(HealthDay News) — Additional weight appears to particularly influence the risk of cancers related to the digestive organs or those driven by hormonal abnormalities, according to a review published in The BMJ.
The new evidence review was led by Maria Kyrgiou, PhD, of Imperial College London’s Department of Surgery and Cancer. The researchers based their evaluation on 204 previous evidence reviews of studies investigating whether excess weight influenced the risk of developing 36 primary cancers.
The review found that an increase in body mass index (BMI) of 5 was associated with a higher cancer risk in the esophagus, bone marrow, biliary tract system, pancreas, and kidneys. The increases ranged from 9% for colorectal cancer among men to 56% for cancer of the biliary tract system. The team also found that a higher BMI increased the risk of colorectal cancer in men, and endometrial cancer in women. Obesity was also linked with a higher risk of gall bladder, stomach, and ovarian cancers. Risk of postmenopausal breast cancer among women increased 11% for each 11 pounds of weight gain, if they’d never used hormone replacement therapy.
Excess weight likely influences the risk of gastrointestinal cancers by altering insulin levels and promoting inflammation, Graham Colditz, MD, DrPH, deputy director of the Institute for Public Health and chief of Public Health Sciences at the Washington University School of Medicine in St. Louis, and author of an editorial accompanying the review, told HealthDay. Overweight and obesity also can alter levels of sex hormones, which could explain the increased risk of breast and endometrial cancer in women. “There’s no easy way to gain weight and not gain an increase in risk of many cancers,” Colditz said.
- Kyrgiou M, Kalliala I, Markozannes G, et al. Adiposity and cancer at major anatomical sites: umbrella review of the literature. BMJ. doi:10.1136/bmj.j477