A very-hot food and beverage thermal exposure index and esophageal cancer risk in Malawi and Tanzania: findings from the ESCCAPE case–control studies

BACKGROUND: Consumption of very-hot beverages/food is a probable carcinogen. In East Africa, we investigated esophageal squamous cell carcinoma (ESCC) risk in relation to four thermal exposure metrics separately and in a combined score. METHODS: From the ESCCAPE case-control studies in Blantyre, Malawi (2017-20) and Kilimanjaro, Tanzania (2015-19), we used logistic regression models adjusted for country, age, sex, alcohol and tobacco, to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for self-reported thermal exposures whilst consuming tea, coffee and/or porridge. RESULTS: The study included 849 cases and 906 controls. All metrics were positively associated with ESCC: temperature of drink/food (OR 1.92 (95% CI: 1.50, 2.46) for 'very hot' vs 'hot'), waiting time before drinking/eating (1.76 (1.37, 2.26) for <2 vs 2-5 minutes), consumption speed (2.23 (1.78, 2.79) for 'normal' vs 'slow') and mouth burning (1.90 (1.19, 3.01) for ≥6 burns per month vs none). Amongst consumers, the composite score ranged from 1 to 12, and ESCC risk increased with higher scores, reaching an OR of 4.6 (2.1, 10.0) for scores of ≥9 vs 3. CONCLUSIONS: Thermal exposure metrics were strongly associated with ESCC risk. Avoidance of very-hot food/beverage consumption may contribute to the prevention of ESCC in East Africa.