Association of tea consumption and the risk of thyroid cancer: a meta-analysis

Objectives: Epidemiological studies evaluating the association of tea consumption and the risk of thyroid cancer risk have produced inconsistent results. Thus, we conducted a meta-analysis to assess the relationship between tea consumption and thyroid cancer risk. Methods: Pertinent studies were identified by a search in PubMed and Web of Knowledge. The random effect model was used based to combine the results. Publication bias was estimated using Egger's regression asymmetry test. Results: Finally, 11 articles with 14 studies (2 cohort studies and 12 case-control studies) involving 2,955 thyroid cancer cases and 106,447 participants were included in this meta-analysis. The relative risk (95% confidence interval) of thyroid cancer for the highest versus the lowest category of tea consumption was 0.774 (95% CI = 0.619-0.967), and the associations were also significant in Europe and America, but not in the Asia. No publication bias was found. Conclusions: Our analysis indicated that higher tea consumption may have a protective effect on thyroid cancer, especially in Europe and America.