Estimating the population at risk

Risk factors for cancers of the upper digestive tract have been investigated using different study designs. These include a population based case-control study in Golestan province, northern Iran, which investigated the association between tea drinking habits and the risk of oesophageal squamous cell carcinoma. In total, 300 cases of histologically confirmed oesophageal squamous cell carcinoma and 571 matched neighbourhood controls were identified. Participants were asked about their tea drinking habits in face to face interviews. Drinking hot tea, compared with drinking lukewarm or warm tea, was found to be strongly associated with increased risk of oesophageal cancer.1

In a study in Denmark, researchers used a population based prospective cohort design to examine the association between different types of alcoholic drink and cancers of the upper digestive tract (oropharyngeal and oesophageal). Participants were assessed at baseline for alcohol intake and smoking habits. Cohort members were 15 117 men and 13 063 women aged 20-98 years, who were followed for a mean of 13.5 years (range 2-19 …