title: Lifelong vegetarianism and breast cancer risk: a large multicentre case control study in India.
abstract: The lower incidence of breast cancer in Asian populations where the intake of animal products is lower than that of Western populations has led some to suggest that a vegetarian diet might reduce breast cancer risk.
  
  
  
  Between 2011 and 2014 we conducted a multicentre hospital based case-control study in eight cancer centres in India. Eligible cases were women aged 30-70 years, with newly diagnosed invasive breast cancer (ICD10 C50). Controls were frequency matched to the cases by age and region of residence and chosen from the accompanying attendants of the patients with cancer or those patients in the general hospital without cancer. Information about dietary, lifestyle, reproductive and socio-demographic factors were collected using an interviewer administered structured questionnaire. Multivariate logistic regression models were used to estimate the odds ratio (OR) and 95% confidence intervals for the risk of breast cancer in relation to lifelong vegetarianism, adjusting for known risk factors for the disease.
  
  
  
  The study included 2101 cases and 2255 controls. The mean age at recruitment was similar in cases (49.7 years (SE 9.7)) and controls (49.8 years (SE 9.1)). About a quarter of the population were lifelong vegetarians and the rates varied significantly by region. On multivariate analysis, with adjustment for known risk factors for the disease, the risk of breast cancer was not decreased in lifelong vegetarians (OR 1.09 (95% CI 0.93-1.29)).
  
  
  
  Lifelong exposure to a vegetarian diet appears to have little, if any effect on the risk of breast cancer.
authors.affiliation: Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Richard Doll Building, Roosevelt Drive, Oxford, OX3 7LF, UK. toral.gathani@ceu.ox.ac.uk.|Oxford University Hospitals NHS Foundation Trust, Oxford, UK. toral.gathani@ceu.ox.ac.uk.
authors.forename: Toral
authors.identifier: 0000-0003-2837-1535
authors.initials: T
authors.lastname: Gathani
authors.affiliation: Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Richard Doll Building, Roosevelt Drive, Oxford, OX3 7LF, UK.
authors.forename: Isobel
authors.initials: I
authors.lastname: Barnes
authors.affiliation: Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Richard Doll Building, Roosevelt Drive, Oxford, OX3 7LF, UK.
authors.forename: Raghib
authors.initials: R
authors.lastname: Ali
authors.affiliation: G Kuppuswamy Naidu Memorial Hospital, Coimbatore, India.
authors.forename: Rajkumar
authors.initials: R
authors.lastname: Arumugham
authors.affiliation: Christian Medical College, Vellore, India.
authors.forename: Raju
authors.initials: R
authors.lastname: Chacko
authors.affiliation: Nizams Institute of Medical Sciences, Hyderabad, India.
authors.forename: Raghunadharao
authors.initials: R
authors.lastname: Digumarti
authors.affiliation: Gujarat Cancer Research Institute, Ahmedabad, India.
authors.forename: Parimal
authors.initials: P
authors.lastname: Jivarajani
authors.affiliation: Cachar Cancer Hospital and Research Centre, Silchar, India.
authors.forename: Ravi
authors.initials: R
authors.lastname: Kannan
authors.affiliation: Kidwai Memorial Institute of Oncology, Bangalore, India.
authors.forename: Dasappa
authors.initials: D
authors.lastname: Loknatha
authors.affiliation: RK Birla Cancer Centre, SMS Medical College, Jaipur, India.
authors.forename: Hemant
authors.initials: H
authors.lastname: Malhotra
authors.affiliation: Regional Cancer Centre, Trivandrum, India.
authors.forename: Beela S
authors.initials: BS
authors.lastname: Mathew
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality; D016022:Case-Control Studies; D004032:Diet / Q000009:adverse effects / Q000401:mortality; D014676:Diet, Vegetarian / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D016015:Logistic Models; D008875:Middle Aged; D016017:Odds Ratio; D018570:Risk Assessment / Q000379:methods
keywords: Breast cancer; Diet; India; Risk factors