title: A prospective study of oral contraceptive use and colorectal adenomas.
abstract: The influence of reproductive factors on colorectal cancer, including oral contraceptive (OC) use, has been examined, but less research is available on OC use and adenomas.
  
  
  
  Participants of the Nurses' Health Study who had a lower bowel endoscopy between 1986 (when endoscopies were first assessed) and 2008 were included in this study. Multivariable logistic regression models for clustered data were used to estimate odds ratios and 95 % confidence intervals [OR (95 % CIs)].
  
  
  
  Among 73,058 participants, 51 % (n = 37,382) reported ever using OCs. Ever OC use was associated with a slight increase in non-advanced adenomas [OR 1.11, 95 % CI (1.02, 1.21)] but not with any other endpoints. Duration of OC use was not associated with adenomas, but longer times since last OC use were associated with increased odds of adenomas [e.g., compared to never use, 15+ years since last use: OR 1.17 (1.07, 1.27)]. Shorter times since last OC use were inversely associated [e.g., ≤4 years since last use: OR 0.74 (0.65, 0.84)].
  
  
  
  We observed a modest borderline increase in risk of colorectal adenomas with any prior OC use. Additionally, more recent OC use may decrease risk, while exposure in the distant past may modestly increase risk of adenomas.
authors.affiliation: Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, USA. bcharlton@mail.harvard.edu.|Division of Adolescent and Young Adult Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA. bcharlton@mail.harvard.edu.|Department of Pediatrics, Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA. bcharlton@mail.harvard.edu.
authors.forename: Brittany M
authors.initials: BM
authors.lastname: Charlton
authors.affiliation: Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, USA.|Department of Nutrition, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, USA.|Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA, 02115, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Giovannucci
authors.affiliation: Department of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA, 02115, USA.
authors.forename: Charles S
authors.initials: CS
authors.lastname: Fuchs
authors.affiliation: Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA, 02115, USA.|Division of Gastroenterology, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114, USA.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Chan
authors.affiliation: Department of Food and Nutrition, Sookmyung Women's University, Cheongpa-ro 47-gil 100, Yongsan-gu, Seoul, 04310, South Korea.
authors.forename: Jung Eun
authors.initials: JE
authors.lastname: Lee
authors.affiliation: Department of Nutrition, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, USA.
authors.forename: Yin
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, USA.|Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA, 02115, USA.|Division of Reproductive Medicine, Brigham and Women's Hospital and Harvard Medical School, 45 St. Francis Street, Boston, MA, 02115, USA.
authors.forename: Stacey A
authors.initials: SA
authors.lastname: Missmer
authors.affiliation: Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA, 02115, USA.
authors.forename: Bernard A
authors.initials: BA
authors.lastname: Rosner
authors.affiliation: Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, USA.|Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA, 02115, USA.|Division of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts, 715 North Pleasant Street, Amherst, MA, 01003, USA.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Hankinson
authors.affiliation: Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, USA.|Department of Nutrition, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, USA.|Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA, 02115, USA.
authors.forename: Walter
authors.initials: W
authors.lastname: Willett
authors.affiliation: Department of Nutrition, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, USA.
authors.forename: Kana
authors.initials: K
authors.lastname: Wu
authors.affiliation: Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, USA.|Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA, 02115, USA.|Obstetrics and Gynecology Epidemiology Center, Brigham and Women's Hospital and Harvard Medical School, 221 Longwood Avenue, Boston, MA, 02115, USA.
authors.forename: Karin B
authors.initials: KB
authors.lastname: Michels
mesh_terms: D000236:Adenoma / Q000453:epidemiology*; D000328:Adult; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000453:epidemiology*; D003276:Contraceptives, Oral / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors
chemical_list: D003276:Contraceptives, Oral
keywords: Adenoma; Colorectal neoplasms; Contraceptives; Intestinal polyps; Oral; Reproductive history