Social factors

Social factors are intimately tied to issues such as race, economic status and religion. Generally, it is difficult to say that the behaviour of one group predisposes them to a particular cancer, but there are some renowned exceptions:

• tobacco consumption - smoking, chewing: polycyclic hydrocarbons in tobacco are potent carcinogens and have been linked to a number of cancers including those of the buccal cavity, nasopharynx, oesophagus, bladder and cervix
• dietary makeup:
  • obesity is associated with an increased incidence of colorectal carcinoma, possibly due to the secretion of excess amounts of bile acid
  • colonic carcinoma is more common in the developed world; it is suggested that the low-residue diet in this setting prolongs the time in which faecal carcinogens are in contact with the bowel wall
  • over-salting of fish in South China may contribute to nasopharyngeal carcinoma