Summary Cancer is a leading cause of death worldwide.
(Online) - People who are obese have a greater risk of developing and dying from several types of cancer including malignancies of the breast, ovary, kidney, pancreas, colon, rectum and bone marrow, a research review confirms.
Cancer is a leading cause of death worldwide, and the prevalence of obesity has more than doubled over the past generation. Even though excess weight is thought to influence the odds of developing and dying from a wide variety of tumors, the study found "strong evidence" supporting this connection for just 11 cancers.
Other associations could also be genuine, but there is still substantial uncertainty about them," lead study author Dr. Maria Kyrgiou of Imperial College London said by email.
Globally, 1.9 billion adults are overweight or obese, according to the World Health Organization. Roughly four in 10 adults are overweight, and more than one in 10 are obese, a condition that increases the risk of heart disease, diabetes, kidney problems and joint disorders in addition to certain cancers.
For the current study, researchers analyzed results from 204 previously published studies exploring the connection between obesity, weight gain, waist circumference and 36 different cancers.
Researchers looked in particular for evidence that the previous results might have exaggerated the link between obesity and cancer or found a connection that was too small to rule out the possibility that it was due to chance.
They found the strongest links were between obesity and malignancies of the digestive organs and for hormone-related tumors in women, according to the report in The BMJ.
When researchers looked at what’s known as body mass index (BMI), a ratio of weight to height, they found increases in BMI tied to a higher risk of developing cancers in the esophagus, bone marrow, biliary tract system, pancreas and kidney. Upticks in BMI were also linked to greater odds of colon and rectal cancers in men as well as endometrial malignancies in younger women.
The increased risk of cancer for every 5-unit gain in BMI ranged from 9 percent for rectal cancer among men to 56 percent for tumors in the biliary tract system.
For women, weight gain and extra belly fat, a measurement known as waist-to-hip circumference ratio, were also associated with an increased risk of certain cancers.
