Breast cancer risk factors in south of Islamic Republic of Iran: a case-control study.

A case-control study was carried out from April 2000 to March 2002 to investigate risk factors for breast cancer in Bandar Abbas, south Islamic Republic of Iran. Using logistic regression analysis, 168 women with pathologically confirmed primary breast cancer were compared with 504 age-matched controls. Significant risk factors were: family history of breast cancer in a first-degree relative, younger age at menarche, never married, first full-term pregnancy age 30+ years and >5 full-term pregnancies. In multivariate analysis, negative history of breastfeeding was also significant. Cases and controls did not differ with regard to parity, history of abortion, oral contraceptive use, menopausal status, age at menopause, ever-use of hormone replacement therapy, history of benign breast disease or history of cigarette smoking.