Abstract

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 1st, 2016 for all the case-control 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 95 confidence interval. Results: Out of the 513 retrieved studies, 17 (9 case-control and 8 cohort) were entered into the meta-analysis. These studies analyzed 26675 cases of breast cancer and over 943557 control or comparison subjects. The results of the random effects meta-analysis indicated a significant association between red meat consumption and breast cancer risk (relative risk: 1.269; 95 confidence interval: 1.117, 1.441; P-value for heterogeneity=0.002). The pooled relative risk was 1.087 (95 confidence interval: 0.999, 1.183) for cohort studies and 1.548 (95 confidence interval: 1.255, 1.909) 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.