Excess body weight causes over 480,000 new cancer cases per year – 3.6 percent of cancers worldwide – in adults, new estimates suggest.

The burden is far higher in more developed countries with almost two-thirds (64 percent) of these obesity-related cancers occurring in North America and Europe, the findings showed.

“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. If this trend continues it will certainly boost the future burden of cancer,” warned Melina Arnold from the International Agency for Research on Cancer (IARC).

Based on the results, the researchers estimate that a quarter of all obesity-related cancers in 2012 were attributable to the rising average body mass index (BMI) in the population since 1982.

Using 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.

The findings reveal 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 nearly 136,000 new cancers in 2012 and in women, it was around 345,000 new cases.

In developed countries, around eight percent of cancers in women and three percent in men were associated with excess bodyweight, compared with 1.5 percent of cancers in women and about 0.3 percent of cancers in men in developing countries.

North America contributed by far the most cases with 111,000 cancers – equivalent to almost a quarter (23 percent) of all new obesity-related cancers globally.

The study appeared in the journal The Lancet Oncology.