Tea drinking habits and oesophageal cancer in a high risk area in northern Iran: population based case-control study
- Study type
- Other
- Design
- Population-based case-control study; in addition, tea-drinking patterns and tea temperature were measured in healthy participants of a cohort study.
- Sample size
- 300 cases and 571 controls in the case-control study; 48,582 participants in the cohort study
- Source
- BMJ · 2009
In plain words
In this research in Golestan Province in northern Iran, the tea-drinking habits of people with oesophageal cancer were compared with those of healthy people from the same neighbourhoods. People who drank very hot tea, or drank their tea very soon after it was poured (less than 2 minutes), were more likely to have developed oesophageal cancer. Waiting until the tea has cooled a little (four minutes or more after pouring) and drinking lukewarm or warm tea instead of hot tea seems to be linked with a lower risk.
Key results
Treatment arms and regimens
300 patients with histologically confirmed oesophageal squamous cell carcinoma. No intervention was given (observational study); the exposure studied was tea-drinking habits (tea temperature and the interval between pouring and drinking the tea).
571 matched neighbourhood controls. No intervention was given (observational study).
Source of the regimen details: Abstract of the paper
Doses are given for the information of specialists, as in this study’s protocol, and are not a prescription. Every drug must be prescribed by the treating physician for the individual patient.
Study population
300 patients with histologically confirmed oesophageal squamous cell carcinoma and 571 matched neighbourhood controls in the case-control study, in Golestan Province in northern Iran, an area with a high incidence of oesophageal squamous cell carcinoma. In addition, 48,582 participants were enrolled in the cohort study.
Endpoints
Main outcome measure: odds ratio of oesophageal squamous cell carcinoma associated with drinking hot tea. Agreement between reported tea-drinking temperature and the actually measured temperature, and agreement between the answers to the question on tea temperature and the question on the interval before drinking (weighted kappa), were also assessed.
Safety and side effects
This is an observational study with no therapeutic intervention, so no treatment adverse events are reported.
Clinical significance and place in guidelines
This study shows that drinking hot tea in an area with a high incidence of oesophageal cancer is strongly associated with an increased risk of oesophageal squamous cell carcinoma, and it can form the basis of educational messages about avoiding very hot tea. Because the study design is case-control, the abstract shows only an association. The status of official recommendations and guidelines should be checked separately.
Limitations
The study is case-control and tea-drinking temperature was self-reported; agreement between this report and the actually measured temperature was moderate (weighted kappa 0.49). The study was conducted in a high-risk area (Golestan Province). Other limitations should be checked in the full text.
This summary was prepared by the editorial team from the published paper; the original paper is the final reference. Read the original abstract on PubMed.