title: Zinc and heme iron intakes and risk of colorectal cancer: a population-based prospective cohort study in Japan.
abstract: BACKGROUND
  Food sources and intakes of zinc and heme iron may differ between Western and Asian populations. However, all of the studies on the association between zinc and heme iron intakes and colorectal cancer have been conducted in Western populations.
  
  
  OBJECTIVE
  We investigated the association between zinc and heme iron intakes and colorectal cancer risk in a Japanese general population.
  
  
  METHODS
  We conducted a large, population-based prospective study in 39,721 men and 45,376 women aged 45-74 y. Heme iron and zinc intakes were measured by using a validated food-frequency questionnaire in either 1995 or 1998.
  
  
  RESULTS
  During as many as 808,053 person-years of follow-up until the end of 2006, 1284 colorectal cancer cases were identified. In multivariate-adjusted models, zinc and heme iron intakes were not associated with colorectal cancer in either men or women. In comparison with the lowest quartile, the HRs (95% CIs) for developing colorectal cancer in the fourth quartile of zinc and heme iron intakes were 0.77 (0.58, 1.03; P-trend = 0.2) and 1.06 (0.79, 1.42; P-trend = 0.6), respectively, for men and 1.05 (0.77, 1.44; P-trend = 0.4) and 0.88 (0.61, 1.29; P-trend = 0.4), respectively, for women.
  
  
  CONCLUSIONS
  Our results in a Japanese population with lower intakes and different major food sources of zinc and heme iron in comparison with those of Western populations suggest that zinc and heme iron intakes are not associated with colorectal cancer.
authors.affiliation: Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan.
authors.forename: Azusa
authors.initials: A
authors.lastname: Hara
authors.forename: Shizuka
authors.initials: S
authors.lastname: Sasazuki
authors.forename: Manami
authors.initials: M
authors.lastname: Inoue
authors.forename: Motoki
authors.initials: M
authors.lastname: Iwasaki
authors.forename: Taichi
authors.initials: T
authors.lastname: Shimazu
authors.forename: Norie
authors.initials: N
authors.lastname: Sawada
authors.forename: Taiki
authors.initials: T
authors.lastname: Yamaji
authors.forename: Ribeka
authors.initials: R
authors.lastname: Takachi
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Tsugane
mesh_terms: D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000208:ethnology / Q000209:etiology* / Q000517:prevention & control; D004032:Diet / Q000009:adverse effects* / Q000208:ethnology; D005260:Female; D005500:Follow-Up Studies; D006418:Heme / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D019266:Iron, Dietary / Q000008:administration & dosage / Q000009:adverse effects*; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012306:Risk; D012727:Sex Characteristics; D014805:Vitamin B 12 / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D025101:Vitamin B 6 / Q000008:administration & dosage / Q000627:therapeutic use; D015032:Zinc / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D019266:Iron, Dietary; D006418:Heme; D025101:Vitamin B 6; D015032:Zinc; D014805:Vitamin B 12