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

• Published in: Nutrition and cancer 2013-04, Vol.65 (3), p.398-409
• Main Authors: Lowcock, Elizabeth C, Cotterchio, Michelle, Anderson, Laura N, Boucher, Beatrice A, El-Sohemy, Ahmed
• Format: Article
• Language: English
• Subjects: Adult; Aged; Breast cancer; breast neoplasms; Breast Neoplasms - epidemiology; Breast Neoplasms - etiology; Breast Neoplasms - genetics; Caffeine; Caffeine - administration & dosage; Caffeine - adverse effects; Case-Control Studies; Coffee; confidence interval; cytochrome P-450; Cytochrome P-450 CYP1A2 - genetics; Diet; estrogen receptors; Estrogens; Female; genes; Genotype; Genotype & phenotype; Humans; metabolism; Middle Aged; Odds Ratio; Ontario - epidemiology; Postmenopause; Receptors, Estrogen - analysis; regression analysis; risk; Risk Factors; risk reduction; T cell receptors
• ISSN: 1532-7914; 0163-5581; 1532-7914
• DOI: 10.1080/01635581.2013.768348

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.