LONDON — A study of nearly a million people has found new evidence to suggest that drinking scalding hot coffees and teas could significantly increase a person’s risk of getting cancer in their esophagus. Drinking these beverages very hot, rather than warm, is associated with a three-fold risk of esophageal cancer, according to the study, conducted in the U.K. and published Tuesday in the International Journal of Cancer. The finding applies specifically to esophageal squamous cell carcinoma (SCC), the most common form of esophageal cancer worldwide. The esophagus, also known as the food pipe, is a muscular tube that passes food and drink from your mouth to your stomach. Globally, there were about 604,000 new cases of esophageal cancer and about 544,000 deaths from esophageal cancer in 2020, according to the World Health Organization’s cancer agency, the International Agency for Research on Cancer (IARC). The agency estimates that global cases will rise by more than 50 per cent, to almost a million new cases a year by 2040. In the U.K., there are around 9,500 new cases each year, according to Cancer Research UK. However, an estimated 14 per cent of new esophageal SCC cases in the country could be avoided if individuals drank their teas and coffees at lower temperatures, the researchers from the U.K.’s University of Oxford said in the study, which is the largest of its kind. The researchers analyzed data from nearly 980,000 middle-aged adults in the U.K. who were asked questions about their hot drink consumption habits, including whether they preferred their drinks “very hot,” “hot,” or “warm” or if they “do not drink hot drinks,” or “prefer not to answer.” They were also asked how many hot drinks they consumed each day, with the option to choose “fewer than 6 hot drinks per day” or “6 or more hot drinks per day.” All the participants were from two large cohorts, the Million Women Study and U.K. Biobank, which both routinely log participants’ health information. Across the cohorts, 2,348 incidents of esophageal cancer occurred during an average follow-up period of 14.2 years and 11.1 years, respectively. The researchers found that just under half of the participants reported consuming six or more hot drinks per day, and approximately 15 per cent said they preferred their drinks very hot. The risk of esophageal SCC increased with the preferred drink temperature, with those who liked their drinks hot having almost twice the cancer risk of those who preferred them warm. For those who liked their drinks very hot, the risk was more than three-fold. The number of drinks consumed also mattered. After the researchers controlled for temperature, they found that drinking six or more hot drinks a day, compared with fewer than six, was associated with a 71 per cent higher risk of esophageal SCC. “This is the largest study to date, and it does really add to the evidence that drinking very hot and hot beverages could increase the risk of this type of cancer,” lead study author Keren Papier, a senior nutritional epidemiologist at Oxford Population Health, told CNN Wednesday. Drinking very hot beverages was classified as probably carcinogenic to humans by the IARC in 2016. The IARC defines “very hot” beverages as being at temperatures above 65 degrees Celsius, or 149 degrees Fahrenheit. However, previous studies were mostly conducted in South America, Asia and the Middle East, where drinking cultures are a bit different, Papier noted. People in the U.K. often add milk to their hot beverages, for example, but the researchers found that the cancer risk did not change based on whether participants added milk to their drinks or not — provided the drinks were still hot. Papier added that the new study finds “evidence from typical drinking habits in the U.K.,” where “most people are consuming tea or coffee on a daily basis, and it shows that how we consume the drinks matters, and that the findings are also relevant in this Western population in the U.K.” Relative risk remains low Despite the findings, the chance of getting diagnosed with esophageal cancer remains relatively low. The cancer makes up only 2 per cent of cancer cases in the U.K., where people have around a 1 per cent lifetime risk of being diagnosed with it, according to Cancer Research U.K. In the US, esophageal cancer is estimated to have made up just 1.1 per cent of new cancer cases this year, according to the National Cancer Institute. However, “for anyone who does enjoy drinking hot drinks and they’re worried about these findings, really a simple step is to let the drink cool down,” Papier said, adding that a drink can be cooled down by letting it sit for a while, adding milk or cold water, blowing on it or taking sips. “There is prior evidence that hot liquids damage the cells lining the oesophagus and can cause inflammation, so there is a plausible explanation for the findings,” epithelial physiologist Ian Johnson, an emeritus fellow at the Quadram Institute in England, who was not involved in the study, told CNN via email Wednesday. “I am inclined to take the research at face value and conclude that it would be prudent for people to consume cooler drinks (less than 65°C) rather than hotter,” Johnson added. “It sounds simple enough, but whether people who favour hot drinks can change their habits so easily is another matter.” That being said, the researchers were not able to explore the exact temperatures of the drinks consumed by participants, who could have different perceptions of heat, and so could not determine whether the self-reported heat levels were likely to have corresponded with specific temperature figures. Physiologist Muy-Teck Teh, a professor of molecular oral oncology at the U.K.’s Queen Mary, University of London, said in a statement released via the Science Media Centre that since the perceived drink temperatures were self-reported by the participants, and since the varying sensitivities of the participants’ mouths to hot drinks were not known, “the results should be interpreted as robust associations rather than causal proof.” Papier said smoking remains the biggest risk factor for this form of cancer, which has higher incidences in Eastern Asia and Southern and Eastern Africa, where alcohol consumption and indoor air pollution are also likely contributing factors, according to the IARC. By Amarachi Orie, CNN
