title: High coffee intake, but not caffeine, is associated with reduced estrogen receptor negative and postmenopausal breast cancer risk with no effect modification by CYP1A2 genotype.
abstract: Associations between caffeine and coffee consumption and breast cancer risk are uncertain, with studies suggesting inverse and null associations. Variation in cytochrome P450 1A2 (CYP1A2), a gene responsible for caffeine metabolism, may modify these associations. Cases (n = 3,062) were recruited through the Ontario Cancer Registry and controls (n = 3,427) through random digit dialing. Logistic regression was used to evaluate associations between breast cancer risk and intakes of 7 caffeine-containing items and total caffeine, and examine whether a genetic variant in CYP1A2 (rs762551) modified these associations. Analyses were stratified by estrogen receptor (ER), menopausal, and smoking status. Generally, coffee and caffeine were not associated with breast cancer risk; however, a significant reduction in risk was observed with the highest category of coffee consumption [≥5 cups per day vs. never, multivariate-adjusted odds ratio (MVOR) = 0.71, 95% confidence interval (CI): 0.51, 0.98]. Variant rs762551 did not modify associations. In stratified analyses, high coffee intake was associated with reduced risk of ER- (MVOR = 0.41, 95% CI: 0.19, 0.92) and postmenopausal breast cancer (MVOR = 0.63, 95% CI: 0.43, 0.94). High coffee consumption, but not total caffeine, may be associated with reduced risk of ER- and postmenopausal breast cancers, independent of CYP1A2 genotype. Further studies are needed to replicate these findings.
authors.affiliation: Prevention and Cancer Control, Cancer Care Ontario, Toronto, Ontario, Canada. beth.lowcock@cancercare.on.ca
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Lowcock
authors.forename: Michelle
authors.initials: M
authors.lastname: Cotterchio
authors.forename: Laura N
authors.initials: LN
authors.lastname: Anderson
authors.forename: Beatrice A
authors.initials: BA
authors.lastname: Boucher
authors.forename: Ahmed
authors.initials: A
authors.lastname: El-Sohemy
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology / Q000209:etiology* / Q000235:genetics; D002110:Caffeine / Q000008:administration & dosage* / Q000009:adverse effects; D016022:Case-Control Studies; D003069:Coffee; D019388:Cytochrome P-450 CYP1A2 / Q000235:genetics*; D004032:Diet; D005260:Female; D005838:Genotype; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D009864:Ontario / Q000453:epidemiology; D017698:Postmenopause; D011960:Receptors, Estrogen / Q000032:analysis*; D012307:Risk Factors
chemical_list: D003069:Coffee; D011960:Receptors, Estrogen; D002110:Caffeine; D019388:Cytochrome P-450 CYP1A2