Meta-Analysis of the Breast Cancer Risk Associated with Three Dietary Patterns

Objectives A meta-analysis was conducted to assess the association between breast cancer risk and three common dietary patterns. Methods The PubMed, Web of Science, CNKI, Wanfang, Embase, and Cochrane Library databases were systematically searched (until June 2022) for studies on the association between three common dietary patterns, including the Western dietary pattern, vegetarian dietary pattern and Mediterranean dietary pattern, and the risk of breast cancer. The Newcastle-Ottawa (NOS) scale was used to assess study quality. Results A total of 24 articles published from 2001 to 2021 that met the criteria were included for meta-analysis. The Western dietary pattern was positively associated with the breast cancer risk in women both before and after menopause, although the heterogeneity in the study was high (HR = 1.05, 95％ CI: 1.01-1.30, I2 = 56.2％, P = 0.019). There was an inverse association between the vegetarian dietary pattern and breast cancer risk among women (HR = 0.87, 95％ CI: 0.78 - 0.97, I2 = 73.7％, P < 0.001). No association was observed between the Mediterranean dietary pattern and women's risk of breast cancer (HR = 0.96, 95％ CI: 0.89 - 1.02, I2 = 64.1％, P = 0.010). Due to the presence of significant heterogeneity among the studies, we performed a subgroup analysis, meta-regression analysis and sensitivity analysis, and found that factors such as the type of study design were the main sources of heterogeneity in each group. These results remained largely unchanged after excluding studies of a specific type from the sensitivity analysis. Conclusion The Western dietary pattern can increase the risk of breast cancer, while the vegetarian dietary pattern can reduce the risk of breast cancer. No association between the Mediterranean dietary pattern and the risk of breast cancer was observed.