Risk Factors of Breast Cancer in North of Iran : A Case-Control in Mazandaran Province


Introduction: Breast cancer is the most common cancer among Iranian women. This study aimed to determinerisk factors for breast cancer in the north of Iran.
Method: A matched case-control study was conducted inMazandaran province of Iran in 2004 of 250 biopsy proven cases of breast cancer and 500 neighbor controlsthat were matched by age within a 3 year period. Statistical analysis was carried out using conditional logisticregression with the backward elimination method and crude and adjusted odds ratios with related 95% CIswere estimated with Stata 8.0 software
Results: Multivariate analysis showed that higher education (OR=4.70,95%CI: 1.71-12.88), late menopause (OR=4.18, 95%CI: 2.54-6.88), history of induced abortion (OR=1.62, 95%CI:1.13-2.31), positive first-degree family history of breast cancer (OR=3.14, 95%CI: 1.37-7.20), and BMI (OR=1.02,95%CI: 1.01-1.03) were risk factors for breast cancer. Furthermore, having more episodes of full term pregnancy(OR=0.87, 95%CI: 0.80-0.95), longer duration of breast feeding (OR=0.993, 95%CI: 0.989-0.997) and paritymore than 2 were shown to be protective factors.
Conclusions: Our study revealed the role of some modifiabledeterminants of breast cancer that can be focused by public health intervention in the northern community ofIran. Accordingly, the women who have one or more of the following risk factors should take the special attentionto risk of breast cancer: obesity, being menopause, positive family history of breast cancer and history of inducedabortion. The protective effect of longer duration of breast feeding should be encouraged too.