New research suggests that members of younger generations, like Generation X and Millennials, have a higher risk of 17 cancer types than members of older generations, like Baby Boomers. Published Wednesday in The Lancet Public Health journal, the new work outlines a significant difference in cancer types and incidence among adults born between 1920 and 1990, separated by 5-year intervals.
Across cancer types, incidence rate in the 1990 cohort ranged from 12 percent higher for ovarian cancer to 169 percent higher for uterine corpus cancer than that in the birth cohort with the lowest incidence rate.
Of the 34 types of cancer the researchers studied, 17 of them had increased incidence rates for every successive cohort born since 1920. Of these 17, 8 of them were newly identified, including cardia gastric, small intestine, estrogen receptor-positive breast, ovary, liver and intrahepatic bile duct and non-HPV-associated oral and pharynx in female individuals, and anus and Kaposi sarcoma in male individuals.
The authors analyzed two sets of data from between 2000 and 2020. One set, from the North American Association of Central Cancer Registries, comprised more more than 23 million patients diagnosed with 34 types of cancer; the other set, from the U.S. National Center for Health Statistics, looked at mortality data from over 7 million deaths from 25 types of cancer.
While experts aren’t certain of the reason behind this increase, they believe it’s linked to lifestyle and environmental factors, including obesity. Increase in 10 of the 17 cancers in younger birth groups are related to obesity, including colon, kidney, pancreas, ovary, and liver. According to the American Cancer Society, about 20 percent of cancer diagnoses in the U.S. are associated with excess body weight. Other factors may include sedentary behavior, ingredients in food or water, common medications, chemical exposure, or chemical agents, the paper says.
The authors also found that mortality trends increased with the incidence of liver (in women only), uterine corpus, gallbladder, testicular, and colorectal cancers. However, endometrial cancer grew most rapidly in terms of diagnoses and mortalities.
“That was a sobering finding,” first author Hyuna Sung, a cancer epidemiologist at the American Cancer Society, told NBC News. “Although many cancer rates are rising, we don’t necessarily see this increase in mortality because we are treating them a lot better than before.”
