Risk Factors of Breast Cancer in the Eastern Mediterranean Region: A Systematic Review and Meta-Analysis

Abstract

<b>Background:</b> Identifying risk factors of breast cancer is a key point for preventive strategies to reduce theincidence. The aim of current study was to determine most important risk factors for breast cancer in the EasternMediterranean Region (EMR) using a systematic review. Materials and <br/><b>Methods</b>: PubMed, Scopus, Web ofScience till August 24, 2012 and the reference lists of all included studies were searched. Analytic studies whichhad reported odds ratios (OR), relative risk (RR) or required data to calculate them were included. A total of 343studies were critically appraised and finally 30 studies were meta-analyzed. Heterogeneity between the studieswas assessed by I² and Cochran’s Q. Egger’s test was used to assess publication bias. <br/><b>Results</b>: Twenty five casecontrolstudies, one nested case-control and four cohort studies were included. The largest ORs were obtained forhistory of no live birth (2.25; 95%CI: 1.58-3.18), body mass index (BMI) more than 30 (2.21; 95%CI: 1.71-2.36),age at first pregnancy more than 30 years old (1.52; 95%CI: 1.30-1.77) and meat consumption more than threetimes per week (1.39; 95%CI: 1.03-1.87). The other important predictors were higher education and smokingas risk factors, physical activity and ovulatory stimulating medication as protective factors. <br/><b>Conclusions</b>: Themost important predictors of breast cancer in EMR were history of no live birth, BMI more than 30, age at firstpregnancy more than 30 years old, physical inactivity and smoking. Almost all these risk factors are consistentwith known risk factors for this cancer in other parts of the world.