According to a new report published this week, excess body weight is one of the major reasons behind cancers worldwide. The report was written by scientists at the American Cancer Society (ACS) and published in the journal CA: A Cancer Journal for Clinicians shows that 3.9% of the cases of cancers were linked to excess body weight and this amounted to 544,300 cases in 2012.

The report speaks about the association between obesity and cancers of 13 regions that include liver cancer, postmenopausal breast cancers, colon or rectal cancers, uterine cancers, esophageal cancer, gallbladder cancers, kidney cancers, ovarian, meningiomas, multiple myeloma, pancreatic cancer, thyroid cancer, and stomach cancer. It has also shown a probable association with prostate cancers, cancers of mouth, pharynx, and larynx.

Hyuna Sung, one of the researchers from the American Cancer Society, in a statement said, “Despite numerous studies on the health effects of overweight/obesity (excess body weight), the message has not been well disseminated. In particular, not many people are aware of the link between overweight/obesity to cancer risk.”

Cancer and obesity

According to the American Cancer Society, new cancer cases are slated to rise to 21.7 million by 2030 and cause 13 million deaths globally. The society says, “The future burden will probably be even larger because of the adoption of western lifestyles, such as smoking, poor diet, physical inactivity, and fewer childbirths, in economically developing countries.”

This latest report from the Harvard University and Imperial College collaboration adds that there is a steady rise in levels of obesity and this is having adverse effects on health. Sung explained that the team looked at cancer and obesity association trends from 1975 to 2016.

They found that a percentage of people living with excess body weight has risen from 21% in men and 24% in women to around 40% in both sexes. People living in the western world are more affected by the obesity epidemic, they noted with rates rising from 9 to 30%.

Another major rise in rates of obesity was seen among women living in Central Asia, the Middle East and North Africa with rates rising from 12 to 35 percent in the last four decades, the authors write.

Sung explained, “The simultaneous rise in excess body weight in almost all countries is thought to be driven largely by changes in the global food system, which promotes energy-dense, nutrient-poor foods, alongside reduced opportunities for physical activity.”

Countries that showed a maximum association of cancers with excess body weight were in Egypt, Mongolia, and Puerto Rico, with 8.2%, 8%, and 7.7%, respectively. The association was least marked (less than 1%) in India, Uganda, and Malawi.

Further women’s association of excess body weight and cancers was almost double that of men. Among women, obesity was linked to postmenopausal breast cancer while among men it was linked to liver cancer.

One-third of all endometrial or uterine cancers and esophageal cancers among women was associated with obesity. Among men around 29 percent of the esophageal cancers were associated with excess body weight.

The World Health Organization has set its goals of 2025 to stop the rise in obesity globally. This report says that the current trends and pace “of increasing and existing challenges, achieving this goal appears unlikely.”

Sung said, “Obesity epidemic should be addressed at a societal level and will not be resolved without policy-based environmental changes under the government leadership.”

The authors of the report write, “The rapid increase in both the prevalence of excess body weight and the associated cancer burden highlights the need for a rejuvenated focus on identifying, implementing, and evaluating interventions to prevent and control excess body weight."

"There is emerging consensus on opportunities for obesity control through the multisectoral coordinated implementation of core policy actions to promote an environment conducive to a healthy diet and active living,” Sung said.