Gen X and millennials are at higher risk of developing certain types of cancer than previous generations, according to a major new study released Wednesday.
In a study published in 2011, The Lancet Journal of Public HealthResearchers from the American Cancer Society (ACS) looked at 34 of the most common cancers and found that cancer rates for 17 types, including breast, pancreatic and stomach cancer, continue to rise among younger populations.
The researchers found that for eight of the 17 cancer types, cancer incidence rates have increased with each birth cohort since 1920. For nine of these cancer types, incidence rates first decreased in higher birth cohorts and then increased in lower birth cohorts.
“These findings add to the evidence of increased cancer risk in post-baby boomer generations and extend previous findings on early-onset colorectal cancer and several cancers associated with obesity to cover a broader range of cancer types,” Hyunah Song, lead author of the study, said in a statement.
The study highlighted the need to identify and address “underlying risk factors in the Gen X and millennial populations” to explain and address rising cancer rates among younger generations, said Ahmedin Jemal, lead author of the study.
“Birth cohorts – groups of people classified by year of birth – share unique social, economic, political and climatic environments that influence their exposure to cancer risk factors during critical developmental periods,” Song added.
“While we have identified cancer trends associated with date of birth, we still don’t have a clear explanation for why these rates are increasing,” Song added.
The study was conducted using data from more than 23 million patients who were diagnosed with 34 different types of cancer between January 1, 2000 and December 31, 2019. It also examined mortality data for more than 7 million people who died from 25 different types of cancer during the same period. All participants were between the ages of 25 and 84.
The researchers then calculated incidence rate ratios for each birth cohort, adjusting for “age and period effects.”
In 1990, the youngest birth cohort, cancer incidence rates were 12 percent higher than the birth cohort with the lowest incidence rate for ovarian cancer and 169 percent higher than the birth cohort with the lowest incidence rate for uterine cancer.
For pancreatic, kidney, and small intestine cancer, the cancer incidence rates in the 1990 birth cohort were two to three times higher than in the 1955 birth cohort.
Jemal warned of the implications of such rising cancer rates.
“This rise in cancer incidence among younger people represents a generational shift in cancer risk and is often an early indicator of the country’s future cancer burden. Without effective population-level interventions, the higher risk among younger people will be carried over to older individuals, potentially increasing the overall cancer burden in the future and halting or reversing decades of progress in cancer control.”
