Association between Non-alcoholic Fatty Liver Disease and Breast Cancer: A Systematic Review and Meta-analysis Study

Background: Breast cancer (BC) is the most prevalent neoplasm in females globally, with an increasing incidence trend almost in all regions. Previous studies have indicated that non-alcoholic fatty liver disease (NAFLD) may be an emerging risk factor for extrahepatic cancers, including BC. This systematic review and meta-analysis study aimed to determine the association between NAFLD and the development of BC. Method: Data were systematically collected without time limitation until 21 April 2022, from the following electronic databases: PubMed, Scopus, Embase, Web of Science, and Google Scholar. The association between NAFLD and BC with odds ratio (OR) was calculated with a 95% confidence interval (CI) and presented via forest plots. Hazard ratios along with incidence rate ratios in the cohort studies transformed into OR. Results: According to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) and the inclusion criteria herein, 11 eligible studies were obtained from various countries. The pooled OR of NAFLD as a risk of developing BC, using a random-effects model, was estimated at 1.61 (95% CI: 1.30-2.00) (Q value: 51.35, I2 = 80.52%, P 0.0001). Multivariate meta-regression analysis showed that the publication year-, country-, detection method-, study design-, and body mass index-adjusted status did not cause heterogeneity. The Egger s regression (P = 0.32) and the symmetry in the funnel plot showed no publication bias in the studies. Conclusion: The present research revealed that NAFLD had a significant association with BC, independent of traditional risk factors.