LONDON—New figures from Cancer Research UK show that obese women are roughly 40 percent more likely to develop a weight-related cancer in their lifetime than women whose weight falls in a healthier range. Bowel, post-menopausal breast, gallbladder, womb, kidney, pancreatic and esophageal cancers are all cancer types women are at a greater risk of developing if they are obese.
Out of 1,000 obese women, 274 will be diagnosed with a bodyweight-linked cancer during their life, while only 194 out of 1,000 women of a healthy weight will receive a cancer diagnosis. In the United Kingdom, Cancer Research UK estimates that some 18,000 women develop cancer as a result of being overweight or obese each year.
The cancer subtypes in which obesity most greatly increases a woman's risk of being diagnosed are esophageal adenocarcinoma and uterine cancer (specifically endometrial). Cancer Research UK reports that while there might be six cases of esophageal adenocarcinoma in 1,000 healthy women, there will likely be 14 cases in 1,000 obese women, an increase of 133 percent. Likewise, while 16 healthy women out of 1,000 might be diagnosed with endometrial cancer, 37 obese women out of 1,000 would face that diagnosis, an increase of 131 percent. Obesity is also linked to a particularly high risk increase in gallbladder and kidney cancers.
Obesity can increase the risk of cancer in a number of ways, including the likelihood that it is linked to fat cells' production of hormones, especially estrogen, which is thought to fuel cancer development. Cancer cells also produce hormones known as adipokines, which can stimulate or inhibit cell growth, the National Cancer Institute (NCI) reports. Specifically, the hormone leptin, which is thought to promote cell proliferation, is found to be more abundant in obese people, while adiponectin, which could have antiproliferative effects, is less abundant in obese individuals.
The NCI adds that “Obese people often have increased levels of insulin and insulin-like growth factor-1 (IGF-1) in their blood (a condition known as hyperinsulinemia or insulin resistance), which may promote the development of certain tumors.” Fat cells might also have direct and indirect influence on tumor growth regulators such as mTOR and AMP-activated protein kinase.
“Losing weight isn’t easy, but you don’t have to join a gym and run miles every day or give up your favorite food forever,” said Dr. Julie Sharp, head of health information at Cancer Research UK. “Just making small changes that you can maintain in the long term can have a real impact. To get started try getting off the bus a stop earlier and cutting down on fatty and sugary foods. Losing weight takes time, so gradually build on these to achieve a healthier lifestyle that you can maintain. And find out about local services, which can provide help and support to make lifestyle changes over the long term.”
“We know that our cancer risk depends on a combination of our genes, our environment and other aspects of our lives, many of which we can control – helping people understand how they can reduce their risk of developing cancer in the first place remains crucial in tackling the disease,” Sharp continued. “Lifestyle changes – like not smoking, keeping a healthy weight, eating a healthy diet and cutting back on alcohol – are the big opportunities for us all to personally reduce our cancer risk. Making these changes is not a guarantee against cancer, but it stacks the odds in our favor.”
