Where a person lives (geographic location) may affect the risk of developing certain types of cancer. The reasons why geographic location may play a role in cancer risk are very complex and are probably related to a number of factors, such as diet, environmental exposures or income.
For example, stomach cancer is very common in Japan and Korea, while North American and European countries have a low incidence. Cultural dietary habits and the incidence of Helicobacter pylori (H. pylori) infection may contribute to the higher incidence in certain geographical areas. Breast and prostate cancer are more common in high-income (developed) countries than in low-income (developing) countries. (The exception is Japan, where the incidence of these cancers remains low.) This may be due to the availability and use of early detection tests.
Within Canada, both incidence and mortality rates for cancer are generally higher in Atlantic Canada and Quebec. They are lowest in British Columbia. There may be a number of explanations for the differences in rates, such as historically higher smoking rates in Quebec and Atlantic Canada and smoking’s link to higher rates of lung and other cancers.
Migrant studies
Migrant studies look at data about people who have migrated from their home countries. They provide important information about the causes of some cancers. They help show how environmental or lifestyle factors influence cancer risk. Migrant studies also look at how a person’s risk of cancer is affected by migration and if it changes over time in their adopted country.