Compared with drinking warm or lukewarm tea (65℃ or less), drinking hot tea (65-69℃) was associated with twice the risk of oesophageal cancer, and drinking very hot tea (70℃ or more) was associated with an eight-fold increased risk.
The speed with which people drank their tea was also important. There was no association between the amount of tea consumed and risk of cancer.
Drinking a cup of tea in under two minutes straight after it was poured was associated with a five-fold higher risk of cancer compared with drinking tea four or more minutes after being poured.
A large proportion of Golestan inhabitants drink hot tea, so this habit may account for a substantial proportion of the cases of oesophageal cancer in this population.
Previous studies from the UK have reported people prefer their tea to be about 56-60℃—cool enough not to be risky.
Oliver Childs, a spokesman for Cancer Research UK, said,“Tea drinking is part of many cultures, and these results certainly don’t point to tea itself being the problem. But they do provide more evidence that a regular habit of eating and drinking very hot foods and drinks could increase your risk of developing cancer of the oesophagus.”He advised tea-drinkers to simply wait a few minutes for their brew to cool from“scalding”to“tolerable”.
《英國醫學期刊》發表的研究表明，喝滾燙的茶水會增加患食道癌的風險。
專家表示，這一發現解釋了非西方國家的人們患食道癌的人數有所增加這個現象。
西方國家的人喝茶時習慣加牛奶，這樣可以降低茶水的溫度，從而降低患癌的風險。
在歐美國家，抽煙和喝酒是導致食道癌的主要原因。
伊朗北部的格列斯坦省是世界上食道癌發病率最高的地區之一。雖然當地居民抽煙喝酒的比例都不高，但是無論男女，發病率都很高。因為，當地的居民都有飲茶的習慣。
德黑蘭大學的專家們研究對比了300名食道癌患者與570名來自相同地域的普通人的飲茶習慣。
幾乎所有的參與者都有喝紅茶的習慣，並且平均每人每天至少飲用一公升。
與飲用較熱茶或溫茶（65度或以下）的人相比，引用熱茶（65-69度）的人患食道癌的危險性要高出兩倍。一旦水溫超過70度，患病的風險將增加8倍。
而飲茶的速度也至關重要。而喝多少茶則與患癌無關。
在茶沏開兩分鍾之內就開始飲用的人，比等茶沏開後四分鍾或更久才喝的人患食道癌的危險要高出5倍。
由於格列斯坦省的居民有飲熱茶的習慣，所以當地人患食道癌的比例一直都很高。
先前英國人的一項調查顯示，他們更喜歡飲用溫度在56度至60度之間的茶水，這樣明顯降低了患食道癌的危險。