Epidemiology (geographical pathology) tumors

The term "epidemiology" against tumors and other non-communicable diseases, such as atherosclerosis, hypertension and so on, has been applied recently. The epidemiology understood not in the sense of studying of epidemics of infectious diseases, as in the original sense of the word (Greek. epidemia - the spread of disease, from epi - on and demos - the country, the people), i.e. the study of the widespread among the population of diseases. The task of epidemiology, or geographic pathology tumors is a comparative study of their distribution in different parts of the countries, different Nations and different more limited populations.
The incidence of cancer is different in different countries, and the prevalence of different types can significantly vary in different parts of the world, but even within the same state.
Setting the frequency of a particular type of cancer in this or that area or a specific group of the population and detection of connection of this phenomenon with some certain effects on the body may help identify the cause of this cancer and to plan ways of its prevention. For example, skin cancer is more common in Australia than in England. These observations, as the most frequent localization of skin cancer on the face and exposed parts of the body, help to think of carcinogenic effects of excessive exposure to the sun, particularly ultraviolet rays that has been proven experimentally.
Cancer of the mouth, tongue, gums occurs relatively frequently in India, Pakistan, Burma and some neighbouring countries. It is connected with a common in these places a bad habit of chewing betel. In some regions of Kazakhstan, Uzbekistan, Tajikistan experienced a similar habit of chewing us. In people who for decades Bethel and us developed cancer occurring in those places that were laid chewing mixture.
Primary liver cancer occurs most frequently in certain ethnic groups of Africa, such as blacks Bantu. It appears to be associated with specific dietary habits and, in particular, with the inferiority of his early childhood.
In some countries, Asia and South America, for example in India, the Democratic Republic of Vietnam, in some areas of China, Peru, is extremely common cancer of the penis. A comparative study of the incidence of this cancer among different population groups showed that his appearance is connected with phimosis. Carcinogenic agent is accumulating and stagnating in prepucialna bag smegma.
Lung cancer is most common in England. This is probably due to the fact that it is the most "smoky" country in the world.
Lung cancer is found in England much more often than in Australia and South Africa. The British, who moved to these countries, take lung cancer more often than the local population, but less than the population of England. Stomach cancer is found in Japan, more so than in the USA. The Japanese, who are now living in San Francisco (USA), fall ill with stomach cancer more often than the other inhabitants of this city, but less often and at a later age than the population of Japan. Cancer of the colon and rectum is found in the U.S. more often than in Poland. The poles residing in the US, this type of cancer is less common than the surrounding population, but more often than in Poland. Thus, the variability in the incidence of one or another type of cancer depends on the change of living conditions (environment) of a given population.