title: Prospective study of the association between grapefruit intake and risk of breast cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC).
abstract: Grapefruit inhibits cytochrome P450 3A4 and may affect estrogen metabolism. In the European Prospective Investigation into Cancer and Nutrition (EPIC), we examined the relationships of grapefruit intake with risk of breast cancer and with serum sex hormone levels. 114,504 women with information on dietary intake of grapefruit and on reproductive and lifestyle risk factors were followed for a median 9.5 years and 3,747 incident breast cancers were identified. Fifty-nine percent of women reported eating grapefruit, 4% ate > or = 60 g/day. Cox proportional hazard models were used to estimate the hazard ratio (HR) for breast cancer according to grapefruit intake, adjusting for study centre, reproductive factors, body mass index, energy intake, and alcohol intake. Grapefruit intake was not related to the risk of breast cancer: compared with women who ate no grapefruit, women with the highest intake of > or =60 g/day had a HR of 0.93 (95% CI 0.77-1.13), p for linear trend = 0.5. There was no relationship between grapefruit intake and breast cancer risk among premenopausal women, all postmenopausal women, or postmenopausal women categorized by hormone replacement therapy use (all p>0.05). There was no association between grapefruit intake and estradiol or estrone among postmenopausal women. In this study, we found no evidence of an association between grapefruit intake and risk of breast cancer.
authors.affiliation: Cancer Epidemiology Unit, University of Oxford, Oxford, UK. elizabeth.spencer@ceu.ox.ac.uk
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Spencer
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Key
authors.forename: Paul N
authors.initials: PN
authors.lastname: Appleby
authors.forename: Carla H
authors.initials: CH
authors.lastname: van Gils
authors.forename: Anja
authors.initials: A
authors.lastname: Olsen
authors.forename: Anne
authors.initials: A
authors.lastname: Tjønneland
authors.forename: Françoise
authors.initials: F
authors.lastname: Clavel-Chapelon
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Boutron-Ruault
authors.forename: Marina
authors.initials: M
authors.lastname: Touillaud
authors.forename: Maria-José
authors.initials: MJ
authors.lastname: Sánchez
authors.forename: Sheila
authors.initials: S
authors.lastname: Bingham
authors.forename: Kay Tee
authors.initials: KT
authors.lastname: Khaw
authors.forename: Nadia
authors.initials: N
authors.lastname: Slimani
authors.forename: Rudolf
authors.initials: R
authors.lastname: Kaaks
authors.forename: Elio
authors.initials: E
authors.lastname: Riboli
mesh_terms: D000328:Adult; D000434:Alcoholic Beverages; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000097:blood / Q000453:epidemiology* / Q000209:etiology*; D016022:Case-Control Studies; D032083:Citrus paradisi; D015331:Cohort Studies; D051544:Cytochrome P-450 CYP3A / Q000378:metabolism; D004034:Diet Surveys; D002149:Energy Intake; D005060:Europe / Q000453:epidemiology; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood; D020249:Hormone Replacement Therapy; D006801:Humans; D015994:Incidence; D008019:Life Style; D008137:Longitudinal Studies; D015201:Meta-Analysis as Topic; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D017698:Postmenopause; D017697:Premenopause; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors
chemical_list: D012739:Gonadal Steroid Hormones; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human