1. Hot tea consumption in combination with excessive smoking or alcohol use was associated with a higher risk for esophageal cancer.
2. In the absence of excessive alcohol use and smoking, daily tea drinking was not linked to increased risk for esophageal cancer.
Evidence Rating Level: 1 (Excellent)
Study Rundown: Esophageal cancer is a concern worldwide due to its rising prevalence and poor rates of survival. High-temperature tea drinking is a suspected risk factor for esophageal cancer, but consistent links have not been made. Furthermore, it is unclear if any association is separate from alcohol and tobacco use. The authors of this prospective cohort study analyzed high-temperature tea drinking, alcohol use, and smoking for possible associations with risk for esophageal cancer. This cohort study of 456 155 participants based in China had a median follow-up of 9.2 years. The authors found that in combination with excessive use of alcohol or tobacco, high-temperature tea drinking was linked to a higher risk for esophageal cancer. In the absence of excessive alcohol use and smoking, daily tea drinking was not linked to increased risk for esophageal cancer. These results suggest that refraining from drinking hot tea may be advantageous for excessive smokers or users of alcohol. Additional studies are needed to confirm the associations found in this study.
Strengths of the study include the high participant number and long follow-up period. A limitation of the study includes the use of self-reported data for tea consumption that was taken only at baseline, which may have led to misclassification of exposure and weakening of the association.
In-Depth [prospective cohort]: In 10 regions across China, 512 891 adults from 30 to 79 years of age were selected as the China Kadoorie Biobank study cohort. Selection took place from 2004 to 2008. Exclusion criteria included previous cancer diagnosis and reduction in consumption of tea, use of alcohol, or smoking. After applying exclusion criteria, 456 155 participants were included in the final analysis. The frequency and amount of tea consumption, alcohol use, and smoking was self-reported via questionnaire at baseline. During a follow-up period with a median 9.2 years, 1 731 incidences of esophageal cancer were recorded. Compared to only drinking hot tea, drinking hot tea in combination with either smoking or alcohol use was linked to an increased risk for esophageal cancer. In comparison to participants who consumed tea less than weekly and drank less than 15 g of alcohol per day, participants who consumed burning-hot tea and at least 15 g of alcohol per day had the highest esophageal cancer risk (hazard ratio [HR]: 5.00 [95% CI, 3.64 to 6.88]). Similarly, the HR was 2.03 (CI, 1.55 to 2.67) for participants who consumed burning-hot tea daily and were current smokers.
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