Residents of Golestan Province in northern Iran have one of the highest rates of esophageal cancer in the world. They don't drink alcohol or smoke--the two primary risk factors for the disease in the west--but they do consume tea, nearly 1.2 liters per day, on average. So local researchers set out looking for a connection. They employed 300 esophageal cancer patients who were diagnosed in the eastern part of Golestan and matched them up with 571 healthy controls who shared their age, gender and place of residence. All but one of them drank tea, and they gave interviewers information about their tea consumption and brewing habits. Teaming up with investigators from the U.S., England, France and Sweden, the researchers calculated that people who said they drank "hot" tea (149 to 156 degrees Fahrenheit) were more than twice as likely to develop esophageal cancer as people who said they drank the beverage "warm" or "lukewarm" (less than 140 degrees). Those who said they took their tea "very hot" (at least 158 degrees) were more than eight times as likely to get esophageal cancer, according to the study, published online Thursday in the British Medical Journal. The scientists have now connected it with esophageal cancer. The problem doesn't appear to be the tea itself, but the temperature at which it is consumed, their study found. The researchers also asked people how long they waited to drink their tea after pouring it. Those who said they waited two to three minutes were nearly 2.5 times more likely to develop the cancer compared with people who said they waited at least four minutes. Impatient tea drinkers who waited less than two minutes were 5.4 times as likely to be diagnosed with esophageal cancer, the study found. The study didn't assess the mechanism linking hot tea to esophageal cancer, but the researchers said the temperature of the liquid was almost certainly to blame rather than the compounds in the tea itself. According to the passage,   _   were thought to be two main causes of esophageal cancer.
drinking hot tea and smoking drinking alcohol and smoking working in the kitchen and smoking taking sunbaths and drinking alcohol