The link between obesity and cancer is a complicated one. There are many different factors that are woven into the mix, making it difficult to simply point to one type of risk that links this category of diseases to being more than overweight. What is known is that the additional body fat isn’t the only issue at play. Obesity changes the body in many ways far beyond the size of fat cells.
The Obesity and Cancer Connection
Despite many attempts to study obesity and cancer as a whole, there is far more study focused on specific forms of the disease. What is believed is that being obese doesn’t raise the risk of all forms of cancers. Instead, according to Cancer.gov there are specific types in which there appear to be a direct risk connection with higher amounts of body fat – and the changes that causes in the body.
These forms include:
- Endometrial
- Esophageal adenocarcinoma
- Gastric cardia
- Liver
- Kidney
- Multiple myeloma
- Meningioma
- Pancreatic
- Colorectal
There is a connection between a BMI higher than normal and an increased risk of colon and rectal cancers in men and women, though that risk appears to be higher in men than in women.
- Gallbladder
- Breast
- Ovarian
- Thyroid
Why Does This Connection Exist?
There are several possible reasons that a link exists between obesity and cancer risk. These can include the following:
- Obese individuals frequently experience low-level inflammation which can damage DNA over time.
- Adipose fat tissue produces excess estrogen amounts. High levels of this hormone in the body can increase the risk of ovarian, endometrial, breast and other cancers.
- Individuals with a high BMI often also have raised insulin or insulin-like growth factor-1 levels. This can promote cancers such as endometrial, kidney, colon or prostate.
- Fat cells produce hormones called adipokines, which can inhibit or stimulate the growth of cells.
- Fat cells are both directly and indirectly linked with other cell growth regulators such as AMP-activated protein kinase and mammalian target of rapamycin (mTOR).
Other Obesity and Cancer Risks
It’s also important to note that even when obesity was not linked to the cancer itself, this weight-related disease can play a substantial role in the effectiveness of treatments and in an individual’s prognosis overall. As large amounts of excess weight do have a spectrum of impacts on the body, it can man that the mortality risk associated with a diagnosis may be higher, regardless of whether the obesity and cancer were connected in any way.