Researchers from the International Agency for Research on Cancer (IARC), the Malawi College of Medicine, the Kilimanjaro Clinical Research Institute (United Republic of Tanzania), and Moi University (Kenya) have investigated risk factors for developing oesophageal squamous cell carcinoma in East Africa and found that the risk of the disease was higher in people who consumed very hot food or beverages, as assessed by several thermal exposure metrics. They also developed the first composite thermal exposure score based on four measures of thermal exposure – metrics for temperature of beverage or food, waiting time before drinking or eating, consumption speed, and mouth burning frequency – which differentiated almost 5-fold relative risks of oesophageal cancer between the highest and lowest categories. These results were published in the British Journal of Cancer.
The study included 849 cases and 906 controls in Malawi and the United Republic of Tanzania. Each individual thermal exposure metric was positively associated with risk of oesophageal squamous cell carcinoma. Temperature of beverage or food increased risk by 1.92-fold for “very hot” compared with “hot” beverage or food. Waiting time before drinking or eating increased risk by 1.76-fold for waiting times of less than 2 minutes compared with 2–5 minutes. Consumption speed increased risk by 2.23-fold for individuals who consumed their food or beverage at a “normal” pace compared with those who consumed it at a “slow” pace. Mouth burning frequency increased the risk by 1.9-fold for 6 or more burns per month compared with no burns per month. Among consumers, the composite thermal exposure score ranged from 1 to 12, and the risk of developing oesophageal squamous cell carcinoma increased with higher scores: individuals with scores of 9 or more were found to be 4.6 times as likely to develop the disease as those with scores of 3 or less.
In 2016, the IARC Monographs programme classified drinking very hot beverages (i.e. consumed at a temperature above 65 °C) as probably carcinogenic to humans (Group 2A). For the current study, the researchers estimated the risk of developing oesophageal squamous cell carcinoma in relation to four thermal exposure metrics, evaluated separately and in a combined score, on the basis of data from the Oesophageal Squamous Cell Carcinoma African Prevention Research (ESCCAPE) case–control studies, which took place in Blantyre (Malawi) in 2017–2020 and in Kilimanjaro (United Republic of Tanzania) in 2015–2019. The results are adjusted for country, age, sex, alcohol consumption, and tobacco use.
The authors concluded that avoidance of consumption of very hot food or beverages may contribute to the prevention of oesophageal squamous cell carcinoma in East Africa.
Masukume G, Mmbaga BT, Dzamalala CP, Mlombe YB, Finch P, Nyakunga-Maro G, et al.
A very-hot food and beverage thermal exposure index and esophageal cancer risk in Malawi and Tanzania: ﬁndings from the ESCCAPE case–control studies
Br J Cancer, Published online 29 June 2022;