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.