Several studies have shown that being overweight or obese can dramatically increase a persons probability of developing several forms of cancer.
Both obesity and a lack of physical activity are thought to account for up to 20 percent of all cancer deaths. An estimated 41,000 new cases of cancer alone were diagnosed in the United States that are thought to be attributable to obesity.
Obesity puts increased oxidative stress on the bodies major internal organs, increasing free radical production and therefore cancer risk. Obesity also affects the secretion of hormones such as estrogen and androgens which may also influence cancer risks in certain parts of the body.
Liver cancer is thought to be the cancer most closely linked with obesity with one study finding an almost five-fold increase in liver cancer in men and two-fold increase in women in those with a BMI greater than 35.
Other cancers that are closely associated with cancer are pancreatic cancer, which is more than two times more likely in those with a BMI greater than 35, stomach, esophageal, colo-rectal and kidney cancer.
In women, cancer of the breast, uterus and cervix were also higher amongst obese individuals and in men, the risk of prostate cancer was also raised by obesity.
Esophageal cancer, which is rapidly becoming one of the most common forms of cancer is also thought to be related to obesity. Gastric reflux problems are more common in obese individuals which leads to an increase in the condition known as Barrett’s esophagus. Barrett’s esophagus progresses into cancer in approximately 0.5% of cases.
With obesity rates sky-rocketing in the western world, the prevalence of these forms of cancer is likely to continue to increase. Fortunately the effects of obesity can be reversed, a drop in BMI of just five points corresponds to approximately a 15 percent reduction in cancer risk.