The influence of overweight and insulin resistance on breast cancer risk and tumour stage at diagnosis: a prospective study

• Published in: Breast Cancer Research and Treatment
• Language: English
• Published: Springer US 2010
• Subjects: Adiponectin; Breast cancer; C-peptide; Glycated haemoglobin; Leptin; Obesity; Overweight; Northern Sweden
• Online Access: http://hdl.handle.net/2262/42233; https://doi.org/10.1007/s10549-008-9958-8

Abstract It is hypothesized that insulin resistance and related metabolic factors may influence breast cancer risk, however the epidemiological evidence remains inconclusive. We conducted a case?control study nested in a prospective cohort in Northern Sweden, to clarify the associations of body mass index (BMI), leptin, adiponectin, C-peptide, and glycated haemoglobin (HbA1c) with breast cancer risk. We also investigated whether these associations may be modified by age at diagnosis, tumour stage, and oestrogen and progesterone receptor status. During follow-up, 561 women developed invasive breast cancer and 561 matched controls were selected. Conditional logistic regression was used to calculate odds ratios (OR) as estimates of relative risk, and 95% confidence intervals (CI). The associations of BMI, leptin and HbA1c with breast cancer risk differed significantly according to whether the tumour was diagnosed as stage I or stage II?IV (P heterogeneity all <0.05). These factors were significantly inversely associated with risk in the group of stage I tumours, with ORs for top vs. bottom tertile for BMI of 0.48 (95% CI, 0.30?0.78, P trend = 0.004); leptin, 0.64 (95% CI, 0.41?1.00, P trend = 0.06); and HbA1c, 0.47 (95% CI, 0.28?0.80, P trend = 0.005). For stage II?IV tumours, there was a suggestion of an increased risk with higher levels of these factors. There were no significant differences in the associations of BMI, leptin, adiponectin, C-peptide and HbA1c with breast cancer risk in subgroups of age at diagnosis or tumour receptor status. This prospective study suggests that BMI, leptin and HbA1c influence breast tumour initiation and progression. phone: [phone] (Stocks, Tanja) [e-mail] (Stocks, Tanja) Centre for MEGA Epidemiology, The University of Melbourne - Melbourne - AUSTRALIA (Cust, Anne E.) School of Public Health, The University of Sydney - Sydney - AUSTRALIA (Cust, Anne E.) Nutrition and Hormones Unit, International Agency for Research on Cancer - Lyon - FRANCE (Cust, Anne E.) Department of Surgical and Perioperative Sciences, Urology and Andrology, Ume? University - 901 85 - Ume? - SWEDEN (Stocks, Tanja) Division of Cancer Epidemiology, German Cancer Research Center - Heidelberg - GERMANY (Lukanova, Annekatrin) Department of Medical Biosciences, Pathology, Ume? University - Ume? - SWEDEN (Lundin, Eva) Department of Public Health and Clinical Medicine, Nutritional Research, Ume? University - Ume? - SWEDEN (Hallmans, Goran) Division of Cancer Epidemiology, German Cancer Research Center - Heidelberg - GERMANY (Kaaks, Rudolf) Department of Radiation Sciences, Oncology, Ume? University - Ume? - SWEDEN (Jonsson, H?kan) Department of Surgical and Perioperative Sciences, Urology and Andrology, Ume? University - 901 85 - Ume? - SWEDEN (Stattin, Par) AUSTRALIA FRANCE GERMANY SWEDEN Registration: 2008-02-27 Received: 2008-01-25 Accepted: 2008-02-26 ePublished: 2008-03-11