Africa’s oesophageal cancer corridor: Do hot beverages contribute?

Abstract

Purpose Hot beverage consumption has been linked to oesophageal squamous cell cancer (EC) but its contribution to the poorly-understood East African EC corridor is not known. Methods In a cross-sectional study of general-population residents in Kilimanjaro, North Tanzania, tea drinking temperatures and times were measured. Using linear regression models, we compared drinking temperatures to those in previous studies, by socio-demographic factors and tea type (“milky tea” which can be 50% or more milk and water boiled together vs “black tea” which has no milk). Results Participants started drinking at a mean of 70.6°C (standard deviation 3.9, n=188), which exceeds that in all previous studies (p≤0.01 for each). Tea type, gender and age were associated with drinking temperatures. After mutual adjustment for each other, milky tea drinkers drank their tea 1.9°C (95% confidence interval: 0.9, 2.9) hotter than drinkers of black tea, largely because black tea cooled twice as fast as milky tea. Men commenced drinking tea 0.9°C (−0.2, 2.1) hotter than women did, and finished their cups 30 (−9, 69) seconds faster. 70% and 39% of milky and black tea drinkers, respectively, reported a history of tongue burning. Conclusions Hot tea consumption, especially milky tea, may be an important and modifiable risk factor for EC in Tanzania. The contribution of this habit to EC risk needs to be evaluated in this setting, jointly with that of the many risk factors acting synergistically in this multi-factorial disease.

Investigating tea temperature and content as risk factors for esophageal cancer in an endemic region of Western Kenya: Validation of a questionnaire and analysis of polycyclic aromatic hydrocarbon content

“…One was the convenience sampling of hospital visitors, which led to a relatively young age distribution in the study population. In our analysis, however, preferred tea temperature was not related to age (p=0.73).The sample size was also relatively small compared to the study by Munishi et al, which had twice as many subjects 23 . There were also limitations to our method of temperature assessment.…”

“…We reviewed the literature for other studies of preferred beverage temperature 16–18,23,31–40 (Table 4), and found that the mean preferred tea temperature in our study was 1.5°C higher than any other studied population. It should be noted that the various studies presented in Table 4 use various methodologies to assess temperature and this limits the ability to compare them, and numerous studies concerning beverage temperature do not report descriptive statistics for temperature.…”

“…However, very limited research on this topic has been conducted in East Africa, which is known as a high-risk area for ESCC 4 . One recent study from Tanzania has measured beverage temperature, and it found that the participants drank their beverages (mainly tea) at an average temperature of 70.6 °C, higher than that reported in previous studies from other populations 23 . A recent case-control study by Middleton et al in Kenya, showed an association between self-reported ingestion of hot beverages with ESCC 24 .…”

“…It should be noted that the various studies presented in Table 4 use various methodologies to assess temperature and this limits the ability to compare them, and numerous studies concerning beverage temperature do not report descriptive statistics for temperature. Previously, the hottest beverage temperature reported in any geographic location was from Tanzania, with a mean of 70.6°C 23 . Such hot temperatures could have an important effect on the risk of esophageal cancer in our population.…”

Informing etiologic research priorities for squamous cell esophageal cancer in Africa: A review of setting‐specific exposures to known and putative risk factors

“…A South African study showed increased ESCC risk associated with daily tea consumption, though temperatures were not measured . Further, hot beverage consumption is prevalent in the Kilimanjaro region of Tanzania where the average temperature at first sip was 71°C, which correlated with a self‐reported history of tongue burning . These tea temperatures far exceeded those in Iran where a strong tea temperature‐ESCC association was observed (odds ratio 8 for very hot vs. warm/lukewarm tea) .…”