title: Total calcium intake and colorectal adenoma in young women.
abstract: BACKGROUND
  Total calcium intake appears to reduce occurrence of colorectal adenoma; however, the dose necessary for prevention in young women is unclear. We examined fine categories of calcium intake in relation to occurrence of first colorectal adenoma in a cohort of mostly premenopausal (88 %) women aged 26-60 at time of endoscopy.
  
  
  METHODS
  We conducted an analysis among 41,403 participants in the Nurses' Health Study II and assessed intakes of calcium prior to endoscopy through participants' responses to biannual questionnaires.
  
  
  RESULTS
  Between 1991 and 2007, we documented 2,273 colorectal adenoma cases. There was a significant trend across categories of calcium intakes with lowest intakes suggestive of higher occurrence of adenoma (p = 0.03) and those in the distal colon (p = 0.03) and rectum (p = 0.04). Compared with 1,001-1,250 mg/day of calcium intake, ≤ 500 mg/day was suggestive of a modest increase in occurrence of adenoma (multivariable RR = 1.21, 95 % CI 0.90-1.61); there were also suggestions of an increased risk with >500 to ≤ 700 mg/day of calcium. The association between ≤ 500 mg/day of calcium intake and adenoma was stronger for multiple (RR = 2.27, 95 % CI 1.38, 3.72), large (≥ 1 cm) (RR = 2.01, 95 % CI 1.27, 3.21), and high-risk adenoma (≥ 1 cm or mention of villous histology/high-grade dysplasia) (RR = 1.76, 95 % CI 1.13, 2.72). No differences in associations were noted between jointly categorized calcium and phosphorus or magnesium intakes.
  
  
  CONCLUSIONS
  Our findings suggest that low intakes of calcium, <500 and possibly 500-700 mg/day, in younger women are associated with an increased risk of multiple and advanced colorectal adenoma.
authors.affiliation: Departments of Nutrition, Harvard School of Public Health, 665 Huntington Ave, Boston, MA, 02115, USA, jmassa@hsph.harvard.edu.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Massa
authors.forename: Eunyoung
authors.initials: E
authors.lastname: Cho
authors.forename: Endel J
authors.initials: EJ
authors.lastname: Orav
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
authors.forename: Kana
authors.initials: K
authors.lastname: Wu
authors.forename: Edward L
authors.initials: EL
authors.lastname: Giovannucci
mesh_terms: D000236:Adenoma / Q000453:epidemiology* / Q000517:prevention & control; D000328:Adult; D002136:Calcium, Dietary / Q000008:administration & dosage*; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000517:prevention & control; D005260:Female; D006801:Humans; D008875:Middle Aged; D017697:Premenopause; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology; D055815:Young Adult
chemical_list: D002136:Calcium, Dietary