title: Relationship Between Breast Density and Selective Estrogen-Receptor Modulators, Aromatase Inhibitors, Physical Activity, and Diet: A Systematic Review.
abstract: Background Lower breast density (BD) is associated with lower risk of breast cancer and may serve as a biomarker for the efficacy of chemopreventive strategies. This review explores parameters that are thought to be associated with lower BD. We conducted a systematic review of articles published to date using the PRISMA strategy. Articles that assessed change in BD with estrogen-receptor modulators (tamoxifene [TAM], raloxifene [RLX], and tibolone) and aromatase inhibitors (AIs), as well as cross-sectional and longitudinal studies (LSs) that assessed association between BD and physical activity (PA) or diet were reviewed. Results Ten studies assessed change in BD with TAM; all reported TAM-mediated BD decreases. Change in BD with RLX was assessed by 11 studies; 3 reported a reduction in BD. Effect of tibolone was assessed by 5 RCTs; only 1 reported change in BD. AI-mediated BD reduction was reported by 3 out of 10 studies. The association between PA and BD was assessed by 21 studies; 4 reported an inverse association. The relationship between diet and BD was assessed in 34 studies. All studies on calcium and vitamin D as well as vegetable intake reported an inverse association with BD in premenopausal women. Two RCTs demonstrated BD reduction with a low-fat, high-carbohydrate intervention. Conclusion TAM induces BD reduction; however, the effect of RLX, tibolone, and AIs on BD is unclear. Although data on association between diet and BD in adulthood are contradictory, intake of vegetables, vitamin D, and calcium appear to be associated with lower BD in premenopausal women.
authors.affiliation: University of Sydney, NSW, Australia University of Calabar, Nigeria eekp9437@uni.sydney.edu.au.
authors.forename: Ernest U
authors.initials: EU
authors.lastname: Ekpo
authors.affiliation: University of Sydney, NSW, Australia.
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Brennan
authors.affiliation: University of Sydney, NSW, Australia.
authors.forename: Claudia
authors.initials: C
authors.lastname: Mello-Thoms
authors.affiliation: University of Sydney, NSW, Australia.
authors.forename: Mark F
authors.initials: MF
authors.lastname: McEntee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D047072:Aromatase Inhibitors / Q000627:therapeutic use*; D001940:Breast / Q000378:metabolism / Q000473:pathology*; D000071060:Breast Density / Q000187:drug effects* / Q000502:physiology*; D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D003430:Cross-Sectional Studies; D004032:Diet; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D020845:Selective Estrogen Receptor Modulators / Q000378:metabolism*; D014807:Vitamin D / Q000378:metabolism
chemical_list: D047072:Aromatase Inhibitors; D020845:Selective Estrogen Receptor Modulators; D014807:Vitamin D
keywords: anastrozole; exercise; letrozole; raloxifene; tamoxifene; tibolone