Overweight and Health (III)

Cancer arises from one single cell. The transformation from a normal cell into a tumor cell is a multistage process, typically a progression from a pre-cancerous lesion to malignant tumors. These changes are the result of the interaction between a person's genetic factors and three categories of external agents, including physical carcinogens (such as ultraviolet and ionizing radiation), chemical carcinogens (such as asbestos, components of tobacco smoke, aflatoxin (a food contaminant) and arsenic (a drinking water contaminant)), biological carcinogens (such as infections from certain viruses, bacteria or parasites).

Many cancers can be prevented by avoiding exposure to common risk factors, such as tobacco smoke. Tobacco use is the single most important risk factor for cancer. Some research indicates that certain lifestyle habits can prevent cancer attack . In addition, a significant proportion of cancers can be cured by surgery, radiotherapy or chemotherapy, especially if they are detected early.

Cancer is a leading cause of death worldwide: it accounted for 7.9 million deaths (around 13% of all deaths) in 2007. Lung, stomach, liver, colon and breast cancer cause the most cancer deaths each year:

Lung (1.4 million deaths/year)

Stomach (866,000 deaths)

Liver (653,000 deaths)

Colon (677,000 deaths)

Breast (548,000 deaths).

The most frequent types of cancer differ between men and women:

Men - lung, stomach, liver, colorectal, oesophagus and prostate.
Women - breast, lung, stomach, colorectal and cervical.

About 30 per cent of cancer deaths can be prevented. Deaths from cancer worldwide are projected to continue rising, with an estimated 12 million deaths in 2030.

In addition, overweight people also have a high risk in suffering diseases in the areas of lungs, stomach, gall bladder and musculoskeletal disorders (especially osteoarthritis). Moreover, overweight makes surgery and pregnancy more dangerous: some abdominal operations may be impossible in badly overweight people.

Obese and overweight people are more accident prone mainly because excess weight limits their mobility so that they cannot easily get out of the way of danger.

Overweight may disguise symptoms of serious diseases and make it difficult for a doctor to make a diagnosis.