The aim of this study was to investigate whether polymorphisms in N-acetyl transferase 1 and 2 modify the association between meat consumption and risk of breast cancer. A nested case–control study was conducted among 24 697 postmenopausal women included in the ‘Diet, Cancer and Health’ cohort study (1993–2000). Three hundred and seventy-eight breast cancer cases were identified and matched to 378 controls. The incidence rate ratio (95% confidence interval) for breast cancer was 1.09 (1.02–1.17) for total meat, 1.15 (1.01–1.31) for red meat and 1.23 (1.04–1.45) for processed meat per 25 g daily increment in intake. Compared with slow acetylators, the IRR (95% confidence interval) among fast N-acetyl transferase 1 acetylators was 1.43 (1.03–1.99) and 1.13 (0.83–1.54) among intermediate/fast N-acetyl transferase 2 acetylators. Interaction analyses revealed that the positive associations between total meat intake and red meat intake and breast cancer risk were confined to intermediate/fast N-acetyl transferase 2 acetylators (Pinteraction=0.03 and 0.04). Our findings support an association between meat consumption and breast cancer risk and that N-acetyl transferase 2 polymorphism has a modifying effect on the association, indicating that the association is confined to only genetically susceptible women.
aInstitute of Cancer Epidemiology, The Danish Cancer Society, Copenhagen
bDepartment of Environmental and Occupational Medicine, Institute of Public Health, University of Aarhus, Aarhus
cDepartment of Nutrition, National Food Institute, Søberg
dDepartment of Clinical Epidemiology, Aalborg Hospital, Aarhus University Hospital, Aalborg, Denmark
Correspondence to Ms Rikke Egeberg, Institute of Cancer Epidemiology, The Danish Cancer Society, Strandboulevarden 49, DK-2100 Copenhagen Ø, Denmark
Tel: +4535257675; fax: +4535257731; e-mail: firstname.lastname@example.org
Received 21 September 2006 Accepted 7 December 2006