceptibility loci to MD.