In May 2019 researchers from The Netherlands, UK, USA, Belgium, Taiwan, Germany, Sweden, Italy, Canada and France published the results of their study to assess the effect of coffee on risk of bladder cancer. A total of 13 individual studies were included and involved 5,911 individuals with bladder cancer and 16,172 healthy individuals who acted as a control group. Results showed no association between bladder cancer risk and coffee consumption amongst smokers, although the risk did appear to significantly increase with a coffee consumption of more than 6 cups/day. However, coffee consumption did appear to significantly increase the risk of bladder cancer in those individuals who had never smoked in a dose dependent manner, ie the higher the consumption, the higher the risk.
Yu EY et al. The association between coffee consumption and bladder cancer in the bladder cancer epidemiology and nutritional determinants (BLEND) international pooled study. Cancer Causes Control. 2019 May 30. [Epub ahead of print]