Half a million new cancers annually due to overweight and obesity

27 November 2014. A new study by the cancer agency of WHO shows that nearly half a million new cancer cases per year can be attributed to high body mass index. 

The study by the International Agency for Research on Cancer (IARC), the specialized cancer agency of the World Health Organization (WHO), published in The Lancet Oncology, highlights that overweight and obesity have become a major risk factor. In 2012 they were responsible for an estimated 3.6% (481 000) of all new cancer cases.

Global analysis shows that cancer due to overweight and obesity is currently far more common in more developed countries (393 000 cases, 5.2% of all new cancer cases in these countries) than in less developed countries (88 000 cases, 1.5% of all new cancer cases in these countries).

North America remains the most affected, with an estimated 111 000 obesity-related cancers in 2012, accounting for 23% of the total global cancer burden linked to high BMI.

In Europe, the proportion of cancers due to overweight and obesity is also large, particularly in eastern Europe (65 000 cases, 6.5% of all new cancer cases in the region).

“Overall, we see that while the number of cancer cases associated with overweight and obesity remains highest in richer countries, similar effects are already visible in parts of the developing world,” says Dr Isabelle Soerjomataram, one of the study’s lead authors and the project’s principal investigator. 

The study highlights that the proportion of cancers related to obesity is higher in women than in men, with population attributable fractions of 5.3% and 1.9%, respectively. “Women are disproportionately affected by obesity-related cancers,” says IARC’s Dr Melina Arnold, one of the study’s lead authors, “For example, for postmenopausal breast cancer, the most common cancer in women worldwide, the study suggests that 10% of these cancers could have been prevented by having a healthy body weight.”

Overall, the countries with the highest cancer burden attributable to overweight and obesity in men are the Czech Republic (5.5% of the country’s new cancer cases), Jordan (4.5%), the United Kingdom (4.4%),and Malta (4.4%). Among women, Barbados (12.7%), the Czech Republic (12.0%), and Puerto Rico (11.6%) are most affected