Green Tea Consumption and Risk of Breast Cancer and Recurrence—A Systematic Review and Meta-Analysis of Observational Studies

Abstract

Breast cancer (BC) is the most common cancer in women and several factors are involved in its onset. Green tea (GT) has been shown to have potential beneficial effects on different types of cancer. The aim of this review was to evaluate the association between GT regular consumption and risk of BC in women. The risk of BC recurrence and risk of BC in relation to menopausal status were also evaluated. A literature search of PubMed, Scopus, and Web of Science was conducted. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to perform the systematic review and meta-analysis. Full texts were downloaded for 40 studies; however, only 13 records were included in the meta-analysis. Eight were cohort studies and five were case-control studies. The pooled sample consisted of 163,810 people. An inverse statistically significant relationship between GT and BC risk, with an Odds Ratio (OR) = 0.85 ((95% CI = 0.80–0.92), p = 0.000)), was found. Egger’s linear regression test did not show a potential publication bias (intercept 0.33, t = 0.40, p = 0.695), which was also confirmed by the symmetry of the funnel plot. Moreover, no high statistical heterogeneity (Chi2 = 31.55, df = 13, I2 = 58.79%, p = 0.003) was found. The results of this meta-analysis showed a potential protective effect of GT consumption on BC, especially for BC recurrence.

Chemoprevention of Breast Cancer With Vitamins and Micronutrients: A Concise Review

“…The significance of case-control studies in defining the causal relationship between exposure and event cannot be overemphasised. Finally, in a sensitivity analysis of the studies with high quality scores included in this metaanalysis, the reduction of breast cancer risk reported was even higher, at 27% (83).…”

Is the Association between Green Tea Consumption and the Number of Remaining Teeth Affected by Social Networks?: A Cross-Sectional Study from the Japan Gerontological Evaluation Study Project

“…Previous studies have shown that it can prevent both dental caries and periodontal disease [10][11][12]. In addition to its beneficial effects on various health outcomes, such as all-cause mortality, cardiovascular disease, cancers, non-alcoholic fatty liver disease, metabolic syndrome, diabetes, and other health outcomes [13][14][15][16][17][18][19][20], green tea consumption is also considered to have an effect on oral health. In spite of abundant benefits from the basic sciences, there are relatively fewer clinical studies on the merit of green tea on oral health [21].…”

Flavonoids and Other Polyphenols Act as Epigenetic Modifiers in Breast Cancer

“…Current reports are conflicting in regards to the correlation between breast cancer occurrence and green tea consumption. Some reports have shown an inverse correlation, while other reports have identified no benefit of tea consumption on breast cancer prevention or occurrence [56,57]. However, breast cancer risk has been reported to be considerably lower among Asian women compared to Western populations.…”