Link found between oesophageal cancer and drinking hot tea

The world's highest rates of oesophageal squamous cell carcinoma (OSCC) are found in the Golestan Province in northern Iran - also known for its widespread consumption of hot tea. In order to determine whether there is a link between tea drinking habits and cancers of the oesophagus, which kill more than 500,000 people worldwide each year, researchers conducted a population based case-control study in northern Iran. They studied the tea drinking habits of 300 people who had been diagnosed with OSCC, the most common type of oesophageal cancer, along with 571 healthy people from the same region. All participants drank black tea on a regular basis.

"Our results show a strong increase in the risk of oesophageal squamous cell carcinoma associated with drinking hot or very hot tea," write the authors of the study, which was published in the British Medical Journal. Specifically, the researchers found that drinking hot team (65-69°C) doubled the risk of oesophageal cancer, while drinking tea above 70°C was associated with an eight-fold increased risk. Letting tea cool for less than two minutes after having been poured was associated with a five-fold increase in risk compared to waiting four or more minutes. No association between the amount of tea consumed and the risk of cancer was found. The researchers also measured the actual temperature that tea was consumed by approximately 50,000 residents in the same region in order to minimize errors between reported and actual tea temperatures. Temperatures ranged from less than 60°C to more than 70°C, with a "moderate agreement between reported temperatures and actual temperatures."

"These results provide persuasive evidence that drinking tea at temperatures greater than 70°C markedly increases the risk of oesophageal squamous cell carcinoma," writes David Whiteman from the Queensland Institute of Medical Research in Australia in an accompanying editorial to the study. The study advises tea drinkers to wait a few minutes before drinking hot tea and suggests that educating the population about the hazards of drinking very hot tea could help reduce the incidence of oesophageal cancer in northern Iran and in other regions of the world where similar habits prevail.

News Release: Drinking very hot tea can increase the risk of throat cancer     www.eurekalert.org    March 26, 2009