About 25 percent of all obesity-related cancers in 2012 (118,000 cases) were attributable to the rising average body mass index (BMI) in the population since 1982, and were therefore "realistically avoidable," according to  a recent study.

Researchers from the International Agency for Research on Cancer (IARC), found that obesity-related cancer is a greater problem for women than men, largely due to endometrial (womb/uterus) and post-menopausal breast cancers. In men, excess weight was responsible for 1.9 percent or 136,000 new cancers in 2012, and in women it was 5.4 percent or 345,000 new cases.

"Our findings add support for a global effort to address the rising trends in obesity. The global prevalence of obesity in adults has doubled since 1980," Dr. Melina Arnold, who led the study, said in a statement. "If this trend continues it will certainly boost the future burden of cancer, particularly in South America and North Africa, where the largest increases in the rate of obesity have been seen over the last 30 years."

For the study, researchers collected and analyzed data from a number of sources including the GLOBOCAN database of cancer incidence and mortality for 184 countries, Arnold and colleagues created a model to estimate the fraction of cancers associated with excess bodyweight in countries and regions worldwide in 2012, and the proportion that could be attributed to increasing BMI since 1982.

They found that post-menopausal breast, endometrial, and colon cancers were responsible for almost three-quarters of the obesity-related cancer burden in women (almost 250,000 cases), while in men colon and kidney cancers accounted for over two-thirds of all obesity-related cancers (nearly 90,000 cases).

In developed (very high human development index; HDI) countries, around 8 percent of cancers in women and 3 percent in men were associated with excess bodyweight, compared with just 1.5% of cancers in women and about 0.3 percent of cancers in men in developing countries (low HDI).

North America contributed by far the most cases with 111,000 cancers -- equivalent to almost a quarter of all new obesity-related cancers globally -- and sub-Saharan Africa contributed the least (7300 cancers or 1.5 percent). Within Europe, the burden was largest in eastern Europe, accounting for over a third of the total European cases due to excess BMI (66,000 cancers).

The findings are detailed in The Lancet.