These substances, produced in excess in overweight people, can stimulate the growth of nascent cancer cells in various organs. For example, the sex steroid estrogen is firmly established as a growth stimulant for most cancers of the breast, as well as cancer of the uterine lining, or endometrium.
Excess fat around the abdomen increases the risk of heartburn, or chronic reflux disease, which causes chronic acid irritation of the esophagus that can lead to the development of esophageal cancer.
Obesity also increases the risk of developing gallstones, which, in turn, increase the risk of gallbladder cancer. Excessive production of insulin by the pancreas in people with a high BMI may explain their increased risk of pancreatic cancer. And so on.
A further possibility to explain the death rates may be a delay in diagnosis because it is hard to find cancers under layers of body fat or, perhaps, because seriously overweight people may resist routine medical care.
Besides a higher incidence of breast cancer in overweight women that could be attributed to estrogen, their cancers tend to be diagnosed at a later stage, possibly compromising their survival.
Perhaps most important in the overall scheme are the effects of dietary constituents and lack of physical activity associated with being overweight and obese. Consuming excess calories starting in early childhood is strongly linked to an increased cancer risk in adults.
RSS