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Analysis

Obesity-Related Cancer: A Growing Concern

By Alicia Arizpe | Wed, 09/09/2015 - 15:21

OBESITY-RELATED CANCER: A GROWING CONCERN

Despite obesity being linked to one fifth of all cancers, the exact connection between the two phenomena remains unclear. Nevertheless, both emerge out of the same complex interactions between lifestyle, genetics, and environment. Obesity, like cancer, is associated with a significant intake of carbohydrates and other foods with high glycemic content. Where Mexico is concerned, the population in general has a low vitamin D and omega-3 intake, as well as low fibers and vitamin B12. Deficiencies in the latter two are linked to postmenopausal breast cancers in particular. One direct causative aspect may be the inflammatory factors secreted by adipose tissue, known as adipokines. Such factors are responsible for insulin resistance which accompanies obesity, augmenting the rate of cancer-associated “free radicals” produced in the body. Direct causal chains have yet to be fully explored in relation to this. The excess estrogen levels associated with obesity have also been linked to breast and uterine cancers. Finally, the chronic, low-level inflammations associated with obesity are also associated with cancer risk.

With breast cancer among the more treatable forms of cancer, issues pertaining to disease screening lie behind the high death rate among Mexican women. Only 50% of the country has access to basic mammograms, meaning that a quarter of all breast cancer patients present for treatment when the illness is already at an advanced stage. Studies of Mexican breast cancer patients have shown that lack of physical activity, diets high in carbohydrates and glycemic load, along with low intake of folate and vitamin B12 have been shown to increase risk of developing the disease, especially in a postmenopausal context. Alcohol intake, vitamin D levels and low consumption of fruit and vegetables are also found to be contributory factors.

LEUKEMIA

An extremely uncommon secondary form of the disease – positive chronic myelogenous leukemia – is nevertheless associated with inhalation of tobacco smoke, exposure to benzene, and a BMI of over 30. Studies carried out in Australia have linked obesity to a five-fold increase in the hazard ratio for the disease. The biological mechanisms behind such a correlation may be linked with increased leptin levels and low insulin, but while an exact causal chain remains difficult to establish, both of these potential trigger-factors are associated with diabetes and obesity.

GASTROINTESTINAL CANCER

Strain on the digestive system, high fat intake, and low levels of exercise are related to cancers of the colon, rectum, anus, and small intestine. Cancer in these sites of the body is on the rise in Mexico, and all are related to obesity levels.

CERVICAL AND CORPUS UTERI CANCER

Deaths from such disorders have doubled in the last ten years – albeit from a low base. Free HPV vaccination and improvements in detection, treatment and coverage are helping to turn the tide against these forms of cancer. The obesity link is associated with endocrine and inflammatory effects caused by increased adipose tissue. Hormones secreted by adipose tissue convert ovarian androgens into estrogens, and these are linked to an increased cancer risk. Additionally, sex hormone-binding levels are lower in obese women, meaning a proliferation of free radicals. Insulin issues linked to diabetes and obesity also exert a proliferative effect in the cancer site.

Alicia Arizpe Alicia Arizpe Senior Writer