title: Early life body fatness and risk of colorectal cancer in u.s. Women and men-results from two large cohort studies.
abstract: BACKGROUND
  The association between body fatness before adulthood and later risk of colorectal cancer remains unclear. We hypothesized that, independent of adult body fatness, early life body fatness would be associated with a higher risk of developing colorectal cancer.
  
  
  METHODS
  We assessed body fatness during childhood and adolescence using a validated 9-level somatotype and inquired body weight in young adulthood in the Nurses' Health Study and Health Professionals Follow-up Study. We used the Cox proportional hazard regression modeling to estimate relative risks [RR, 95% confidence intervals (CI)] adjusting for adult body mass index (BMI) and other known colorectal cancer risk factors.
  
  
  RESULTS
  We identified 2,100 incident colorectal cancer cases (1,292 in women and 808 in men) during 22 years of follow-up. Among women, the RR (95% CI) for childhood body fatness of level 5 or higher versus level 1 was 1.28 (1.04-1.58; Ptrend = 0.08) and for adolescent body fatness, it was 1.27 (1.01-1.60; Ptrend = 0.23). The corresponding RRs for men were 1.04 (0.82-1.31; Ptrend = 0.48) and 0.98 (0.75-1.27; Ptrend = 0.20), respectively. Results were generally similar across anatomic subsites within the colorectum. In addition, the RRs comparing BMI categories ≥27.5 to <19 kg/m(2) were 1.44 (1.06-1.95, at age 18; Ptrend = 0.009) for women and 1.18 (0.84-1.65, at age 21; Ptrend = 0.57) for men.
  
  
  CONCLUSIONS
  Increased body fatness in early life, independent of adult obesity, might be a risk factor for colorectal cancer in women, but we observed a weaker association in men.
  
  
  CONCLUSIONS
  Our findings support the growing evidence that early life body fatness affects the risk of colorectal cancer many decades later.
authors.affiliation: Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts. poxue@channing.harvard.edu.
authors.forename: Xuehong
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts.
authors.forename: Kana
authors.initials: K
authors.lastname: Wu
authors.affiliation: Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts. Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts. Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts.
authors.forename: Edward L
authors.initials: EL
authors.lastname: Giovannucci
authors.affiliation: Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Jing
authors.initials: J
authors.lastname: Ma
authors.affiliation: Department of Surgery, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Graham A
authors.initials: GA
authors.lastname: Colditz
authors.affiliation: Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts. Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts.
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, Harvard Medical School, Boston, Massachusetts. Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts. Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts.
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
authors.affiliation: Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts. Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts. Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts.
authors.forename: Meir J
authors.initials: MJ
authors.lastname: Stampfer
authors.affiliation: Max Delbrück Center for Molecular Medicine, Berlin, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Nimptsch
authors.affiliation: Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts. Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts. Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Shuji
authors.initials: S
authors.lastname: Ogino
authors.affiliation: California Pacific Medical Center Research Institute, San Francisco, California.
authors.forename: Esther K
authors.initials: EK
authors.lastname: Wei
mesh_terms: D000273:Adipose Tissue; D000293:Adolescent; D000328:Adult; D000368:Aged; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology*; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D063766:Pediatric Obesity / Q000453:epidemiology; D011446:Prospective Studies; D012306:Risk; D012307:Risk Factors; D012737:Sex Factors; D014481:United States; D055815:Young Adult