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Association between tea consumption and risk of cancer: a prospective cohort study of 0.5 million Chinese adults.
Li, X, Yu, C, Guo, Y, Bian, Z, Shen, Z, Yang, L, Chen, Y, Wei, Y, Zhang, H, Qiu, Z, et al
European journal of epidemiology. 2019;(8):753-763
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Abstract
Current experimental and epidemiological studies provide inconsistent evidence toward the association between tea consumption and cancer incidence. We investigated whether tea consumption was associated with the incidence of all cancers and six leading types of cancer (lung cancer, stomach cancer, colorectal cancer, liver cancer, female breast cancer and cervix uteri cancer) among 455,981 participants aged 30-79 years in the prospective cohort China Kadoorie Biobank. Tea consumption was assessed at baseline (2004-2008) with an interviewer-administered questionnaire. Cancer cases were identified by linkage to the national health insurance system. Cox proportional hazard regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). In the present population, daily tea consumers were more likely to be current smokers and daily alcohol consumers. 22,652 incident cancers occurred during 10.1 years follow-up (5.04 cases/1000 person-years). When we restricted analyses to non-smokers and non-excessive alcohol consumers to minimize confounding, tea consumption was not associated with all cancers (daily consumers who added tea leaves > 4.0 g/day vs. less-than-weekly consumers: HR, 1.03; 95%CI, 0.93-1.13), lung cancer (HR, 1.08; CI, 0.84-1.40), colorectal cancer (HR, 1.08; CI, 0.81-1.45) and liver cancer (HR, 1.08; CI, 0.75-1.55), yet might be associated with increased risk of stomach cancer (HR, 1.46; CI, 1.07-1.99). In both less-than-daily and daily tea consumers, all cancer risk increased with the amount of tobacco smoked or alcohol consumed. Our findings suggest tea consumption may not provide preventive effect against cancer incidence.
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Tea and coffee consumption and risk of laryngeal cancer: a systematic review meta-analysis.
Chen, J, Long, S
PloS one. 2014;(12):e112006
Abstract
BACKGROUND Tea and coffee are the most commonly consumed beverages in the worldwide. The relationship between tea and coffee consumption on the risk of laryngeal cancer was still unclear. METHODS Relevant studies were identified by searching electronic database (Medline and EMBASE) and reviewing the reference lists of relevant articles until Oct. 2013. Observational studies that reported RRs and 95% CIs for the link of tea and coffee consumption on the risk of laryngeal cancer were eligible. A meta-analysis was obtained to combine study-specific RRs with a random-effects model. RESULTS A total of 2,803 cases and 503,234 controls in 10 independent studies were identified. The overall analysis of all 10 studies, including the case-control and cohort studies, found that tea drinking was not associated with laryngeal carcinoma (RR = 1.03; 95% CI: 0.66-1.61). However, coffee consumption was significantly associated with the laryngeal carcinoma (RR = 1.47; 95% CI: 1.03-2.11). A dose-response relationship between coffee intake and laryngeal carcinoma was detected; however, no evidence of dose-response link between tea consumption and laryngeal carcinoma risk was detected. CONCLUSIONS The results from this meta-analysis of observational studies demonstrate that coffee consumption would increase the laryngeal cancer risk, while tea intake was not associated with risk of laryngeal carcinoma.