Tea consumption and risk of bladder cancer in the Bladder Cancer Epidemiology and Nutritional Determinants (BLEND) Study: Pooled analysis of 12 international cohort studies

Abdulmohsen H Al-Zalabani, Anke Wesselius, Evan Yi-Wen Yu, Piet van den Brandt, Eric J Grant, Emily White, Guri Skeie, Fredrik Liedberg, Elisabete Weiderpass, Maurice P Zeegers

Research output: Contribution to journalArticleAcademicpeer-review


BACKGROUND & AIMS: Tea has been shown to be associated with reduced risk of several diseases including cardiovascular diseases, stroke, metabolic syndrome, and obesity. However, the results on the relationship between tea consumption and bladder cancer are conflicting. This research aimed to assess the association between tea consumption and risk of bladder cancer using a pooled analysis of prospective cohort data.

METHODS: Individual data from 532,949 participants in 12 cohort studies, were pooled for analyses. Cox regression models stratified by study centre was used to estimate hazard ratios (HR) and corresponding 95% CIs. Fractional polynomial regression models were used to examine the dose-response relationship.

RESULTS: A higher level of tea consumption was associated with lower risk of bladder cancer incidence (compared with no tea consumption: HR = 0.87, 95% C.I. = 0.77-0.98 for low consumption; HR = 0.86, 95% C.I. = 0.77-0.96 for moderate consumption; HR = 0.84, 95% C.I. = 0.75-0.95 for high consumption). When stratified by sex and smoking status, this reduced risk was statistically significant among men and current and former smokers. In addition, dose-response analyses showed a lower bladder cancer risk with increment of 100 ml of tea consumption per day (HR-increment = 0.97; 95% CI = 0.96-0.98). A similar inverse association was found among males, current and former smokers while never smokers and females showed non-significant results, suggesting potential sex-dependent effect.

CONCLUSIONS: Higher consumption of tea is associated with reduced risk of bladder cancer with potential interaction with sex and smoking status. Further studies are needed to clarify the mechanisms for a protective effect of tea (e.g. inhibition of the survival and proliferation of cancer cells and anti-inflammatory mechanisms) and its interaction with smoking and sex.

Original languageEnglish
Pages (from-to)1122-1130
Number of pages9
JournalClinical Nutrition
Issue number5
Early online date29 Mar 2022
Publication statusPublished - May 2022


  • Cohort studies
  • Dose-response analysis
  • Epidemiology
  • Smoking
  • Tea
  • Urinary bladder cancer

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