“If we don’t drastically change the obesity epidemic, the rates of cancer associated with obesity will inevitably continue to rise,” says Jin-Kui Yang, the paper’s corresponding author and an endocrinologist at Capital Medical University in Beijing. “It will place a large burden on China’s economy and healthcare system.”

Cancer remains one of the leading causes of death in China, with lung cancer being the most common type. However, obesity-related cancers, such as colorectal, breast, and thyroid cancers, have been growing rapidly. Previous studies have suggested that obesity will soon overtake smoking to become the main modifiable risk factor of cancer.

“Overweight and obesity rates among Chinese children and adolescents are approaching those of the US despite years of public health efforts focused primarily on raising awareness,” Yang says. “These strategies have not been sufficient. Moving forward, we urgently need more effective and aggressive approaches, possibly including medications and calorie labeling, to reduce obesity in the country.”

Yang and his team analyzed all newly diagnosed cancers in China between 2007 and 2021. During this period, the country recorded more than 651,000 cancer cases of cancer, with about 48% identified as one of the 12 obesity-related cancers recognized by the World Health Organization.

Notably, obesity-related cancer incidence increased by 3.6% per year between 2007 and 2021, while the incidence of non-obesity-related cancers, such as lung and bladder cancers, remained stable. In addition, the researchers found that obesity-related cancer incidence rose more quickly as the age group got younger. For people aged 60 to 65, obesity-related cancer rates increased by less than 1.6% per year. Meanwhile, the rates increased by more than 15% annually among those aged 25 to 29. Moreover, people born between 1997 and 2001 were 25 times more likely to be diagnosed with obesity-related cancers compared to those born between 1962 and 1966.

Colorectal, breast, thyroid, kidney, and uterus cancers were among the fastest growing obesity-related cancer types among young people.

“The trend is consistent with the growing overweight and obesity rates among young people in China,” Yang says.

The adoption of a Westernized lifestyle, including increased meat and alcohol consumption, contributed to the increased prevalence of obesity in China. As of 2019, 34% of Chinese adults were overweight, and 16% were classified as obese. The situation is particularly concerning among children and adolescents, who are experiencing even faster increases in overweight and obesity rates.

The team predicted that, without aggressive public health measures, obesity-related cancer rates in China could double in the next decade.