Obesity has been linked to an increased risk for at least 13 types of cancers. A new study has found that these types of cancers may be increasing disproportionately among younger people in the United States.
During the past 17 years, new diagnoses of obesity-associated cancers increased particularly among those aged 50–64 years, while rates of new diagnoses decreased among those aged 65 years or older. In the past, obesity-associated cancer developed more commonly among older individuals.
The shift in obesity-associated cancers was even more pronounced among racial and ethnic minorities, with black and Hispanic women and men experiencing the highest percentage increase.
“Physicians should urge young patients to maintain normal weight because obesity promotes or accelerates cancer. The literature suggests that obesity-associated cancers in younger patients may be more aggressive and present at more advanced stages, requiring more intensive therapy,” she emphasized.
The study was published online on August 14 in JAMA Network Open.
Rising in Younger People
The authors note that data from the Centers for Disease Control and Prevention suggest that overweight or obesity contributed to 40% of cancers diagnosed in 2014. The increase in these types of cancers, combined with increasing rates of obesity in younger age groups, raised the question of whether cancer rates are rising in younger people.
To investigate the issue, the team analyzed data for January 2000 to December 2016 from the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) database, which is representative of the US population and includes about 97% of new cancer cases diagnosed in surveyed regions. Researchers evaluated change in cancer burden over time, categorized by age, sex, and race/ethnicity.
The analysis included 2,665,574 new obesity-associated cancer diagnoses (70.3% of which were in women) and 3,448,126 new nonobesity associated cancer diagnoses (32.0% of which were in women).
Obesity-associated cancers included colorectal cancer; female breast cancer; cancer of the uterus and gallbladder and other biliary cancers; cancer of the esophagus, stomach, liver, intrahepatic bile duct, pancreas, ovary, kidney, and renal pelvis; cancer of the thyroid; and myeloma.
The analysis showed a shift in the age distribution of new diagnoses of obesity-associated cancers during the past 17 years, with the greatest increase among individuals aged 50–64 years.
Among persons in younger age groups, there was also a higher likelihood that annual rates of new cases of obesity-associated cancer would outstrip cancers not related to obesity.
The opposite was true for the group aged 65 years or older, with greater odds that annual rates of new cancers not associated with obesity would be higher than those associated with obesity, regardless of race/ethnicity.
Although incidence rates for obesity-associated cancers generally decreased over this period among those aged 65 and over, the total number of new cases increased. This finding was most likely due to individuals who aged into this group from the younger age group, according to the