Summary
A UK analysis of around 980,000 adults found that people reporting six or more cups of tea or coffee at “very hot” temperatures had three times the risk of oesophageal squamous cell carcinoma compared with those reporting warm drinks. The result came from more than 10 years of health-record follow-up and describes an association.
A UK cohort analysis of around 980,000 adults has linked drinking tea or coffee at very hot temperatures with a higher risk of oesophageal squamous cell carcinoma (SCC). Among participants who reported drinking six or more cups at “very hot” temperatures, the reported risk of oesophageal SCC was three times that of people who usually drank beverages warm.
The finding came from more than 10 years of health-record follow-up. It concerns a specific type of oesophageal cancer rather than oesophageal cancer as a single, uniform disease.
What the researchers compared
The study combined data from two large UK cohort studies: UK Biobank and the Million Women Study. It was funded by Cancer Research UK and led by researchers at Oxford Population Health, University of Oxford.
Participants reported whether they typically drank tea or coffee at a “very hot,” “hot” or “warm” temperature. Researchers then linked those reports with subsequent health records to identify oesophageal cancer diagnoses.
During the follow-up period, 2,348 oesophageal cancers were recorded. Of these, 1,045 were squamous cell carcinomas and 1,303 were adenocarcinomas. The researchers reported a substantially higher risk of SCC among the 15% of participants who drank at least six cups of tea or coffee at very hot temperatures, compared with participants who reported drinking them warm.
SCC develops from squamous cells, which form part of the oesophageal lining. Adenocarcinoma develops from glandular cells. The study counted both forms, but the prominent temperature-related result reported in the BMJ account was for SCC.
How to interpret the threefold figure
This was a cohort analysis based on participants’ reported drinking habits and later diagnoses. People were not assigned to drink beverages at particular temperatures, so the result describes a relationship between reported temperature and subsequent SCC diagnoses rather than the outcome of an intervention.
The threefold figure is a relative comparison between the very-hot and warm groups. It does not by itself indicate the number of additional cancer cases for an individual person, because that also depends on the underlying risk in the population being considered. The report supplied here does not provide an absolute-risk estimate.
The result therefore narrows the public-health question: the signal highlighted by the researchers concerned repeated consumption of very hot tea or coffee and oesophageal SCC, not simply whether someone drinks tea or coffee. The broad temperature categories were self-reported, and the study followed participants for more than a decade, making the distinction between reported exposure and later diagnosis important when interpreting the finding.