A new study lead by scientist and epidemiologist Hyuna Sung found that cancer rates are increasing and related to obesity in young US adults, as published in The Lancet Public Health. The research also looked at rates for 18 cancers unrelated to obesity, and found rates increasing for only two of these.

In a previous study, researchers identified increases in early onset colorectal cancer in the US, a trend observed in many high-income countries. The current paper presents an extension of their analysis by examining age-specific trends in 30 types of cancers, including 12 known to be associated with obesity.

For the new study, investigators analysed 20 years of incidence data between 1995 and 2014 for 30 cancers in 25 states from the Cancer in North America database. This information was provided by the North American Association of Central Cancer Registries, covering 67% of the population of the US. This is the first time that a systematic examination of trends for obesity-related cancers in young adults in the US has ben conducted.

Incidence increased for six of the 12 obesity-related cancers (colorectal, endometrial, gallbladder, kidney, multiple myeloma, and pancreas) in young adults. In contrast, rates in successive younger birth cohorts either remained stable or decreased in all but two of 18 other, non-obesity related cancers, including smoking-related and infection-related cancers.

“Although the absolute risk of these cancers is small in younger adults, these findings have important public health implications,” said Ahmedin Jemal, a researcher involved in the study. “Given the large increase in the prevalence of overweight and obesity among young people and increasing risks of obesity-related cancers in contemporary birth cohorts, the future burden of these cancers could worsen as younger cohorts age, potentially halting or reversing the progress achieved in reducing cancer mortality over the past several decades.”

The authors say innovative strategies are required in order to mitigate morbidity and premature mortality associated with obesity-related diseases, both by healthcare providers and policy makers.