Material and methods
2.1. Study's design and sample
This is a case–control study, with face-to-face interviews with
the participants. Between November 1, 2010 and July 31, 2012, 250
consecutive, newly (within 6 months) diagnosed breast cancer female
patients (defined by physical examination and biopsy) that visited
pathology-oncology clinics of five major general hospitals in Athens,
Greece (i.e., “Alexandra” General Hospital, “Elena Venizelos” Maternity-
General Hospital, “Agioi Anargyroi” General Oncological Hospital of
Kifissia, “Saint Savvas” Cancer Hospital and “I. Metaxa” Special Cancer
Hospital) were contacted to participate in the study. Patients with
diagnosis older than 6 months (in order to avoid changes in their dietary
habits or other behaviors), were not included. In the same period, 250
female subjects (controls) without any clinical symptoms, signs or
suspicion of any type of cancer in their medical history, were selected
on a volunteer basis. Control subjects were age-matched (±3 years)
with the cancer patients, population-based and selected from the same
catchment area (i.e., Athens metropolitan area, i.e., 76% or other areas)
of the patients (i.e., controls were selected from the same city or town
patients were living or working; there were no substantial differences
between living and working areas of the participants).