Effects of Coffee, Black Tea and Green Tea Consumption on the Risk of Non-Hodgkin's Lymphoma: A Systematic Review and Dose-Response Meta-Analysis of Observational Studies.

Aim: Several studies have evaluated the association between coffee, black and green tea consumption and non-Hodgkin's lymphoma (NHL) risk, while the results were inconsistent. We conducted a dose-response meta-analysis of available observational studies to assess the association among coffee, black and green tea intake and the risk of NHL in the general population.

Methods

Studies published up to August 2018 were identified on the basis of a literature search in PubMed, ISI Web of Science, Scopus and Cochrane databases using Mesh and non-Mesh relevant keywords. Relative risks (RRs) with 95% confidence intervals (CIs) and the dose-response relationships were calculated using random-effects models.

Results

In the meta-analysis of 19 effect sizes (315,972 participants with 4,914 cases of NHL), we found that higher green tea intake was associated with a 39% reduced risk of NHL (pooled RR = 0.61; 95% CIs = 0.38-0.99, I2=60.4%, pheterogeneity=0.080) in high- versus low-intake meta-analysis. No association was observed between coffee intake (pooled RR = 1.21; 95% CIs = 0.97-1.50, I2=52.6%, pheterogeneity  <  0.05), black tea intake (pooled RR = 1.01; 95% CI = 0.82-1.24, I2=0%, pheterogeneity=0.875) and risk of NHL in high- versus low-intake meta-analysis.

Conclusions

Findings from this dose-response meta-analysis suggest that green tea intake may be associated with reduced risk of NHL.