Increased cancer risk in adiposity patients

What is the corelation between adiposity and increasingly occuring cancer?

Many diseases such as diabetes, high blood pressure or fatty liver occur with an increased frequency in morbidly overweight people. During the past years various studies have shown that cancer is among them. That is especially problematic since the number of overweight people keeps increasing in many countries and with it the number of associated diseases and cancer. On the occassion of the World Cancer Day (4th of February), the IFB AdiposityDiseases offers an overview of the corelations between obesity and cancer.

A meta-analysis (1)  in Great Britain from 2008 showed that overweight and obese (adipose) people in particular suffer from cancer more often. Adipose men had a particular high occurence of tumors in the esophagus followed by tumors of the colon, kidneys and liver. With women it was especially the number of cancers in endometrium, breast, gall bladder, esophagus and kidneys. According to a big study of the American Cancer Society (2) the risk of dying from cancer is increased by 10, if the body mass index rises from 30 to 40 kg/m² the risk is increased by 30 percent and with a body mass index of over 40 it is even increased by 88 percent. The more frequent tumors in the esophagus of adipose people, however, can be explained by the constant reflux: chyme and gastric acid rises from the stomach into the esophagus and causes irritations and heartburn.

The causes for the increased cancer risk are, however, not yet conclusively explained. There is a number of complex changes of the hormone and metabolic system happening in adipose people that are at least partially suspected to increase the tumor risk. Fat cells for example produce a certain kind of hormones. In adipose women estrogen e.g. is increasingly produced in fat tissue. Scientists see a correlation between an increased estrogen level and the development of cervical and breast cancer. Equally an increased insulin level in the blood of adipose patients is suspected to promote the growth of cancer cells. Prof. Mathias Faßhauer mainly researches the substances produced by fat cells (adipokines) at the IFB AdiposityDiseases. He explains: "The increased number of fat cells in adipose people produce different hormones that can contribute to the increased development of tumors by stimulating growth and irritation. Some studies furthermore suggest that indirect factors such as an decreased keeping of preventive medical checkup appointments can also contribute to an increased cancer risk in adipose people. Many questions in this area remain unanswered so far."

Doris Gabel

Sources:
(1)      Renehan AG , Tyson M, Egger M,  Heller RF, Zwahlen M (2008) Body-mass index and incidence of cancer: a systematic review and meta-analysis of prospective observational studies;  The Lancet, Volume 371, Issue 9612, Pages 569 - 578, 16 February 2008,doi:10.1016/S0140-6736(08)60269-X
(2)     Calle EE, Rodriguez C, Walker-Thurmond K, Thum MJ (2003) Overweight, obesity, and mortality from cancer in a prospectively studied cohort of US adults. N Engl J Med 348: 1625-1638

Keywords: associated diseases