Drinking very hot beverages could triple cancer risk, large study finds

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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 UK 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%, to almost a million new cases a year by 2040.

In the UK, there are around 9,500 new cases each year, according to Cancer Research UK . However, an estimated 14% 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 UK’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 UK 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 UK 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% 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% higher risk of esophageal SCC.

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“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 UK 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 UK,” 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 UK.”

Despite the findings, the chance of getting diagnosed with esophageal cancer remains relatively low. The cancer makes up only 2% of cancer cases in the UK, where people have around a 1% lifetime risk of being diagnosed with it, according to Cancer Research UK. In the US, esophageal cancer is estimated to have made up just 1.1% 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 UK’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.

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一项针对近百万人的研究发现了新的证据，表明饮用滚烫的咖啡和茶可能会显著增加患食道癌的风险。

根据英国进行的一项研究，饮用过热的饮料（而不是温热的饮料）会使患食道癌的风险增加三倍。该研究结果于周二发表在《国际癌症杂志》上。

该研究结果特别适用于食管鳞状细胞癌（SCC），这是全球最常见的食管癌类型。

食道，又称食物管道，是一条肌肉管，负责将食物和饮料从口腔输送到胃部。

根据世界卫生组织下属的国际癌症研究机构（IARC）的数据，2020年全球约有60.4万例食管癌新发病例，约有54.4万人死于食管癌。该机构估计，到2040年，全球食管癌病例将增加50%以上，达到每年近100万例。

据英国癌症研究中心统计，英国每年约有9500例新增食管鳞状细胞癌病例。然而，英国牛津大学的研究人员在一项迄今为止规模最大的研究中指出，如果人们饮用温度较低的茶和咖啡，英国约有14%的新增食管鳞状细胞癌病例是可以避免的。

研究人员分析了来自英国近 98 万名中年人的数据，询问了他们有关热饮消费习惯的问题，包括他们是否喜欢“很热”、“热”或“温”的饮料，或者他们是否“不喝热饮”，或者“不愿回答”。

他们还被问及每天喝多少热饮，可以选择“每天少于 6 杯热饮”或“每天 6 杯或更多热饮”。

所有参与者均来自两个大型队列研究，即“百万女性研究”和“英国生物银行”，这两个研究均定期记录参与者的健康信息。在平均随访期分别为14.2年和11.1年期间，这两个队列共发生2348例食管癌病例。

研究人员发现，近一半的参与者表示每天饮用六杯或更多热饮，约 15% 的人表示他们喜欢喝很热的饮料。

食管鳞状细胞癌的风险随着饮用温度的偏好而增加，喜欢喝热饮的人患癌风险几乎是喜欢喝温饮的人的两倍。而喜欢喝非常热饮的人，患癌风险则超过三倍。

饮用饮品的数量也很重要。研究人员在控制了温度因素后发现，与每天饮用少于六杯热饮相比，每天饮用六杯或更多热饮会使食管鳞状细胞癌的风险增加71%。

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“这是迄今为止规模最大的研究，它确实进一步证实了饮用非常热的食物和热饮可能会增加患此类癌症的风险，”该研究的主要作者、牛津人口健康中心的高级营养流行病学家凯伦·帕皮尔周三告诉 CNN。

2016年，国际癌症研究机构（IARC）将饮用过热的饮料列为可能对人类致癌的因素。IARC将“过热”的饮料定义为温度高于65摄氏度（或149华氏度）的饮料。

帕皮尔指出，但之前的研究大多是在南美洲、亚洲和中东进行的，这些地区的饮酒文化略有不同。

例如，英国人经常在热饮中加入牛奶，但研究人员发现，只要饮料还是热的，参与者是否在饮料中加入牛奶并不会改变患癌风险。

帕皮尔补充说，这项新研究“从英国典型的饮酒习惯中发现了证据”，在英国，“大多数人每天都喝茶或咖啡，这表明我们喝饮料的方式很重要，而且研究结果也适用于英国的西方人群。”

尽管有这些发现，但罹患食管癌的几率仍然相对较低。据英国癌症研究中心（Cancer Research UK）的数据显示，食管癌仅占英国癌症病例的2%，英国人一生中罹患食管癌的风险约为1%。在美国，据美国国家癌症研究所（National Cancer Institute）估计，今年食管癌仅占新增癌症病例的1.1%。

然而，帕皮尔表示：“对于任何喜欢喝热饮并担心这些发现的人来说，其实一个简单的步骤就是让饮料冷却下来。”他还补充说，可以通过让饮料静置一段时间、加入牛奶或冷水、吹气或小口啜饮来使其冷却。

“此前已有证据表明，热液体会损伤食道内壁细胞并引起炎症，因此这一发现是有合理解释的，”英国夸德拉姆研究所的上皮生理学家伊恩·约翰逊（Ian Johnson）周三通过电子邮件告诉 CNN，他并未参与这项研究。

约翰逊补充道：“我倾向于相信这项研究，并得出结论：人们最好饮用温度较低的饮料（低于65摄氏度），而不是热饮。这听起来很简单，但那些喜欢喝热饮的人能否轻易改变习惯，则是另一回事了。”

尽管如此，研究人员无法探究参与者所饮用饮料的确切温度，因为每个人对热度的感知可能不同，因此无法确定自我报告的热度水平是否可能与具体的温度数字相对应。

英国伦敦玛丽女王大学分子口腔肿瘤学教授、生理学家 Muy-Teck Teh 通过科学媒体中心发表声明称，由于参与者对饮料温度的感知是他们自己报告的，而且参与者口腔对热饮的敏感度各不相同，因此“研究结果应被解释为可靠的关联，而不是因果证明”。

帕皮尔表示，吸烟仍然是这种癌症的最大风险因素，这种癌症在东亚以及南部和东部非洲的发病率较高，根据国际癌症研究机构（IARC）的说法，饮酒和室内空气污染也可能是这些地区的致病因素。