Drinking burning-hot tea was associated with an increased risk for esophageal cancer when combined with excessive alcohol or tobacco use among a Chinese population, a study found.
A prospective cohort study in 10 areas across China from 2004 to 2008 included 456,155 persons ages 30 to 79 years. Those who had cancer at baseline or who reduced consumption of tea, alcohol, or tobacco before baseline were excluded.
Participants self-reported the usual temperature at which they drank tea (room temperature or warm, hot, or burning hot), other factors such as the volume of tea leaves used and the type of tea, and other lifestyle behaviors. The primary outcome was esophageal cancer incidence up to 2015.
Results were published Feb. 6 by Annals of Internal Medicine.
During a median follow-up of 9.2 years (4.1 million person-years), there were 1,731 cases of esophageal cancer. Both men and women who reported preferring burning-hot tea were more likely to be current smokers, to consume alcohol daily, to drink more cups of tea, and to add more tea leaves when making tea per day.
High-temperature tea drinking combined with alcohol consumption or smoking was associated with a greater risk for esophageal cancer than hot tea drinking alone. Compared with participants who drank tea less than weekly and consumed fewer than 15 g of alcohol daily, those who drank burning-hot tea and consumed 15 g or more of alcohol daily had the greatest risk for esophageal cancer (hazard ratio [HR], 5.00; 95% CI, 3.64 to 6.88). Current smokers who drank burning-hot tea daily had twice the risk (HR, 2.03; 95% CI, 1.55 to 2.67). There was no statistically significant association between tea temperature and esophageal cancer in women (P<0.001 for interaction with sex). In the absence of both excessive alcohol consumption and smoking, daily tea drinking was not associated with esophageal cancer risk, regardless of tea temperature or other consumption factors.
The researchers noted that it is biologically plausible for high-temperature tea drinking, excessive alcohol consumption, and tobacco use to affect esophageal cancer risk.
“Research has suggested that thermal injury may damage the epithelium and impair barrier function, subsequently augmenting the risk for damage from other risk factors, such as excessive alcohol consumption and smoking,” they wrote. “The release of N-nitroso compounds, which are formed as a result of inflammatory processes associated with chronic thermal irritation of the esophageal mucosa, also may contribute to esophageal cancer development.”
An accompanying editorial called the study well designed and said its results contribute to an “emerging picture” of a cancer risk linked to frequent consumption of very hot beverages. However, they also urged caution, pointing out that the study was observational and that its findings may reflect confounding by chance and other factors. In addition, they noted that most people who drink hot beverages do so below the “burning-hot” temperatures associated with risk in the study.
“Perhaps those of us who drink hot beverages often should be prudent and wait for the liquid to cool a bit first,” the editorialists wrote. “However, the results of this study should not cause people to abandon their favorite beverage.”