%0 Journal Article
%T Mammographic density and breast cancer risk: the role of the fat surrounding the fibroglandular tissue
%A Mari£¿tte Lokate
%A Petra HM Peeters
%A Linda M Peelen
%A Gerco Haars
%A Wouter B Veldhuis
%A Carla H van Gils
%J Breast Cancer Research
%D 2011
%I BioMed Central
%R 10.1186/bcr3044
%X We performed a nested case-control study within the EPIC-NL cohort (358 postmenopausal breast cancer cases and 859 postmenopausal controls). We used multivariate logistic regression analyses to estimate breast cancer odds ratios adjusted for body mass index and other breast cancer risk factors.Large areas of dense (upper (Q5) vs lower quintile (Q1): OR 2.8 95% CI 1.7 to 4.8) and fat tissue (Q5 vs Q1: OR 2.4; 95% CI 1.3 to 4.2) were independently associated with higher breast cancer risk. The combined measure showed that the highest risk was found in women with both a large (above median) area of dense and fat tissue.Fibroglandular and breast fat tissue have independent effects on breast cancer risk. The results indicate that the non-dense tissue, which represents the local breast fat, increases risk, even independent of body mass index (BMI). When studying dense breast tissue in relation to breast cancer risk, adjustment for non-dense tissue seems to change risk estimates to a larger extent than adjustment for BMI. This indicates that adjustment for non-dense tissue should be considered when studying associations between dense areas and breast cancer risk.In the last two decades, many researchers have observed a strongly elevated breast cancer risk in women with a high percent mammographic density [1,2]. Percent mammographic density represents the relative amount of fibroglandular tissue, which is radiographically dense, and fat tissue, which is radiographically lucent. A high percent mammographic density is associated with a three-to-six-fold increase in breast cancer risk comparing the extremes of the breast density distribution [2].Increasingly, the absolute area of dense tissue is reported in the literature along with the percent density measure. The reason for this is that the dense area is considered to represent the actual target tissue for tumor development [3,4]. As percent density is strongly influenced by the size of the fat area, or non-dense tissue, in
%U http://breast-cancer-research.com/content/13/5/R103