Vitamin D and liver cancer risk: A meta-analysis of prospective studies

The association between circulating vitamin D and liver cancer risk has been controversial on the basis of epidemiological studies. The aim of this study was to quantitatively evaluate this association with prospective studies.

A systematic literature search was implemented in PubMed and Scopus databases up to June 2019. Using a random-effects model, the multivariate-adjusted relative risks (RRs) with corresponding 95% confidence interval (CI) were pooled for the highest versus lowest category. Trend estimation was conducted with a two-stage dose-response meta-analysis.

Six independent prospective studies (992 liver cancer events and 60,811 participants) were included for data synthesis. The summary estimate showed that a higher circulating vitamin D was associated with lower risk of liver cancer (Summary RR=0.78; 95% CI: 0.63, 0.95; I2=53.6%, p=0.035). Dose-response analysis indicated that liver cancer was associated with 8% (95% CI: 0.89, 0.95) lower risk with a 10 nmol/L increment of circulating vitamin D concentration.

The present study provides substantial evidence that a higher concentration of circulating vitamin D would have conferred protection against liver cancer.