Excess body weight causes around 481,000 new cancer cases a year in adults worldwide, according to new estimates published Friday in the British medical journal The Lancet Oncology.
Using data from a number of sources including the Globocan database of cancer for 184 countries, researchers from the International Agency for Research on Cancer (IARC) created a model to estimate the fraction of cancers associated with excess body weight in 2012, and the proportion that could be attributed to increasing body mass index (BMI) since 1982.
Based on the results, the researchers estimate that a quarter of all obesity-related cancers in 2012 (118,000 cases) were attributable to the rising BMI in the population since 1982, and were therefore "realistically avoidable."
The findings reveal that obesity-related cancer is a greater problem for women than men, largely due to endometrial and post-menopausal breast cancers. In men, excess weight was responsible for 1.9 per cent or 136,000 new cancers in 2012, while in women it was 5.4 per cent or 345,000 new cases.
The burden is far higher in more developed countries, with almost two-thirds (64 per cent) of these obesity-related cancers occurring in North America and Europe.
"Our findings add support for a global effort to address the rising trends in obesity," said Dr. Melina Arnold from IARC, who led the study.
"The global prevalence of obesity in adults has doubled since 1980. If this trend continues, it will certainly boost the future burden of cancer," she added.