title: γ-Glutamyltransferase and Breast Cancer Risk Beyond Alcohol Consumption and Other Life Style Factors - A Pooled Cohort Analysis.
abstract: OBJECTIVE
  Elevated γ-Glutamyltransferase serum levels are associated with increased risk of overall cancer incidence and several site-specific malignancies. In the present prospective study we report on the associations of serum γ-Glutamyltransferase with the risk of breast cancer in a pooled population-based cohort considering established life style risk factors.
  
  
  METHODS
  Two cohorts were included in the present study, i.e. the Vorarlberg (n = 97,268) and the Malmoe cohort (n = 9,790). Cox proportional hazards regression models were fitted to estimate HRs for risk of breast cancer.
  
  
  RESULTS
  In multivariate analysis adjusted for age, body mass index and smoking status, women with γ-Glutamyltransferase levels in the top quartile were at significantly higher risk for breast cancer compared to women in the lowest quartile (HR 1.21, 95% CI 1.09 to 1.35; p = 0.005). In the subgroup analysis of the Malmoe cohort, γ-Glutamyltransferase remained an independent risk factor for breast cancer when additionally considering alcohol intake. A statistically significant increase in risk was seen in women with γ-Glutamyltransferase-levels in the top versus lowest quartile in a multivariate model adjusted for age, body mass index, smoking status, physical activity, parity, oral contraceptive-use and alcohol consumption (HR 1.37, 95% CI 1.11-1.69, p = 0.006).
  
  
  CONCLUSIONS
  Our findings identified γ-Glutamyltransferase as an independent risk factor for breast cancer beyond the consumption of alcohol and other life style risk factors.
authors: Agency for Preventive and Social Medicine, Bregenz, Vorarlberg, Austria.
authors: Oliver
authors: O
authors: Preyer
authors: Surgery Research Unit, Lund University, Malmoe, Sweden.
authors: Dorthe
authors: D
authors: Johansen
authors: Department of Obstetrics and Gynaecology, Innsbruck Medical University, Innsbruck, Austria.
authors: Jessica
authors: J
authors: Holly
authors: Lund University Diabetes Centre, Diabetes and Cardiovascular Disease-Genetic Epidemiology Department of Clinical Sciences Malmö, CRC, Malmoe, Sweden.
authors: Tanja
authors: T
authors: Stocks
authors: Department of Experimental Pathology, University of Pisa, Medical School, Pisa, Italy.
authors: Alfonso
authors: A
authors: Pompella
authors: Agency for Preventive and Social Medicine, Bregenz, Vorarlberg, Austria.|Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany.
authors: Gabriele
authors: G
authors: Nagel
authors: Agency for Preventive and Social Medicine, Bregenz, Vorarlberg, Austria.
authors: Hans
authors: H
authors: Concin
authors: Department of Medical Statistics, Informatics and Health Economics, Innsbruck Medical University, Innsbruck, Austria.
authors: Hanno
authors: H
authors: Ulmer
authors: Department of Obstetrics and Gynaecology, Innsbruck Medical University, Innsbruck, Austria.
authors: Nicole
authors: N
authors: Concin
mesh_terms: D000328:Adult; D000428:Alcohol Drinking; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000201:enzymology*; D003276:Contraceptives, Oral / Q000627:therapeutic use; D003625:Data Collection; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008019:Life Style; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012044:Regression Analysis; D012307:Risk Factors; D005723:gamma-Glutamyltransferase / Q000378:metabolism*
chemical_list: D003276:Contraceptives, Oral; D005723:gamma-Glutamyltransferase