Dairy consumption and liver cancer risk: A meta-analysis of observational studies

The connection between the consumption of dairy products and the risk of developing primary liver cancer (PLC) remains unclear. The present study performed a comprehensive meta-analysis with the aim of providing evidence for any connection between the risk of developing PLC and the consumption of dairy products. For this purpose, eligible studies were screened from the PubMed, Cochrane Library and Embase databases before December 2022. A total of 10 cohort studies and 8 case-control studies were included, making a total of 18 studies with 6,562,714 participants and 7,970 PLC cases. The relative risks (RRs) for milk and yogurt were 1.38 [95% confidence interval (CI), 1.07-1.77] and 0.49 (95% CI, 0.27-0.91), which revealed a positive and negative association, respectively, with the risk of developing PLC. There was no association between total dairy (RR, 1.04; 95% CI, 0.84-1.30) or cheese and curd (RR, 1.05; 95% CI, 0.87-1.27) consumption and the risk of developing PLC. On the whole, the findings of the present study demonstrated that high milk consumption was associated with a higher risk of developing PLC, while by contrast, yogurt consumption was associated with a lower risk of developing PLC. Consequently, further studies are required to further examine this association.