Fruit and vegetable intake and liver cancer risk: a meta-analysis of prospective cohort studies.

The associations of vegetable and fruit intake with liver cancer risk have been inconsistent based on epidemiological studies. The present study aimed to quantitatively evaluate these associations with prospective cohort studies. A systematic literature search was performed with PubMed and Scopus databases up to June 2019. Multivariate-adjusted relative risks (RRs) with a corresponding 95% confidence interval (CI) for the highest versus lowest category were pooled by using a random-effects model. Pre-specified subgroup and univariate meta-regression analyses were performed to identify the sources of heterogeneity. Dose-response analysis was conducted by using the variance weighted least squares regression model. Nine independent prospective cohort studies with 1703 liver cancer events and 1 326 176 participants were included for data synthesis. The summary estimates showed that higher vegetable intake was associated with a 39% (95%CI: 0.50, 0.75) reduction in liver cancer risk, with no significant between-study heterogeneity (P = 0.057). Dose-response analysis indicated that the risk of liver cancer was reduced by 4% (95%CI: 0.97, 0.95; P for trend <0.001) with a 100 gram per day increment of vegetable intake. Subgroup analysis showed that higher intakes of vegetables were associated with a 50% (95%CI: 0.35, 0.72) reduction of liver cancer risk in males, but not in females. However, a non-significant association was found between fruit intake and liver cancer risk. The present study provides strong evidence that higher intakes of vegetables would have beneficial effects on the prevention of liver cancer, especially for males.

Effects of EPA and DHA on blood pressure and inflammatory factors: a meta-analysis of randomized controlled trials.

The present study aimed to clarify whether eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have differential effects on blood pressure and inflammatory mediators. A systematic literature search was conducted in PubMed and Scopus updated to Apr. 2018. The mean changes in risk factors of chronic diseases were calculated as weighted mean difference (WMD) by using a random-effects model. Twenty randomized controlled trials (RCTs) were included. The summary estimate showed that EPA intervention significantly reduced systolic blood pressure (SBP) (-2.6 mmHg; 95%confident interval (CI): -4.6, -0.5 mmHg), especially in subjects with dyslipidemia (-3.8 mmHg; 95%CI: -6.7, -0.8 mmHg). The pooled effect indicated that supplemental DHA exerted a significant reduction in diastolic blood pressure (DBP) in subjects with dyslipidemia (-3.1 mmHg; 95%CI: -5.9, -0.2 mmHg). Both EPA (-0.56 mg/L; 95%CI: -1.13, 0.00) and DHA (-0.5 mg/L; 95%CI: -1.0, -0.03) significantly reduced the concentrations of C-reactive protein (CRP), respectively, especially in subjects with dyslipidemia and higher baseline CRP concentrations. Given that limited trials have focused on EPA or DHA intervention on concentrations of interleukin (IL)-6 and tumor necrosis factor (TNF)-α, further RCTs should be explored on these inflammatory factors. The present meta-analysis provides substantial evidence that EPA and DHA have independent (blood pressure) and shared (CRP concentration) effects on risk factors of chronic diseases, and high-quality RCTs with multi-center and large simple-size should be performed to confirm the present findings.