The effect of food and drink on oesophageal cancer risk in east Africa
Valerie McCormack's (far right, with research team) study is on dietary factors in the African oesophageal cancer corridor
Topic: Oesophageal cancer
Institution: International Agency for Research on Cancer (IARC)
Oesophageal cancer is the seventh most common type of cancer worldwide and causes the sixth highest number of cancer deaths. In certain parts of the world, higher numbers of people develop oesophageal cancer than elsewhere; this is true for Africa, where 28,000 people developed oesophageal cancer in 2012. The disease mostly affects east African countries, running north to south from Ethiopia to South Africa. There are two main types of oesophageal cancer, which differ by the type of cell in the body where the cancer starts. The type called oesophageal squamous cell carcinoma (ESCC) affects 90 per cent of the oesophageal cancer patients in this area. oesophageal cancer is often diagnosed after it is too late for treatment to be successful, leading to a low recovery rate. This makes it crucial to uncover the causes of oesophageal cancer and prevent it from developing in the first place. Unsurprisingly, there are a number of dietary factors that are linked to this type of cancer, including alcohol consumption, low consumption of fruit and vegetables, low amounts of vitamins and minerals present in the diet, exposure to chemicals from burned and chargrilled food, and damage to the food pipe from hot food and drinks. Other factors include smoking, opium use, poor dental hygiene, animal contact, untreated drinking water, low income, and not eating a varied diet. Genetic factors may also play a role, in combination with people’s lifestyles.
Aims and objectives
We predict that the joint effect of high intake of strong alcoholic drinks, repeated heat damage from hot food and drinks, and a restricted diet consisting of maize intake, acting in black Africans with particular genetic features that make them more vulnerable to these factors, are responsible for the high rates of oesophageal cancer in east Africa. To test our predictions, we plan to do the following:
1. To investigate the effect of alcohol on oesophageal cancer risk in Africa: overall, by amount consumed, how long people have been consuming, alcohol type and the additional effects of tobacco, genetic traits and hot beverages and foods.
2. To investigate the effect of hot beverages or food, and additional effects of alcohol and chemical exposures from chargrilled food.
3. To investigate the effect of low mineral intakes.
4. To identify genetic characteristic associated with oesophageal cancer risk in east Africa.
5. For factors that act in combination with others, to estimate the proportion of EC that result because of these factors in different groups of the population.
How it will be done
This study will use existing questionnaire responses from the IARC ESCCAPE hospital study and collect genetic information from DNA (available for 93 per cent of participants) extracted either from blood or saliva. In addition to various social and economic indicators, we will combine data on history of alcohol intake, damage from hot drinks and food, low mineral consumption and genetic characteristics. By comparing the lifestyles and genetic features of oesophageal cancer patients with the non-oesophageal cancer controls, we will obtain insights into causes for this cancer.
This study will provide important findings in two main areas. First, for prevention of oesophageal cancer in eastern Africa, the factors being studied are particularly important because they are relatively easy to communicate. Regarding alcohol and low fruit and vegetable intake, changes would have benefits for multiple diseases and social problems in society. Second, if the strength of relationships found are strong, they can be used to predict oesophageal cancer risk and target risk groups for the early detection of the disease. The importance of alcohol in ESCC risks will help to identify health messages for oesophageal cancer, especially those that refer to local alcohols. The proportion of the population affected by different factors will translate the findings to numbers of cancers that could be prevented, providing public health messages specific to the affected people.