Associations between food groups and liver cancer: a systematic review and meta-analysis of observational studies.

CONTEXT: Diet is emerging as a modifiable component of lifestyle for influencing the incidence of liver cancer. OBJECTIVE: To investigate and quantify the potential relationship between food groups and liver cancer. DATA SOURCES: PubMed and Web of Science were searched for eligible observational studies until 31st March, 2023. DATA EXTRACTION: The meta-analysis was conducted by pooling relative risk (RR), odds ratio (OR) or hazards ratio (HR) with 95% confidence intervals (CIs). Potential sources of heterogeneity were detected by subgroup analysis. Sensitivity analysis and publication bias test were also carried out. DATA ANALYSIS: Through stepwise screening, a total of 27 studies were included. The pooled estimates of liver cancer for whole grains and legumes intake were 0.66 (95% CI: 0.54-0.82; I2 = 25.3%) and 0.86 (95% CI: 0.75-0.99; I2 = 14.3%), respectively. However, there were null associations of nuts, poultry, egg and sweetened beverages consumption with liver cancer and the association between refined grains and liver cancer was inconclusive. In dose-response meta-analysis, the pooled estimates of liver cancer were 0.77 (95% CI: 0.65-0.91) for every 50 g/day increment in whole grains intake. Non-linear dose-response relationship (P = 0.031) was observed in the association between the intake of legumes and liver cancer, and the protective effect occurred with the dose ranging from 8 g/day to 40 g/day. CONCLUSIONS: This meta-analysis shows that whole grains and legumes were inversely associated with liver cancer, whereas intake of nuts, poultry, egg and sweetened beverages may not be associated with liver cancer. Further quantitative research needs to be undertaken within a range of populations to investigate the relationship between food groups and liver cancer. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42021246142.

The effect of vitamin D on the occurrence and development of colorectal cancer: a systematic review and meta-analysis.

PURPOSE: There has been a lot of controversies about the correlation between vitamin D and colorectal cancer (CRC). In this meta-analysis, we purposed to explore the relationship between vitamin D and the incidence of CRC/the prognosis of CRC. METHODS: A systematic search for articles in databases (Pubmed, Web of Science, EBSCO and Cochrane Library) was terminated in April 2020. The primary outcomes were the incidence rate of CRC and the long-term survival of patients with CRC. RESULTS: According to the estimated pooled OR from 21 eligible studies, covering 904,152 people, the use of vitamin D was inversely associated with the incidence of CRC [OR = 0.87, (0.82-0.92)]. Among the four studies included in this meta-analysis, covering 7486 patients, compared the overall survival (OS) of CRC between the vitamin D users and the non-users. Based on the estimated pooled HR, vitamin D potentially improved the long-term survival of CRC patients [HR = 0.91, (0.83-0.98)]. CONCLUSION: This meta-analysis demonstrates that vitamin D not only has a positive impact on the incidence of CRC from either the dietary or supplemental sources but also benefits clinical outcomes and improves the long-term survival of CRC patients. However, further studies are recommended to clarify the above phenomena.