title: Dietary Fat and Fiber Intakes Are Not Associated with Patterns of Urinary Estrogen Metabolites in Premenopausal Women.
abstract: BACKGROUND
  Interindividual differences in the bioavailability of potentially carcinogenic estrogen and estrogen metabolites (EMs) may play a role in the risk of breast cancer.
  
  
  OBJECTIVE
  We examined whether dietary intakes of fiber and fat influence premenopausal EM profiles through effects on estrogen synthesis, metabolism, or excretion.
  
  
  METHODS
  We conducted a cross-sectional analysis of 598 premenopausal women who participated in a reproducibility study (n = 109) or served as controls in a nested case-control study of breast cancer (n = 489) within the Nurses' Health Study II. Dietary intakes of fiber and fat were assessed via semiquantitative food frequency questionnaires in 1995 and 1999. Midluteal urine samples were collected between 1996 and 1999 and EMs were quantified with the use of HPLC-tandem mass spectrometry. Linear mixed models were used to estimate creatinine-adjusted geometric means for individual EMs and their pathway groups across categories of dietary intake while controlling for total energy intake and potential confounders.
  
  
  RESULTS
  Higher total dietary fiber intake (>25 g/d vs. ≤15 g/d) was associated with significantly higher concentrations of 4-methoxyestradiol (50% difference, P-difference = 0.01, P-trend = 0.004) and lower concentrations of 17-epiestriol (-27% difference, P-difference = 0.03, P-trend = 0.03), but was not associated with any other EMs. The associations did not vary by fiber intake from different sources. Total fat intake (>35% energy vs. ≤25% energy) was suggestively positively associated with 17-epiestriol (22.6% difference, P-difference = 0.14, P-trend = 0.06); the association was significant for polyunsaturated fatty acid (37% difference, P-difference = 0.01, P-trend = 0.01) and trans fat (36.1% difference, P-difference = 0.01, P-trend = 0.01) intakes.
  
  
  CONCLUSIONS
  Fiber and fat intakes were not strongly associated with patterns of estrogen metabolism in premenopausal women. Our data suggest estrogen metabolism is not a major mechanism through which dietary fiber and fat may affect breast or other hormone-related cancer risks.
authors.affiliation: Department of Epidemiology, Department of Nutrition, and Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA; hao383@mail.harvard.edu.
authors.forename: Hannah
authors.identifier: http://orcid.org/0000-0002-8368-3032
authors.initials: H
authors.lastname: Oh
authors.affiliation: Department of Epidemiology, Department of Nutrition, and.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Smith-Warner
authors.affiliation: Department of Epidemiology, Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA;
authors.forename: Rulla M
authors.identifier: http://orcid.org/0000-0003-2306-8668
authors.initials: RM
authors.lastname: Tamimi
authors.affiliation: Department of Epidemiology, Department of Biostatistics, Harvard School of Public Health, Boston, MA; Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA;
authors.forename: Molin
authors.initials: M
authors.lastname: Wang
authors.affiliation: Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD;
authors.forename: Xia
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Epidemiology, Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Division of Biostatistics and Epidemiology, University of Massachusetts, Amherst, MA;
authors.forename: Susan E
authors.initials: SE
authors.lastname: Hankinson
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD; and Department of Epidemiology, Fay W Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR.
authors.forename: Barbara J
authors.identifier: http://orcid.org/0000-0002-1777-9888
authors.initials: BJ
authors.lastname: Fuhrman
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD; and.
authors.forename: Regina G
authors.initials: RG
authors.lastname: Ziegler
authors.affiliation: Department of Epidemiology, Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA;
authors.forename: A Heather
authors.identifier: http://orcid.org/0000-0002-3961-6609
authors.initials: AH
authors.lastname: Eliassen
mesh_terms: D000328:Adult; D001682:Biological Availability; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000652:urine; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004041:Dietary Fats / Q000008:administration & dosage*; D004043:Dietary Fiber / Q000008:administration & dosage*; D004958:Estradiol / Q000031:analogs & derivatives / Q000652:urine; D004967:Estrogens / Q000378:metabolism / Q000652:urine*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016014:Linear Models; D017697:Premenopause; D011374:Progesterone / Q000097:blood; D015203:Reproducibility of Results; D012307:Risk Factors; D053719:Tandem Mass Spectrometry
chemical_list: D004041:Dietary Fats; D004043:Dietary Fiber; D004967:Estrogens; C045018:4-methoxyestradiol; D011374:Progesterone; D004958:Estradiol
keywords: diet; estrogen; estrogen metabolites; fat; fiber; premenopausal