title: Carotenoid intakes and risk of breast cancer defined by estrogen receptor and progesterone receptor status: a pooled analysis of 18 prospective cohort studies.
abstract: BACKGROUND
  Epidemiologic studies examining associations between carotenoid intakes and risk of breast cancer by estrogen receptor (ER) and progesterone receptor (PR) status are limited.
  
  
  OBJECTIVE
  We investigated these associations in a pooled analysis of 18 cohort studies.
  
  
  METHODS
  Of 1,028,438 participants followed for a maximum follow-up of 26 y across studies, 33,380 incident invasive breast cancers were identified. Study-specific RRs and 95% CIs were estimated by using Cox proportional hazards regression and then pooled by using a random-effects model.
  
  
  RESULTS
  α-Carotene, β-carotene, and lutein/zeaxanthin intakes were inversely associated with the risk of ER-negative (ER-) breast cancer (pooled multivariable RRs of the comparison between the highest and lowest quintiles): α-carotene (0.87; 95% CI: 0.78, 0.97), β-carotene (0.84; 95% CI: 0.77, 0.93), and lutein/zeaxanthin (0.87; 95% CI: 0.79, 0.95). These variables were not inversely associated with the risk of ER-positive (ER+) breast cancer (pooled multivariable RRs for the same comparison): α-carotene (1.04; 95% CI: 0.99, 1.09), β-carotene (1.04; 95% CI: 0.98, 1.10), and lutein/zeaxanthin (1.00; 95% CI: 0.93, 1.07). Although the pooled RRs for quintile 5 for β-cryptoxanthin were not significant, inverse trends were observed for ER- and ER+ breast cancer (P-trend ≤ 0.05). Nonsignificant associations were observed for lycopene intake. The associations were largely not appreciably modified by several breast cancer risk factors. Nonsignificant associations were observed for PR-positive and PR-negative breast cancer.
  
  
  CONCLUSIONS
  Intakes of α-carotene, β-carotene, and lutein/zeaxanthin were inversely associated with risk of ER-, but not ER+, breast cancer. However, the results need to be interpreted with caution because it is unclear whether the observed association is real or due to other constituents in the same food sources.
authors.affiliation: Department of Nutrition, Harvard School of Public Health, Boston, MA, USA. pooling@hsphsun2.harvard.edu
authors.forename: Xuehong
authors.initials: X
authors.lastname: Zhang
authors.forename: Donna
authors.initials: D
authors.lastname: Spiegelman
authors.forename: Laura
authors.initials: L
authors.lastname: Baglietto
authors.forename: Leslie
authors.initials: L
authors.lastname: Bernstein
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Boggs
authors.forename: Piet A
authors.initials: PA
authors.lastname: van den Brandt
authors.forename: Julie E
authors.initials: JE
authors.lastname: Buring
authors.forename: Susan M
authors.initials: SM
authors.lastname: Gapstur
authors.forename: Graham G
authors.initials: GG
authors.lastname: Giles
authors.forename: Edward
authors.initials: E
authors.lastname: Giovannucci
authors.forename: Gary
authors.initials: G
authors.lastname: Goodman
authors.forename: Susan E
authors.initials: SE
authors.lastname: Hankinson
authors.forename: Kathy J
authors.initials: KJ
authors.lastname: Helzlsouer
authors.forename: Pamela L
authors.initials: PL
authors.lastname: Horn-Ross
authors.forename: Manami
authors.initials: M
authors.lastname: Inoue
authors.forename: Seungyoun
authors.initials: S
authors.lastname: Jung
authors.forename: Polyna
authors.initials: P
authors.lastname: Khudyakov
authors.forename: Susanna C
authors.initials: SC
authors.lastname: Larsson
authors.forename: Marie
authors.initials: M
authors.lastname: Lof
authors.forename: Marjorie L
authors.initials: ML
authors.lastname: McCullough
authors.forename: Anthony B
authors.initials: AB
authors.lastname: Miller
authors.forename: Marian L
authors.initials: ML
authors.lastname: Neuhouser
authors.forename: Julie R
authors.initials: JR
authors.lastname: Palmer
authors.forename: Yikyung
authors.initials: Y
authors.lastname: Park
authors.forename: Kim
authors.initials: K
authors.lastname: Robien
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Rohan
authors.forename: Julie A
authors.initials: JA
authors.lastname: Ross
authors.forename: Leo J
authors.initials: LJ
authors.lastname: Schouten
authors.forename: James M
authors.initials: JM
authors.lastname: Shikany
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Tsugane
authors.forename: Kala
authors.initials: K
authors.lastname: Visvanathan
authors.forename: Elisabete
authors.initials: E
authors.lastname: Weiderpass
authors.forename: Alicja
authors.initials: A
authors.lastname: Wolk
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
authors.forename: Shumin M
authors.initials: SM
authors.lastname: Zhang
authors.forename: Regina G
authors.initials: RG
authors.lastname: Ziegler
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Smith-Warner
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000517:prevention & control; D002338:Carotenoids / Q000008:administration & dosage*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D014975:Lutein / Q000008:administration & dosage*; D008875:Middle Aged; D015999:Multivariate Analysis; D011446:Prospective Studies; D011960:Receptors, Estrogen / Q000032:analysis* / Q000378:metabolism; D011980:Receptors, Progesterone / Q000032:analysis* / Q000378:metabolism; D012307:Risk Factors; D011795:Surveys and Questionnaires; D024341:Xanthophylls / Q000008:administration & dosage*; D055815:Young Adult; D065146:Zeaxanthins; D019207:beta Carotene / Q000008:administration & dosage*
chemical_list: D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D024341:Xanthophylls; D065146:Zeaxanthins; D019207:beta Carotene; D002338:Carotenoids; C041635:alpha-carotene; D014975:Lutein