Obesity-related cancers on the rise among young adults

Some obesity-related cancers—including colorectal, gallbladder, kidney and pancreatic cancer—are on the rise among adults aged 25 to 49, compared to older generations, according to new research published in The Lancet: Public Health on World Cancer Day.

“Our findings expose a recent change that could serve as a warning of an increased burden of obesity-related cancers to come in older adults,” said lead author Ahmedin Jemal, PhD, of the Surveillance and Health Services Research Program at the American Cancer Society in Atlanta, in an emailed press statement obtained by HealthExec. “Most cancers occur in older adults, which means that as the young people in our study age, the burden of obesity-related cancer cases and deaths are likely to increase even more.”

While the researchers have found increases in incidences of cancer among younger individuals in the United States, the American Cancer Society recently reported a 27 percent decline in cancer deaths over the last 25 years in the nation. One of the major causes of decreases cancer deaths is a decline in smoking. 

“Over the past few decades, death rates have been in decline for most cancers, but in the future obesity could reverse that progress, barring any interventions,” Jemal noted. “Younger generations are experiencing earlier and longer-lasting exposure to excess fat and to obesity-related health conditions that can increase cancer risk.” 

In this analysis, Jemal and colleagues examined the prevalence of 12 obesity-related cancers that occurred between 1995 and 2014. Additionally, the researchers analyzed the prevalence data of 18 common cancers that are not associated with weight. Approximately 67 percent of the US population was used as the study cohort. There were more than 14 million cases of the 30 types of cancers studied during the time studied.

Patients were divided into five-year age groups from 25-29 to 80-84 years old. Jemal et al. found increased incidences for six of the 12 obesity-related cancers including colorectal, uterine corpus or endometrial, gallbladder, kidney, multiple myeloma and pancreas. The average annual change for pancreatic cancer, they illustrated, was equal to or less than 1 percent of people aged 40 to 84; however, those who were 25 to 29 years of age, saw an annual change of 4.3 percent.

The researchers also established that of the 18 other types of cancers included in the study, two cancers showed similar trends; eight cancers, which were related mostly to smoking, infection or both, showed a decline; and the rest of the remaining cancers were stable.

In spite of the risk increases, overall incidences of these cancers remain higher in older age groups than in younger ones, the authors noted. However, the researchers noted a need for increased obesity screening, as less than half of primary care physicians regularly assess BMI in patients, despite national recommendations. 

“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,” Jemal noted in a prepared statement issued by the American Cancer Society. “Cancer trends in young adults often serve as a sentinel for the future disease burden in older adults, among whom most cancer occurs.”