Abstract
Tea contains polyphenols such as flavonoids, anthocyanidins, flavanols and phenolic acids which in laboratory studies have reported to promote antioxidant enzyme formation, reduces excess inflammation, slow cancer cell proliferation and promote apoptosis. Evidence from epidemiological studies, on the effect of tea consumption on CaP incidence has been conflicting. We analysed data from 25 097 men within the intervention arm of the 155000 participant Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial screening trial. Histologically confirmed cases of prostate cancer were reported in 3,088 men (12.3%) during the median 11.5 year follow up. Tea consumption was assessed with a food frequency questionnaire. Baseline characteristics were compared between groups using Chi-square and Kruskal-Wallis tests. Cox regression models were used to assess associations between tea intake and CaP incidence. There was no statistical difference between the risk of CaP between men who never drank tea to those who drank tea at any quantity. Amongst tea drinkers, those in the highest third of consumption group had a small but significantly lower risk compared to those in the lowest third (11.2% v 13.2% HR 1.16; 95% CI 1.05-1.29, p=0.004). This pattern persisted with adjustments for demographics and lifestyle. In conclusion, among tea drinkers, there was a small positive association between drinking tea and a reduced risk of prostate cancer. It does not support starting to drink tea, if men previously did not, to reduce the risk. Further research is needed to establish whether tea is justified for future prospective nutritional intervention studies investigating CaP prevention.
Dietary carbohydrate, glycemic index, glycemic load, and risk of prostate cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) cohort
