Researchers from the American Cancer Society found, in a new study, that American Generation X and Millennials are at a higher risk of developing 17 different cancers when compared to the generations above them.
A press release from the ACS confirms the study found an increase in mortality trends for various cancers as well.
“These findings add to growing evidence of increased cancer risk in post-Baby Boomer generations, expanding on previous findings of early-onset colorectal cancer and a few obesity-associated cancers to encompass a broader range of cancer types,” said Dr. Hyuna Sung, lead author of the study and a senior principal scientist of surveillance and health equity science at the American Cancer Society, in the release. “Birth cohorts, groups of people classified by their birth year, share unique social, economic, political, and climate environments, which affect their exposure to cancer risk factors during their crucial developmental years. Although we have identified cancer trends associated with birth years, we don’t yet have a clear explanation for why these rates are rising.”
The study looked at data on 23,654,000 patients with 34 kinds of cancer and the mortality data on 7,348,137 deaths across 25 cancers. They looked at people ages 25-84 from Jan. 1, 2000, to Dec. 31., 2019.
“To compare cancer rates across generations, they calculated birth cohort-specific incidence rate ratios and mortality rate ratios, adjusted for age effect and period effect, by birth years, separated by five-year intervals, from 1920 to 1990,” the release reads.
The study found that, since 1920, each cohort born has had an increased incidence rate for eight of the 34 cancers. They note that “the incidence rate was approximately two-to-three times higher in the 1990 birth cohort than in the 1955 birth cohort” for the following cancers:
- Pancreatic
- Kidney
- Small intestinal
- Liver cancer in women
Dr. Ahmedin Jemal, senior vice president, surveillance and health equity science at the American Cancer Society and senior author of the study, said the increase in cancer rates indicates a generational shift in risk and “an early indicator of future cancer burden” in the U.S.
“Without effective population-level interventions, and as the elevated risk in younger generations is carried over as individuals age, an overall increase in cancer burden could occur in the future, halting or reversing decades of progress against the disease,” Jemal said in the release. “The data highlights the critical need to identify and address underlying risk factors in Gen X and Millennial populations to inform prevention strategies.”
The release also noted a higher incidence rate in younger cohorts for these other cancers as well:
- Breast cancer for estrogen-receptor positive only
- Uterine corpus cancer
- Colorectal cancer
- Non-cardia gastric cancer
- Gallbladder cancer
- Ovarian cancer
- Testicular cancer
- Anal cancer in men
- Kaposi sarcoma in men
The release also states that mortality rates—alongside the incidence rates—saw increases in younger birth cohorts for the following cancers:
- Liver cancer for women only
- Uterine corpus
- Gallbladder
- Testicular
- Colorectal cancers
"The increasing cancer burden among younger generations underscores the importance of ensuring people of all ages have access to affordable, comprehensive health insurance, a key factor in cancer outcomes," said Lisa Lacasse, president of the American Cancer Society Cancer Action Network, in the release. "To that end, ACS CAN will continue our longstanding work to urge lawmakers to expand Medicaid in states that have yet to do so as well as continue to advocate for making permanent the enhanced Affordable Care Act tax subsidies that have opened the door to access to care for millions."
The study was published in "The Lancet Public Health."