Red Meat Consumption and Breast Cancer Risk in Premenopausal Women: A Systematic Review and Meta-Analysis

Background: This comprehensive meta-analysis aimed to determine the impact of red meat consumption on breast cancer risk in premenopausal women.Methods: We conducted a systematic search in major electronic databases (MEDLINE, Scopus, and ScienceDirect) until January ۱st, ۲۰۱۶ for all the casecontrol and cohort studies that addressed the association between red meat consumption and breast cancer risk. The full-texts of the retrieved articles were reviewed by two independent authors. The quality of the studies was assessed using a score assigned to each item according to STROBE statement. We used the random effects model to obtain summary measures of odds ratio or relative risk with ۹۵% confidence interval.Results: Out of the ۵۱۳ retrieved studies, ۱۷ (۹ case-control and ۸ cohort) were entered into the meta-analysis. These studies analyzed ۲۶۶۷۵ cases of breast cancer and over ۹۴۳۵۵۷ control or comparison subjects. The results of the random effects metaanalysis indicated a significant association between red meat consumption and breast cancer risk (relative risk: ۱.۲۶۹; ۹۵% confidence interval: ۱.۱۱۷, ۱.۴۴۱; P-value for heterogeneity=۰.۰۰۲). The pooled relative risk was ۱.۰۸۷ (۹۵% confidence interval: ۰.۹۹۹, ۱.۱۸۳) for cohort studies and ۱.۵۴۸ (۹۵% confidence interval: ۱.۲۵۵, ۱.۹۰۹) for case-control studies.Conclusion: The results of this meta-analysis showed that the women who consumed red meat had an increased risk of breast cancer. Further studies are required to investigate this association.