Smoking and Breast Cancer: A Systematic Review and Meta-Analysis of Iranian Studies

Introduction &Aim: Various studies in Iran on the role of smoking in breast cancer reported different results. The current study found to estimate the overall odds ratio and explore the association smoking with breast cancer. Methods: Scopus, Web of Science, PubMed, Google Scholar and Iranian databases such as Magiran and SID, breast cancer key journals (Asian pacific journal of cancer prevention, Iranian quarterly journal of breast) and conferences (international breast cancer congresses in Iran, annual breast cancer conferences and seminars in Iran) were searched from 2004 to 2014. The observational studies in Iran that had reported the relationship smoking with breast cancer were searched. The exposure was smoking and the outcome was breast cancer with pathological confirmation. Data extraction: Using strengthening the reporting of observational studies in epidemiology (STROBE) checklist, quality assessment of the articles and data extraction were performed separately by two authors. Results: Of 4396 Iranian articles, 8 studies with a sample size of 2412, were analyzed to estimate the overall odds ratio (OR) of smoking. A significant relationship was observed between breast cancer and smoking (OR =1.72, 95% confidence interval (CI) = 1.23, 2.41). Conclusions: Smoking increases the odds of breast cancer. Therefore, effective educational programs to avoid smoking for people, especially women through mass media, should be designed and implemented. Breast cancer prevention and screening programs are needed to reduce the burden of this cancer and improve the quality of females‘lives especially for smokers.